Science Questions

Question 1 of 243

1

Attached are the solute concentrations for a normal mammalian cell under resting conditions. Which value will be closest to the resting membrane potential of this cell?

Select one of the following:

100 mV
4 mV
-80 mV
-183 mV
-22 mV

Explanation

Question 2 of 243

1

The attached figure shows data obtained by measuring the uptake of L-alanine into a mammalian cell from an isotonic salt solution made without (“Without Na+”) versus with (“With Na+”) sodium. Sodium was replaced on a mole-per-mole basis with choline in the “Without Na+” isotonic saline solution. Which of the following statements about L-alanine uptake into this cell is most correct?

Select one of the following:

L-alanine moves into the cell via an antiporter for Na+
In the absence of Na+, L-alanine moves into the cell via a uniporter with a Km for L-alanine of 50  microM
At 500 microM L-alanine in the extracellular solution, the majority of L-alanine uptake is through a  Na+-dependent process
ATP depletion would not affect the rate of L-alanine uptake into the cell
Increasing the extracellular isotonic saline solution K+ concentration will decrease the Na+-dependent component of L-alanine uptake into the cell

Explanation

Question 3 of 243

1

You are examining the uptake into cells of a proposed peptide growth factor, Gribel. You show there are no membrane transporters that mediate the movement of Gribel across the plasma membrane. You measure the internalization of Gribel into neuronal cells after you add Gribel to the extracellular solution. You also measure the uptake of a fluid phase marker, a soluble compound that quantitates the rate of fluid uptake, in the absence and presence of Gribel. The data are attached. Based on the presented data, which of the following statements about Gribel is most correct?

Select one of the following:

Gribel is internalized in vesicles that are greater than 250 nm in size
Gribel is not internalized in coated pits 
Gribel internalization is not energy-dependent 
Gribel is internalized via a mechanism other than endocytosis
Gribel is not internalized by receptor-mediated endocytosis

Explanation

Question 4 of 243

1

Spectrin is an integral part in which of the following intracellular structure(s)?

Select one of the following:

Intermediate filaments
Centrosome
Basal body
Desmosome
Cell cortex

Explanation

Question 5 of 243

1

Which protein is necessary to create the forces that result in the bending movements of cilia and flagella?

Select one of the following:

Myosin
Dynein
Actin
Kinesin
Keratin

Explanation

Question 6 of 243

1

Which intracellular process would be primarily disrupted by inhibition of Arp2/3 complexes?

Select one of the following:

Microtubule nucleation
Dynamic instability
Microfilament nucleation
Treadmilling
Intracilliary transport

Explanation

Question 7 of 243

1

Which type of the anchoring contact is used by the migrating (crawling) fibroblasts?

Select one of the following:

Desmosome
Adherence junction
Hemidesmosome
Tight junctions
Focal adhesion

Explanation

Question 8 of 243

1

What is the primary function of tissue fibronectin?

Select one of the following:

It binds to laminin
It binds to collagen
It binds to desmosomes
It binds to cadherins
It binds to actin filaments

Explanation

Question 9 of 243

1

Which of the following extracellular matrix components assembles proteoglycans into the gigantic complexes called proteoglycan aggregates?

Select one of the following:

Collagen type I
Hyalumnan
Heparan sulfate
Fibronectin
Laminin

Explanation

Question 10 of 243

1

Which type of gene mutations confer a selective growth advantage in cancers?

Select one of the following:

Passenger mutations
Frameshift mutations
Driver mutations
Deletions
Insertions

Explanation

Question 11 of 243

1

Ninety-five percent of the mutations in tumors are:

Select one of the following:

Deletions
Insertions
Translocations
Frameshift mutations comprise 1.7% of mutations
Single base substitutions

Explanation

Question 12 of 243

1

A man and his wife are carriers of a gene for sickle cell disease (autosomal recessive inheritance). What is the probability that this couple may have a phenotypically normal child?

Select one of the following:

100%
25%
50%
67%
75%

Explanation

Question 13 of 243

1

A man with porphyria starts a cult which soon increases in number. Many of his descendants were found to have porphyria. A smallpox epidemic soon occurs in the cult. Which one of the following terms best describes this situation?

Select one of the following:

Genetic isolation
Founder effect
Heterozygote advantage
Population bottleneck
Carriers of porphyria have a higher immunity to smallpox

Explanation

Question 14 of 243

1

A female alcoholic presents to the emergency department with confusion and memory loss. She also exhibits rolling of her eyeballs. Her diet consists mainly of canned soup. Lack of which vitamin is most likely to be responsible for her symptoms?

Select one of the following:

Vitamin C
Folic acid
Thiamine
Vitamin B6 (pyridoxine)
Vitamin B12

Explanation

Question 15 of 243

1

Which vitamin is involved in collagen synthesis?

Select one of the following:

Folic acid
Niacin
Vitamin B12
Vitamin C
Vitamin D

Explanation

Question 16 of 243

1

The attached image depicts a histological image of the human mammary gland stained with H&E. What type of connective tissue is most abundant immediately around the glands (arrows)?

Select one of the following:

Dense irregular
Dense regular
Embryonic
Loose connective
Wharton's jelly

Explanation

Question 17 of 243

1

As a pathologist you would like to make sure that the magenta colored staining result of a cancerous liver specimen with Periodic acid-Schiff (PAS) reaction is real. Which enzyme would you use to confirm your positive staining result?

Select one of the following:

Amylase
DNase
Lipase
Proteinase
RNase

Explanation

Question 18 of 243

1

Which of the following antigens is the most immunogenic?

Select one of the following:

Streptococcal polysaccharide
DNA from a hepatitis B virus
RNA from HIV
The protein toxoid from tetanus
The lipids isolated from the milk of a cow with an udder infection

Explanation

Question 19 of 243

1

Which multilobed lymphatic organ serves as the place for T cell maturation?

Select one of the following:

Spleen
Trachea
Thymus
Bone marrow
Salivary gland

Explanation

Question 20 of 243

1

The term redundancy of cytokines means that:

Select one of the following:

One cytokine can have many effects
One cytokine can act synergistically with another
One cytokine produced by one cell can effect another cell
One cytokine is antagonistic to another
More than one cytokine can have the same function

Explanation

Question 21 of 243

1

When a cell is infected and presents the antigen of the infection, in which molecule does it present the antigen and which type of cell responds?

Select one of the following:

Class II molecule; CD4+ T cell
Class II molecule; CD8+ T cell
Class I molecule; CD8+ T cell
Class I molecule; CD4+ T cell
Toll-like receptors; macrophages

Explanation

Question 22 of 243

1

Compared to a secondary response, a primary response is:

Select one of the following:

Faster and higher in amount of IgG
Slower and lower in amount of IgG
Slower but higher in amount of IgG
Slower and lower in amount of IgM
Faster, more specific but lower in amount of IgG

Explanation

Question 23 of 243

1

Which is the most accurate description of the type of organism that a laboratory would try to isolate on MacConkey agar?

Select one of the following:

Gram-positive coccus
Gram-negative enteric bacillus
Gram-positive bacillus
Yeast-like fungus
Spirochetal bacteria

Explanation

Question 24 of 243

1

The designated purpose of the “A” (bacitracin)-disc is to distinguish:

Select one of the following:

Alpha-hemolytic bacteria from beta-hemolytic bacteria 
Staphylococcus aureus from other staphylococcal bacteria
Staphylococcus aureus from streptococcus pyogenes
Streptococcus pyogenes from other beta hemolytic streptococcus 
Streptococcus pneumoniae from other alpha-hemolytic streptococcus

Explanation

Question 25 of 243

1

You suspect that your patient may have an infection. You send a patient sample to the clinical microbiology lab for analysis. The lab cultures an organism on blood agar which is catalase positive. A coagulase test is done next and the result is clumping of the test plasma. The likely cause of this patient’s infection is:

Select one of the following:

Streptococcus pyogenes
Streptococcus pneumoniae
Staphylococcal aureus
Staphylococcal epidermidis
Staphylococcal saprophyticus

Explanation

Question 26 of 243

1

What type of epithelial tissue is normally keratinized?

Select one of the following:

Simple cuboidal epithelium of the kidney tubules
Transitional epithelium of the ureter
Simple squamous epithelium of a blood vessel
Stratified squamous epithelium of skin
Mesothelial lining of the lungs

Explanation

Question 27 of 243

1

The inner lining of this blood vessel allows for passive diffusion and filtration. It is best classified as what type of epithelium? (Please see attachment)

Select one of the following:

Pseudostratified
Simple squamous
Cuboidal
Simple columnar
Transitional

Explanation

Question 28 of 243

1

Which of the tissues/organs listed below is most likely to be lined by transitional epithelium?

Select one of the following:

Bladder
Large intestine
Skin
Esophagus
Uterus

Explanation

Question 29 of 243

1

Which of the following features does cardiac muscle have in common with skeletal muscle?

Select one of the following:

Peripheral, multiple nuclei
Voluntary control
Striations
Location
Intercalated discs

Explanation

Question 30 of 243

1

A 66-year-old woman has multiple bladder stones and undergoes a cystoscopy. Irregular areas of her bladder mucosa are biopsied and reveal that the normal transitional epithelium has been replaced in areas by mature normal appearing squamous epithelium. What is this process known as?

Select one of the following:

Pathological hyperplasia
Metaplasia
Atrophy
Physiological hypertrophy
Dysplasia

Explanation

Question 31 of 243

1

The accompanying photo represents a microscopic section of an unidentified organ with an area of necrosis which shows preserved cellular architecture with loss of nuclei, resulting from loss of blood supply. What does this most likely represent? (Please see attachment)

Select one of the following:

A kidney infarct
Acute pancreatitis
Pulmonary tuberculosis
Brain abscess
Vascuilitis

Explanation

Question 32 of 243

1

A pathologist is examining tissue under the microscope and sees an area where the cells are necrotic and the nuclei of the cells are pyknotic and have undergone karyorrhexis and karyolysis. The enzymes responsible for these changes were activated by a molecule which enters the cell because of:

Select one of the following:

Loss of intracellular Na+
Increased pH
Increased ATP production
Failure of the Ca+2 pump
Decrease in anaerobic glycolysis

Explanation

Question 33 of 243

1

A 4-year-old girl has recurrent acute bacterial infections. During the most recent bout of acute bacterial cellulitis of her arm, caused by Staphylococcus aureus, she has an elevated white blood cell count with an increased percentage of neutrophils in her peripheral blood. A biopsy taken from an area of soft tissue necrosis shows many bacteria but very few neutrophils. An analysis of neutrophil function shows a defect in rolling. Which of the following is most likely to be dysfunctional?

Select one of the following:

Complement C3b
Selectins
Integrins
NADPH oxidase
Leukotrienes

Explanation

Question 34 of 243

1

A 20-year-old woman has two days of low grade fever with malaise, cough, and nasal congestion. Physical examination reveals clear breath sounds. A white blood cell count shows mild to moderate elevation in lymphocytes. The most likely etiology for this woman’s condition is:

Select one of the following:

Acute, bacterial infection
Parasitic infection
Allergic reaction
Viral infection
Anaphylaxis

Explanation

Question 35 of 243

1

A 33-year-old morbidly obese man undergoes a colectomy with a large incision because of difficulties during the surgery. During recovery after the surgery, he experiences severe nausea and has an episode of vomiting without fever. Which of the following complications is most likely to be a deterrent in his surgical wound healing?

Select one of the following:

Infection
Malnutrition
Foreign body
Dehiscence
Contracture

Explanation

Question 36 of 243

1

A 33-year-old woman undergoes successful surgery for a ruptured appendix. Approximately five to seven days post-operatively, the healing skin suture site predominantly contains:

Select one of the following:

Neutrophils
Collagen
Granulomas
Keloid
Granulation tissue

Explanation

Question 37 of 243

1

A 37-year-old woman has a Pap smear which is abnormal. A subsequent colposcopy shows a 1 cm flat red area on her cervix which is excised, and is diagnosed as carcinoma-in-situ. This lesion:

Select one of the following:

Is commonly associated with metastatic disease
Will most likely not recur once completely excised
Derives from mesenchyme and is invasive
Occurred because of previous cervical hyperplasia
Is genetically transmitted and is not influenced by environmental factors

Explanation

Question 38 of 243

1

A large, bulky retroperitoneal mass is removed from a 58-year-old woman. Microscopic examination reveals no distinct glands, keratin, or other structures and the cells are extremely disorganized. There is marked anaplasia and pleomorphism with increased mitoses, including bizarre mitotic figures. Special stains are needed to make a final diagnosis. This tumor is most likely:

Select one of the following:

Benign
Well-differentiated
Slow-growing
High grade
Well-circumscribed

Explanation

Question 39 of 243

1

A 69-year-old man has guaiac positive stools and weight loss. He undergoes a colonoscopy and a large ulcerating mass is discovered in his sigmoid colon. A biopsy of the mass reveals invasive, irregular, crowded glands with pleomorphic nuclei. There is invasion into blood vessels and lymphatics. What is the tumor best classified as?

Select one of the following:

Leiomyosarcoma
Melanoma
Fibroadenoma
Papiloma
Adenocarcinoma

Explanation

Question 40 of 243

1

An 8-year-old boy falls on his elbow while running on a sidewalk. He does not sustain an open skin wound but the area first becomes red and then swells up. Pain develops and his mother decides to bring him to the emergency department for an X-ray. Which of the following contributes to the initial redness of the injury?

Select one of the following:

Constriction of vascular smooth muscle
Formation of the membrane attack complex
Increased intravascular oncotic pressure
Expression of integrins on endothelium
Release of histamine from trauma injury

Explanation

Question 41 of 243

1

Which of the following is a signal that mammalian cells use to communicate between themselves?

Select one of the following:

Light
Sound
Smell
Heat
Gas

Explanation

Question 42 of 243

1

Beta 2 adrenergic receptor has a Kd of 10-10 M for epinephrine and 10-8 for norepinephrine. This means that:

Select one of the following:

Epinephine will produce a greater end effect in the target cell at saturation
The affinity for epinephrine is greater
The receptor will bind epinephrine faster
The receptor will bind norepinephrine faster
The receptor will cycle norepinephrine on/off more slowly

Explanation

Question 43 of 243

1

Which of the following statements is true regarding Cholera toxin and Pertussis toxin?

Select one of the following:

Both inhibit adenylyl cyclase activity
Both inhibit G protein alpha subunit
Both activate G protein alpha subunit
Both increase adenylyl cyclase activity
Both decrease cAMP production

Explanation

Question 44 of 243

1

Which of the following statements is true regarding the second messenger cAMP?

Select one of the following:

cAMP is generated downstream of an activated Gq subunit
the enzyme adenylyl cyclase converts AMP to cAMP
cAMP activates protein kinase C
cAMP modifies existing proteins as well as affecting gene expression resulting in new protein synthesis
The enzyme cAMP phosphodiesterase helps terminate a cAMP-mediated response by converting cAMP to ATP

Explanation

Question 45 of 243

1

Which of the following statements is true regarding PIP2 (Phosphatidylinositol 4,5-bisphosphate) and PIP3 (Phosphatidylinositol 3,4,5-trisphosphate)?

Select one of the following:

PIP2 and PIP3 are membrane-bound inositol phospholipids
PIP3 is broken apart by phospholipase C to produce Inositol trisphosphate (IP3) and Diacylglycerol  (DAG)
PIP2 recruits Akt to plasma membrane where Akt is activated
PIP2 is made from PIP3 by the action of phosphatidylinositide 3-kinase (PI-3-kinase)
PIP3 is a second messenger that carries the message directly from Gαq

Explanation

Question 46 of 243

1

If a healthy adult carries a Robertsonian 21:21 translocation, what is the approximate chance that any of their live-born biological offspring will have Down syndrome?

Select one of the following:

0%
100%
50%
25%
5%

Explanation

Question 47 of 243

1

Which of the following genetic disorders is caused by a chromosomal abnormality usually not detectable on routine karyotype but usually detectable using a specific FISH (Fluorescent In-Situ Hybridization) probe?

Select one of the following:

Down syndrome
Edwards syndrome
DiGeorge syndrome
Patau syndrome
Turner syndrome

Explanation

Question 48 of 243

1

A patient taking a particular antiepileptic medication is given an antimicrobial agent that is metabolized by CYP3A4. Because of drug interaction involving CYP3A4, the dose of the antimicrobial is increased, according to the manufacturer’s recommendations. The CYP3A4 inducer is most likely:

Select one of the following:

Carbamazepine
Erythromycin
Itraconazole
Probenecid
Ritonavir

Explanation

Question 49 of 243

1

An adult with a history of prescription drug abuse presents to the emergency department with signs and symptoms consistent with morphine overdose. The drug’s therapeutic and toxic effects are both related to its activity on specific G protein-coupled receptors. The seriousness of the drug’s toxic effects is proportionately related to the drug concentration. This is an example of:

Select one of the following:

Dose dependent toxicity
Gentoxicity
Idiosyncratic toxicity
Supra-additive toxcitiy
Unpredictable toxicity

Explanation

Question 50 of 243

1

A cancer patient is given an antineoplastic drug that causes damage to the cancer cells’ DNA which ultimately activates intracellular signaling leading to programmed cell death. This phenomenon is termed:

Select one of the following:

Apoptosis
Fibrosis
Mutagenesis
Necrosis
Teratogenesis

Explanation

Question 51 of 243

1

A patient presenting with a morphine overdose is given a rapid-acting antidote that acts at the same receptors and reverses the effects of the morphine. (Morphine is a mu receptor agonist.) The mechanism of this antidote-agonist drug action is:

Select one of the following:

Allosteric antagonism
Chemical antagonism
Partial antagonism
Physiologic antagonism
Receptor antagonism

Explanation

Question 52 of 243

1

A patient’s sputum sample is sent to the microbiology laboratory for culture and susceptibility testing. The pathogen is found to have intermediate resistance to the first-line antibiotic. As a result of this resistance, the drug exhibits reduced:

Select one of the following:

Efficacy
Half-life
Potency
Selectivity
Spectrum

Explanation

Question 53 of 243

1

A pharmaceutical company investigating an experimental antibiotic finds that the drug produces a faster kill rate and more extensive degree of killing as the drug concentrations increase. Additionally, the drug produces prolonged, persistent antibacterial effects. This activity profile is best described by which one of the following?

Select one of the following:

EC50 right shift
Emax decrease
Peak/MIC
T>MIC
24h-AUC/MIC

Explanation

Question 54 of 243

1

Which of the following provide glutamatergic input to granule cells?

Select one of the following:

Stellate cells
Purkinje cells
Climbing fibers
Mossy fibers
Parallel fibers

Explanation

Question 55 of 243

1

Cerebellar efferents destined for the right red nucleus exit through which peduncle?

Select one of the following:

Left inferior peduncle
Left middle peduncle
Left superior peduncle
Right inferior peduncle
Right superior peduncle

Explanation

Question 56 of 243

1

Striatal neurons possessing D1 receptors:

Select one of the following:

Exhibit decreased excitability with dopamine
Excite the globus pallidus external
Inhibit the globus pallidus external
Inhibit the substantia nigra pars reticulata
Inhibit the subthalamic nucleus

Explanation

Question 57 of 243

1

This basal ganglia disorder has a strong genetic component:

Select one of the following:

Hemiballismus
Dementia pugilistica
Idiopathic Parkinson's disease
MPTP
Wilson's disease

Explanation

Question 58 of 243

1

Which of the following basal ganglia nuclei receive direct input from the cerebral cortex?

Select one of the following:

Globus pallidus external
Globus pallidus internal
Substantia nigra pars compacta
Substantia nigra pars reticulata
Subthalamic nucleus

Explanation

Question 59 of 243

1

The presence of these neuron-embedded protein aggregations are a hallmark of Parkinson’s disease:

Select one of the following:

Amyloid plaques
Lewy bodies
Melanin
MPTP
Neurofibrillary tangles

Explanation

Question 60 of 243

1

The cell bodies of which neurons are found in the middle layer of the cerebellar cortex?

Select one of the following:

Climbing fibers
Deep cerebellar nuclei
Granule cells
Inhibitory interneurons
Purkinje cells

Explanation

Question 61 of 243

1

Primary somatosensory cortex receives direct input from which nuclei?

Select one of the following:

Gracile and cuneate nuclei
Medial dorsal nuclei (MD)
Mesencephalic trigeminal nucleus
Reticular formation
Ventral posterior lateral nuclei (VPL)

Explanation

Question 62 of 243

1

A lesion to this neural substrate would blunt the sensation of light touch along the left forehead:

Select one of the following:

Left spinal trigeminal nucleus
Left pontine trigeminal nucleus
Left mesencephalic trigeminal nucleus
Left ventral posterior medial nucleus
Right ventral posterior lateral nucleus

Explanation

Question 63 of 243

1

Which sensation would be least affected by blocking the activity of myelinated afferent fibers?

Select one of the following:

Limb position
Muscle force
Sharp pain
Vibration
Warmth

Explanation

Question 64 of 243

1

Accurate two-point discrimination is dependent on which sensory organ?

Select one of the following:

Joint receptors
Merkel disks
Muscle spindles
Pacinian corpuscles
Ruffini corpuscles

Explanation

Question 65 of 243

1

Neurons of the corticobulbar tract:

Select one of the following:

Are "lower motor neurons"
Arise from the medial portion of the primary motor cortex
Mostly terminate bilaterally in the brainstem
Mostly terminate contralaterally in the brainstem
Mostly terminate ipsilaterally in the brainstem

Explanation

Question 66 of 243

1

What percentage of pyramidal tract fibers form the ventral corticospinal tract?

Select one of the following:

5%
15%
50%
85%
95%

Explanation

Question 67 of 243

1

Which of the following is characteristic of a lower motor neuron lesion?

Select one of the following:

Atrophy of the muscle
Muscle spasms leading to altered limb posture
Extension of hallux evoked by stroking the foot sole
Sustained limb oscillations to a tendon tap
Tremor present during passive rest

Explanation

Question 68 of 243

1

What is the lateral-medial representation within primary motor cortex?

Select one of the following:

Face-arm-hand-trunk-leg
Face-hand-arm-trunk-leg
Hand-face-arm-trunk-leg
Leg-trunk-arm-face-arm
Leg-trunk-arm-hand-face

Explanation

Question 69 of 243

1

A carotid angiogram demonstrates occlusion of the left middle cerebral artery. Based on the location of this occlusion, you expect to see which of the following deficits?

Select one of the following:

Paralysis and sensory deficits in the right leg and perineuim, weakness of the right face, tongue and upper limb, and anosmia
Paralysis of the lower right side of the face and right arm and bilateral hemianopsia of the contralateral visual fields of both eyes
Paralysis of the right-side of the body, right-sided hemianopsia, and left-sided blindness
Paralysis of the lower left side of the face and left arm, bilateral hemianopsia of the contralateral  visual fields of both eyes, and global aphasia
Paralysis and sensory deficits in the left leg and perineuim, weakness of the left face, tongue and  upper limb, and anosmia

Explanation

Question 70 of 243

1

An 8-year-old male is brought in by ambulance to the emergency department after being hit in the head by a fast moving foul ball at a baseball game. He is currently awake and alert, and responds to questions and commands. However, a CT scan of the head shows a collection of blood that does not cross suture lines. The most likely source of this blood is a(n):

Select one of the following:

Rupture of the bridging veins
Tear of the middle meningeal artery
Rupture of a berry aneurysm
Embolus to the left posterior cerebral artery
Rupture of a Charcot-Bouchard microaneurysm

Explanation

Question 71 of 243

1

A 55-year-old Caucasian male presents to the emergency department with left-sided loss of pain and temperature sensation to the upper and lower limb. While conducting a neurological exam, you also note that his right eye is exhibiting ptosis and miosis. After conducting an MRI, it is verified that the patient has a lesion to the right caudal pons. Which of the following symptoms might this patient also have presented with based on the location of the lesion?

Select one of the following:

Left facial paralysis
Left facial paralysis with sparing of the forehead
Decreased gag reflex
Right facial paralysis
Right facial paralysis with sparing of the forehead

Explanation

Question 72 of 243

1

An 80-year-old African American female is brought into the emergency department via ambulance from her nursing home facility. The paramedics activated the advanced care life support protocol for a code stroke based on the patient’s signs and symptoms. Once you begin examining her, you note that she has left-sided hemiparesis, right-sided total facial paralysis, and right-sided conjugate gaze paralysis. Before sending your patient for an MRI you suspect she is suffering from which of the following syndromes?

Select one of the following:

Raymond's syndrome
Wallenberg's syndrome
Millard-Guebler syndrome
Weber's syndrome
Foville's syndrome

Explanation

Question 73 of 243

1

A patient with receptive aphasia presents to the emergency department. Neuroimaging reveals no injury to Wernicke’s area. What other neural structure might exhibit injury/lesion to produce this clinical presentation?

Select one of the following:

Occipital lobe
Middle cerebellar peduncle
Arcuate fasciculus
Cerebral peduncle
Precentral gyrus

Explanation

Question 74 of 243

1

An unconscious patient presents to the emergency department with left-side parietal lobe injury evident in neuroimaging. Which of the following might a clinician suspect will be present in this patient upon return of consciousness?

Select one of the following:

Voluntary motor control deficits
Auditory deficits
Hemi-neglect
Expressive aphasia
Vertigo

Explanation

Question 75 of 243

1

Neurons in the neocortex with pyramidal morphology and dendritic spines release which of the following neurotransmitters?

Select one of the following:

Acetylcholine
Gamma amino-butyric acid
Glutamate
Norepinephrine
Serotonin

Explanation

Question 76 of 243

1

Genetic mutations affecting this cellular process have been implicated in microcephaly?

Select one of the following:

Neurotransmitter release
Dendritic growth
Cell division
Axonal sprouting
Neuronal excitability

Explanation

Question 77 of 243

1

Which of the following best describes the developmental sequence for neocortical layer IV?

Select one of the following:

Layer IV neurons are born after layer III 
Layer IV neurons are born before layer III neurons and migrate closer to the pial surface than layer III neurons 
Layer IV neurons are born after layer V neurons and migrate past layer V neurons
Layer IV neurons are born before layer V neurons and migrate past layer V neurons 
Layer IV neurons are born after layer V neurons and migrate further away from the pial surface than layer V neurons

Explanation

Question 78 of 243

1

Which of the following best describes the function of the massa intermedia?

Select one of the following:

Constitutes the speech-language pathway
Connects the cerebral hemispheres
Connects the thalamic hemispheres
Connects the thalamus and cortex
Connects the mammillary bodies and thalamus

Explanation

Question 79 of 243

1

Which of the following constitutes the axonal pathway connecting the thalamus and neocortex?

Select one of the following:

Arcuate fasciculus
Corpus callosum
Internal capsule
Massa intermedia
Mammilothalamic tract

Explanation

Question 80 of 243

1

Neurons in the primary auditory cortex project to which of the following thalamic nuclei?

Select one of the following:

Only the medial geniculate
Only the reticular nucleus
Medial geniculate and reticular nucleus
Medial dorsal and reticular nucleus
Medial geniculate and medial dorsal

Explanation

Question 81 of 243

1

A patient with sudden onset blindness is brought to the emergency department. Imaging of the eye and visual cortex reveals no obvious pathology. The next brain region to examine for possible lesions would include which of the following thalamic nuclei?

Select one of the following:

Ventral posterior medial
Ventral posterior lateral
Lateral geniculate
Medial dorsal
Medial geniculate

Explanation

Question 82 of 243

1

Which of the following hypothalamic nuclei is the feeding center of the brain?

Select one of the following:

Lateral nucleus
Medial preoptic nucleus
Arcuate nucleus
Ventromedial nucleus
Mammillary nucleus

Explanation

Question 83 of 243

1

Which of the following hormones participates in the short-term control of pre-meal hunger and meal initiation?

Select one of the following:

Agouti-related peptide
Corticotropin-releasing factor (CRF)
Ghrelin
Leptin
Glucagon

Explanation

Question 84 of 243

1

Which of the following hypothalamic nuclei is the satiety center of the brain?

Select one of the following:

Lateral nucleus
Suprachiasmatic nucleus
Supraoptic nucleus
Paraventricular nucleus
Ventromedial nucleus

Explanation

Question 85 of 243

1

A 7-year-old girl presents to your office with severe obesity (body mass index of >40), hyperphagia and metabolic neuroendocrine and immune dysfunction. Sequencing of the ob gene for both the proband and her parents reveals the child to be homozygous for deletion of a single guanine nucleotide in codon 133 of the ob gene reading frame. Based upon these findings, you would suspect the above mutation to be localized to cells of the:

Select one of the following:

Hypothalamus
Brown adipose tissue
Pituitary
Duodenum
Proximal small intestine

Explanation

Question 86 of 243

1

Stringing together unrelated or inappropriate facts, as often seen in patients with chronic alcohol consumption, is known as:

Select one of the following:

Confabulation
Diplopia
Vertigo
Hyperorality
Hyperphagia

Explanation

Question 87 of 243

1

A 42-year-old man is brought to the emergency department from the site of a collapsed building after an earthquake. Suspecting a brain injury, the attending physician orders a CT (computerized tomography) scan. This reveals bilateral damage to rostral aspects of the temporal lobes. After recovering from the initial trauma, this man displays compulsive exploratory behavior around the hospital and repeatedly examines objects by placing them in his mouth. These behavioral aberrations, when correlated with the CT findings, suggest which of the following syndromes?

Select one of the following:

Foster-Kennedy syndrome
Kluver-Bucy syndrome
Wernicke-Korsakoff syndrome
Wallenberg syndrome
Septal rage syndrome

Explanation

Question 88 of 243

1

This clinical condition results from a thiamine (vitamin B1) deficiency and is characterized by ocular disturbances and nystagmus, gait ataxia and cognitive deficits. Brain pathology includes lesions to the mammillary nuclei, dorsomedial nucleus of the thalamus, periaqueductal gray and pontine tegmentum. What is the name of this condition?

Select one of the following:

Amnestic syndrome
Foster-Kennedy syndrome
Korsakoff syndrome
Strachan's syndrome
Wernicke's enceophalopathy

Explanation

Question 89 of 243

1

Which of the following nuclei is associated with the neural control of micturition?

Select one of the following:

Supraoptic nucleus
Raphe nucleus
Barrington's nucleus
Edinger-Westphal nucleus
Nucleus of Maynert

Explanation

Question 90 of 243

1

Which of the following conditions is a common side effect of opioid medication?

Select one of the following:

Hemorrhoids
Constipation
Ascites
Proctorrhea
Diarrhea

Explanation

Question 91 of 243

1

Which of the following brain regions modulates the phenomenon of stimulus-induced analgesia?

Select one of the following:

Ventral tegmental area
Suprachiasmatic nucleus of the hypothalamus
Amygdala
Hippocampus
Periaqueductal gray area

Explanation

Question 92 of 243

1

Which of the following brain waves best represents stage 3-4 of the sleep-wake cycle? (Please see attachment)

Select one of the following:

A
B
C
D
E

Explanation

Question 93 of 243

1

A 50-year-old man with a history of severe insomnia presents to the neurology department complaining of bizarre sensations in his legs such as “pulling, searing, crawling and shimmering”. On examination, he is noted to have iron-deficiency anemia. Which of the following diagnoses should you suspect?

Select one of the following:

Obstructive sleep apnea
Restless leg syndrome
Narcolepsy
Delayed-sleep syndrome
Circadian-rhythm disorder

Explanation

Question 94 of 243

1

Which of the following physical exam findings are clinical features of narcolepsy?

Select one of the following:

Confabulation
Retrograde amnesia
Hypnagogic hallucinations
Dysphagia
Anorexia

Explanation

Question 95 of 243

1

Which of the following neuropeptides plays an essential role in maintaining wakefulness and regulating transitions between sleep and wake cycles?

Select one of the following:

Orexins
Melanocortins
Indoleamines
Cannabinoids
Endorphins

Explanation

Question 96 of 243

1

At what vertebral level can one most easily introduce a needle into the dural sac without piercing the spinal cord?

Select one of the following:

C5/6
L3/4
S3/4
T4/5
T8/L1

Explanation

Question 97 of 243

1

Which neural structure is located on the ventral medulla?

Select one of the following:

Gracile tubercle
Inferior olive
Mammillary bodies
Medial eminence
Superior colliculus

Explanation

Question 98 of 243

1

What neural structure is immediately inferior to the inferior colliculus?

Select one of the following:

Gracile tubercle
Inferior olive
Pyramidal decussation
Superior colliculus
Trochlear nerve

Explanation

Question 99 of 243

1

The tonsils belong to what part of the cerebellum?

Select one of the following:

Anterior lobe
Floculonodular lobe
Inferior vermis
Posterior lobe
Uvula

Explanation

Question 100 of 243

1

Impaired temperature and pain sensation from the right leg would result from a lesion to which white matter tract of the spinal cord?

Select one of the following:

Left antero-lateral tract
Left gracile fasciculus
Right antero-lateral tract
Right cuneate fasciculus
Right gracile fasciculus

Explanation

Question 101 of 243

1

Which is the largest descending tract of the spinal cord?

Select one of the following:

Cuneate fasciculus
Lateral corticospinal tract
Rubrospinal tract
Ventral corticospinal tract
Vestibulospinal tract

Explanation

Question 102 of 243

1

Which portion of the spinal cord is involved in processing pain information?

Select one of the following:

Onuf's nucleus
Phrenic nucleus
Nucleus dorsalis
Spinal accessory nucleus
Substantia gelatinosa

Explanation

Question 103 of 243

1

Damage to which of the cerebral lobes is likely responsible for the majority of expressive aphasia cases?

Select one of the following:

Left cerebellar lobe/hemisphere
Left frontal lobe
Left parietal lobe
Right occipital lobe
Right temporal lobe

Explanation

Question 104 of 243

1

 Which cortical invagination divides the primary motor cortex from the primary sensory cortex?

Select one of the following:

Central sulcus
Lateral fissure
Longitudinal fissure
Pre-occipital notch
Sylvian fissure

Explanation

Question 105 of 243

1

Which cerebral lobe controls primary motor movement on the right side of the body?

Select one of the following:

Left frontal lobe
Left parietal lobe
Left temporal lobe
Right frontal lobe
Right parietal lobe

Explanation

Question 106 of 243

1

Which of the following general statements applies to the human brain?

Select one of the following:

Female brains tend to contain more glial cells than male brains
Human brains consist of more neurons than glial cells
Human brains do not grow anymore after birth
Male brains are generally heavier than female brains
Male brains generally contain more neurons than female brains

Explanation

Question 107 of 243

1

Which process/event initiates the invagination of neuroectodermal tissue and is thereby responsible for the formation of the neural tube?

Select one of the following:

Accumulation of folic acid in neuroectoderm
Closure of the rostral neuropore
Production of bone morphogenetic proteins (BMPs) by neural crest cells
Release of alpha-fetoprotein (AFP) by neuroectoderm
Release of the signaling protein sonic hedgehod (SHH) notochord cells

Explanation

Question 108 of 243

1

What defect, most commonly observed in infants, will most likely result from excessive cerebrospinal fluid?

Select one of the following:

Anencephaly
Arnolad-Chiari malformation
Hydrocephalus
Meroanencephaly
Spina bifida with meningomyelocele

Explanation

Question 109 of 243

1

How can genetic defects that specifically affect central and peripheral nervous system cells also affect skin pigmentation?

Select one of the following:

Because certain pigment forming cells are of neural crest origin
Because melanocytes are of mesodermal origin
Because of a direct innervation of pigment forming cells
Because of the involvement of Schwann cells in skin pigmentation
Because pigment forming chromaffin cells are of neuroectodermal origin

Explanation

Question 110 of 243

1

What distinguishes microglia from all other major resident cell types found in the central nervous system?

Select one of the following:

Microglia are derived from mesoderm
Microglia are derived from neural crest cell
Microglia are non-phagocytic
Microglia form processes that wrap around brain endothelial capillaries
Microglia have the ability to differentiate into macroglia

Explanation

Question 111 of 243

1

Neural signals mediating touch and proprioception are carried by the:

Select one of the following:

Corticospinal pathway which decussates in the midbrain
Corticospinal pathway which decussates in the medulla
Pyramidal tract which decussates in the midbrain
Spinothalamic tract which is medially located throughout the length of the brainstem
Dorsal column-medial lemniscus pathway which decussates in the medulla

Explanation

Question 112 of 243

1

The inferior olivary complex of nuclei:

Select one of the following:

Project axons across the midline to the red nuclei
Control eye movements
Are anterior to the pyramids in the brainstem
Are located in the midbrain
Project axons across the midline to the cerebellum

Explanation

Question 113 of 243

1

A patient has pain and temperature loss on the right side of the body, but unaffected movement control. A possible location of the lesion in the brainstem is in:

Select one of the following:

The left ventral pons
The left medial pontine tegmentum
The right medial medulla
The right ventral midbrain
A lateral part of the tegmentum

Explanation

Question 114 of 243

1

Of the following, you most suspect that a patient with a localized brainstem injury who complains of loud noise would also:

Select one of the following:

Be able to blink both eyes
Have difficulty sticking out his tongue symmetrically
Have hemiparisis
Have impaired ocular elevation
Have impaired lateral gaze

Explanation

Question 115 of 243

1

The medial rectus muscle:

Select one of the following:

Depresses the eye
Elevates the eye
Extorts the eye
Intorts the eye
Participates in conjugate eye movements

Explanation

Question 116 of 243

1

A patient has muscle weakness and intact sensation on the left side of the body. To rule out medial medullary syndrome you test:

Select one of the following:

Contralateral facial pain
Facial paralysis
Lateral gaze
Upward gaze
Tongue movement

Explanation

Question 117 of 243

1

An absent bilateral corneal reflex may be due to unilateral injury of:

Select one of the following:

CN II
CN III
CN VI
CN VII
CN V

Explanation

Question 118 of 243

1

A lesion in the midbrain will most likely affect:

Select one of the following:

Pain and temperature sense on the face
Blink reflex
Swallowing
Touch and proprioception on the face
Chewing

Explanation

Question 119 of 243

1

Each CN XI projects to the:

Select one of the following:

Bilateral sternocleidomastoids and the contralateral trapezius
Contralateral sternocleidomastoid and the contralateral trapezius
Contralateral sternocleidomastoid and the ipsilateral trapezius
Ipsilateral sternocleidomastoid and the contralateral trapezius
Ipsilateral sternocleidomastoid and the ipsilateral trapezius

Explanation

Question 120 of 243

1

CN IX affects:

Select one of the following:

Somatosensation, blood pressure feedback, lacrimation, and salivation
Trapezius control, taste, blood pressure feedback, and salivation
Somatosensation, taste, blood pressure feedback, lacrimation, and swallowing
Somatosensation, taste, blood pressure feedback, mastication, and swallowing
Somatosensation, taste, blood pressure feedback, salivation, and swallowing

Explanation

Question 121 of 243

1

Including facial expression, CN VII also affects:

Select one of the following:

Somatosensation, taste, and blood pressure feedback
Somatosensation, taste, blood pressure feedback, and salivation
Somatosensation, taste, blood pressure feedback, and swallowing
Taste, salivation, and swallowing
Somatosensation, taste, salivation, and hearing

Explanation

Question 122 of 243

1

Cranial nerves involved with muscular control of swallowing include:

Select one of the following:

V, VII, IX, X
V, X, XII
VII, X, XII
VIII, IX, X
IX, X

Explanation

Question 123 of 243

1

The number of cranial nerves projecting directly to each eye is:

Select one of the following:

3
4
10
8
5

Explanation

Question 124 of 243

1

Cranial nerve VII is involved with:

Select one of the following:

The gag reflex
Parotid gland secretion
Proprioception from the posterior part of the tongue
Taste from the posterior part of the tongue
Controlling the stapedius

Explanation

Question 125 of 243

1

Cranial nerve IX is involved with:

Select one of the following:

Controlling facial expression muscles
Producing tears and saliva
Skin sense from the back of the ear
Taste from the anterior part of the tongue
Regulating blood pressure

Explanation

Question 126 of 243

1

The pyramidal decussation:

Select one of the following:

Accounts for the cortical activity related to sensation of contralateral proprioception
Accounts for the cortical activity related to sensation of contralateral bodily pain
Is dorsal to the inferior cerebellar peduncles
Is where all corticospinal fibers cross the midline
Accounts for the cortical control of contralateral movement

Explanation

Question 127 of 243

1

Which of the following is responsible for the transition between the action potential undershoot and the return of the membrane potential back to rest:

Select one of the following:

Opening of voltage-gated K+ channels
Activation of glutamate receptors
Opening of voltage-gated Na+ channels
Closing of voltage-gated K+ channels
Opening of voltage-gated Ca+ channels

Explanation

Question 128 of 243

1

Opening of voltage-gated K+ channels during the action potential is responsible for which of the following?

Select one of the following:

Only the falling phase
Only the rising phase
Only the undershoot
The overshoot and the falling phase
The falling phase and the undershoot

Explanation

Question 129 of 243

1

Which of the following cell types make contact with the brain vasculature?

Select one of the following:

Purkinje cells
Oligodendrocytes
Schwann cells
Astrocytes
Satellite cells

Explanation

Question 130 of 243

1

Which of the following cell types are stained black in the attached photomicrograph? (Please see attachment)

Select one of the following:

Schwann cells
Satellite cells
Purkinje cells
Astrocytes
Microglial cells

Explanation

Question 131 of 243

1

Which of the following cell types produce myelin insulating axons of the PNS?

Select one of the following:

Oligodendrocytes
Satellite cells
Schwann cells
Choroid plexus cells
Microglial cells

Explanation

Question 132 of 243

1

Which of the following values would be the resting membrane potential of a neuron given the ionic conditions, permeability values, and reversal potentials shown in the attached table?

Select one of the following:

+62 mV
0 mV
-80 mV
+123 mV
-72 mV

Explanation

Question 133 of 243

1

Which of the following is an active mechanism that contributes to a hyperpolarized resting membrane potential in neurons?

Select one of the following:

Leak K+ channels
Glutamate receptors
Na-K+ pump
Voltage-gated Na+ channels
Voltage-gated K+ channels

Explanation

Question 134 of 243

1

Which of the following clinical conditions is often associated with the breakdown of the blood-brain barrier?

Select one of the following:

Grave's disease
Autism spectrum disorder (ASD)
Multiple sclerosis (MS)
Serotonin syndrome
Metabolic syndrome (e.g. clinical obesity)

Explanation

Question 135 of 243

1

Which of the following brain sites lacks a blood-brain-barrier?

Select one of the following:

The area postrema
The cerebellum
The falx cerebri
The hippocampus
The Virchow-Robin space

Explanation

Question 136 of 243

1

Significant amounts of serotonin (5-HT)-containing neurons are found in the upper brain stem, particularly in the pons and medulla, areas that are collectively called the:

Select one of the following:

Paraventricular nucleus (PVN) of the hypothalamus
Ventral tegmental area (VTA)
Meso-striatal pathways
Raphe nuclei
Supraoptic nucleus

Explanation

Question 137 of 243

1

Which of the following physiological conditions is modulated by the actions of substance P?

Select one of the following:

Nociceptive transmission
Cognitive processes
Metabolic signaling cascades
Feeding signals
Spinal reflexes

Explanation

Question 138 of 243

1

Which of the following receptors can modulate the release of neurotransmitters from the same nerve ending?

Select one of the following:

Inositol trisphosphate receptors/channels
Auto-receptors
Metabotropic receptors
Intra-cellular receptors
Post-synaptic receptors

Explanation

Question 139 of 243

1

Which of the following structural brain deficits have been repeatedly reported in patients with schizophrenia?

Select one of the following:

Expansion of the ventricular system
Expansion of the Virchow-Robin space
Selective atrophy of the hippocampus
Degeneration of the frontal cortex
Malformations of the cerebellum

Explanation

Question 140 of 243

1

An expansion of the ventricles due to tissue loss, as in the case of Alzheimer’s disease, is termed:

Select one of the following:

Hydrocephalus ex vacuo
Focal cerebral ischemia
Cytotoxic cerebral edema
Traumatic brain injury
Epidural hematoma

Explanation

Question 141 of 243

1

Which modification of histones is associated with a decrease in transcription?

Select one of the following:

Phosphorylation
Methylation
Acetylation
Glycosylation
Addition of a coenzyme

Explanation

Question 142 of 243

1

In an experimental polymerase chain reaction (PCR), 12 out of 25 total cycles have been completed. During the 13th cycle, immediately after a DNA polymerase synthesizes the target DNA sequence on all available DNA templates, which one of the following will occur next?

Select one of the following:

The samples will be cooled down
Additional reactants will be added
The flanking primers hybridize to their complementary DNA sequences
The double -stranded DNA will be denatured by heating
Taq polymerase will catalyze DNA synthesis

Explanation

Question 143 of 243

1

During DNA replication:

Select one of the following:

Addition of nucleotides occurs at the 5' end of a new strand
The double helix is unwound by SSB protein
RNA primers are removed by DNA polymerase
Multiple primers are added to the leading strand
Okazaki fragments are joined by DNA ligase

Explanation

Question 144 of 243

1

Antibiotics in the quinolone family:

Select one of the following:

Disrupt the initiation step of bacterial protein synthesis
Block the action of bacterial RNA polymerase
Act as inhibitors of bacterial DNA topoisomerases
Are incorporated into new DNA and stop replication of the AIDS virus
Degrade bacterial DNA

Explanation

Question 145 of 243

1

The toxin of the Amanita phalloides mushroom:

Select one of the following:

Binds to eukaryotic RNA polymerase and blocks transcription
Acts to prematurely remove the new mRNA from its DNA template
Inhibits the splicing process in eukaryotes
Stops the post-transcriptional processing of mRNA
Blocks the action of topoisomerases

Explanation

Question 146 of 243

1

What is the definition of an intron?

Select one of the following:

It connects the codon to the anticodon
It codes for a nonfunctional part of a protein
It is part of the final protein
It is a mutation in the DNA
It is one type of a promoter

Explanation

Question 147 of 243

1

A 32-year-old man with AIDS (CD4 count is 21/mm3) presents with shortness of breath. Despite treatment with piperacillin-tazobactam, he has progressive respiratory failure and is intubated. Chest radiographs show a diffuse interstitial pneumonia. Silver staining of sputum reveals the presence of irregularly shaped 5 micron organisms that do not grow in the laboratory. This disease is most likely caused by which of the following fungi?

Select one of the following:

Pneumocystis jirovecii
Aspergillus niger
Candida albicans
Sporothrix schenckii
Coccidioides immmitis

Explanation

Question 148 of 243

1

Which of the following diseases is orally acquired and spreads to the central nervous system causing flaccid paralysis mostly in children?

Select one of the following:

Infectious mononucleosis
Measles
Polio
Herpes simplex virus
Chicken pox

Explanation

Question 149 of 243

1

e reverse transcriptase of HIV:

Select one of the following:

Transcribes viral DNA to cell DNA
Transcribes viral RNA to DNA
Transcribes cellular DNA to viral DNA
Is attached to the viral DNA
Translate viral RNA to DNA

Explanation

Question 150 of 243

1

Which is the correct sequence (first to last) of events in viral replication?

Select one of the following:

Penetration, uncoating, synthesis, adsorption, assembly, release
Uncoating, penetration, synthesis, assembly, absorption, release
Adsorption, penetration, uncoating, synthesis, assembly, release
Assembly, synthesis, uncoating, release, penetration, adsorption
Synthesis, uncoating, release, penetration, adsorption, assembly

Explanation

Question 151 of 243

1

Which is the protein shell around the nucleic acid core of a virus?

Select one of the following:

Capsid
Spike
Envelope
Monolayer
Canon

Explanation

Question 152 of 243

1

A 53-year-old man with a renal transplant develops shortness of breath and fevers. His chest radiograph reveals a dense left upper lobe infiltrate. A bronchoscopy with biopsy is performed. The pathologist calls to inform you that encapsulated yeast cells ~5 micrometer (μm) in diameter are present in the biopsy specimen. Which of the following is the cause of this patient’s disease?

Select one of the following:

Histoplasma capsulatum
Aspergillus fumigatus 
Cryptococcus neoformans
Blastomyces dermatitidis
Candida albicans

Explanation

Question 153 of 243

1

Outbreaks of systemic mycoses have been associated with:

Select one of the following:

Urban areas
Summer season
Cold weather
Regions over sea level
Disturbances of the environment in endemic regions

Explanation

Question 154 of 243

1

Which of the following combination of characteristics apply only to fungi?

Select one of the following:

Eukaryotic, autotrophic, rigid cell wall
Eukaryotic, heterotrophic, rigid cell wall
Eukaryotic, heterotrophic, no cell wall
Eukaryotic, autotrophic, no cell wall
Prokaryotic, heterotrophic, rigid cell wall

Explanation

Question 155 of 243

1

Viruses are distinguishable from both bacteria and protozoan parasites because viruses have:

Select one of the following:

Flagella
DNA or RNA genomes and not both
Chromosomal DNA
Intracellular organelles
Ribosomes that assist in RNA synthesis

Explanation

Question 156 of 243

1

The Rickettsia microbe is a good example of a type of pathogen that:

Select one of the following:

Is a frequent cause of gastroenteritis
Causes a condition known as oral thrush
Grows and divides inside various host cells
Produces spores under harsh conditions
Has a cell similar to yeast-like fungi

Explanation

Question 157 of 243

1

Which of the following is an accurate description for the pathogen that can cause encephalitis in immunocompromised patients and congenital abnormalities, and can be acquired from contact with infected cat feces?

Select one of the following:

Protozoan parasite
Acid-fast bacillus
Gram negative bacillus
Gram positive coccus
Dimorphic fungus

Explanation

Question 158 of 243

1

A widespread infection or disease with high attack rates that includes either high morbidity or mortality rates and occurs worldwide or in a particular region is known as a/an:

Select one of the following:

Endemic situation
Epidemic situation
Pandemic situation
Incubation period
Prolonged carrier state

Explanation

Question 159 of 243

1

Your patient is a 54-year-old man who presents with a fever, cough and chest pain. A sputum sample reveals numerous neutrophils and extracellular gram-positive diplococci. The likely etiologic agent is

Select one of the following:

Chlamydophila pneumoniae
Haemophilus influenzae 
Mycoplasma pneumoniae
Streptococcus pneumoniae
Klebsiella pneumoniae

Explanation

Question 160 of 243

1

A 3-year-old girl presents to the emergency department in severe respiratory distress. She has a fever and difficulty breathing. A gram-negative pathogen is isolated from a respiratory sample which is only culturable on chocolate agar. This clinical scenario could have been prevented if the patient had been immunized with:

Select one of the following:

The BCG vaccine
Pneumovax
Lipopolysaccharide
Serotype b vaccine
Acelluar pertussis vaccine

Explanation

Question 161 of 243

1

Your patient is a 9-year-old boy who presents with a fever and a severe sore throat. A rapid test for Group A streptococcal antigen is done using a throat swab and it comes back positive. Which of the following tests would confirm the likely diagnosis?

Select one of the following:

Giemsa stain of a patient sample
Growth on MacConkey agar
Presence of a peptidoglycan capsule
Alpha hemolysis on a blood agar plate
Inhibition of a growth by bacitracin

Explanation

Question 162 of 243

1

A 64-year-old homeless man presents to the emergency department complaining of fever, chills and night sweats. He also has a productive cough and a sputum sample reveals acid-fast bacilli. A PPD skin test is done and 48 hours later the area of induration measures 10 mm. The likely diagnosis is:

Select one of the following:

Psittacosis
Tuberculosis
Pneumococcal pneumonia
Influenza
Legionnaires disease

Explanation

Question 163 of 243

1

An experimental drug is found to produce its maximum effect at concentrations in which all of its targeted receptors are bound by the drug. This example describes the relationship between drug dose, receptor occupancy, and:

Select one of the following:

Magnitude of effect
Physiochemical properties
Physiologic response
Therapeutic window
Variability in drug serum levels

Explanation

Question 164 of 243

1

Fluconazole has an oral bioavailability factor of 1. What percentage of an oral dose reaches the systemic circulation?

Select one of the following:

0.01%
0.1%
1%
10%
100%

Explanation

Question 165 of 243

1

A hospitalized hypotensive patient is started on a continuous intravenous infusion of a drug that raises blood pressure. The serum concentration of the drug reaches steady state when the dosing rate equals the clearance multiplied by:

Select one of the following:

Concentration of drug in plasma (Cp) 
Half-life (t1⁄2) 
Hepatic blood flow (Qhepatic) 
Maximum rate of drug metabolism (Vmax)
Volume of distribution (Vd)

Explanation

Question 166 of 243

1

A hospitalized patient stabilized on an intravenous medication is being switched to the oral form of the same drug. Which of the following equations is used to calculate the maintenance dose?

Select one of the following:

1- (CL / Q)
(CL X Css) / F
Dose / AUC 
(t1⁄2 x CL) / 0.693
(Vd xCss)/F

Explanation

Question 167 of 243

1

A particular receptor agonist is given to a patient for pain management. The patient is directed to take the medicine once daily at the same time of day. After a couple of weeks, the patient notices that the drug is not controlling the pain as well as it did when she first started taking it, even though she is taking it exactly as directed. She does not smoke or take any other drugs or alcohol. Which one of the following best describes the receptor-related mechanism for the reduced efficacy of this drug?

Select one of the following:

Constitutive activity
Desensitization
Reduced affinity
Saturation
Upregulation

Explanation

Question 168 of 243

1

A series of increasing doses of an experimental drug in preclinical development is administered to a group of experimental animals. The therapeutic index of this drug in this population is found to be large. This parameter is indicative of:

Select one of the following:

Competitive antagonism
Hepatic blood flow
First-order elimination kinetics
Time to steady state
Variation of effect between subjects

Explanation

Question 169 of 243

1

The ability of a drug bound to its receptor to activate downstream effector mechanisms defines the drug’s:

Select one of the following:

Affinity
Bioavailability
Dose-response relationship
Intrinsic activity
Specificity

Explanation

Question 170 of 243

1

A particular drug undergoes significant first-pass effect by diffusing into the lipid bilayer of the endoplasmic reticulum in hepatocytes where it undergoes an oxidation reaction. The enzymes involved in the metabolism of this drug are most likely:

Select one of the following:

Cytochrome P450 enzymes
Isomerases
Glucuronosyltransferases 
Metalloproteinases
Oxidoreductases

Explanation

Question 171 of 243

1

A pharmacologic hormone undergoes hepatic glucuronidation and biliary secretion. Intestinal bacterial flora cleave the glucuronic acid from the therapeutic molecule, which is then reabsorbed. Which one of the following best fits this description?

Select one of the following:

Clearance
Enterohepatic circulation
First-pass metabolism
Phase 1 metabolism
Zero-order process

Explanation

Question 172 of 243

1

A pharmaceutical company develops a second-generation version of an antihistamine that prevents seasonal allergy symptoms (sneezing, itchy, runny nose and watery eyes). The advantage of the new version is that, unlike the first-generation drug, it does not cause central nervous system side effects, such as sedation and dizziness. Both drugs are taken orally. Compared to the older antihistamine, the second-generation agent has a low degree of:

Select one of the following:

Absorption
CYP metabolism
Effectiveness
Ionization
Lipid solubility

Explanation

Question 173 of 243

1

A woman experiencing menopausal symptoms is given a prescription for estrogen in a drug delivery system that allows for gradual diffusion of the hormone across the skin and dermal layers and into the venous circulation. Which one of the following is a disadvantage of this route of administration?

Select one of the following:

Frequent administration
First-pass metabolism
Gastric hyperacidity
Pain on injection
Skin irritation

Explanation

Question 174 of 243

1

A weak acid, HA, has a pK of 5.75. A solution is made by dissolving HA in water to a final concentration of 10 mM. The pH of this solution is adjusted to 7.75. Which of the following statements about this solution is true?

Select one of the following:

The concentration of the conjugate base (A-) in the solution is less than 5 mM
The solution strongly resists changes to its pH 
All HA is dissociated into H+ and A-
The concentration of A- is greater than the concentration of HA
The pH of the solution was adjusted to 7.75 by adding HCl

Explanation

Question 175 of 243

1

Which of the following will be the most effective buffer pair for a solution that is adjusted to pH 6.80?

Select one of the following:

H3AH+ +H2A,pK=2.32
H2A- H+ + HA-2, pK = 5.45
H2B H+ + HB-, pK = 6.70
HB- H+ +B-2,pK=9.1
HA-2 H+ + A-3, pK = 7.20

Explanation

Question 176 of 243

1

A test subject hyperventilates (breathes deeply and much faster than usual) for 3 minutes. Which of the following statements will be true of this test subject at the end of this 3 minute period?

Select one of the following:

The test subject’s [HCO3-]plasma will be decreased
The test subject’s [HCO3-]plasma will be increased
The test subject’s pHplasma will be below 7.20
The test subject’s pHplasma will be above 7.40
The test subject’s [CO2]plasma will be increased

Explanation

Question 177 of 243

1

Living cells are placed in a solution of 300 mM sucrose. The intracellular environment contains 140 mM NaCl and 5 mM KCl. These compounds have the following reflection coefficients: σsucrose =1,σNa =0.8,σK =1,σCl =1. Which of the following statements about this experiment is true?

Select one of the following:

The cells will swell
Sucrose will move into the cells
K+ will move out of the cells
The cells will shrink
Cl- will move into the cells

Explanation

Question 178 of 243

1

In early July, a 28-year-old woman is brought to the emergency department complaining of profuse diarrhea, weight loss, weakness, and dizziness for the past three days. She says she weighed 55 kg the morning her diarrhea began. Her weight upon admission is 50 kg. Lab tests of the diarrheal fluid indicate it has an osmolarity of 147 mOsm. Which Darrow-Yannet diagram reflects what has occurred in this patient during her diarrhea period?

Select one of the following:

Diagram A
Diagram B
Diagram C
Diagram D
Diagram E

Explanation

Question 179 of 243

1

A patient has lost a significant amount (1-2 L) of blood through hemorrhage. In the emergency department, a new resident administers 2 L of hypertonic saline solution by IV. Which diagram shows what would be the correct treatment for this patient to restore their blood volume? (Please see attachment)

Select one of the following:

Diagram A
Diagram B
Diagram C
Diagram D
Diagram E

Explanation

Question 180 of 243

1

Which of the following situation would produce a Hill plot with nH<1.0:

Select one of the following:

The protein has multiple subunits, each with a single ligand-binding site. Binding of ligand to one site increases the binding affinity of other sites for the ligand
The protein is a single polypeptide with two ligand binding sites, each having a different affinity for the ligand
The protein is single polypeptide with a single ligand-binding site. As purified, the protein preparation is heterogeneous, containing some protein molecules that partially denatured and thus have a lower affinity for the ligand
The protein has two different subunits. Only one subunit has a binding site for the ligand
The protein has multiple subunits, each with a single ligand-binding site. Binding of ligand to one site decreases the binding affinity of other sites for the ligand

Explanation

Question 181 of 243

1

Which of following is the allosteric regulator of hemoglobin oxygen binding?

Select one of the following:

1,3-Bisphosphoglyceric
Fructose 1,6-bisphosphate
2,3-Bisphosphoglycerate
3-phosphglycerate
Glucose 6-phosphate

Explanation

Question 182 of 243

1

Vitamin C deficiency may cause the following collagen related disease:

Select one of the following:

Osteogenesis imperfecta
Ehlers Danlos syndrome
Scurvy
Sticker syndrome
Marfan syndrome

Explanation

Question 183 of 243

1

Collagens are the major components of:

Select one of the following:

Mitchondria matrix
Endoplasmic reticulum
Nuclear matrix
Extracellular matrix
Golgi

Explanation

Question 184 of 243

1

A patient of yours has elevated levels of Alanine aminotransferase (ALT). The patient most likely has a problem with his:

Select one of the following:

Liver
Eyes
Heart
Bones
Pancreas

Explanation

Question 185 of 243

1

A patient of yours has been admitted to the cardiac care unit after having a myocardial infarction (heart attack). You are monitoring his recovery by measuring serum enzymes. Over the next two days, you find that his CK-MB levels are decreasing towards normal. On the third day, you see a sudden increase in CK-MB levels. This suggests that the patient:

Select one of the following:

Is recovering from the myocardial infarction (heart attack) and ready to go home
Is recovering from the myocardial infarction (heart attack) but is having a liver damage
Had another recent myocardial infarction (heart attack)
Is recovering from the myocardial infarction (heart attack) but is having some other muscle damage
Never had a myocardial infarction (heart attack); the diagnosis was wrong

Explanation

Question 186 of 243

1

Rotenone, a chemical derived from some roots, kills fish when added to ponds and is often used to kill non-native invasive species. Rotenone seems to affect the mitochondria by inhibiting complex I enzymes. When mitochondria are inhibited by rotenone, the:

Select one of the following:

Rate of respiration will increase
Rate of ATP synthesis will increase
Rate of NADH oxidation by the electron transport chain will decrease
Rate of succinate oxidation by the electron transport chain will decrease
Extent of reduction of Coenzyme Q in mitochondria will increase

Explanation

Question 187 of 243

1

In the rare Luft disease, patients show some microscopic disorder in mitochondrial structures. Mitochondrial respiratory chain complexes show normal levels of activities. When patients with Luft disease complain of feeling hot, have high rates of oxygen consumption and elevated heart rate, this may indicate:

Select one of the following:

Defective tricarboxylic acid cycle (TCA cycle) enzymes
Inhibition of complex III enzymes
Lack of Coenzyme Q
Uncoupling of the mitochondria electron transfer chain
Defective electron shuttles into the mitochondria

Explanation

Question 188 of 243

1

The glycerol phosphate dehydrogenase shuttle is not as good as the malate-aspartate shuttle because the glycerol phosphate dehydrogenase shuttle:

Select one of the following:

Brings electrons in at the NADH level
Produces less ATP than the malate-aspartate shuttle electrons
Can also transport ADP
Does not depend on the proton gradient
Is unidirectional

Explanation

Question 189 of 243

1

A new drug that you are studying has the unfortunate side effect of inhibiting cytochrome c oxidoreductase (complex III). This suggests that the drug will:

Select one of the following:

Decrease the reduction levels of complex II but not complex I
Decrease the reduction levels of complex I but not complex II
Increase the proton gradients
Decrease the reduction level of complex IV
Increase respiration

Explanation

Question 190 of 243

1

What are the effects of an increase in the plasma glucagon level on the activity of the tandem enzyme and the level of fructose 2,6-bisphosphate?

Select one of the following:

Increase in tandem enzyme kinase activity and an increase in the cellular level of fructose 2,6-bisphosphate
Decrease in tandem enzyme kinase activity and an increase in the cellular level of fructose 2,6-bisphosphate
Increase in tandem enzyme phosphatase activity and a decrease in the cellular level of fructose 2,6-bisphosphate 
Decrease in tandem enzyme phosphatase activity and an increase in the cellular level of fructose 2,6-bisphosphate 
No effect on tandem enzyme and no change in cellular level of fructose 2,6-bisphosphate

Explanation

Question 191 of 243

1

In red blood cells, the reduction of pyruvate produces:

Select one of the following:

Acetaldehyde, CO2, and NAD
Propionyl CoA, and FADH2
Ethanol and NADH + H+
Lactate and NAD 
Acetyl CoA, CO2, and NADH + H+

Explanation

Question 192 of 243

1

The irreversible reaction(s) of glycolysis is(are) catalyzed by:

Select one of the following:

Hexokinase, phosphofructokinase, and pyruvate kinase
Glyceraldehyde 3-phosphate dehydrogenase 
Phosphoglucisomerase, and triose phosphate isomerase
Phosphoglycerate kinase, enolase, and pyruvate kinase
Aldolase

Explanation

Question 193 of 243

1

Sulfate groups are most likely to be components of:

Select one of the following:

Monosaccharides
Disaccharides
Heteropolysaccharides
Homopolysaccharides
Oligosaccharides

Explanation

Question 194 of 243

1

The correct feature of glycosylaminoglycans is that they:

Select one of the following:

Contain a phosphate group on every fourth sugar residue
Are composed of repeating disaccharide units
Are a storage form of glucose in invertebrates
Contain codes for molecular targeting
Are chains of 50-100 fructosamine residues

Explanation

Question 195 of 243

1

The correct statement about the anomeric carbon of a sugar molecule is that it:

Select one of the following:

Is formed from an optically active carbon
Contains a carboxylic acid group formed in the creation of a hemiacetal
Can be any carbon in a sugar with an OH attached to it
Contains an OH group formed from a carbonyl group during the creation of a hemiacetal
Is the terminal carbon in a monosaccharide containing an H2COH group

Explanation

Question 196 of 243

1

In regard to main catabolism, the goal of the citric acid cycle is to form:

Select one of the following:

CO2 to maintain the normal plasma pCO2 level
Water to aid in water balance
Reducing equivalents for use by the electron transport chain
Nucleotide triphosphates by substrate level phosphorylation
CO2 by breakdown of acetyl groups (from acetyl-CoA) to regulate cellular levels of metabolites

Explanation

Question 197 of 243

1

Decarboxylation reactions during the TCA cycle are catalyzed by:

Select one of the following:

Citrate synthetase and glyceraldehye 3-phosphate dehydrogenase
Malate dehydrogenase and fumerase
Isocitrate dehydrogenase and alpha-ketoglutrate dehydrogenase
Succinate dehydrogenase and pyruvate carboxylase
Lactate dehydrogenase and malate dehydrogenase

Explanation

Question 198 of 243

1

During the conversion of pyruvate to acetyl-CoA catalyzed by the pyruvate dehydrogenase complex (PDH), the reaction that utilizes thiamine pyrophosphate (TPP) as the coenzyme is:

Select one of the following:

Oxidative phosphorylation of glyceraldehyde 3-phosphate
Shift of a hydroxyl group in the conversion of citrate to isocitrate
Decarboxylation of pyruvate
Hydrolysis of succinyl-CoA
Phosphorylation and decarboxylation of oxaloacetate

Explanation

Question 199 of 243

1

The correct statement about ketone bodies is: 

Select one of the following:

They are used by liver when plasma glucose is low
Acetone is the major intermediate in ketone body synthesis
Excess acetyl-CoA is the starting material for ketone body synthesis
They do not contain ionizable H+ ions
Tissues that use ketone bodies convert them to pyruvate

Explanation

Question 200 of 243

1

The purpose of transferring a fatty acid to carnitine to form acyl-carnitine is:

Select one of the following:

Carnitine is the acyl group carrier used in fatty acid synthesis
In the circulation, carnitine is the carrier of fatty acids destined for breakdown in the liver
Carnitine is the coenzyme required for formation of a carbon-carbon double bond in a fatty acid  chain during synthesis
Acyl-carnitine can be transported across the inner mitochondrial membrane
Carnitine is the acyl group carrier used during lipolysis

Explanation

Question 201 of 243

1

The reaction at the main control point for fatty acid breakdown is:

Select one of the following:

Lipolysis
Thiolysis
Oxidation
Hydration
Reduction

Explanation

Question 202 of 243

1

The correct sequence of reactions in fatty acid synthesis is:

Select one of the following:

Condensation -> oxidation -> hydration -> oxidation
Oxidation -> hydration -> reduction -> condensation
Condensation -> reduction -> dehydration -> reduction
Reduction -> condensation -> carboxylation -> reduction
Condensation -> carboxylation -> dehydration -> reduction

Explanation

Question 203 of 243

1

The main control point for fatty acid synthesis is:

Select one of the following:

Carboxylation of acetyl-CoA
Transfer of acetyl and malonyl groups to acyl carrier protein
Condensation reaction of fatty acid synthesis
Elongation reaction
Formation of triacylglycerol

Explanation

Question 204 of 243

1

The role of the malonyl group in fatty acid metabolism is to:

Select one of the following:

Aid in the transport of acetyl groups across the inner mitochondrial membrane
Supply energy through decarboxylation for reactions in fatty acid synthesis
Supply three carbon groups for synthesis of fatty acids with odd numbers of carbons
React with acetyl-CoA to form 3-hydroxy-3-methylglutaryl CoA 
Supply reducing equivalents for use in fatty acid synthesis

Explanation

Question 205 of 243

1

If a cell requires both reducing equivalents and five carbon sugars for use in biosynthesis reactions, the products of the pentose phosphate pathway will be:

Select one of the following:

Ribulose 5'-phosphate and FADH2
Fructose 6'-phosphate and glyceraldehyde 3-phosphate
Ribose 5'-phosphate and NADPH+H+
Xyulose 5'-phosphate, erythrose 4-phosphate and NADPH+H+
Ribose 5'-phosphate and NADH+H+

Explanation

Question 206 of 243

1

The enzyme that can be used to replenish the levels of citric acid cycle intermediates through its anaplerotic function is:

Select one of the following:

Pyruvate carboxylase
Aconitase
Pyruvate dehydrogenase
Citrate synthetase
Phosphopentose epimerase

Explanation

Question 207 of 243

1

Compounds that can enter gluconeogenesis include:

Select one of the following:

Acetyl-CoA, succinyl-CoA, and acetoacetate
Fatty acids and acetyl-CoA
Fatty acids, glycerol, and beta-hydroxybutyrate
Lactate and glycerol
Hydroxymethylglutaryl-CoA, acetone, and lactate

Explanation

Question 208 of 243

1

The effects of insulin on hepatic glycogen metabolism are:

Select one of the following:

Activation of glycogen synthesis and inactivation of glycogen breakdown through activation of phosphatase I
Activation of glycogen synthesis and inactivation of glycogen breakdown through phosphorylation and inactivation of cAMP-dependent protein kinase
Activation of glycogen synthesis and inactivation of glycogen breakdown by causing glucagon to dissociate from its receptor
Activation of glycogen breakdown and inactivation of glycogen synthesis through inactivation of phosphodiesterase
Activation of glycogen breakdown and inactivation of glycogen synthesis through activation of adenylate cyclase

Explanation

Question 209 of 243

1

During a period of starvation all glycogen reserves in a patient’s body have been consumed. Following treatment with glucose, synthesis of new glycogen will be initiated by:

Select one of the following:

Glycogen phosphorylase
UDP-glucose pyrophosphorylase
Glycogen synthase
Glycogenin
Phosphoglucomutase

Explanation

Question 210 of 243

1

Pyridoxal phosphate is used as a prosthetic group by:

Select one of the following:

Debranching enzyme
Glycogen synthetase
Branching enzyme
Glycogen phosphorylase
UDP-glucose pyrophosphatase

Explanation

Question 211 of 243

1

A McDonald's McCafé Frappé Mocha has 18 grams of fat, 65 grams of sugar and 7 grams of proteins. Approximately how many Kcalories is that?

Select one of the following:

300
450
840
45
250

Explanation

Question 212 of 243

1

Right after a big and heavy lunch:

Select one of the following:

Blood glucose is high and fat breakdown is high
Blood glucose is low and fat synthesis is high
Blood glucose is high and insulin is high
Fat synthesis is high and glycogen breakdown is high
Fat breakdown is high and insulin is high

Explanation

Question 213 of 243

1

When a man has not eaten for 20 hours, it is likely that his blood sugar levels are maintained by:

Select one of the following:

Glycogen breakdown
Gluconeogenesis
Fat breakdown
Beta oxidation
Glucose synthesis from acetyl-CoA

Explanation

Question 214 of 243

1

A phosphate group is a component of:

Select one of the following:

Sphingomylein
Ceramide
Globoside
Sulfatide
Ganglioside

Explanation

Question 215 of 243

1

In the CDP-diacylglycerol branch of phosphoglyceride synthesis, CDP-diacylglycerol can react with:

Select one of the following:

CDP-choline
Acyl-CoA
Inositol
Phosphatidate
S-adenosylmethionine

Explanation

Question 216 of 243

1

The starting materials for synthesis of sphingosine are:

Select one of the following:

Phosphatidate and glycine
Palmitoyl-CoA and serine
Glycerol 3-phosphate and acyl-CoA
Cerebroside and UDP-glucose
Arachidonate and CMP-N-acetylneuraminate

Explanation

Question 217 of 243

1

You have isolated a new enzyme that catalyzes the attached reaction. This enzyme would be classified as a/an: (Please see attachment)

Select one of the following:

Oxidoreductase
Transferase
Hydrolase
Lyase
Isomerase

Explanation

Question 218 of 243

1

Many drugs are competitive inhibitors of the target enzymes. Such competitive inhibitors will:

Select one of the following:

Increase the apparent Km of the target enzymes
Decrease the apparent Km of the target enzymes
Decrease the Vmax of the target enzymes
Increase the Vmax of the target enzymes
Not affect the Vmax of Km of the target enzymes

Explanation

Question 219 of 243

1

You are developing a new drug to treat a new disease by stabilizing the native form of a protein. You believe that phosphorylation of a particular amino acid in the protein will stabilize the protein. Your target is likely to be a/an:

Select one of the following:

Val
Ser
Asp
Leu
Gly

Explanation

Question 220 of 243

1

A new enzyme you have isolated is activated only when a very nonpolar small effector molecule binds to a control site; you have also found that a single mutation at the control site abolishes the binding of the effector molecule to the enzyme. Which of the following mutations is the most likely candidate?

Select one of the following:

Asp is replaced by Glu
Glu is replaced by Asp
Ala is replaced by Val
Leu is replaced by Arg
Leu is replaced by Ile

Explanation

Question 221 of 243

1

A man presents with back pain. He also complains that his urine is sometimes dark-colored. His ear cartilage has a gray appearance. The most likely cause of his symptoms is:

Select one of the following:

Homocystinuria
Maple syrup urine disease
Deficient enzyme in the degradation of tyrosine
Deficient enzyme in the formation of heme
Deficiency of the branched-chain alpha-keto acid dehydrogenase

Explanation

Question 222 of 243

1

Ammonia is transported in a nontoxic form in the blood primarily as:

Select one of the following:

Glutamine
Glutamate
Urea
A diglucuronide
Aspartate

Explanation

Question 223 of 243

1

A patient with cystinuria cannot properly:

Select one of the following:

Synthesize cystathionine
Form urea
Degrade cystine
Degrade methionine
Transport arginine and cystine

Explanation

Question 224 of 243

1

Two infants appeared normal at birth but developed hyperammonemia after 24 hours. Their laboratory data is attached. Both infants had above normal levels of blood ammonia. Which one of the following enzymes could be deficient and cause this abnormality in infant II?

Select one of the following:

Carbamoyl phosphate synthetase I
Ornithine transcarbamoylase
Argininosuccinate synthetase
Argininosuccinate lyase
Arginase

Explanation

Question 225 of 243

1

Patients with a defect in the degradation of which amino acid should not consume aspartame?

Select one of the following:

Tyrosine
Phenylalanine
Glutamate
Glutamine
Aspartate

Explanation

Question 226 of 243

1

A 23-year-old female is brought to the emergency department because she is having hallucinations and is very confused. She spent the day painting outside in bright sunlight. The patient has undergone two previous laparotomies (exploratory pelvic surgery) for acute abdominal pain, but no pathology was found. What is the most likely reason for her symptoms?

Select one of the following:

She has taken barbiturates
She has eaten a lot of aged cheese
She has Lesch-Nyhan syndrome
She has porphyria cutanea tarda
She has acute intermittent porphyria

Explanation

Question 227 of 243

1

A 52-year-old obese male comes to his family doctor complaining of severe pain in the first metatarsophalangeal joint that began after he ate and drank too much on Thanksgiving Day. He has a history of kidney stones. The patient:

Select one of the following:

Should be treated with allopurinol to decrease the activity of xanthine oxidase
Should be treated with allopurinol to increase the purine salvage pathway
Has a deficiency of adenosine deaminase
Has a deficiency in PRPP synthetase activity
Has an decrease in the purine salvage pathway

Explanation

Question 228 of 243

1

In what genetic disorder is there a deficiency in a canalicular protein that transports bilirubin glucuronides into bile?

Select one of the following:

Dubin-Johnson syndrome
Gilbert syndrome
Newborn jaundice
Crigler-Najjar syndrome type II
Rotor syndrome

Explanation

Question 229 of 243

1

Two infants appeared normal at birth but developed hyperammonemia after 24 hours. Their laboratory data is attached. Both infants had above normal levels of blood ammonia. Which one of the following enzymes would likely be abnormal in infant I? (Please see attachment)

Select one of the following:

Carbamoyl phosphate synthetase I
Ornithine transcarbamoylase
Glutamate dehydrogenase
Argininosuccinate synthetase
Arginase

Explanation

Question 230 of 243

1

Which of the following brain areas receive olfactory sensory information prior to thalamic relay and must be considered primary olfactory cortex?

Select one of the following:

Insular cortex
Locus coeruleus
Orbitofrontal cortex
Piriform cortex
Ventromedial prefrontal cortex

Explanation

Question 231 of 243

1

What would a patient with a partial bilateral lesion of taste fibers projecting to the geniculate ganglion most likely present with?

Select one of the following:

A general reduction of taste sensitivity of the anterior 2/3 of the tongue
A general reduction of taste sensitivity on the entire tongue and epiglottis
A general reduction of taste sensitivity on the rear 1/3 of the tongue
A specific reduction of taste for "bitter"
A specific reduction of taste for "salty" and "sweet"

Explanation

Question 232 of 243

1

What is the primary function of sustentacular cells found in the olfactory epithelium?

Select one of the following:

They act as inhibitory interneurons in fine pitch and tuning
They cover axons with a layer of myelin
They form Bowman's olfactory gland
They provide structural support and mucous secretions
They transmit action potentials to the olfactory bulb

Explanation

Question 233 of 243

1

Irrigating the ear of a healthy patient with cold water causes:

Select one of the following:

Nystagmus toward the irrigated ear
Nystagmus away from the irrigated ear
Torsional ocular counter-roll
Vertical ocular counter-roll
Horizontal ocular counter-roll

Explanation

Question 234 of 243

1

Changing visual fixation to different external places is achieved by:

Select one of the following:

Smooth pursuit eye movement
Saccadic eye movement
Ocular counter-roll
Fast-phase nystagmus
Slow-phase nystagmus

Explanation

Question 235 of 243

1

The membranous labyrinth of the inner ear is filled with:

Select one of the following:

Endolymph
Perilymph
Cerebrospinal fluid
Blood
Bile

Explanation

Question 236 of 243

1

Iridectomy treats:

Select one of the following:

Cataracts
Closed angle glaucoma
Open angle glaucoma
Retinal detachment
Macular degeneration

Explanation

Question 237 of 243

1

Beta-blockers and/or cholinergic medication treats:

Select one of the following:

Cataracts
Closed angle glaucoma
Open angle glaucoma
Retinal detachment
Macular degeneration

Explanation

Question 238 of 243

1

How is pupil size increased?

Select one of the following:

Parasympathetic innervation to the dilator pupillae muscle causing mydriasis
Parasympathetic innervation to the sphincter pupillae muscle causing miosis
Sympathetic innervation to the ciliary muscle causing miosis
Sympathetic innervation to the dilator pupillae muscle causing mydriasis
Sympathetic innervation to the sphincter pupillae muscle causing miosis

Explanation

Question 239 of 243

1

Myopic vision is due to the inability to:

Select one of the following:

Stretch the lens enough to accommodate far stimuli
Relax the lens enough to accommodate far stimuli
Stretch the lens enough to accommodate near stimuli
Relax the lens enough to accommodate near stimuli
Compensate for anterior-posterior elongation of the eye

Explanation

Question 240 of 243

1

Retinal detachment occurs directly between the: 

Select one of the following:

Amacrine cell layer and the pigment epithelium
Ganglion cell layer and the choroid layer
Photoreceptor layer and the choroid layer
Photoreceptor layer and the pigment epithelium
Pigment epithelium and the choroid layer

Explanation

Question 241 of 243

1

Which of the following best describes the anatomical organization of the ossicles from the tympanic membrane to the round window?

Select one of the following:

Uncus, malleus, stapes
Malleus, stapes, uncus
Malleus, uncus, stapes
Stapes, malleus, uncus
Uncus, stapes, malleus

Explanation

Question 242 of 243

1

Which of the following would cause hearing deficits due to middle ear dysfunction?

Select one of the following:

Cerumen impaction
Otitis externa
Otitis media
Hair cell degeneration
Cranial nerve VIII leison

Explanation

Question 243 of 243

1

Which of the following best describes the fluid found in the scala vestibule?

Select one of the following:

Is high in potassium
Is different from the fluid in the scala tympani
Is low in potassium
Contains leukocytes and erythrocytes
Contains only leukocytes

	Created by jochamplin over 9 years ago

Quiz on Science Questions, created by jochamplin on 10/12/2014.

Science Questions

Science Questions

Question 1 of 243

Attached are the solute concentrations for a normal mammalian cell under resting conditions. Which value will be closest to the resting membrane potential of this cell?

Select one of the following:

Explanation

Question 2 of 243

Select one of the following:

Explanation

Question 3 of 243

Select one of the following:

Explanation

Question 4 of 243

Spectrin is an integral part in which of the following intracellular structure(s)?

Select one of the following:

Explanation

Question 5 of 243

Which protein is necessary to create the forces that result in the bending movements of cilia and flagella?

Select one of the following:

Explanation

Question 6 of 243

Which intracellular process would be primarily disrupted by inhibition of Arp2/3 complexes?

Select one of the following:

Explanation

Question 7 of 243

Which type of the anchoring contact is used by the migrating (crawling) fibroblasts?

Select one of the following:

Explanation

Question 8 of 243

What is the primary function of tissue fibronectin?

Select one of the following:

Explanation

Question 9 of 243

Which of the following extracellular matrix components assembles proteoglycans into the gigantic complexes called proteoglycan aggregates?

Select one of the following:

Explanation

Question 10 of 243

Which type of gene mutations confer a selective growth advantage in cancers?

Select one of the following:

Explanation

Question 11 of 243

Ninety-five percent of the mutations in tumors are:

Select one of the following:

Explanation

Question 12 of 243

A man and his wife are carriers of a gene for sickle cell disease (autosomal recessive inheritance). What is the probability that this couple may have a phenotypically normal child?

Select one of the following:

Explanation

Question 13 of 243

A man with porphyria starts a cult which soon increases in number. Many of his descendants were found to have porphyria. A smallpox epidemic soon occurs in the cult. Which one of the following terms best describes this situation?

Select one of the following:

Explanation

Question 14 of 243

A female alcoholic presents to the emergency department with confusion and memory loss. She also exhibits rolling of her eyeballs. Her diet consists mainly of canned soup. Lack of which vitamin is most likely to be responsible for her symptoms?

Select one of the following:

Explanation

Question 15 of 243

Which vitamin is involved in collagen synthesis?

Select one of the following:

Explanation

Question 16 of 243

The attached image depicts a histological image of the human mammary gland stained with H&E. What type of connective tissue is most abundant immediately around the glands (arrows)?

Select one of the following:

Explanation

Question 17 of 243

As a pathologist you would like to make sure that the magenta colored staining result of a cancerous liver specimen with Periodic acid-Schiff (PAS) reaction is real. Which enzyme would you use to confirm your positive staining result?

Select one of the following:

Explanation

Question 18 of 243

Which of the following antigens is the most immunogenic?

Select one of the following:

Explanation

Question 19 of 243

Which multilobed lymphatic organ serves as the place for T cell maturation?

Select one of the following:

Explanation

Question 20 of 243

The term redundancy of cytokines means that:

Select one of the following: