Pregunta 1
Pregunta
L’acide phosphorique est tri-basique, avec des valeurs de pKa de 2.14, 6.88 et 12.4. Quelle forme ionique est prédominante à pH = 5.9 ?
Respuesta
-
H3PO4
-
H2PO4-
-
HPO42-
-
PO43-
Pregunta 2
Pregunta
What is the basic formula of Carbohydrates?
Respuesta
-
Cn(OH)n
-
Cn(CO2)n
-
Cn(H2O)n
-
C(H2O)n
Pregunta 3
Pregunta
Which of these is not these is not a polysaccharide?
Respuesta
-
Cellulose
-
Glycogen
-
Starch
-
Fructose
Pregunta 4
Pregunta
Long chains of single sugars covalently linked describes what types of carbohydrates?
Respuesta
-
Oligosaccharides
-
Multisaccharides
-
Polysaccharides
-
Megasaccharides
Pregunta 5
Pregunta
Which pair of molecules are epimers?
Pregunta 6
Pregunta
Which of these structures is glucose?
Pregunta 7
Pregunta
Galactose is a ___ epimer of glucose.
Pregunta 8
Pregunta
Which one of these is a ketohexose
Respuesta
-
Fructose
-
Glucose
-
Ribose
-
2-Deoxy-Ribose
Pregunta 9
Pregunta
Which of these is not true?
Respuesta
-
Enantiomers are stereoisomers that are not mirror images
-
In sugars that contain the most chiral centers only the one that is the most distant from the caronyl carbon is designated as D or L
-
hemiacetals are formed by alcohols attacking aldehydes
-
Alcohol oxygen atom is nucleophilic
Pregunta 10
Pregunta
During the cyclisation of Monosaccharides which is/are true?
Respuesta
-
The carbon atom furthest from the former carbonyl atom becomes the anomeric carbon
-
The position of anomeric carbon's oxygen determines whether the anomer is α or β
-
The position of the anomeric carbon's hydroxyl group determines whether the anomer is α or β
-
The carbon atom furthest from the former carbonyl atom becomes the chiral center
Pregunta 11
Pregunta
Which of these are carbohydrates that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom?
Pregunta 12
Pregunta
The disaccharide formed upon condesation of two glucose molecules via the 1-4 bond is called
Respuesta
-
Trehalose
-
Sucrose
-
Maltose
-
Lactose
Pregunta 13
Pregunta
Which of these describes cellobiose
Respuesta
-
α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside
-
β-D-glucopyranosyl-(1→4)-β-D-glucopyranose
-
β-D-galactopyranosyl-(1→4)-α-D-glucopyranose
-
α-D-glucopyranosyl-(1→4)-β-D-glucopyranose
Pregunta 14
Pregunta
Polysaccharides...
Respuesta
-
can be branched but cannot have multiple monomer types
-
cannot be unbrached
-
have defined molecular weights
-
with only two monomer types cannot be branched
Pregunta 15
Pregunta
Which one of these hetero-polysaccharides has the largest size
Respuesta
-
peptidoglycan
-
agarose
-
hyaluronan
Pregunta 16
Pregunta
which of these is used in Algae cell walls
Respuesta
-
Peptidoglycan
-
hyaluronan
-
agarose
Pregunta 17
Pregunta
Glucose is stored in animals as
Respuesta
-
Glucagon
-
Glycogen
-
Glucose
-
Insulin
-
Starch
Pregunta 18
Pregunta
Glycogen is a polysaccharide in which glucose is joined by β-(1→4) linkages
Pregunta 19
Pregunta
Glycogen is a polysaccharide in which glucose is joined by α-(1→6) linkages
Pregunta 20
Pregunta
Which of the following is true
Respuesta
-
Amylose is the branched form of starch
-
α-amylase is a pancreatic enzyme that hydrolyses the α (1→4) linkages of starch
-
Glycogen has less α (1→4) linkages than starch
-
Glycogen has less α (1→6) linkages than starch
Pregunta 21
Pregunta
hydrolysis of cotton occurs
Respuesta
-
at the β (1→2) linkages of D-glucose
-
at the α (1→2) linkages of D-glucose
-
at the β (1→4) linkages of D-glucose
-
at the α (1→4) linkages of D-glucose
Pregunta 22
Pregunta
Which of the following is not true
Respuesta
-
Glycosidic bonds can freely rotate
-
more than 10^9 metric tonnes of cotton are produced/year
-
Starch can be coiled into a helical structure
-
Glycogen and amylopectin have only one reducing end
Pregunta 23
Pregunta
Which of these lack enzymes that can hydrolyse D-glucose β (1→4) linkages
Respuesta
-
Fungi
-
bacteria
-
termites
-
protozoa
Pregunta 24
Pregunta 25
Pregunta
Sephadex gels separate proteins by
Respuesta
-
size
-
charge
-
polarity
-
shape
Pregunta 26
Pregunta
Which of these would you find in the first fractions after size exclusion chromatography
Respuesta
-
acidic proteins
-
the smallest proteins
-
the largest proteins
-
basic proteins
Pregunta 27
Pregunta
which of these are homoglycans
Respuesta
-
Agar
-
Dextrans
-
Peptidoglycan
-
None
Pregunta 28
Pregunta
Which of these can be linked to epichlorohydrin in sephadex beaded gels
Respuesta
-
Agar
-
Agarose
-
Peptidoglycan
-
Dextran
Pregunta 29
Pregunta
Agar is a complex mixture of heteropolysaccharides containing modified
Respuesta
-
Glucose units
-
Mannose units
-
Fructose units
-
None of the above
Pregunta 30
Pregunta
Which of these is false
Respuesta
-
Agarose can be used for growing bacteria
-
Agarose is a component of bacterial cell walls
-
Agarose can be used for DNA separation
-
Agar is a component of seaweed cell walls
Pregunta 31
Pregunta
N-acetyl-galactosamine is a ___ epimer of N-acetyl-glucosamine
Pregunta 32
Pregunta
Where wold yo expect to find hyaluronate
Respuesta
-
ECM of Cartilage
-
Hair
-
Nails
-
Horns
Pregunta 33
Pregunta
Which one of these glycosaminoglycans acts as a lubricant?
Respuesta
-
Chondrotin-4-sulfate
-
keratan sulfate
-
heparin
-
hyaluronate
Pregunta 34
Pregunta
which one of the has approximately 50'000 disaccharides per chain
Respuesta
-
hyaluronate
-
keratan sulfate
-
heparin
-
chondrotin-4-sulfate
Pregunta 35
Pregunta
Which one of these glycosaminoglycans consists of [galactose β(1,4) Glc-NAc6S] repeating disaccharides
Respuesta
-
hyaluronate
-
chondrotin-4-sulfate
-
heparin
-
keratan sulfate
Pregunta 36
Pregunta
Which of these repeating disaccharides make dermantan sulfate?
Respuesta
-
glucaronic acid and N-acetylglucosamine
-
glucaronic acid and N-acetylgalctosamine-4-sulfate
-
Iduronic acid and N-acetylgalactosamine-4-sulfate
-
Iduronic acid and N-acetylglucosamine
Pregunta 37
Pregunta
The cabohydrate attached to a protein in a Glycoconjugate attaches via...
Pregunta 38
Pregunta
Which of the following most likely contains the most glycosylated proteins (Glycoproteins)
Respuesta
-
Humans
-
E.coli
-
Ebola virus
-
Cats
Pregunta 39
Pregunta
O linked oligosaccharides are linked through the N terminus of the amino acid
Pregunta 40
Pregunta
In glycoproteins, sugars are attached either to the amide nitrogen atom in the side chain of asparagine (termed an N-linkage) or to the oxygen atom in the side chain of serine or threonine (termed an O-linkage)
Pregunta 41
Pregunta
Glycophorin A is the most important attachment site for which of the following parasites in order to enter erythrocytes
Respuesta
-
Plasmodium falciparum
-
Chilomastix mesnili
-
Entamoeba coli
-
Entamoeba dispar
Pregunta 42
Pregunta
Which of these sulfated glycosaminoglycans are attached to a protein anchored to a membrane lipid?
Pregunta 43
Pregunta
NB! Select all which are functions of polysaccharides
Respuesta
-
Labelling of proteins for destruction
-
Recognition sites for growth factors
-
recognition sites for bacteria
-
localization of certain proteins
Pregunta 44
Pregunta
Which one of these is not a main component of the extracellular matrix (ECM)
Respuesta
-
Proteoglycan aggregates
-
Collagen fibers
-
Elastin
-
Fatty acids
Pregunta 45
Pregunta
Which one of these in not a characteristic of Glycosaminoglycans
Pregunta 46
Pregunta
Plasmodium flaciparum requires which of these as an attachment site to enter erythrocytes
Respuesta
-
Glycophorin A
-
Hyaluronan
-
syndecan
-
Podocalyxin
Pregunta 47
Pregunta
Which of these about proteoglycans is not true
Respuesta
-
Proteoglycan aggregates are found in articula cartilage
-
Proteoglycans influence growth factor activation and adhesion
-
glycosaminoglycans are linked to the core protein from the anomeric carbon
-
proteoglycanaggregates form high friction material
Pregunta 48
Pregunta
Which of these are integral receptors for extracellular proteoglycans
Respuesta
-
Integrins
-
actin
-
collagen fibers
-
elastin
Pregunta 49
Pregunta
Which of these about enzymatic reactions is true
Respuesta
-
Enzymes directly affect equilibrium (∆G)
-
Entropy cost is paid during binding
-
enzymes increse reaction rates (κ ) by increasing (∆G)
-
slow reactions do not have high activtaion barriers
Pregunta 50
Pregunta
Rate of enzymatic reactions are affected by....? (Click all true)
Pregunta 51
Pregunta
Which one of these describes a micelle
Respuesta
-
individual units are wedge shaped
-
artificial carriers of molecules
-
individual units are cylindrical
-
composed lipid-based structures that form pliable sheets
Pregunta 52
Pregunta
Which of these is false
Respuesta
-
membranes vary from 3-10nm
-
membranes form spontaneously by noncovalent forces
-
membranes are symmetric
-
membranes can be found within cells
Pregunta 53
Pregunta
Which of these is true about fatty acids
Respuesta
-
Most natural fatty acids are branched
-
Saturated fatty acids have double bonds between carbons in the chain
-
Most natural fatty acids have an even number of C's
-
linoleic acid is a saturated fatty acid
Pregunta 54
Pregunta
Which of these is false about fatty acids
Respuesta
-
Fatty acids solubility decreases as the chain length increases
-
Melting point decrases as the chain length decreses
-
Melting point increases as the number of double bonds increases
-
unsaturated cis fatty acids have a lower melting point than saturated fatty acids
Pregunta 55
Pregunta
Omega-3 (ω-3) fatty acids have
Respuesta
-
a double bond between the 2nd and 3th carbon from the methyl end of the chain.
-
a double bond between the 3rd and 4th carbon from the methyl end of the chain.
-
a double bond between the 1st and 2nd carbon from the methyl end of the chain.
-
a double bond between the 2nd and 3nd as well as 3rd and 4th carbon from the methyl end of the chain.
Pregunta 56
Pregunta
Which of these is untrue
Respuesta
-
Triacylglycerols are polar
-
Triacylglycerols are non hydrated
-
Vegetable oils are composed of triacylglycerols with unsaturated fatty acids
-
Animal fats are composed of triacylglycerols with saturated fatty acids
Pregunta 57
Pregunta
which of these is a greasy solid at room tempreature
Pregunta 58
Pregunta
which of these is a sphingolipid
Pregunta 59
Pregunta
Which of these is the head group of phosphatidylserine
Pregunta 60
Pregunta
Which of these has a net charge of -4 at pH7
Pregunta 61
Pregunta
Which of these is the major component of most eukaryotic cell membranes
Respuesta
-
phophatidylcholine
-
phosphatidylglycerol
-
cardiolipin
-
phosphatidylethanolamine
Pregunta 62
Pregunta
a fatty acid is joined to sphingosine via an
Respuesta
-
ester linkage
-
amide linkage
-
glycosidic linkage
-
phosphodiester linkage
Pregunta 63
Pregunta
ganglioside GM2 has which of these as a head group
Pregunta 64
Pregunta
The blood groups are determined in part by the
Pregunta 65
Pregunta
The structure of sugars located on the head groups in glycosphingolipids is determined by an expression of specific glycosyltransferases. Individuals with a glycosyltransferase that transfers an N-acetylgalactosamine group will
Respuesta
-
will have the O antigen
-
A blood group
-
B blood group
-
AB blood group
Pregunta 66
Pregunta
which of thes is false
Respuesta
-
Cholesterol modulates cell membrane fluidity
-
Mammals can not synthesize cholesterol
-
cholesterol in loe density lipoproteins tend to deposit in arteries
-
most bacteria lack sterols
Pregunta 67
Pregunta
which of these polyketides is an antibiotic
Respuesta
-
erythromycin
-
amphotericin B
-
lovastatin
Pregunta 68
Pregunta
which of these lipids are hormone precursors
Respuesta
-
vitamins E and K
-
vitamins A and D
-
steroid hormones
-
eicosanoids
Pregunta 69
Pregunta
which of these lipids are paracrine hormones
Respuesta
-
phosphatidylinositols
-
vitamins A and D
-
vitamins E and K
-
Dienes
-
eicosanoids
Pregunta 70
Pregunta
which of these is true
Respuesta
-
cholesterol is predominant in mitochondrial membranes
-
galactolipids are abundant in animals
-
membranes have non-selective import and export across the membrane
-
archaebacteria have monolayer instead of a bilayer
Pregunta 71
Pregunta
which of these is a type 6 integral membrane protein
Pregunta 72
Pregunta
Which of these amino acid residues would you find predominantly in the transmembrane segments of membrane proteins
Pregunta 73
Pregunta
Proteins can be targeted to the INNER leaflet of the plasma
membrane by farnesylation. The primary sequence of the protein contains a signature for farnesylation which is
Pregunta 74
Pregunta
hutchinson-gilford progeria syndrome is caused by
Respuesta
-
palmitoylation defect
-
myristoylation defect
-
farnesylation defect
Pregunta 75
Pregunta
which of these are only found on the outside of cell membranes
Respuesta
-
proteins
-
lipids
-
carbohydrates
Pregunta 76
Pregunta
which of these statements about the physical properties of membranes is true
Respuesta
-
Permeable to large polar solutes and ions
-
Not permeable to small polar solutes and nonpolar
compounds
-
Permeability can be artificially increased by chemical
treatment
-
Exist in a single phase and cannot undergo phase
transitions
Pregunta 77
Respuesta
-
cell membrane transition from the gel to fluid
-
cell membrane transition from the fluid to gel
-
cell membrane changed to become not permeable to large polar solutes
-
cell membrane changed to become permeable to small polar solutes and nonpolar compounds
Pregunta 78
Pregunta
Which of these statements on membrane fluidity is incorrect
Respuesta
-
is determined mainly by the fatty acid composition
-
more fluid membranes require shorter and more unsaturated fatty acids
-
At higher temperatures cells need more saturated fatty
acids to maintain fluidity
-
Gel phase means that the individual molecules do not move
around
Pregunta 79
Pregunta
which of these increase in membrane compisition percentage when temperatures increase
Respuesta
-
Myristic acid
-
palmitoleic acid
-
oleic acid
-
hydroxymyristic acid
Pregunta 80
Pregunta
Cell membranes of .... contain hopanols instead of sterols
Respuesta
-
animals
-
bacteria
-
plants
-
fungi
Pregunta 81
Pregunta
Membrane Dynamics: Transverse Diffusion.
Spontaneous flips of individual lipids from one leaflet to another are rare because...
Respuesta
-
the hydrophobic head group must transverse the hydrophilic tail region of the membrane
-
membrans are rigid and individual lipids cannot move at all
-
the charged head group must transverse the hydrophobic tail region of the membrane
Pregunta 82
Pregunta
Which is false about flippases
Respuesta
-
catalyze transverse diffusion
-
catalyze lateral diffusion
-
use ATP
-
move lipids against the concentratiion gradient
Pregunta 83
Pregunta
Tick ALL that are true!!
Respuesta
-
Membrane Lipid Rafts contain clusters of glycosphingolipids with longer-than-usual tails
-
Membrane Lipid Rafts are more ordered than the rest of the membrane
-
Membrane fusion can only occur through protein mediation
-
Passive diffuision of polar molecules across cell membranes has a high activation barrier
Pregunta 84
Pregunta
Which of these is a membrane receptor that detects light
Respuesta
-
opsin
-
insulin receptor
-
acetylcholine receptor
-
maltoporin
Pregunta 85
Pregunta
Which of these is a membrane receptor that detects neurotransmitters
Respuesta
-
opsin
-
acetylcholine receptor
-
maltoporin
-
insulin receptor
Pregunta 86
Pregunta
Cystic fibrosis (Mucoviscidose) is caused by
Respuesta
-
a mutation to a Cl- ion channel in epithelial cells
-
a mutation to a K+ ion channel in epithelial cells
-
a mutation to a Na+ ion channel in epithelial cells
-
a mutation to a Ca2+ ion channel in epithelial cells
Pregunta 87
Pregunta
Tick ALL that are correct
Respuesta
-
Energy of ATP hydrolysis can be used to drive protons through the membrane
-
Energy of the proton gradient can be used to synthesize ATP
-
Primary active transport is a form of active transport across a biological membrane in which a transporter protein couples the movement of an ion (typically Na+ or H+) down its electrochemical gradient to the uphill movement of another molecule or ion against a concentration/electrochemical gradient.
-
glucose is cotransported with Na+ in intestinal epithelial cells
Pregunta 88
Pregunta
Which of these plasma proteins is the most abundant
Respuesta
-
transferrin
-
ceruloplasmin
-
immunoglobulins
-
albumin
Pregunta 89
Pregunta
What is labelled as B?
Respuesta
-
blood
-
plasma
-
White blood cells
-
ficoli
Pregunta 90
Pregunta
What is labelled as D
Respuesta
-
Plasma
-
White blood cells
-
Ficoli
-
white blood cells
Pregunta 91
Pregunta
Which of these are not a hematopoietic cells
Respuesta
-
eosinophils
-
basophils
-
neutrophils
-
thrombocytes
Pregunta 92
Pregunta
Which of these is derived from lymphoid stem cells
Respuesta
-
erythrocytes
-
T cells
-
basophil
-
neutrophil
Pregunta 93
Pregunta
Which one of these leukocytes secretes histamine and mediates inflammation
Respuesta
-
neutrophils
-
basophils
-
eosinophils
-
macrophages
Pregunta 94
Pregunta
Which of these leukocytes produces Ab (antibodies)
Respuesta
-
Neutrophils
-
T cells
-
B cells
-
Macrophages
Pregunta 95
Pregunta
Where is myoglobin found
Respuesta
-
in the bone marrow
-
freely circulating in the blood
-
in skeletal and striated muscles
-
restricted to erythrocytes
Pregunta 96
Pregunta
which of these is false
Respuesta
-
myogloblin stores oxygen in the cytoplasm and delivers it to mitochondrion
-
hemoglobin is restricted to erythrocytes
-
Heme (B) is the oxygen binding molecule found only in hemoglobin
-
the distal histidine of the myglobin protein hydrogen bonds with oxygen bound to the protein
Pregunta 97
Pregunta
Consider a process in which a ligand (L) bind reversibly to a site in a protein (P). After some time, the process will reach equilibrium where the Ka (association rate constant) and Kd (dissociation rate constant) rates are equal. which of these equations represents the equilibrium.
Respuesta
-
kd [P].[L] = ka [PL]
-
ka [P].[L] = kd [PL]
-
[P].[L] = [PL]
-
ka [P].[L] > kd [PL]
Pregunta 98
Pregunta
Which of these statements is false
Respuesta
-
when the first binding event increases affinity at the remaining sites it is called positive cooperativity
-
when the first binding event decreases affinity at the remaining sites it is called negative cooperativity
-
oxygen binds to heme better than carbon monoxide
-
nH( hill coefficient) > 1 equals positive cooperativity
Pregunta 99
Pregunta
Cooperativity can be described as
Respuesta
-
positive homotropic regulation
-
negative homotropic regulation
-
positive heterotropic regulation
-
negative heterotropic regulation
Pregunta 100
Pregunta
Which of these statement on hemoglobin is false
Respuesta
-
oxygen binding triggers a tense to relaxed state conformational change
-
tense state has a higher affinity for oxgen than the relaxed state
-
conformational change from the T state to the R state invloves breaking ion pairs between the alpha1-beta2 interface of hemoglobin
-
2,3 -Bisphosphoglycerate is a negative heterotropic regulator of hemoglobin function
Pregunta 101
Pregunta
which of these is a non-phosphorylated nitrogenous base
Respuesta
-
nucleoside
-
nucleotide
-
nucleobase
-
nucleomide
Pregunta 102
Pregunta
Which side are the purines
Pregunta 103
Pregunta
Which color is encircling where a glycosidic bond between the nitrogenous base and the sugar would be present
Respuesta
-
red
-
green
-
blue
-
none of the above
Pregunta 104
Pregunta
Which letter represents deoxyadenylate
Pregunta 105
Pregunta
Which letter represents deoxythymidylate
Pregunta 106
Pregunta
Which letter represents deoxyguanylate
Pregunta 107
Pregunta
Which letter is representing cytidylate (CMP)
Pregunta 108
Pregunta
Which of these statements about the purine and pyrimidine bases is true
Pregunta 109
Pregunta
In nucleotides the pentose ring is attached to the nucleobase via a
Respuesta
-
β -N-Glycosidic Bond
-
α -N-Glycosidic Bond
-
Hydrogen bond
-
none of the above
Pregunta 110
Pregunta
In DNA structure there is free rotation about
Respuesta
-
C-1’-N-glycosyl bond
-
C-2’-N-glycosyl bond
-
C-3’-N-glycosyl bond
-
C-4’-N-glycosyl bond
Pregunta 111
Pregunta
How many base pairs do you find in the A form of DNA
Pregunta 112
Pregunta
The aromaticity of the nucleotide bases and their dipole moments is important for which interactions in DNA
Respuesta
-
Van der Waal forces in base stacking
-
link between base and sugar in a nucleotide
-
the link between two different nucleotides
-
interstrand bonding and complementarity
Pregunta 113
Pregunta
Figure A represents which type of DNA secondary structure
Respuesta
-
hairpin
-
mirror image
-
palindrome
-
cruciform
Pregunta 114
Pregunta
Figure C represents which type of DNA secondary structure
Respuesta
-
Cruciform
-
Palindrome
-
Hairpin
-
Mirror image
Pregunta 115
Pregunta
DNA sequences with a very high proportion of G residues forms which unusual DNA structure found on chromosome telomeres
Respuesta
-
tetraplex DNA
-
triplex DNA
-
inverted repeats
-
cruciforms
Pregunta 116
Pregunta
Which of these are a quaternary DNA structure
Respuesta
-
Chromatin
-
hairpin
-
supercoil
-
Triplex
Pregunta 117
Pregunta
In mammals ____ Functions as an autocoid, or "local hormone"
Respuesta
-
Adenosine
-
Guanine
-
Cytosine
-
Thymine
Pregunta 118
Pregunta
Which one of these is an RNase enzyme that prevents inbreeding of plants
Respuesta
-
S-RNase
-
RNase-P
-
Dicer
-
None of the above
Pregunta 119
Pregunta
_____ is an enzyme that cleaves double-stranded RNA into oligonucleotides
Pregunta 120
Pregunta
Why would animal cells need an enzyme that cleaves double-stranded RNA into oligonucleotides
Respuesta
-
processessing tRNA precursors
-
protection from viral genomes
-
using RNA as an energy source
-
using RNA in Coenzymes
Pregunta 121
Pregunta
RNA would be unstable in which of the conditions listed below