Quiz
Section 3 Previous Exam
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Perguntas do quiz (33)
1Oxidation of glucose-6-phosphate by the pentose phosphate pathway produces all of the following molecules EXCEPT?
- ANADPH
- BRibose-5-phosphate
- CGlyceraldehyde-3-phosphate
- DSuccinate
- EFuctose-6-phosphate
2Deficiency of glucose-6-phosphate dehydrogenase in red blood cells confers resistance to the malaria parasite Plasmodium falciparum by maintaining which of the following conditions in the cell?
- AHIGH levels of ketogenesis
- BHIGH levels of reduced glutathione
- CHIGH levels of cholesterol biosynthesis
- DLOW levels of reduce glutathione
- ELOW levels of fatty acid biosynthesis
3Acetyl-CoA used in fatty acid and cholesterol synthesis is shuttled from the mitochondrial matrix to the cytoplasm in the form of which of the following compounds?
- Amalate
- Bpyruvate
- Coxaloacetate
- Dcitrate
- Efumarate
4Arrange the final steps of fatty acid synthesis in the proper order.
I. Dehydration
II. Condensation
III. Release of palmitate
IV. Reduction
V. Formation of malonyl-CoA- AV, III, IV, IV, II, I
- BV, IV, I, II, I, III
- CI, III, II, IV, V
- DII, I, III, IV, V
- EV, II, IV, I, IV, III
5When considering fatty acid synthesis following a meal high in glucose, which of the statements is CORRECT?
- ACitrate lyase activity is decreased.
- BCarnitine transport of fatty acids into the mitochondria is increased.
- CGlucagon will increase fatty acid synthesis.
- DExcess of palmitoyl-CoA will increase activity of acetyl-CoA carboxylase.
- ECitrate will increase the activity of acetyl-CoA carboxylase.
6Which of the following fatty acids is an "essential fatty acid" and must be obtained from the diet?
- AArachidonate 20:4
- BStearate 18:0
- CPalmitate 16:0
- DOleate 18:1
- ELinoleate 18:2
7All of the following metabolic states promote ketogenesis EXCEPT:
- AHigh levels of acetyl-CoA in the mitochondrial matrix of liver cells
- BLow levels of oxaloacetate in the mitochondrial matrix of liver cells
- CFasting and/or starvation
- DHigh levels of insulin in blood plasma
- EDiabetes
8Which of the following statements about cholesterol synthesis is INCORRECT?
- ASynthesis occurs in the cytoplasm of cells
- BThe cyclization of squalene forms the steroid nucleus
- CNADPH, 02, ATP, and Acetyl-CoA are required
- DThe synthesis of mevalonate by HMG-CoA reductase is the committed step in the pathway
- EGlucagon increases cholesterol synthesis
9All of the following strategies can reduce the level of cholesterol in human blood plasma EXCEPT:
- Aincreased levels of HDL
- Bincreased bile salt production and excretion
- Cdecreased activity of HMG-CoA reductase
- Dincreased levels of LDL receptor on the surface of cells
- Eincreased levels of LDL
10Dietary triaclyglycerols and cholesterol are transported from the small intestine to adipose tissue and muscle in the blood stream by which of the following lipoproteins?
- Achylomicrons
- BVLDL
- CIDL
- DLHL
- EHDL
11Which of the following molecules is NOT a substrate for an increase in NET glucose production by gluconeogenesis in mammalian liver?
- Aalanine
- Bacetyl-CoA
- Cglycerol
- Dlactate
- Epyruvate
12Alcoholics can suffer from thiamine deficiency because ethanol can inhibit thiamine uptake in the intestines. Which of the following pathways is directly affected by a thiamine deficiency?
- Agluconeogenesis
- Bphosphoinositide cascade
- Cketogenesis
- Dpentose phosphate pathway
- Eglycogen synthesis
13Which of the following statements regarding steroid hormones and their receptors is INCORRECT?
I. All steroid hormones are derived from arachidonate
II. progesterone is an example of a steroid hormone
III. all steroid hormone receptors have a similar DNA binding domain
IV. steroid hormones can diffuse across cell membranes- AI
- BII
- CIII
- DIV
- EIII and IV
14Which of the following statements regarding the phsophoinositide cascade is INCORRECT?
- APhosphlipase C is activated as a result of a peptide hormone binding to its receptor
- BA G-protein is coupled to a receptor
- Cthe pathway involves release of calcium from the ER into the cytosol
- Dinositol triphosphate (IP3) a diacylglycerold (DAG) are generated as secondary messengers
- Ephosphatidylinositol cleavage is coupled to ATP hydrolysis
15Which of the following statements regarding eicosanoids is INCORRECT?
- Athey function in the inflammatory response and in the regulation of pain and fever
- BThey are long-lived, with half-lives of hours
- CThree major classes are prostaglandins, leukotrienes, and thromboxanes
- DThey are derived from arachidonate
- EThey function as local hormones, acting on cells in the immediate vicinity of production
16In liver and muscle cells, the role of glycogenin is:
- ATo break down glycogen at the reducing end
- BTo serve as primer for glycogen synthesis
- CTo convert glucose-6-phosphate to glucose-1-phosphate
- DTo convert glucose-1-phosphate to UDP-glucose for glycogen synthesis
- ETo create a-1,5-glycosidic bonds during glycogen breakdown
17Glycogen breakdown in muscle cells does not contribute to the regulation of blood glucose because an enzyme needed to release free glucose is absent in muscle cells. Which of the following enzymes is NOT present in muscle cells?
- Ahexokinase
- Bphosphfructokinase (PFK-1)
- Cinsulin receptor-tyrosine kinase
- Dglucose-6-phosphatase
- Ephosphorylase b kinase
18Glucagon binding to cell surface receptors on hepatocytes (liver cells) will:
- Aincrease the level of fructose-2,6-bisphosphate (F-2,6-BP) and the rate of glycolysis will decrease
- Bdecrease the level of F-2,6-BP and the rate of glycolysis will decrease
- Cdecrease the level of F-2,6-BP and the rate of glycolysis will increase
- Dincrease the level of F-2,6-BP and the rate of glycolysis will increase
- Eincrease the level of F-2,6-BP and the the rate of glycolysis will be unaffected
19In type I diabetes, the pancreas does not produce adequate amounts of a hormone to mediate glucose uptake by muscle and adipose cells. What hormone, produced by the pancreas, mediates glucose uptake?
- Aglucagon
- Binsulin
- Cepinephrine
- Dsomatostatin
- Eadrenaline
20Which of the following enzymes' activity level will decrease when levels of blood glucose are HIGH?
- Aglycogen synthase
- Bglucokinase
- Cglycogenin
- Dglycogen branching enzyme
- Eglycogen phosphorylase
21If an individual has a nonfunctional debranching enzyme, how many molecules of glucose-1-phosphate can be released from the chain in the box?
- A0 molecules
- B1 molecule
- C5 molecules
- D6 molecules
- E7 molecules
22If three moelcules of glucose-1-phosphate are released from a molecule of glycogen, how many NET molecules of ATP can be produced in glycolysis?
- A2 molecules
- B3 molecules
- C4 molecules
- D6 molecules
- E9 molecules
23Which of the following amino acids is an "essential amino acid" and must be obtained in the diet?
- Aalanine
- Bglycine
- Ctryptophan
- Dproline
- Eserine
24Catecholamines such as dopamine and norepinephrine are synthesized from which of the following amino acids?
- Aglycine
- Bhistidine
- Ctyrosine
- Dleucine
- Evaline
25Which of the following pathways can provide substrates for the synthesis of amino acids?
- Acholesterol synthesis
- Bfatty acid synthesis
- Cglycolysis
- Dprostaglandin synthesis
- Ethromboxane synthesis
26The liver plays a prominent role in metabolism, serving as the primary site for multiple biochemical reactions. Which of the following biosynthetic pathways occurs ONLY in the mitochondria of the liver?
- Agluconeogenesis
- Bketogenesis
- Cglycolysis
- Dcholesterol synthesis
- Eglycogen synthesis
27Methotrexate is an effective anticancer agent because:
- AIt inhibits deoxythymidine monophosphate (dTMP) nucleotide synthesis
- BIt inhibits glycolysis
- CIt activates fatty acid synthesis
- DIt promotes elevated levels of reactive oxygen species
- EIt activates oxidative phosphorylation
28Which of the following statements is INCORRECT regarding the enzyme ribonucleotide reductase of E.coli?
- AUnder cellular conditions it converts deoxyribonucleotides to ribonucleotides
- BIt contains two allosteric regulatory sites, on for activity and one for specificity
- CThe catalytic mechanism involves a free radical intermediate
- DIt catalyzes a redox reaction
- ENADPH provides reducing power
29Which of the following is NOT used in de novo synthesis of purine nucleotides?
- Aglycine
- Bformate
- Cribose-5-phosphate
- Daspartate
- EO2
30High cellular levels of AMP can inhibit the committed step in the purine biosynthesis pathway. The synthesis of which of the following nucleotides will be inhibited when AMP levels are high?
- AGuanosine monophoasphate (GMP)
- BCytosine monophosphate (CMP)
- CThymine monophosphate (TMP)
- DUridine monophosphate (UMP)
- EDeoxythymine monophosphate (dTMP)
31Regulation of metabolism by phosphorylation of enzymes is usually a fast process and occurs in multiple cells.
- AVerdadeiro
- BFalso
32Leptin is a hormone generated in adipose cells that signals to the brain to increase food intake.
- AVerdadeiro
- BFalso
33During fasting the brain can use ketone bodies as a source of fuel
- AVerdadeiro
- BFalso
Informações
- Descrição
- Undergraduate Biochemistry 501 (Section 3) Quiz sobre Section 3 Previous Exam, criado por taweis em 09-04-2014.
- Autor
- taweis
- Idioma
- English
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