O 1. X: The hydrophobic core of Lipoprotiens contain phospholipids and cholesterol.
Y: High Density lipoproteins (HDL) transport internally produced cholesterol from liver to tissues. a) Both X and Y are true
b) Both X and Y are false c) Only X is true
d) Only Y is true
2. X: Bile acids have both hydrophobic and hydrophilic properties.
Y: An intracellular lipoprotein lipase hydrolyzes triacylglycerols from chylomicrons. (extracellular) a) Both X and Y are true
b) Both X and Y are false c) Only X is true d) Only Y is true
3. X: Clathrin is a plant protein preventing coalescence of oil bodies during dry season. Y: LDL transports cholesterol into cells via receptor-mediated endocytosis.
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
4. X: Adipocytes are specialized in storage and transport of triacylglycerols. (don’t transport) Y: Pancreatic lipase and phospholipase A2 catalyze the hydrolysis of triacylglycerols to glycerol.
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
5. X: Bile acids and nonpolar products of lipid digestion form micelles.
Y: VLDL are synthesized in the liver and are gradually degraded by lipoprotein lipase first to LDL and then to IDL. a) Both X and Y are true
b) Both X and Y are false c) Only X is true d) Only Y is true
W 1. X: Cellular response only occurs if the receptors have specificity for a specific signal.
Y: If the signal transduction pathway is inhibited by another signal molecule, cellular response may not occur. a) Both X and Y are true
b) Both X and Y are false c) Only X is true
d) Only Y is true
2. Tyrosine kinase activity of RTK's takes place ... a) at the intracellular N-terminus b) at the intracellular C-terminus c) at the extracellular C-terminus
d) at the intracellular trimerized binding site
3. The phosphoinositide pathway ....
a) leads to increased intracellular Ca2+ due to opening IP3-gated channels b) is important for extracellular Ca2+ signal transduction
c) begins when IP3 and DAG bind to form membrane-bound phospholipase C (PLC) d) releases Ca2+ from cell into the extracellular matrix via IP3-gated channels
4. X: Tyrosine-P of RTK activates GRB2 which activates G-protein RAF. (SP-2 domain)
Y: The RAS signaling cascade works to regulate transcription factors located inside the nucleus. a) Both X and Y are true
b) Both X and Y are false c) Only X is true
5. X: Tumor cells develop due to normal, excessive signal transduction proteins, because defective proteins are destroyed. Y: Defective proteins (which result in tumors) can exist only between receptors and transcription factors.
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
U 1. X. Exertion causes a 30 fold increase in the rate of muscle respiration (20) Y. glucokinase is inhibited by [G6P] (hexokinas)
a) Only X is true b) Only Y is true c) Both are true d) Both are false
2. In the liver phosphorylation of glucose to G6P is catalzed by hexokinase (glucokinase) a) True
b) false
3. X .Adipose tissue obtain triglycerols from circulating lipoproteins Y. A normal 70 kg man has enough fat to last 3 months of startvation a) Only X is true
b) Only Y is true c) Both are true d) Both are false
4. G6P is used in which one of the following pathways:
a) Conversion to glucose, by a phosphatase when blood glucose is <5mM b) Conversion to R5P in pentose phosphate pathway generating NADH c) Conversion to glycogen when blood glucose is low
d) All of the above are fates of G6P
5. A cross-country runner’s body relies mainly on which of the following: a) Phosphocreatine
b) Glycolysis
c) Oxidative phosphorylation d) None of the above
6. X. During fasting the brain immediately switches to ketone bodies for energy Y. Na+/K+ ATPase maintains membrane potential
a) Only X is true b) Only Y is true c) Both are true d) Both are false
P 1. X. B-oxidation takes place at the alpha carbon
Y. The B-carbon becomes a carboxyl carbon in the next round of B-oxidation a) Both X and Y are true
b) Both X and Y are false c) Only X is true
d) Only Y is true
2. X. Each round of B-oxidation produces 3 NADh, FADH2, GTP, and 1 acetyl Co-A (1 NADH, 1 FADH, 1 acetyl Co-a) Y. Oxidation of acetyl Co-A in CAC generates 1 FADH2 and 1 NADH (3 NADH, 1 Fadh, 1 GTP)
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
Y. B-oxidation produces propionyl-CoA in the end a) Both X and Y are true
b) Both X and Y are false c) Only X is true
d) Only Y is true
4. X. Oxidation of unsaturated fatty acids needs 3 extra enzymes (4) Y. These enzymes convert cis double bond to trans double bond a) Both X and Y are true
b) Both X and Y are false c) Only X is true
d) Only Y is true
5. X. Condensation of C2 units is the opposite of B-oxidation
Y. Ketone bodies are lipid soluble, therefore, lipids are the main fuel for the brain a) Both X and Y are true
b) Both X and Y are false c) Only X is true d) Only Y is true
6. X. Biosynthesis of fatty acids is an anabolic process
Y. The major cofactors of anabolic pathways are NADP+ and NAD+ (NADP and NADPH) a) Both X and Y are true
b) Both X and Y are false c) Only X is true d) Only Y is true
7. X. Acetyl Co-A carboxylase converts Acetyl Co-A to palmitoyl-ACP (convert to Malonyl-Coa) Y. Fatty acid synthesis involves the conversion of ATPADP and NADPHNADP+
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
8. X. Elongases catalyze the synthesis of longer fatty acids
Y. Desturases catalyze reactions that convert double bonds to single bonds in saturated fatty acids (single to double) a) Both X and Y are true
b) Both X and Y are false c) Only X is true d) Only Y is true
9. X. The backbone of triacylglygerols can be provided by dihydroxyacetone Y. The backbone of triacylglygerols can be provided by G3P
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
S 1. X: Mammals synthesize essential amino acids and obtain nonessential amino acids from diet. (opposite) Y: Arginine and Glutamine are essential amino acids. (Arg,His,Lys are necc, Asp,Glu not necce)
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
2. X: Oxidation of amino acids yield metabolic intermediates and can only be classified as glucogenic or ketogenic amino acids, not both. (can be both)
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
3. X: Methionine breakdown to succinyl-CoA involves propionyl-CoA as an intermediate.
Y: Sulfonamide antibiotics are deadly to mammals because they block the synthesis of THF from self-produced folic acid. (note toxic because they do not synthesise folic acid or tetrahydrofolate, which bacterica does)
a) Both X and Y are true b) Both X and Y are false c) Only X is true d) Only Y is true
4. Phenylalanine degradation
a) requires phenylalanine hydroxylase to yield tyrosine, an intermediate in the overall degradation.
b) can be prevented by a deficiency in phenylalanine hydroxylase, resulting in increased levels of phenylpyruvate and the depletion of neural tissue oxaloacetate.
c) yields only acetoacetate as the final product, which then goes on to become fatty acids and ketone bodies. d) Only A and B are correct
e) Only A and C are correct
5. X: Glutamine, ATP, and Asparagine synthetase are all required for the transamination of aspartate to asparagine. Y: Aspartate, ATP and Glutamine synthetase are all required for the transamination of glutamate to glutamine. a) Both X and Y are true
b) Both X and Y are false c) Only X is true d) Only Y is true
6. X: Acetate and alanine are responsible for forming porphyrins, which complex with iron to form Heme. (Acetate and Glycine with intermediates ALA and PBG)
Y: The concentration of PBG, an intermediate in the heme biosynthesis pathway, increases when ALA synthase is inhibited by lead. (it is the other way around, switch the intermediates, ALA accumulates as result of converting PBG lead inhibited to ALA)
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
7. X: An abnormally high rate of erythrocyte degradation raises the concentration of bilirubin in the blood, causing jaundice, where the skin and the whites of the eyes become coloured.
Y: Kidney dysfunction and bile duct obstruction also cause jaundice. (liver not kidney) a) Both X and Y are true
b) Both X and Y are false c) Only X is true d) Only Y is true
8. X: Diazatrophs are the only bacteria that cannot fix N2; i.e. use N2 by converting it to NH3. Y: Nitrogenase catalyzes the reaction that converts N2 to NH3.
a) Both X and Y are true b) Both X and Y are false c) Only X is true
d) Only Y is true
Uu 1. X. If blood glucose concentration drops to 1mM, one will experience coma, and brain damage Y. Muscle cells cannot export glucose due to the lack of GLUT-4 channels
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2. X. The pain that we feel after muscle exertion is due to the build up of H+ from anaerobic glycolysis
Y. This pain we feel help stop us from further exertion which would deplete ATP supply and ultimately kill muscle. a. Only X is true
b. Only Y is true
c. both X and Y are true d. neither X or Y are correct
3. The heart uses which of the following for metabolic fuels: a. fatty acids
b. glucose c. ketone bodies d. lactate
e. all of the above
4. What pathway(s) use(s) glucose-6-phospate?
a. conversion to glucose by glucose-6-phosphatases b. conversion to glycogen
c. conversion to acetyl-CoA
d. degradation to ribose-5-phosphate e. all of the above
5. Conclusion for this graph is that:
a. hexokinase activity increases rapidly with blood [glucose] but glucokinase activity changes gradually when both at normal physiological ranges
b. hexokinase activity does not change with blood [glucose] at its physiological
concentrations but glucokinase activity increases rapidly with blood [glucose] at wide physiological range c. hexokinase has a higher affinity for glucose whereas glucokinase has lower affinity
d. glucokinase is used in liver to phosphorylate glucose whereas hexokinase is used in other organs
6. During low demand for metabolic fuels:
a. liver synthesizes triacylglycerols from fatty acids
b. triacyglycerols are released into the bloodstream in the form of VLDL c. adipose tissue takes up VLDL
d. all of the above e. b and c
T 1. Nucleotides are important because: a. components of nucleic acids b. part of coenzymes
c. high-energy compounds
d. are significant source of metabolic energy e. a, b and c
2. Inosine monophosphate is the starting material of: a. AMP
b. CMP c. GMP d. a and c e. b and c
3. What is the salvage pathway for nucleotides?
a. ability salvage nucleotides from sources with the body b. salvaging the foods we eat that are high in nucleotides
c. ability to convert ribose to deoxyribose thereby reducing our dietary need for deoxyribose d. none of the above
4. How is RNA different from DNA
a. RNA is ribose residue whereas DNA is 2-deoxyribose residue b. RNA has uracil wereas DNA has 5-methyuracil
d. all of the above e. a and c
5. X. Overproduction of dNTP is mutagenic because the increased concentration of dNTP increased probability of its erroneous incorporation in DNA
Y. The enzyme used to catalyze dNDP to dNTP with use of ATP is nucleoside monophosphate kinase (diphosphate NOT mono)
a. Only X is true b. Only Y is true c. both X and Y are true d. neither X or Y are correct
6. Cancer chemotherapy, in addition to killing cancerous cells, also does the following: a. decreases our immunity
b. affect blood cell production c. hair loss
d. all of the above e. a and c
7. nucleoside phosphorylases catalyzes: a. degradation of DNA to oligonucleotides b. synthesis of oligonucleotides from nucleosides
c. hydrolysi of nucleosides to ribose-1-phosphate and free bases d. degradation of oligonucleotides to nucleosides
e. none of the above
8. X. A disease where there is arthritic inflammation of joints can be caused by elevated levels of uric acid in body fluids (called glout)
Y. catabolism of beta-alanine and beta-aminoiosobutyrate gives us metabolic energy a. Only X is true
b. Only Y is true
c. both X and Y are true d. neither X or Y are correct
V 1. X: Gluconeogenesis is the process of converting lactose to pyruvate in the liver.
Y: The Cori cycle occurs when glucose (from the liver) is exchanged for lactate (from muscle) during exercise. a) Both X and Y are true
b) Both X and Y are false c) Only X is true
d) Only Y is true
2. In the Glucose-Alanine cycle, after pyruvate and amino acids combine in the muscle to form a keto-acid and alanine ... a) The toxic keto-acid is broken down in the liver
b) Glucose supply is drastically reduced and the organism must ingest more energy
c) Alanine is transported to the liver to undergo transamination which produces pyruvate and urea d) Alanine is transaminated into a different amino acid which the muscle cells can use to synthesize proteins
3. X: Glucose requires a conformational membrane receptor, GLUT1, to regulate glucose uptake by cells Y: GLUT2 limits the rate of glucose uptake, and GLUT4 limits glucose uptake but is controlled by insulin a) Both X and Y are true
b) Both X and Y are false c) Only X is true
d) Only Y is true
4. The following takes place during starvation ...
a) Highly obese individuals can survive one year without food (ex. 650 lb man) b) When carbohydrates are used up, the body mobilizes fatty acids for energy c) Severly starved individuals produce ketone bodies from fatty acids for energy d) Both B and C are correct
5. Leptin which is synthesized in the liver decreases appetite. (adipocytes NOT liver) a) True b) False
6. X: Diabetes is caused by an insulin uptake defect, which eventually dehyrdates the body is not severe enough to cause death Y: Excess blood glucose, as well as Pi, Na+, K+, H20 and H+ are excreted and not reabsorbed when insulin does not work Z: In insulin-dependent diabetes, patients must inject daily insulin requirements
a) All of the above are true b) X and Y are true c) X and Z are true d) Y and Z are true e) Only Z is true
R 1. What is the half life of Ornithine decarboxylase?
a) 0.1h b) 5h (PEP) c) 118h (adolase) d) 150h(Cytochrome) e) 0.2h
2. X. lysozyme [H] is roughly 100 times lower than cytosolic [H] (higher)
Y. Ubiquitin is a small protein that marks proteins for lysosome dependent degradation. (Independent) a) X and Y true
b) X and Y false c) only X true d) only Y true
3. ___________ cleave N-terminal residues. a) N-terminus cleaving enzyme
b) aminopeptidases c) peptidase
d) N-terminus amino e) carboxypeptidases
4. The major nitrogenous compound of protein metabolism and urine is: (it is urea) a) urine
b) N containing amino acids c) keto acids
d) glutamate
e) none of the above
5. X. aminotransferases require coenzymes known as peridoxal-5-phosphate.
Y. If the circulating level of ammonia rises a pathological condition known as hyperammonemia will develop. a) X and Y true
b) X and Y false c) only X true d) only Y true
