2022 Quizes Flashcards
High intake of sucrose increases the risk of obesity because:
A. Fructose metabolism bypasses the highly regulated PFK-1 step in glycolysis
B.Sucrose cannot be cleaved to fructose and glucose in the intestine
C. The glucose released from sucrose is metabolized slower
D. Fructose metabolism requires an enzyme that is often mutated
E. Fructose cannot be used as a substrate for glycolysis
A. Fructose metabolism bypasses the highly regulated PFK-1 step in glycolysis
The initial reaction in glycolysis is NOT the commitment step because
A. The reaction has a positive ΔG.
B. The reaction is reversible.
C. Glucose-6-phosphate can exit the cell.
D. Glucose-6-phosphate can be utilized in other pathways.
E. Glucose-6-phosphate is very unstable.
D. Glucose-6-phosphate can be utilized in other pathways.
Which of the following statements about ketone bodies is FALSE?
A. Ketone bodies are used only by the brain.
B. Ketone body production involves hydroxyl-methyl-glutaryl-CoA (HMG-CoA) as an intermediate.
C. Ketone bodies are water-soluble.
D. High levels of ketone bodies in the blood result in exhaling of acetone.
E. Ketone bodies are mainly produced in the liver.
A. Ketone bodies are used only by the brain.
Pyruvate dehydrogenase uses a complex mechanism to convert pyruvate to acetyl-CoA. Which of the following is NOT a substrate, product or coenzyme in the pyruvate dehydrogenase reaction?
A. coenzyme A
B. ATP
C. CO2
D. NADH
E. FADH2
B. ATP
A futile cycle is
A. When alanine is transported from muscle to liver to produce glucose
B. A way for cells to conserve energy
C. When two opposing metabolic pathways are active at the same time
D.An example of feedforward regulation of metabolism
E. A pathway to store glucose during fasting
C. When two opposing metabolic pathways are active at the same time
Which of the following is NOT a fate of acetyl CoA in human?
A. Precursor for fatty acid synthesis
B. Precursor for cholesterol synthesis
C. Precursor for glucose synthesis
D. Precursor for synthesis of ketone bodies
E. Fuel of TCA cycle
C. Precursor for glucose synthesis
Which of the following is the reason why oxidation of FADH2 generates less ATP than oxidation of NADH in oxidative phosphorylation?
A. NADH is oxidized in both Complex I and II, thus contributing one more electron for the generation of the proton gradient.
B. Since NADH is produced in both glycolysis and TCA cycle the local concentration of NADH is higher than FADH2.
C. Oxidation of FADH2 occurs in complex II, bypassing one proton-pumping step across the inner mitochondrial membrane.
D. NADH has higher affinity for Coenzyme Q, thus competes with FADH2 and donates electrons more easily.
C. Oxidation of FADH2 occurs in complex II, bypassing one proton-pumping step across the inner mitochondrial membrane.
Brown adipose tissue is common in hibernating animals because of
A. The need to reduce oxygen consumption
B. The need to increase circulating glucose
C. The need to store more energy
D. The need to produce more glycogen
E. The need to generate heat while energy need is low
E. The need to generate heat while energy need is low
Which of the following is FALSE regarding Nicotinamide coenzymes?
A. They are polar and water soluble
B. They act as high energy electron carriers in glycolysis (cytosol)
C. They act as prosthetic groups on enzymes
D. They act as high energy electron carriers in the TCA cycle (mitochondria)
E. They cannot be used to produce ATP in the absence of mitochondria
C. They act as prosthetic groups on enzymes
Which of the following statements is INCORRECT about the regulation of fatty acid synthesis?
A. Citrate activates fatty acid synthesis.
B. Acyl CoAs inhibit fatty acid synthesis.
C. Malonyl CoA inhibits fatty acid synthesis.
D. Isocitrate activates fatty acid synthesis.
C. Malonyl CoA inhibits fatty acid synthesis.
Which of the following lipoproteins has the role in reverse cholesterol transport?
A. HDL
B. Chylomicron
C. IDL
D. LDL
E. VLDL
A. HDL
Which of the following is NOT a fate of cholesterol in human?
A. Used as a precursor for steroid synthesis
B. Stored in the liver as cholesterol ester
C. Converted to bile acids
D. Broken down to acetyl CoA through fatty acid oxidation
E. Used as a membrane component
D. Broken down to acetyl CoA through fatty acid oxidation
Which of the following amino acids can be made from pyruvate via transamination reaction?
A. Serine
B. Isoleucine
C. Aspartate
D. Alanine
E. Glycine
D. Alanine
Which of the following pairs is INCORRECT for the metabolite and its precursor amino acid?
A. Serotonin from phenylalanine
B. Dopamine from tyrosine
C. GABA from glutamate
D. Histamine from histidine
E. Oxalate from glycine
A. Serotonin from phenylalanine
It’s tryptophan
Which of the following is LEAST soluble in water?
A. Cholic acid
B. Glycocholic acid
C. Deoxycholic acid
D. Cholesterol
E. Cholesterol ester
E. Cholesterol ester
