Integrated Tissue Metabolism MCQs

28 clinical MCQs in Enzymes, Vitamins and Minerals. The disadvantage of anaerobic glycolysis in high-intensity muscle contractions is —. Kenya, Africa a...

Questions, Answers & Explanations

1. Q1. The disadvantage of anaerobic glycolysis in high-intensity muscle contractions is ---

   • The heart muscle "soaks" up most of the lactic acid for its energy needs
   • ATP production cannot be sustained for long events
   • The production of excessive amounts of CO₂ and H₂O that interferes with exercise
   • Lactic acid accumulation that inhibits key glycolytic enzymes and eventually causes fatigue
   • Both B and D

   Answer: Both B and D

2. Q2. Chylomicrons ---

   • Enter the blood via the lymphatic system
   • Are fat-soluble nutrients covered with a protein coat
   • Are one of several kinds of lipoproteins
   • Are formed in the walls of the small intestine
   • All of the above

   Answer: All of the above

3. Q3. Phosphocreatine is used to store energy in ---

   • Adipose tissue
   • Epidermal tissues
   • Brain
   • Cardiac muscles

   Answer: Cardiac muscles

4. Q4. In the Cori cycle, lactate is converted into ---

   • Glucose
   • Minerals
   • Proteins
   • Vitamins

   Answer: Glucose

5. Q5. Long-term heavy alcohol consumption can cause ---

   • Pancreatitis, cirrhosis, and alcoholic hepatitis
   • Heart disease, heart attack, and cancer
   • High blood pressure and alcohol abuse
   • All of the above

   Answer: All of the above

6. Q6. What are symptoms of alcoholism? ---

   • Craving, loss of control, physical dependence, and tolerance
   • Obesity, slowed respiratory rate, rash
   • Pale skin, brittle hair and nails, and white tongue
   • All of the above

   Answer: Craving, loss of control, physical dependence, and tolerance

7. Q7. There are many types of alcohol. Intoxication as we know it is caused by ---

   • Methanol
   • Ethanol
   • Ethylene glycol
   • Isopropanol

   Answer: Ethanol

8. Q8. Enzymes involved in the transfer of methyl groups are collectively called ---

   • Transferases
   • Methyltransferases
   • Both A and B
   • Dehydrogenases
   • Amylases

   Answer: Both A and B

9. Q9. All are involved in the function of serotonin, except ---

   • Smooth muscle contraction in bronchioles and arterioles
   • Regulation of cerebral activity
   • Control of behavioral patterns
   • Maintain heart rate

   Answer: Maintain heart rate

10. Q10. Degradation of glucose under aerobic conditions yields ---

    • Lactate
    • Pyruvate
    • Oxaloacetate
    • Amines

    Answer: Pyruvate

11. Q11. Synthesis of glutamine usually occurs in ---

    • Brain
    • Liver
    • Muscles
    • All of the above

    Answer: All of the above

12. Q12. The body's central metabolic clearinghouse is known to be the ---

    • Serine
    • Liver
    • Skeletal muscles
    • Adipose tissues

    Answer: Liver

13. Q13. Ammonia is temporarily stored in the form of ---

    • Serine
    • Glutamate
    • Glutamine
    • Valine

    Answer: Glutamine

14. Q14. In white adipose tissue, which process is NOT stimulated by insulin? ---

    • Rate of glucose uptake
    • Lipogenesis
    • Glycolysis
    • Lipolysis

    Answer: Lipolysis

15. Q15. Hydroxycitrate is an inhibitor of ATP-citrate lyase. What would be the most likely effect of adding hydroxycitrate to cells undergoing lipogenesis? ---

    • The amount of acetyl-CoA in the cytoplasm would decrease
    • Production of ATP would go up
    • Mitochondrial acetyl-CoA levels would rapidly deplete
    • The rate of fatty acid production would increase
    • Cytoplasmic acetyl-CoA levels would increase

    Answer: The amount of acetyl-CoA in the cytoplasm would decrease

16. Q16. Which statement best describes the relationship between the pentose phosphate pathway (PPP) and lipogenesis? ---

    • The PPP produces glycerol for esterification of newly formed fatty acids
    • Lipogenesis provides glycerol phosphate for the PPP
    • Lipogenesis uses NADPH produced by the PPP
    • The PPP provides ATP to fuel lipogenesis
    • The PPP provides carbon dioxide to produce malonyl-CoA

    Answer: Lipogenesis uses NADPH produced by the PPP

17. Q17. Which statement best describes chylomicrons? ---

    • Lipoproteins that carry dietary fat to the peripheral tissues
    • Discs of phospholipid that mop up loose cholesterol in the blood
    • Milky droplets formed from lipid/salt mixtures in the small intestine
    • Microscopic droplets excreted by tissues with too much cholesterol
    • An emulsion of fat and protein in the stomach

    Answer: Lipoproteins that carry dietary fat to the peripheral tissues

18. Q18. Which statement best describes the role of high-density lipoprotein (HDL)? ---

    • HDL is formed by removal of fat from LDL
    • HDL is assembled in peripheral tissues and secreted into the bloodstream
    • HDL is assembled in peripheral tissues and secreted into the lymphatic system
    • A high HDL:LDL ratio is positively correlated with heart disease
    • HDL is produced by the liver and picks up cholesterol from the periphery

    Answer: HDL is produced by the liver and picks up cholesterol from the periphery

19. Q19. Which of the following is the primary fuel source for low-intensity exercise? ---

    • Plasma free fatty acids
    • Adipose tissue
    • Phosphocreatine
    • Proteins

    Answer: Plasma free fatty acids

20. Q20. An increase in intracellular Na+ concentration in astrocytes can be stimulated by ---

    • Lactate
    • Glutamate
    • Low-density lipoproteins
    • Calcium

    Answer: Glutamate

21. Q21. Which one of the following molecules is not involved in cessation of contractile activity in muscles? ---

    • Acetylcholinesterase
    • Calsequetrin
    • Glutamate uptake
    • All of the above

    Answer: Glutamate uptake

22. Q22. Glutamate uptake can induce metabolic activation and may also be used as an energetic fuel through transformation into ---

    • alpha-ketoglutarate
    • Lactate
    • Pyruvate
    • Acetyl-CoA

    Answer: alpha-ketoglutarate

23. Q23. Which statement BEST describes the fate of the amine group derived from the metabolism of amino acids in muscle? ---

    • Mainly excreted as ammonia
    • Mainly excreted as urea
    • Linked to pyruvate for transport to the liver
    • Stored on pre-existing proteins by converting glutamate to glutamine
    • Stored on nucleotides by converting thymine to cytosine

    Answer: Linked to pyruvate for transport to the liver

24. Q24. Why doesn't muscle glycogen contribute significantly to blood glucose homeostasis during starvation? ---

    • Muscle lacks glucose-6-phosphatase
    • Muscle lacks phosphorylase
    • Muscle stores little glycogen
    • Muscle has non-branched glycogen
    • Glycogen synthase is insensitive to G6P

    Answer: Muscle lacks glucose-6-phosphatase

25. Q25. Consequences of inhibition of lipolysis during early starvation include ---

    • Rise in blood ketone bodies
    • Rise in blood glucose
    • Rise in blood fatty acids
    • Fewer substrates for gluconeogenesis
    • Increased fatty acid oxidation in muscles

    Answer: Fewer substrates for gluconeogenesis

26. Q26. Regulation of muscle pyruvate dehydrogenase (PDH) during starvation ---

    • Fully activated in early starvation, then switched off
    • Becomes more dephosphorylated as starvation progresses
    • PDH kinase is activated in the first 48h and stays active
    • PDH phosphatase becomes more active over time
    • PDH becomes more active over time

    Answer: PDH kinase is activated in the first 48h and stays active

27. Q27. Which of the following does NOT increase glucose output from the liver? ---

    • Phosphorylase induction
    • Insulin
    • Glucagon
    • Increased protein kinase A
    • Epinephrine

    Answer: Insulin

28. Q28. Other than phosphocreatine breakdown, the fastest way to resupply ATP to a muscle is

    • Fat breakdown and conversion to glucose
    • Anaerobic glycolysis
    • Aerobic glycolysis
    • Eating a carbohydrate-rich meal

    Answer: Anaerobic glycolysis