Glycolysis is also known as the EMP pathway. It’s named after the three scientists who devised the glycolysis scheme: Gustav Embden, Otto Meyerhof, and J. Parnas. It’s the glucose catabolism pathway. It can be found in the cytoplasm of all live cells, whether aerobic and anaerobic.
The EMP pathway, often known as glycolysis, is the first stage in cellular respiration. In this mechanism, glucose is partially oxidised to pyruvate. It is followed by the Krebs cycle in aerobic organisms for the complete oxidation of glucose to CO2 and water. Glycolysis is followed by fermentation in anaerobic organisms.
Q1. What is glycolysis?
Synthesis of glycogen
Breakdown of glycogen
Utilisation of glucose
Synthesis of glucose
Ans. Here the correct answer is option ‘c’ i.e. utilization of glucose. In the presence of oxygen, a molecule of glucose is destroyed by a sequence of enzymes to generate two molecules of pyruvate, similar to glycolysis. Some of the free energy released by glucose is stored as ATP and NADH during glycolysis.
Q2. Where does glycolysis take place?
Ribosomes
Nucleus
Mitochondria matrix
Cytosol
Ans. The correct option is ‘d’ cytosol. Glycolysis occurs in all of the body’s cells. The glycolysis enzymes are predominantly found in the cell’s cytoplasm.
Q3. The first enzyme in glycolysis is
Phosphofructokinase
Hexokinase
Pyruvate dehydrogenase
None of the above
Ans. Here, the correct answer is option ‘b’ i.e. hexokinase. Hexokinase is an allosteric enzyme that catalyses glycolysis’ initial stage. Its product has been inhibited (glucose-6-phosphate). The presence of a high concentration of glucose-6-phosphate signals to the cell that it no longer needs glucose for energy or other functions.
Q4. Which of the following enzymes converts pyruvate to lactate?
Enolase
Pyruvate kinase
Pyruvate carboxylase
Pyruvate dehydrogenase
Ans. The correct option is ‘d’ pyruvate dehydrogenase.
Q5. Name the hormone that stimulates the process of glycolysis
Growth hormone
Insulin
Glucagon
All of the above
Ans. Here, the correct answer is option ‘b’ insulin. High concentration of insulin helps in activating the process of glycolysis.
Q6. Which of the following hormones inhibits glycolysis?
Growth hormone
Insulin
Glucagon
All of the above
Ans. Here, the correct answer is option ‘c’ glucagon. A higher concentration of glucagon inhibits the process of glycolysis.
Q7. Glycolysis can also be referred to as
Embden Meyerhof pathway
Respiratory cycle
Kreb’s cycle
HMP-shunt
Ans. In this question the correct option is ‘a’ Embden Meyerhof Pathway.
Q8. Which of the following processes shares the same pathway as glycolysis but in the opposite direction?
HMP-shunt
Glycogenesis
Glycogenolysis
Gluconeogenesis
Ans. The correct option is ‘d’ gluconeogenesis. As reversal of the glycolysis process with some other arrangements may lead to the synthesis of glucose, this process is known as gluconeogenesis.
Q9. Which statement is not true?
Glycolysis generates CO2
Glycolysis generates ATP
It also helps in fructose metabolism
It occurs in cytosol of the cell
Ans. In this question the correct option is ‘a’ glycolysis generates CO2. Glycolysis occurs both in presence and in absence of oxygen. The end product of aerobic glycolysis is mainly pyruvate which is further oxidized to form CO2 and H2O. Whereas, the end product of anaerobic glycolysis is lactate.
Q10. Name the general term used for the anaerobic breakdown of glucose in order to produce energy.
a) Metabolism
b) Fermentation
c) Oxidation
d) Anabolism
Ans. Here, the correct answer is option ‘b’ fermentation. Fermentation represents the general term used for the breakdown of glucose to obtain energy in the form of ATP.
Q11. When the cell’s ATP supply gets depleted, then which among the following enzyme’s activity is increased?
a) Glucokinase
b) Phosphofructokinase-1
c) Hexokinase
d) Pyruvate kinase
Ans. Here, the correct answer is option ‘b’ phosphofructokinase-1. Phosphofructokinase-1 refers to a regulatory enzyme; it is the major point of regulation in glycolysis. Its activity increases whenever the cell’s ATP supply gets depleted.
Q12. Cleavage of Fructose 1, 6-bisphosphate produces which of the following?
a) An aldose and a ketose
b) Two ketoses
c) Only a ketose
d) Two aldoses
Ans. Here, the correct answer is option ‘c’ only a ketose. Fructose 1, 6-bisphosphate is cleaved in order to produce glyceraldehyde 3-phosphate, which is an aldehyde and dihydroxyacetone phosphate, a ketose.
Q13. Dihydroxyacetone phosphate is quickly and reversibly id converted to which among the following?
a) 1, 3-bis-phosphoglycerate
b) Glyceraldehyde 3-phosphate
c) Fructose 6-phosphate
d) Fructose 1, 6-bisphosphate
Ans. Here, the correct answer is option ‘b’ glyceraldehyde 3-phosphate. Dihydroxyacetone phosphate is rapidly and reversibly converted to glyceraldehyde 3-phosphate via triose phosphate isomerase.
Q14. Which among the following represents the first step in the payoff phase of glycolysis?
a) Reduction of 1, 3-bisphosphoglycerate to glyceraldehyde 3-phosphate
b) Irreversible conversion of dihydroxyacetone phosphate to glyceraldehyde 3-phosphate
c) Reversible conversion of dihydroxyacetone phosphate to glyceraldehyde 3-phosphate
d) Oxidation of glyceraldehyde 3-phosphate to 1, 3-bisphosphoglycerate
Ans. The correct option is ‘d’ oxidation of glyceraldehyde 3-phosphate to 1, 3-bisphosphoglycerate. Glyceraldehyde 3-phosphate dehydrogenase catalyses the first step in the payoff phase, oxidation of glyceraldehyde 3-phosphate to form 1, 3-bisphosphoglycerate.
Q15. Which of the following substrates can be used in the last step of glycolysis?
a) Glyceraldehyde 3-phosphate
b) Phosphoenolpyruvate
c) 1, 3-bisphosphoglycerate
d) Pyruvate
Ans. Here, the correct answer is option ‘b’ phosphoenolpyruvate. The last step in glycolysis is accompanied by the transfer of a phosphoryl group from phosphoenolpyruvate to ADP which is catalyzed by pyruvate kinase.
Q16. High concentration of glucose 6-phosphate is usually inhibitory to which of the following enzymes?
a) Glucokinase
b) Pyruvate kinase
c) Hexokinase
d) Phosphofructokinase-1
Ans. Here, the correct answer is option ‘c’ hexokinase. Hexokinase catalyses the reaction which involves the conversion of glucose to glucose 6-phosphate.
Q17. During catabolism, only about 40% of the energy is available from oxidizing glucose is used to synthesize ATP. What happens to the remaining 60%.
is stored as fat.
remains in the products of metabolism
is used to reduce NADP
is lost as heat
Ans. In this question, the correct answer is option ‘d’ is lost as heat.
Q18. Name the enzyme which is inhibited by iodoacetate and arsenate.
Glyceraldehyde-3-phosphate dehydrogenase
Glucokinase
Hexokinase
Both A and B
Ans. The correct option is ‘a’ glyceraldehyde-3-phosphate dehydrogenase.
Q19. Choose the correct enzyme that catalyses the reversible reaction of glycolysis
Pyruvate kinase
Phosphofructokinase
Glucokinase
None of the above
Ans. In this question the correct answer is option ‘d’ none of the above.
Q20. Hexokinase enzyme is dependent on which of the following
Sodium dependent
Magnesium
Iron
Zinc
Ans. Here, the correct answer is option ‘d’ zinc.
Q21. When yeasts carry out alcoholic fermentation of glucose, the coenzyme – thiamine pyrophosphate is needed by
Pyruvate decarboxylase
Transaldolase
Hexokinase
Lactate dehydrogenase
Ans. In this question, the correct option is ‘a’ pyruvate decarboxylase.