MCQ Bank

The payoff phase of glycolysis is where energy is generated through substrate-level phosphorylation and NADH production. This phase produces ATP and reducing equivalents from glyceraldehyde-3-phosphate.

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Q10

Dihyd phosphate is only converted to glyceraldehyde 3-phosphate by ------ enzyme.

A) Triose phosphate isomerase
B) Pyruvate kinase
C) Phosphofructokinase-1
D) Aldolase

AI Explanation

Triose phosphate isomerase converts dihydroxyacetone phosphate (DHAP) into glyceraldehyde-3-phosphate (G3P). This reaction allows both three-carbon products of glycolysis to proceed through the payoff phase.

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Q11

If AG is negative

A) Reaction will not occur
B) Reaction will stop
C) Reaction will be spontaneous
D) No product will be formed

AI Explanation

A negative Gibbs free energy change (ΔG < 0) indicates that a reaction is thermodynamically spontaneous. Such a reaction can proceed in the forward direction without requiring additional free energy input.

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Q12

Which one of the following enzymes catalyze the addition of CO2 to double bonds?

A) Peptidase
B) Lyase
C) Phospholipase
D) Hydrolase

AI Explanation

Lyases catalyze the addition or removal of groups to form or break double bonds without hydrolysis or oxidation. Some lyases catalyze the addition of CO2 to double bonds.

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Q13

A process that generates a product by the mass culture of microorganism is called

A) Hydration
B) Alloy formation
C) Fermentation
D) Radiation process

AI Explanation

Fermentation is a process in which microorganisms are cultured under controlled conditions to produce useful products. These products can include alcohols, organic acids, enzymes, and other compounds.

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Q14

Name the enzyme secreted by pancreas?

A) Pepsin
B) Chymotrypsin
C) Alcohol dehydrogenase
D) Trypsin

AI Explanation

Trypsin is a proteolytic enzyme secreted by the pancreas in the inactive form trypsinogen. It becomes active in the small intestine and helps digest proteins.

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Q15

Which of the following enzymes catalyze the transfer of electrons from one substrate to another?

A) Oxidoreductases
B) Hydrolases
C) Lyases
D) Transferases

AI Explanation

Oxidoreductases catalyze oxidation-reduction reactions involving the transfer of electrons or hydrogen between substrates. Examples include dehydrogenases and oxidases.

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Q16

Most biochemical reactions occur near pH

A) 14
B) 10
C) 7
D) 0

AI Explanation

Most biochemical reactions occur around neutral pH, close to pH 7. Many cellular enzymes function optimally within a range near neutrality.

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Q17

RNAs make up of the total RNA in the cell.

A) 5%
B) 20%
C) 80%
D) 50%

AI Explanation

Ribosomal RNA (rRNA) constitutes approximately 80% of the total RNA in a typical cell. It is a major structural and functional component of ribosomes.

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Q18

Enzyme is the liver variant of hexokinase.

A) Phosphofructokinase
B) Fructose-2,6-bisphosphate
C) Fructose-1,6-bisphosphatase
D) Glucokinase

AI Explanation

Glucokinase is the liver-specific variant of hexokinase. It phosphorylates glucose to glucose-6-phosphate and has a higher Km for glucose than most hexokinases.

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Q19

Which of the following enzymes catalyze the hydrolysis of substrate?

A) Oxidoreductases
B) Hydrolases
C) Transferases
D) Lyases

AI Explanation

Hydrolases catalyze the cleavage of chemical bonds through the addition of water. They include enzymes such as proteases, lipases, and phosphatases.

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Q20

Which one of the following enzymes catalyze the removal of H2O from 2-Phosphoglycerate?

A) Hydrolase
B) Lyase
C) Phospholipase
D) Enolase

AI Explanation

Enolase catalyzes the dehydration of 2-phosphoglycerate, removing H2O to form phosphoenolpyruvate (PEP). This is the ninth step of glycolysis.

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Q21

Acceptor arm of tRNA is made up of unpaired sequences of at the 3'end.

A) Adenine-cytosine-adenine
B) Adenine-adenine-cytosine
C) cytosine-cytosine-adenine
D) Adenine-adenine-Adenine

AI Explanation

The acceptor arm of tRNA ends at the 3′ terminus with the conserved sequence CCA. Thus, the unpaired terminal sequence is cytosine-cytosine-adenine, corresponding to option C.

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Q22

The stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as bonding.

A) Hydrogen
B) Ionic
C) Covalent
D) Peptide

AI Explanation

Covalent bonding occurs when atoms share electrons. The bond is stabilized by a balance between attractive and repulsive forces between the atoms.

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Q23

Formulation of the fermentation medium is involved in

A) Product purification
B) Upstream processing
C) Both the upstream and downstream processing
D) Downstream processing

AI Explanation

Formulation of the fermentation medium is part of upstream processing because it occurs before and during cultivation of the microorganism. Upstream processing includes media preparation, sterilization, inoculation, and fermentation.

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Q24

In glycolysis, of the two molecules of glyceraldehyde 3-phosphate derived from each molecule of glucose converts two molecules of NAD+ to two of NADH.

A) Hydrogenation
B) Carboxylation
C) Decarboxylation
D) Dehydrogenation

AI Explanation

During glycolysis, glyceraldehyde-3-phosphate is oxidized and NAD+ is reduced to NADH. This reaction is catalyzed by glyceraldehyde-3-phosphate dehydrogenase.

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Q25

Bioenergetics is the study of the energy transductions changes of one form of energy into another.

A) None of given
B) Both Quantitative and Qualitative
C) Qualitative
D) Quantitative

AI Explanation

Bioenergetics examines energy transformations in biological systems from both quantitative and qualitative perspectives. It considers how much energy is involved as well as the nature and direction of energy changes.

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Q26

The rate of gluconeogenesis is determined by the concentration of -

A) Glucose
B) Fumarate
C) Lactate
D) Malate

AI Explanation

The rate of gluconeogenesis is regulated in response to blood glucose concentration and cellular energy status. Low glucose levels stimulate gluconeogenesis to help maintain blood glucose.

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Q27

Thioesters contain a atom in the position occupied by an oxygen

A) Carbon
B) Sulfur
C) Chlorine
D) Calcium

AI Explanation

Thioesters are sulfur-containing analogs of esters. In a thioester, sulfur occupies the position that oxygen occupies in an ordinary ester.

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Q28

The unit of reduction potential is.

A) Candela
B) Kelvin
C) Volt
D) Ampere

AI Explanation

Reduction potential measures the tendency of a chemical species to gain electrons. Its SI-derived unit is the volt (V).