Biochemistry MCQ

Question 1

How many reactions are involved in glycolysis?

Accepted Answer

10

Answer

5

Answer

7

Answer

12

Question 2

Which reaction generates water as a byproduct during glycolysis?

Accepted Answer

Conversion of phosphoenolpyruvate to pyruvate

Answer

Conversion of glucose to glucose-6-phosphate

Answer

Conversion of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate

Answer

None generate water directly

Question 3

What type of phosphorylation occurs during glycolysis?

Accepted Answer

Substrate-level phosphorylation

Answer

Oxidative phosphorylation

Answer

Photophosphorylation

Answer

Chemiosmotic phosphorylation

Question 4

In which cellular component does substrate-level phosphorylation occur during glycolysis?

Accepted Answer

Cytoplasm

Answer

Mitochondria

Answer

Nucleus

Answer

Endoplasmic reticulum

Question 5

Which of the following statements about glycolytic intermediates is true?

Accepted Answer

Most are phosphorylated metabolites.

Answer

They can easily diffuse out of the cell.

Answer

They do not participate in other metabolic pathways.

Answer

They are all five-carbon sugars.

Question 6

What regulates the flux through the irreversible steps in glycolysis?

Accepted Answer

All of these factors

Answer

Concentration of substrates

Answer

Activity levels of specific enzymes

Answer

Availability of oxygen

Question 7

What happens to NAD+ during glycolysis?

Accepted Answer

It is reduced to NADH.

Answer

It is consumed.

Answer

It is oxidized.

Answer

It is converted to FADH2.

Question 8

What does the term "ATP payoff phase" refer to in glycolysis?

Accepted Answer

The phase where ATP is generated

Answer

The phase where ATP is consumed

Answer

The phase where glucose is broken down

Answer

The phase where NADH is produced

Question 9

Which reaction in glycolysis has a large negative ΔG and is essentially irreversible?

Accepted Answer

Reaction 10 (Pyruvate kinase)

Answer

Reaction 1 (Hexokinase)

Answer

Reaction 5 (Triose phosphate isomerase)

Answer

Reaction 7 (Phosphoglycerate kinase)

Question 10

Which of the following sugars can enter glycolysis?

Accepted Answer

All of the above

Answer

Sucrose

Answer

Fructose

Answer

Galactose

Question 11

What does fructose-6-phosphate convert into during glycolysis?

Accepted Answer

Fructose-1,6-bisphosphate

Answer

Glucose-6-phosphate

Answer

Glyceraldehyde-3-phosphate

Answer

Pyruvate

Question 12

What is the overall reaction of glycolysis?

Accepted Answer

Glucose + 2 NAD+ + 2 ADP + 2 Pi → 2 Pyruvate + 2 NADH + 2 H+ + 2 ATP + 2 H2O

Answer

Glucose + O2 → CO2 + H2O + ATP

Answer

Pyruvate + NADH → Lactate + NAD+

Answer

Glucose + ATP → Glucose-6-phosphate + ADP

Question 13

Which enzyme catalyzes the conversion of phosphoenolpyruvate to pyruvate?

Accepted Answer

Pyruvate kinase

Answer

Phosphofructokinase

Answer

Aldolase

Answer

Enolase

Question 14

What happens to pyruvate when oxygen is present?

Accepted Answer

It enters the TCA cycle.

Answer

It is converted to lactate.

Answer

It is converted to ethanol.

Answer

It remains in the cytoplasm.

Question 15

What role does glyceraldehyde-3-phosphate play in glycolysis?

Accepted Answer

It acts as a substrate for further reactions.

Answer

It is a product that exits the pathway.

Answer

It serves as an energy carrier.

Answer

It inhibits hexokinase activity.

Question 16

Which of the following enzymes catalyzes a key regulatory step in glycolysis?

Accepted Answer

All of the above

Answer

Hexokinase

Answer

Phosphofructokinase-1

Answer

Pyruvate kinase

Question 17

Which compound can enter anabolic pathways from glycolytic intermediates?

Accepted Answer

Both glucose and pyruvate

Answer

Glucose only

Answer

Pyruvate only

Answer

None of these

Question 18

Which glycolytic intermediate can be converted into glycerol for lipid synthesis?

Accepted Answer

Dihydroxyacetone phosphate

Answer

Fructose-6-phosphate

Answer

Glyceraldehyde-3-phosphate

Answer

Pyruvate

Question 19

The conversion of which molecule leads to the production of lactate in anaerobic conditions?

Accepted Answer

Pyruvate

Answer

Glyceraldehyde-3-phosphate

Answer

Fructose-1,6-bisphosphate

Answer

Acetyl-CoA

Question 20

What is the role of NAD+ in glycolysis?

Accepted Answer

It gets reduced to NADH.

Answer

It acts as an electron donor.

Answer

It generates ATP directly.

Answer

It phosphorylates glucose.

Question 21

What is the primary function of glycolysis?

Accepted Answer

To produce ATP

Answer

To generate oxygen

Answer

To synthesize proteins

Answer

To break down fatty acids

Question 22

What happens to glucose when it enters glycolysis?

Accepted Answer

It gets phosphorylated.

Answer

It remains unchanged.

Answer

It gets oxidized directly.

Answer

It forms fatty acids.

Question 23

What type of reaction occurs during substrate-level phosphorylation in glycolysis?

Accepted Answer

Phosphorylation reaction

Answer

Oxidation-reduction reaction

Answer

Hydrolysis reaction

Answer

Condensation reaction

Question 24

Where does glycolysis occur in the cell?

Accepted Answer

Cytoplasm

Answer

Mitochondria

Answer

Nucleus

Answer

Endoplasmic reticulum

Question 25

Which metabolic pathway does pyruvate enter when oxygen is present?

Accepted Answer

TCA cycle

Answer

Glycolysis

Answer

Fermentation

Answer

Lipid synthesis

Question 26

Which compound serves as an allosteric regulator derived from glycolytic intermediates?

Accepted Answer

2,3-Bisphosphoglycerate

Answer

Lactate

Answer

Acetyl-CoA

Answer

Fructose-1,6-bisphosphate

Question 27

What is the net gain of ATP molecules from one molecule of glucose during glycolysis?

Accepted Answer

2 ATP

Answer

1 ATP

Answer

4 ATP

Answer

6 ATP

Question 28

Which enzyme regulates one of the key irreversible steps in glycolysis by converting fructose-6-phosphate into fructose-1,6-bisphosphate?

Accepted Answer

Phosphofructokinase-1

Answer

Hexokinase

Answer

Pyruvate kinase

Answer

Aldolase

Question 29

What drives the directionality of reactions in glycolysis?

Accepted Answer

All of these factors

Answer

Temperature and pressure

Answer

Concentration of reactants and products

Answer

Enzyme concentration

Question 30

Which enzyme catalyzes the first step of glycolysis?

Accepted Answer

Hexokinase

Answer

Phosphofructokinase

Answer

Pyruvate kinase

Answer

Aldolase

Question 31

Which compound serves as an allosteric regulator derived from a glycolytic intermediate?

Accepted Answer

2,3-Bisphosphoglycerate

Answer

Lactate

Answer

Acetyl-CoA

Answer

Fructose-2,6-bisphosphate

Question 32

What is produced from pyruvate under anaerobic conditions?

Accepted Answer

Lactate

Answer

Acetyl-CoA

Answer

Ethanol

Answer

NADH

Question 33

How many molecules of NADH are produced per molecule of glucose during glycolysis?

Accepted Answer

2

Answer

1

Answer

4

Question 34

Which of the following is an intermediate of glycolysis?

Accepted Answer

Fructose-1,6-bisphosphate

Answer

Acetyl-CoA

Answer

Citrate

Answer

Oxaloacetate

Question 35

What does the term "ATP investment phase" refer to in glycolysis?

Accepted Answer

The initial steps where ATP is consumed.

Answer

The phase where no ATP is consumed.

Answer

The phase where ATP is generated.

Answer

The final steps where energy is released.

Question 36

Which terms describe two atoms when they form a bond in which electrons are completely transferred?

Accepted Answer

Anion and cation

Answer

Proton and electron

Answer

Ionic and covalent

Answer

Polar and nonpolar

Question 37

Which step of the cellular respiration pathway can take place in the absence of oxygen?

Accepted Answer

Glycolysis

Answer

Krebs cycle

Answer

Fermentation

Answer

Electron transport chain

Question 38

Which of the following statements is true of the bonds in a water molecule?

Accepted Answer

Oxygen holds electrons more tightly, net charge is zero

Answer

Oxygen acts as the electron acceptor and is oxidized.

Answer

Electron in each hydrogen transferred, net +1 charge

Answer

Equal sharing of electrons, net charge zero

Question 39

Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?

Accepted Answer

Carbon dioxide

Answer

Water

Answer

ATP

Answer

NADH

Question 40

Which of the following statements is not true of most cellular redox reactions?

Accepted Answer

A hydrogen atom is transferred to the atom that loses an electron.

Answer

Changes in potential energy can be released as heat.

Answer

The reactant that is oxidized loses electrons.

Answer

The electron acceptor is reduced

Question 41

Which of the following statements about the electron transport chain is true?

Accepted Answer

NADH and FADH₂ donate electrons

Answer

First step in cellular respiration

Answer

Water is the last electron acceptor

Answer

Electrons gain energy as they move down the chain

Question 42

What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?

Accepted Answer

Ionic

Answer

Nonpolar covalent

Answer

Redox

Answer

Polar covalent

Question 43

Which stage of glucose metabolism produces the most ATP?

Accepted Answer

Electron transport and chemiosmosis

Answer

Krebs cycle

Answer

Glycolysis

Answer

Fermentation of pyruvate to lactate

Question 44

Gaseous hydrogen burns in the presence of oxygen to form water: 2H₂ + O₂ → 2H₂O + energy

Accepted Answer

Hydrogen, polar

Answer

Oxygen, polar

Answer

Oxygen, nonpolar

Answer

Hydrogen, nonpolar

Question 45

True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria.

Accepted Answer

TRUE

Answer

FALSE

Question 46

Which of the following best describes the main purpose of the combined processes of glycolysis and cellular respiration?

Accepted Answer

The breakdown of glucose to carbon dioxide and water

Answer

Molecules in chemical bonds that cells can use for work

Answer

Producing complex molecules from chemical building blocks

Answer

Breaking down ATP, so that ADP and P can be reused

Question 47

What is the oxidizing agent in the reaction: Pyruvate + NADH + H⁺ → Lactate + NAD⁺

Accepted Answer

Pyruvate

Answer

Oxygen

Answer

NADH

Answer

Lactate

Question 48

Which of the following describes the process of glycolysis?

Accepted Answer

First stage of glucose oxidation

Answer

Converts glucose to pyruvate and CO₂

Answer

Occurs in mitochondria

Answer

Produces 30 ATP, NADH

Question 49

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

Accepted Answer

pH of the matrix increases

Answer

NAD⁺ is oxidized

Answer

ATP synthase pumps protons

Answer

Cytochromes phosphorylate ADP

Question 50

How many NADH are produced by glycolysis?

Accepted Answer

2

Answer

3

Answer

4

Answer

5

Question 51

Most CO₂ from catabolism is released during

Accepted Answer

Citric acid cycle

Answer

Oxidative phosphorylation

Answer

Glycolysis

Answer

Electron transport

Question 52

In glycolysis, ATP molecules are produced by

Accepted Answer

Substrate-level phosphorylation

Answer

Photosynthesis

Answer

Cellular respiration

Answer

Photophosphorylation

Question 53

In muscle cells, fermentation produces _____

Accepted Answer

Lactate and NAD⁺

Answer

CO₂, ethanol, NADH, ATP

Answer

Pyruvate

Answer

CO₂, ethanol, and NAD⁺

Question 54

Which of these is NOT a product of glycolysis?

Accepted Answer

FADH₂

Answer

NADH

Answer

Pyruvate

Answer

ATP

Question 55

In fermentation _____ is reduced and _____ is oxidized.

Accepted Answer

Pyruvate ... NADH

Answer

Lactate ... NADH

Answer

NADH ... Lactate

Answer

NAD⁺ ... Pyruvate

Question 56

In glycolysis, what starts the process of glucose oxidation?

Answer

ADP

Answer

FADH₂

Answer

Hexokinase

Answer

NADPH

Question 57

In glycolysis, there is a net gain of _____ ATP.

Accepted Answer

2

Answer

3

Answer

5

Answer

4

Question 58

Which statement about the citric acid cycle is correct?

Answer

Depends on NAD+, a product of glycolysis

Answer

Requires molecular oxygen

Answer

Produces most ATP

Answer

Final product is substrate for first reaction

Question 59

Which molecule is metabolized in a cell to produce energy for performing work?

Accepted Answer

ATP

Answer

ADP

Answer

Phosphate

Answer

Glucose

Question 60

True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.

Accepted Answer

TRUE

Answer

FALSE

Question 61

Which term describes the degree to which an element attracts electrons?

Accepted Answer

Electronegativity

Answer

Redation

Answer

Polarity

Answer

Oxidation.

Question 62

Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?

Accepted Answer

Fermentation

Answer

Electron transport chain

Answer

Glycolysis

Answer

Krebs cycle

Question 63

What is the function of thermogenin?

Accepted Answer

To uncouple oxidation from phosphorylation in the mitochondria

Answer

To generate ATP in the mitochondria

Answer

To transport NADH from the cytoplasm to the mitochondria

Answer

To synthesize glucose in the liver

Question 64

Which of the following is an inhibitor of Complex I in the ETC?

Accepted Answer

Rotenone

Answer

Malonate

Answer

Antimycin

Answer

Cyanide

Biochemistry MCQ

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