Cell Energetics: Master Cellular Respiration and ATP Production

Question 1

Which characteristic is unique to oxidative phosphorylation?

Accepted Answer

It uses oxygen as the final electron acceptor.

Answer

It occurs in the mitochondrial matrix.

Answer

It produces ATP molecules directly.

Answer

It is not essential for cellular respiration.

Question 2

What is the name of the high-energy molecule that is produced directly during glycolysis?

Accepted Answer

ATP

Answer

Pyruvate

Answer

Acetyl-CoA

Answer

NADH

Question 3

What is the primary role of NADH and FADH2 in cellular respiration?

Accepted Answer

Electron carriers

Answer

Electron acceptors

Answer

Energy carriers

Answer

Oxygen carriers

Question 4

In the electron transport chain, which molecule receives the final electrons?

Accepted Answer

Oxygen

Answer

Hydrogen

Answer

Carbon dioxide

Answer

Water

Question 5

In which location does the Krebs cycle take place?

Accepted Answer

Mitochondrial matrix

Answer

Cytoplasm

Answer

Intermembrane space

Answer

Outer mitochondrial membrane

Question 6

The chemiosmotic hypothesis proposes that ATP is generated by:

Accepted Answer

The flow of protons down a concentration gradient

Answer

The breakdown of glucose

Answer

The transfer of electrons along the electron transport chain

Answer

The oxidation of NADH

Question 7

Write the overall equation for cellular respiration:

Accepted Answer

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy

Answer

C6H12O6 → 2C3H6O3 + Energy

Answer

6CO2 + 6H2O + Energy → C6H12O6 + 6O2

Answer

C6H12O6 + 6H2O → 6CO2 + 12H2 + Energy

Question 8

Which enzyme is a key regulatory factor in glycolysis?

Accepted Answer

Phosphofructokinase

Answer

Hexokinase

Answer

Pyruvate kinase

Answer

Lactate dehydrogenase

Question 9

Where is the electron transport chain located?

Accepted Answer

Inner mitochondrial membrane

Answer

Mitochondrial matrix

Answer

Cytoplasm

Answer

Outer mitochondrial membrane

Question 10

Which process occurs in both prokaryotic and eukaryotic cells during cellular respiration?

Accepted Answer

Glycolysis

Answer

Krebs cycle

Answer

Oxidative phosphorylation

Answer

Electron transport chain

Question 11

What is the primary product of glycolysis?

Accepted Answer

Pyruvate

Answer

Acetyl-CoA

Answer

ATP

Answer

NADH

Question 12

Which coenzyme is reduced during glycolysis?

Accepted Answer

NAD+

Answer

FAD+

Answer

Coenzyme A

Answer

Ubiquinone

Question 13

Where does the Krebs cycle occur within the cell?

Accepted Answer

Mitochondrial matrix

Answer

Mitochondrial intermembrane space

Answer

Cytoplasm

Answer

Nucleus

Question 14

Where does ATP synthesis occur during oxidative phosphorylation?

Accepted Answer

ATP synthase

Answer

Cytochrome oxidase

Answer

Complex I

Answer

Krebs cycle

Question 15

What is the primary significance of cellular respiration in living organisms?

Accepted Answer

Providing energy for cellular activities

Answer

Regulating body temperature

Answer

Transporting molecules across cell membranes

Answer

Storing genetic information

Question 16

Which of the following is NOT a substrate for glycolysis?

Accepted Answer

Oxaloacetate

Answer

Glucose

Answer

Fructose

Answer

Pyruvate

Question 17

What is the function of the chemiosmotic gradient in oxidative phosphorylation?

Accepted Answer

To drive the synthesis of ATP

Answer

To transport electrons

Answer

To regulate the pH of the mitochondrial matrix

Answer

To create a concentration gradient of protons

Question 18

Which of the following metabolic pathways produces the most ATP molecules?

Accepted Answer

Oxidative phosphorylation

Answer

Glycolysis

Answer

Krebs cycle

Answer

All of the above produce equal amounts

Question 19

In the electron transport chain, which substance ultimately receives the electrons?

Accepted Answer

Oxygen

Answer

NADH

Answer

FADH2

Question 20

Which molecule acts as the terminal electron acceptor in the electron transport chain?

Accepted Answer

Oxygen

Answer

NADH

Answer

FADH2

Answer

Cytochrome c

Question 21

Name the enzymatic reaction that converts pyruvate to Acetyl CoA.

Accepted Answer

Pyruvate dehydrogenase reaction

Answer

Glycolysis

Answer

Citric acid cycle

Answer

Electron transport chain

Question 22

Identify the enzyme responsible for catalyzing the conversion of glucose-6-phosphate to fructose-6-phosphate in glycolysis.

Accepted Answer

Glucose-6-phosphate isomerase

Answer

Hexokinase

Answer

Phosphofructokinase

Answer

Aldolase

Question 23

Which factor from the following list does NOT influence the rate of cellular respiration?

Accepted Answer

Light intensity

Answer

Substrate concentration

Answer

Temperature

Answer

pH

Question 24

Describe the primary purpose of fermentation when oxygen is unavailable.

Accepted Answer

NAD+ regeneration

Answer

ATP production

Answer

Ethanol generation

Answer

Carbon dioxide release

Question 25

What is the initial stage of cellular respiration?

Accepted Answer

Glycolysis

Answer

Pyruvate oxidation

Answer

Krebs cycle

Answer

Oxidative phosphorylation

Question 26

Which cellular compartment is responsible for oxidative phosphorylation?

Accepted Answer

Mitochondria

Answer

Glycolysis

Answer

Krebs cycle

Answer

Cytoplasm

Question 27

Which molecule is regarded as a high-energy molecule?

Accepted Answer

ATP

Answer

Starch

Answer

ADP

Answer

NADH

Question 28

What is the primary function of NAD+ and FAD in cellular respiration?

Accepted Answer

Electron and proton acceptors

Answer

Electron and proton donors

Answer

Enzymes in the Krebs cycle

Answer

Inhibitors of glycolysis

Question 29

How does the structure of the mitochondrial inner membrane contribute to the formation of a proton gradient during oxidative phosphorylation?

Accepted Answer

The inner mitochondrial membrane is selectively permeable to protons, creating a concentration gradient.

Answer

The electron transport chain directly pumps protons from the matrix into the intermembrane space.

Answer

The inner membrane contains channels that allow protons to move freely across it.

Answer

The proton gradient is generated independently of the electron transport chain.

Question 30

Which stage of cellular respiration is primarily responsible for ATP synthesis?

Accepted Answer

Oxidative phosphorylation

Answer

Glycolysis

Answer

Krebs cycle

Answer

Electron transport chain

Question 31

Identify the key enzyme involved in the Krebs cycle:

Accepted Answer

Citrate synthase

Answer

Pyruvate dehydrogenase

Answer

Phosphofructokinase

Answer

Glyceraldehyde-3-phosphate dehydrogenase

Question 32

During oxidative phosphorylation, which molecule serves as the electron acceptor?

Accepted Answer

Oxygen

Answer

NADH

Answer

FADH2

Answer

Carbon dioxide

Question 33

Which of the following processes does NOT release CO2 as a byproduct?

Accepted Answer

Oxidative phosphorylation

Answer

Glycolysis

Answer

Krebs cycle

Answer

Electron transport chain

Question 34

What is the purpose of the proton gradient created during oxidative phosphorylation?

Accepted Answer

To power ATP synthase

Answer

To produce heat

Answer

To regulate cellular respiration

Answer

To transport electrons

Question 35

Explain the significance of the chemiosmotic theory in cellular respiration:

Accepted Answer

It elucidates ATP synthesis in oxidative phosphorylation

Answer

It highlights the electron transport chain's function

Answer

It predicts ATP yield per glucose molecule

Answer

It connects glycolysis to the Krebs cycle

Question 36

Which of the following is NOT a product of glycolysis?

Accepted Answer

Citrate

Answer

Pyruvate

Answer

ATP

Answer

NADH

Question 37

What is the primary function of ATP in cells?

Accepted Answer

Energy currency

Answer

Genetic material

Answer

Structural component

Answer

Hormonal signal

Question 38

Which of the following processes is NOT involved in the generation of ATP during cellular respiration?

Accepted Answer

Photophosphorylation

Answer

Substrate-level phosphorylation

Answer

Oxidative phosphorylation

Answer

Glycolysis

Question 39

What is the role of cytochrome c oxidase in the electron transport chain?

Accepted Answer

To transfer electrons from cytochrome c to oxygen

Answer

To transfer electrons from NADH to cytochrome c

Answer

To pump protons across the inner mitochondrial membrane

Answer

To generate ATP

Question 40

In which organelle of eukaryotic cells does the electron transport chain take place?

Accepted Answer

Mitochondrial inner membrane

Answer

Golgi apparatus

Answer

Cytoplasm

Answer

Nucleus

Question 41

What is the primary role of NADH in cellular respiration?

Accepted Answer

To donate electrons to the electron transport chain

Answer

To transport carbon dioxide out of the cell

Answer

To provide energy for glycolysis

Question 42

During oxidative phosphorylation, the energy released from the electron transport chain is used to:

Accepted Answer

Pump protons across the mitochondrial membrane

Answer

Transport pyruvate into the mitochondria

Answer

Synthesize ATP directly

Answer

Break down glucose

Question 43

A mutation that prevents the production of ATP synthase would most directly affect a cell's ability to:

Accepted Answer

Generate ATP through oxidative phosphorylation

Answer

Perform glycolysis

Answer

Produce pyruvate

Answer

Break down glucose

Question 44

Which of the following molecules is NOT involved in the Krebs cycle?

Accepted Answer

Glucose

Answer

Acetyl-CoA

Answer

NADH

Answer

FADH2

Question 45

Under anaerobic conditions, pyruvate is primarily converted to:

Accepted Answer

Lactate

Answer

Acetyl-CoA

Answer

Carbon dioxide

Question 46

Which of the following is a key difference between aerobic and anaerobic respiration?

Accepted Answer

Aerobic respiration requires oxygen, while anaerobic respiration does not

Answer

Aerobic respiration produces much more ATP than anaerobic respiration

Answer

Anaerobic respiration occurs in the mitochondria, while aerobic respiration occurs in the cytoplasm

Question 47

A scientist studying the effects of a new drug on cellular respiration discovers that the drug inhibits the activity of the enzyme pyruvate dehydrogenase. This would directly affect:

Accepted Answer

The conversion of pyruvate to acetyl-CoA

Answer

Glycolysis

Answer

The electron transport chain

Answer

The Krebs cycle

Question 48

Muscle fatigue experienced by a marathon runner during a race is most likely caused by:

Accepted Answer

The build-up of lactate from anaerobic respiration

Answer

A depletion of glucose in the muscles

Answer

The inhibition of the electron transport chain

Answer

The accumulation of ATP in the muscles