Bio Energetics | Biology | Target Mdcat 2025

Question 1

Reduced cytochromes typically exhibit which color?

Purple

Green

Pink

Blue

Question 2

The most electronegative substance in the respiratory electron transport chain is:

Coenzyme – Q

Cytochrome – c

Cytochrome – a

Oxygen

Question 3

Each pair of H atoms entering the respiratory chain as NADH yields:

3 ATPs

2 ATPs

4 ATPs

1 ATP

Question 4

In oxidative phosphorylation, which complex directly transfers electrons to molecular oxygen (O₂)?

Complex I

Complex II

Complex III

Complex IV

Question 5

The flow of protons through the F₀ channel of ATP synthase is directly coupled to:

The reduction of oxygen.

The oxidation of NADH and FADH₂.

The synthesis of ATP.

The establishment of the proton gradient.

Question 6

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

Initial electron donor

Mobile electron carrier

Final electron acceptor

Proton pump

Question 7

Glycolysis is also called:

Pyruvic pathway

EMP pathway

Anaerobic pathway

G₃ pathway

Question 8

Formation of fructose 1,6-bisphosphate from fructose 6-phosphate involves:

Isomerization

Splitting

Phosphorylation

Dehydrogenation

Question 9

Synthesis of ATP corresponds to which step of glycolysis:

Step #7

Step #11

Step #7 and 10

Step #1 and 3

Question 10

What is the net gain of ATP in glycolysis?

1 ATP

2 ATP

4 ATP

36 ATP

Question 11

What is meant by the 'pay off' phase of Glycolysis?

It produces pyruvate.

It uses up NAD⁺.

It generates a net gain of ATP and NADH.

It completes the process.

Question 12

The regulation of glycolysis is crucial. Which of the following is NOT a key regulatory point?

Phosphofructokinase

Hexokinase

Pyruvate kinase

Glyceraldehyde-3-phosphate dehydrogenase

Question 13

The Krebs cycle's overall purpose is to:

Produce glucose.

Generate pyruvate.

Oxidize acetyl-CoA.

Fix atmospheric carbon.

Question 14

The process of pyruvate oxidation is described as a 'link reaction' because:

It links glycolysis to the electron transport chain.

It links glycolysis to fermentation.

It links glycolysis to the Krebs cycle.

It links the Krebs cycle to the electron transport chain.

Question 15

Which steps involve a decarboxylation reaction (loss of CO₂) in the Krebs cycle?

Steps 3 and 6; these yield ATP.

Steps 3 and 4; these generate NADH.

Steps 2 and 7; these yield FADH₂.

Steps 1 and 8; these regenerate oxaloacetate.

Question 16

In aerobic respiration, the glucose molecule is completely broken down into carbon dioxide (CO₂), water (H₂O), and energy. C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ?

2 ATP

4 ATP

34 ATP

36 ATP

Question 17

Which of the following is the source of electrons for photosystem II?

NADPH

ATP

Chlorophyll a

Water

Question 18

The porphyrin ring in chlorophyll is essential because:

Anchors chlorophyll to the membrane.

Holds magnesium for redox reactions.

Creates a hydrophobic transport environment.

Catalyzes CO₂ to glucose conversion.

Question 19

Accessory pigments like carotenoids mainly:

Convert light to chemical energy.

Protect chlorophyll from oxidation.

Transfer electrons to NADP⁺.

Split water molecules.

Question 20

Non-cyclic photophosphorylation yields ATP and NADPH by:

A proton gradient and NADP⁺ reduction.

Substrate phosphorylation and cytochrome b₆f activity.

Water splitting as a direct product.

Chemiosmosis and PS I electron flow.