Respiration in Plants
Test 3

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which structure in plant cells facilitates gas exchange for respiration?

Lysosomes
Stomata and lenticels
Chloroplasts
Ribosomes
2

Stomata in leaves and lenticels in stems facilitate gaseous exchange for respiration in plants.

Which molecule is regenerated at the end of the Krebs cycle to continue the cycle?

Citric acid
Acetyl-CoA
Oxaloacetic acid
Succinic acid
3

Oxaloacetic acid is regenerated at the end of the Krebs cycle, allowing the cycle to continue.

Which of the following is the primary site for glycolysis in a cell?

Mitochondria
Chloroplast
Cytoplasm
Nucleus
3

Glycolysis occurs in the cytoplasm where glucose is broken down into pyruvate.

Which step of respiration produces the highest number of reduced coenzymes (NADH and FADH₂)?

Glycolysis
Krebs cycle
Electron Transport Chain
Fermentation
2

The Krebs cycle produces the highest number of reduced coenzymes, generating 6 NADH and 2 FADH₂ per glucose molecule.

Which of the following statements about glycolysis is CORRECT?

It occurs in the mitochondrial matrix.
It directly produces 38 ATP molecules per glucose.
It is a common pathway for both aerobic and anaerobic respiration.
Oxygen is required for glycolysis to proceed.
3

Glycolysis occurs in both aerobic and anaerobic respiration, making it a universal metabolic pathway.

Which of the following statements about fermentation is CORRECT?

It requires oxygen.
It takes place in the mitochondria.
It produces ethanol or lactic acid as byproducts.
It generates more ATP than aerobic respiration.
3

Fermentation produces ethanol or lactic acid as byproducts under anaerobic conditions.

Which of the following represents the correct order of events in aerobic respiration?

Glycolysis → Krebs cycle → Electron Transport System
Krebs cycle → Glycolysis → Electron Transport System
Electron Transport System → Glycolysis → Krebs cycle
Glycolysis → Electron Transport System → Krebs cycle
1

Aerobic respiration follows this sequence: Glycolysis occurs first, followed by the Krebs cycle, and then the Electron Transport System.

Which of the following is an alternative respiratory substrate that can be used when glucose is unavailable?

Proteins
Lipids
Organic acids
All of the above
4

In certain conditions, proteins, lipids, and organic acids can serve as alternative respiratory substrates.

How many molecules of NADH are produced per glucose molecule in the Krebs cycle?

2
4
6
8
3

Each turn of the Krebs cycle produces 3 NADH molecules, and since one glucose generates two Acetyl-CoA molecules, a total of 6 NADH molecules are produced.

Which of the following is the correct sequence of events in aerobic respiration?

Glycolysis → Krebs cycle → Electron Transport Chain
Krebs cycle → Glycolysis → Electron Transport Chain
Electron Transport Chain → Krebs cycle → Glycolysis
Glycolysis → Electron Transport Chain → Krebs cycle
1

The correct sequence is Glycolysis (cytoplasm) → Krebs cycle (mitochondrial matrix) → Electron Transport Chain (inner mitochondrial membrane).

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