Question

Question 6 (0.5 point) How many stages are used in describing the pathways of catabolism?

• 1

• 2

• 3

• 4

Question 7 (0.5 point) Most of the energy generated during the breakdown of biomolecules [from your food] is produced during Stage .

• 1

• 2

• 3

• 4

Question 8 (0.5 point) What are the names of the two parts of Stage 4?

• Citric Acid Cycle and Electron Transport

• Electron Transport and Oxidative Phosphorylation

• Oxidative Phosphorylation and Glycolysis

• Glycolysis and the Krebs Cycle

Question 9 (0.5 point) Oxygen is required during Stage 4.

• True

• False

Question 10 (0.5 point) The energy generated during metabolism is released in ______ portions as the result of _______ reactions.

• small; many

• small; a few

• large; many

• large; a few

Answer 1

Q 6. 4 stages

The pathways of catabolism are described in 4 stages as

Stage 1: Digestion, Stage 2: Formation of Ac CoA, Stage 3: Citric acid cycle, Stage 4: Electron transport chain. Sometimes, Citric acid cycle and ETC are together grouped as Stage 3.

Q 7. Stage 3.

Most energy is released during stage 3 of catabolic reactions, i.e., the citric acid cycle. 2 ATP and 2 NADH are produced during stage 2 (Glycolysis) and 8 NADH, 2 FADH2 and 2 ATP are formed during citric acid cycle.

Q 8. Electron Transport and Oxidative Phosphorylation

Chemical potential energy stored in NADH and FADH2 is used to make ATP in stage 4. The electrons from NADH or FADH2 are transferred, through a series of electron transfer proteins, to dissolved oxygen (O2) in order to create a proton motive force. This force drives the synthesis of ATP from ADP by oxidative phosphorylation.

Q 9. True

Oxygen acts as the terminal electron acceptor in Electron transport chain.

Q 10. The energy generated during metabolism is released in small portions as the result of many reactions.

So much of energy is released during cellular respiration but, in small portions as temporary storage units. This is to avoid cellular damage which may be caused due to the release of high amount of energy at once.