3.2 Aerobic Respiration (CQ - exam)

Question 1

Differentiate between cellular respiration and aerobic cellular respiration.

Answer 1

• Cellular respiration is a metabolic pathway that breaks down glucose and produces ATP
• Aerobic cellular respiration is a type of cellular respiration that only occurs in with the presence of oxygen.

Question 2

What is the general or summary equation that describes cellular respiration?

Answer 2

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP

Question 3

What are the 4 stages of energy transfer from glucose to ATP in a general overview of aerobic respiration, and in what parts of the cell do they occur (in eukaryotes)?

Answer 3

1. Glycolysis - cytoplasm
2. pyruvate oxidation/Link reaction - mitochondrial matrix
3. Krebs cycle - mitochondrial matrix
4. oxidative phosphorylation - inner mitochondrial membrane and intermembrane space

Question 4

distinguish between substrate-level phosphorylation and oxidative phosphorylation - how does each generate ATP, how much ATP is made, and where is it done?

Answer 4

• Substrate-level phosphorylation in glycolysis and krebs cycle
• Transfer of phosphate
• 4 ATP is made in glycolysis
• 2 ATP is made in Kreb’s
• Oxidative phosphorylation is in chemiosmosis
• Inorganic phosphate is added from the floating of the cell
• chemiosmosis produces 32 ATP

Question 5

What is glycolysis, and what are its starting materials and products?

Answer 5

Glycolysis is the processing of 1 glucose into 2 ATP, 2 NADH, and 2 pyruvates.

Question 6

Compare and contrast NADH and FADH2 in terms of their production, processing, and yield in aerobic respiration.

Answer 6

• NADH can create 3 ATP molecules, is made by the reduction reaction of NAD+
• FADH2 can create 2 ATP molecules, is made by the reduction reaction of FAD

Question 7

What is the Krebs cycle, and what is its significance in the process of aerobic respiration?

Answer 7

The Krebs cycle is a biochemical process that breaks down nutrients to release energy.

Question 8

What happens to the pyruvate generated in glycolysis before it enters the Krebs cycle?

Answer 8

Pyruvate Oxidation, meaning it does a REDOX reaction to reduce NAD+ into NADH and decarboxylation.

Question 9

Explain why for each molecule of glucose that enters glycolysis there is more than one turn of the Krebs cycle

Answer 9

Glucose in glycolysis produces 2 pyruvates. Krebs cycle can only process 1 pyruvate at a time so it must turn twice to process one glucose overall.

Question 10

identify the stages in the Krebs cycle that involve oxidation reactions and the reduction reactions that are coupled to them.

Answer 10

REDOX reactions occur when
- Isocitrate → alpha ketoglutarate
- Alpha ketoglutarate → succinyl-CoA
- Succinate → Fumarate
- Malate → oxaloacetate

Question 11

State the reactions in the Krebs cycle that generate the following molecules: C02, ATP, NADH, and FADH2.

Answer 11

CO2 - Decarboxylation
ATP - Phosphorylation (substrate-level or oxidative)
NADH/FADH2 - REDOX reaction

Question 12

What is the electron transport chain, and what is its function?

Answer 12

• NADH and FADH2 transfer electrons to a series of proteins in the inner mitochondrial membrane
• This process is highly exergonic, and the free energy is used to move protons (H+) across the membrane and set up a proton gradient across the inner mitochondrial membrane

Question 13

NAD+ and FAD are sometimes described as being like a “shuttle bus.” Is this an accurate analogy? Explain your answer.

Answer 13

Those electrons shuttle the high energy molecules that are going to be used to turn the ATP synthase.
- Shuttle protons and electrons, they are reduced and when dropped the shuttle gets oxidizes
- shuttle between cytoplasm and the intermembrane space
- Constantly going back and forth being recycled as a shuttle

Question 14

Describe the process of chemiosmosis. What is the role of chemiosmosis in cellular respiration?

Answer 14

Chemiosmosis is the phosphorylation of ADP which then transforms it to be ATP. ATP that can be used for cellular respiration later.

Question 15

Why would lack of oxygen completely inhibit the Krebs cycle and the electron transport chain but not glycolysis?

Answer 15

• Glycolysis is done solely in the cytoplasm and does not use oxygen so it is not inhibit
• For pyruvate to get into the mitochondria it requires oxygen for the channel to transport it
• Krebs does not need it for its process but it is needed for transportation
• Lack of oxygen in the ETC would mean it would have no where to go because it is the final e’ acceptor

Question 16

Rotenone is a broad-spectrum insecticide that inhibits the electron transport chain. Why might it be toxic to humans?

Answer 16

Rotenone could be toxic to humans because we rely on the ETC as an essential part of cellular respiration to produce energy. Without that cell having energy to perform its functions, the cells would die. Humans having dying cells is lethal

Question 17

Why is the actual number of ATP molecules per glucose molecule lower than the theoretical amount?

Answer 17

The theoretical amount is if everything happens the way it should happen and potential energy is properly brought out. With the potential of error along every step of every process is why the maximum theoretical amount is usually never met.

Question 18

How is the cell able to regulate the rate of ATP generation?

Answer 18

Cells regulates ATP generation by the amount of supply in materials required for the formation of ATP. the cell has the ability to increase or decrease the amount, thereby impacting the rate of ATP generation.

Question 19

Why is it important for the cell to regenerate oxaloacetate in the Kreb’s cycle? What would be the effect of oxaloacetate deficiency?

Answer 19

If there was no regeneration of oxaloacetate in the Kreb’s then, the acetyl-CoA would have nothing to combine with so there would be an offset of potential energy needed to create ATP. Therefore, no ATP could be made by the time carbons are used.

Question 20

Why is it important that NADH is oxidized before ATP is produced?

Answer 20

• NADH is required to be oxidized before ATP is produced because it turns into an electron carrier that can be used in later processes.
• Without NADH being oxidized, there is no electrochemical gradient
• ATP synthase needs hydrogen to be diffused— this is done because of the electrochemical gradient—before doing oxidative phosphorylation

Question 21

The process of glycolysis depends on the correct functioning of many enzymes. How could the effects of a toxin that blocks any of the glycolytic enzymes be overcome by an aerobic organism?

Answer 21

Aerobic organisms rely on oxygen for efficient ATP production, increasing oxygen consumption can help overcome the toxins

Question 22

Coenzyme A and NAD+ are vitamin B derivatives. Why would a deficiency of this vitamin complex lead to fatigue?

Answer 22

Deficiency of the vitamin would result in fatigue because without a coenzyme it can cause the slowing of energy production therefore causing fatigue