[Biology][Practical-15] Cellular Respiration Questions

General Discussion
1

CELLULAR RESPIRATION

  • The most common hydrogen carrier is NAD+ which is reduced to form NADH

  • A less common hydrogen carrier is FAD which is reduced to form FADH2

  • The byproduct of glycolysis is 2 pyruvates

  • What is the net gain of glycolysis? 2 ATP + 2 NADH,H+ + 2 pyruvate

  • What are the 3 steps of the electron transport chain?

  1. generating a proton motive
  2. chemiosmosis and ATP synthase activity
  3. oxygen acta as the final electron acceptor

  • Glycolysis occurs in the cytosol and does not require oxygen

  • What are the possible fates of pyruvate?

image

  • Describe alcoholic fermentation: starting molecule, products, a molecule produced

  • Describe aerobic oxidation: starting molecule, products, a molecule produced

  • Aerobic respiration involves 3 types of chemical reactions:

  1. decarboxylation
  2. oxidation
  3. phosphorylation

  • Describe lactic acid fermentation: starting molecule, products, a molecule produced

  • Which reactions are anaerobic?

  1. lactic acid formation
  2. alcoholic fermentation

Anwer: both

  • What are link reactions? A stage in cellular respiration that “links” two other stages

  • Pyruvate, through link reactions, produces a 2 carbon compound called acetyl-CoA inside the mitochondria

  • 1 glucose, through the Krebs cycle, yeilds 4 CO2, 2ATP, 6NADH, and 2 FADH2

  • The second step of aerobic respiration is the Krebs Cycle

  • In the Krebs cycle, we use Acetyl CoA and a 4C (oxaloacetate) compound to make a 6C compound (Citrate), and the Coenzyme A returns to the link reactions to form another molecule of Acetyl CoA.

  • Decarboxylation occurs in:

  1. glycolysis
  2. link reaction
  3. Krebs cycle
  4. electron transport chain

Answer: 2 & 3

  • Electron transport chain occurs inside there mitochondria

  • How is proton motive generated?

image

  • Phosphorylation occurs in:
  1. glycolysis
  2. Krebs cycle
  3. electron transport chain

Answer: 1, 2 & 4

  • Oxidation occurs in:
  1. glycolysis
  2. link reaction
  3. Krebs cycle
  4. electron transport chain

Answer: 1, 2 & 3

  • Describe the chemiosomis and ATP synthase activity of the electron transport chain

image

  • 1 Glucose molecule will yield about 32-36 molecules of ATP on average, 6CO2, 10xNADH, and 2xFADH2.

  • The electron transport chain is made of 4 complexes: the first and second complexes accept electrons of NADH and FADH2

  • Describe the last step of the electron transport chain

image

9 Likes
2

Hi, do the ‘‘Q’’ , ‘‘Cyst C’’ and ATP synthase not count as complexes of the ETC?

1 Like
3

They do but not as protein pumps. For the IMAT, we focus mainly on the main complexes and the ATP synthases.

2 Likes
4

Hi, Phosphorylation occurs when ATP is synthesized, doesn’t it? well, why can’t we say that in Krebs cycle where we have 2 ATP phosphorylation occurs ? in link reaction these no ATP directly

5

for this question, doesn’t ‘‘oxidation occurs’’ mean here that NADH get oxidized into NAH+? if I’m not mistaken that only occurs in number 4…I’m confused

6

Phosphorylation only occurs in 1, 3, 4 as you are saying:)

Oxidation occurs in all of the processes 1, 2, 3 and 4, because remember whenever NAD+ or FAD+2 is reduced, the other thing must be oxidised.

3 Likes
7

Hi, so can I assume that all the options are correct since
A. It’s a redox reaction and
B. Oxygen accepts hydrogen ion in the final step of ETC?

8

Where does Phosphorylation occur in the Link reaction?
CO2 & Reduced NAD are formed.

9

Thank you for the correction!