Cell respiration 8.2

Question 1

Outline the glycolysis reaction + formula

Answer 1

• occurs in cytoplasm of mitochondria
• converts glucose into 2 pyruvates:
  1. glucose is phosphorylated using two ATPS into two 3Carbon molecules
  2. each 3 C M. undergoes oxidation, (reducing NAD+ to NADH) + dephosphorylation to produce in total 4 ATPs. Results in 2 Pyruvates and net: 2 ATP per 3 Carbon molecule

Glucose + 2 NAD+ + 2 ADP + 2 Pi –> 2 Pyruvate + 2 NADH + 2 H+ + 2 ATP + 2 H2O

Question 2

how is NAD+ resupplied in anaerobic respiration?

Answer 2

fermentation of pyruvate into H+ and lactate/ ethanol resupplies NAD+. (end of anaerobic resp.)

Question 3

Define decarboxylation

Answer 3

chemical reaction tht removes a carboxyl group and releases CO2

Question 4

outline the process of the link reaction

Answer 4

• occurs in matrix so pyruvate must travel from cytoplasm to matrix (requires 1 ATP each)

Reactants: 2 pyruvate, 2 NAD+, 2 co- enzyme A.
products: 2 NADH, 2 CO2 and 2 aceytl CoA molecules

1. pyruvate -> oxidation, reduces NAD+ into NADH, + decarboxylation, produces CO2 => results in two acetyl molecules
2. acetly mol. combine with co-enzyme A to form Acetyl CoA.

Question 5

Outline the events of the Krebs cycle

Answer 5

• occurs in matrix
• conversion of each acetyl CoA mol. into 6C molecule for oxidation.
  1. acetyl CoA releases its acetyl and combines with 4 C mole to form 6 C molecule.
  2. 6 C Mol. oxidation, reducing NAD+, and decarboxylation, CO2 => resulting in 5 C Mol.
  3. 5 C mol. oxidation, reducing NAD+, and decarboxylation, CO2, each molecules produces 1 ATP in this stage => resulting in 4 C Mol.
  3. 4 C mol oxidation, reducing FAD+ into FADH2 + oxidation again, reducing NAD+ (into NADH like always.) => results in original 4 C Mol. that the acetyl group combined with in beginning.
  hence a cycle

Question 5

Draw and label a diagram of the mitochondria.
State the function of the following mitochondrial structures: outer membrane, inner membrane, cristae, intermembrane space, matrix, ribosome and mtDNA.

Answer 5

see notion

Question 5

outline the events of oxidative phosphorylation in the ETC

Answer 5

• occurs in inner mitochondrial membrane
  1. FADH2 and NADH carry e- to protein complexes in intermembrane space, where they donate them (oxidation, they also leave behind an H+).
  2. protein complexes will pass e- from protein to protein (ETC).
  3. this allows the proteins to pump H+ ions into the intermembrane space from matrix.
  4. when e- reaches last protein (4th) , oxygen will accept e- to bind with H+ ions to form H20. this allows the ETC to keep going. Oxygen is final electron acceptor in ETC and water helps maintain the H gradient
  Chemiosmosis
  -ATP synthase allows H+ to flow through them, forming ATP from ADP.
• known as oxidative phosphorylation: using power of oxditation to phosphorylate.
  -This is only possible bc of H+ ion gradient which is only possible from ETC which is only possible from the krebs cycle, the link reaction, etc.

Question 6

Outline the stages of anaerobic and aerobic respiration

Answer 6

Anaerobic respiration: glycolysis
Aerobic respiration: glycolysis, link reaction, Krebs cycle, oxidative phosphorylation