Respiration

Question 1

Describe the process of Glycolysis

Answer 1

Location: Cytoplasm
1. Phosphorylation
2. Isomerization
3. Phosphorylation
4. Lysis
5. Isomerization
*End of the energy consumption phase
6. Redox
7. Phosphorylation
8. Isomerization
9. Water Molecule Lost?
10. Phosphorylation
Net gain: 2 pyruvate, 2 ATP, 2 NADH
Summary: Glucose is converted into 2 Pyruvate through a series of 10 enzymatic reactions

Question 2

Describe the Link Reaction

Answer 2

Location: Matrix of the mitochondria
1. Pyruvate enters the matrix
2. Pyruvate is oxidized [NADH + H is formed through the reduction of NAD+]
3. Decarboxylation occurs [one CO2 is formed]
4. acetyl CoA (acetyl coenzyme A) is formed
Summary: Pyruvate (3C) is converted into acetyl CoA (2C)

Question 3

Describe the Krebs Cycle [Citric Acid Cycle]

Answer 3

1. Acetyl CoA combines with Oxaloacetate -> Citric acid (6C)
2. Isomerization -> Isocitrate
3. Oxidation / Decarboxylation -> Alpha-ketoglutarate [CO2 and NADH] (5C)
4. Oxididation / Decarboxylation -> succinyl CoA [CO2 and NADH] (4C)
5. Phosphorylation -> Succinate [GTP]
6. Oxidation -> Fumarate [FADH+]
7. Hydration -> Malate
8. Oxidation -> Oxaloacetate [NADH]
   Products: 3 NADH + 3H, 1 FADH2, 1 ATP, 2 CO2
   Regenerates: Oxoacetate

Question 4

What is the purpose of the Krebs Cycle?

Answer 4

To generate NADH and FADH2 to enter the ETC and transport electrons

Question 5

What stimulates the Krebs Cycle?

Answer 5

The presence of ADP and Calcium (stimulates the link reaction)

Question 6

What inhibits the Krebs Cycle?

Answer 6

The presence of ATP, NADH, and FADH2

Question 7

Describe the Electron Transport Chain [Oxidative Phosphorylation]

Answer 7

Location -> Inner membrane [mitochondria]
Chemiosmosis -> The movement of ions across a selectively permeable membrane down their electrochemical gradient
1. Oxidation -> NADH and FADH2 [electrons and hydrogen ions removed]
2. Electrons passed between protein complexes
3. Negative electrons draw positive hydrogens across the membrane [H+ concentration increased in intermembrane space]
4. Chemiosmosis -> H+ diffuses rapidly through ATP synthase [energy from movement used by ATP synthase]
5. Phosphorylation -> ADP + Pi = ATP
6. Reduction -> O2 is used as the final electron acceptor [H20 is formed and the concentration gradient is kept]

Question 8

Name Substrates for the production of ATP

Answer 8

Glucose and fatty acids are the principal substrates for cell respiration, however, a wide range of carbon/organic compounds can be used.

Question 9

What variables might affect cellular respiration?

Answer 9

1. Temperature [37C]
2. Oxygen levels
3. Glucose Concentration

Question 10

Compare aerobic and anaerobic respiration

Answer 10

Anaerobic:
Substrate -> Glucose
O2? -> No
ATP yield -> 2
Waste products -> Lactic acid and CO2
Location -> Cytoplasm

Aerobic:
Substrate -> Glucose, Fatty Acids, Amino Acids
O2? -> Yes
ATP yield -> 36
Waste products -> H2O and CO2
Location -> Mitochondria

Question 11

What is the equation for alcoholic fermentation?

Answer 11

Glucose -> C6H12O6
Pyruvate -> C3H5O3
Ethanol -> C2H6O
Carbon dioxide -> CO2

Question 12

What is the equation for lactic acid fermentation?

Answer 12

Lactic acid -> C3H6O3

Question 13

What is Hydrolysis?

Answer 13

When water breaks the phosphate bond in ATP releasing energy.

Question 14

What are the products and reactants of cellular respiration?

Answer 14

Reactants -> Oxygen and Glucose
Products -> CO2, Water, and ATP