C2

Question 1

Cellular Respiration

Answer 1

• Can occur aerobically (oxygen present)
• Can occur anaerobically (oxygen not present)

Question 2

Aerobic Cellular Respiration Equation

Answer 2

C₆H₁₂O₆ + 6O₂ + 36ADP + 36P_i → 6CO₂ + 6H₂O + 36ATP + heat

Glucose is completely oxidized with oxygen present

Question 3

Glycolysis

Answer 3

Step 1
Location: Cytoplasm

Glucose + 2ATP → 2G3P + 2NAD⁺ → 2 Pyruvate + 4ATP + 2 NADH

• Anerobic process
• Glucose is oxidized
• NAD⁺ is reduced
• Produces 2 NADH

Question 4

Pyruvate Oxidization / Linking Reaction

Answer 4

Step 2
Location: Matrix of Mitochondria

1. Pyruvate + NAD⁺ → Acetyl (2 carbon compound) + CO₂ + NADH
2. Acetyl + Coenzyme-A → Acetyl Coenzyme-A (goes to krebs cycle)

• Oxygen binds to the loose carbon to make CO₂; this this is aerobic
• This happens twice overall (once for each pyruvate created from glycolysis)
• Pyruvate is oxidized
• Pyruvate is a 3 carbon molecule → One carbon is lost and becomes CO₂
• Acetyl is oxidized by NAD⁺ → NADH is formed
• Acetyl joins to a carrier called coenzyme A

Question 5

Krebs Cycle

Answer 5

Location: Matrix of Mitochondria

• Aerobic process
• Main purpose is to produce NADH and FADH₂

Acetyl CoA + 3 NAD⁺ + FAD⁺ + ADP → 3NADH + FADH₂ + ATP + 2 CO₂

• This occurs twice (for each Acetyl CoA molecule)
• NAD⁺ is reduced
• FAD is reduced
• ATP is formed
• All 6 carbon atoms of glucose have been oxidized to CO₂

Question 6

ETC & Chemiosmosis

Answer 6

Location: Inner mitrochondrial membrane

• Aerobic process
• NADH and FADH₂ release electrons which move through carrier proteins
• Each time e^- moves from protein to protein; it releases energy into intermembrane space
• Hydrogen ions gain potential energy as they move through proton pump into intermembrane space
• Hydrogen ion on one side of membrane creates electrochemical gradient
• ATP synthase channel = only place permeable to hydrogen ions
• Forces hydrogen ions into matrix → energy is released (used to synthesize ATP)

Question 8

Aerobic Cellular Respiration

Total ATP produced per glucose

Answer 8

Glycolysis: 2
Pyruvate Oxidization: 0
Krebs Cycle: 2
ETC/Chemiosmosis: 34
Total: 36

Question 9

Anerobic Cellular Respiration

Alcohol Fermentation

Answer 9

• NADH produced in glycolysis pass their H atoms to acetaldehyde
• Acetaldehyde: CO₂ removevd from pyruvate by pruvate decarboxylase (enzyme) - Forms ethanol
• Reycles NAD⁺ to be used in glycolysis again
• 2 ATP produced
• CO₂ and ethanol released as waste

Question 10

Anaerobic Respiration

Lactic Acid Fermentation

Answer 10

• Lack of O₂ can cause cramping (buildup of lactic acid)
• NADH transfers H atoms to pyruvate in cytoplasm → Regenerates NAD⁺; glycolysis can continue
• Pyruvate is reduced
• Oxygen available again = Lactic acid → Pyruvate (used in krebs)
• Short burst of energy when O₂ not available