Energy Transfers in and Between Organisms: Respiration - Glycolysis

Question 1

What does aerobic and anaerobic respiration both produce?

Answer 1

• ATP

- Anaerobic respiration produces less ATP

Question 2

What is the first stage of both aerobic and anaerobic respiration?

Answer 2

• Glycolysis

Question 3

Where does glycolysis occur?

Answer 3

• In the cytoplasm

Question 4

Does glycolysis require oxygen?

Answer 4

• No, it’s an anaerobic process

Question 5

What are the main stages of glycolysis?

Answer 5

• Phosphorylation of glucose to glucose phosphate, using energy from the hydrolysis of ATP
• Production of triose phosphate
• Oxidation of triose phosphate to pyruvate, using energy from reduction of NAD and phosphorylation of ADP

Question 6

What happens during phosphorylation of glucose in glycolysis?

Answer 6

• Production of glucose phosphate

• Glucose is phosphorylated using a phosphate
• Phosphate from hydrolysis of ATP
• This creates 1 molecule of glucose phosphate

• Production of hexose bisphosphate

• Glucose phosphate is phosphorylated using a phosphate
• Phosphate from hydrolysis of ATP
• This creates 1 molecule of hexose bisphosphate

• Production of triose phosphate
- Hexose bisphosphate is split into 2 molecules of triose phosphate

Question 7

What happens during the oxidation stage of glycolysis?

Answer 7

• 2 molecules of triose phosphate are oxidised (loses hydrogen), forming 2 molecules of pyruvate
• 2 NAD use hydrogen ions, forming 2 reduced NAD (NADH)
• 4 ATP are produced as phosphates are removed from triose phosphate, but 2 were used in phosphorylation, so there’s a net gain of 2 ATP

Question 8

How many carbons do all of the main organic compounds in glycolysis have?

Answer 8

• Glucose - 6C
• Glucose phosphate - 6C
• Hexose bisphosphate - 6C
• Triose phosphate - 3C
• Pyruvate - 3C

Question 9

What are the products of glycolysis?

Answer 9

• 2 reduced NAD (NADH)
• 2 pyruvate
• 2 ATP

Question 10

Where does the 2 NADH from glycolysis go in aerobic respiration?

Answer 10

• To oxidative phosphorylation

Question 11

Where do the 2 pyruvates from glycolysis go in aerobic respiration?

Answer 11

• Actively transported into mitochondrial matrix for use in link reaction

Question 12

Where do the 2 ATP from glycolysis go in aerobic respiration?

Answer 12

• Used for energy

Question 13

Where do the 2 pyruvates from glycolysis go in anaerobic respiration?

Answer 13

• In plants and yeast, pyruvate is converted into ethanol

- In animal cells and bacteria, pyruvate is converted into lactic acid

Question 14

What does the production of lactic acid and ethanol produce? How can this product be used?

Answer 14

• Production of lactic acid and ethanol regenerates NAD

- This NAD can be used to continue glycolysis even when little oxygen is present