2.2 Cellular Respiration

Question 1

Glycolysis

Answer 1

In the cytoplasm

Oxygen is not required

Glucose broken down into pyruvate in two phases

1- Energy investment Phase requiring 2 ATP

2- Energy Pay Off Phase forming 4 ATP

3- Dehydrogenase enzymes remove hydrogen ions and electrons

4- They are passed to coenzyme NAD to form NADH

Question 2

Citric Acid Cycle

Answer 2

In the matrix of the mitochondria

Oxygen is required

1- Pyruvate converted to Acetyl, combining with Coenzyme A to form Acetyl Coenzyme A

2- Acetyl Coenzyme A combines with Oxaloacetate, forming Citrate

3- Enzyme controlled reactions convert Citrate back to Oxaloacetate, releasing CO2

4- Dehydrogenase enzymes remove more hydrogen ions and electrons and go to ETC

Question 3

Electron Transport Chain

Answer 3

In the inner mitochondrial membrane

Oxygen is required

1- Energy is used to pump hydrogen ions across the membrane

2- They flow through ATP synthase protein and generate ATP

3- Hydrogen ions combine with electrons and oxygen to form water

4- ATP synthase generates 36 ATP when hydrogen ions fall through it

Question 4

Fermentation in animals

Answer 4

Pyruvate converted to lactate in a reversible reaction

Question 5

Fermentation in plants and yeast

Answer 5

Pyruvate converted to ethanol and CO2 in an irreversible reaction