3.3 Repiration

Question 1

What is respiration?

Answer 1

A set of metabolic reactions that take place in organisms and break down respiratory substances into smaller inorganic molecules

Question 2

Why is respiration described as a catabolic process?

Answer 2

Complex molecules (respiratory substrates) are broken down into smaller, simpler molecules

Question 3

Why do organisms need to respire?

Answer 3

• Produce chemical energy for a variety of processes such as active transport
• releases heat energy for thermoregulation

Question 4

Define aerobic respiration

Answer 4

Respiration which takes place in the presence of oxygen and produces carbon dioxide, water and ATP

Question 5

Name the four main stages of aerobic respiration and state where they occur

Answer 5

• glycolysis- Cystosol
• link reaction - mitochondrial matrix
• Krebs cycle - mitochondrial matrix
• ETC - inner mitochondrial membrane

Question 6

Outline the stages of glycolysis

Answer 6

1. Glucose phosphorylated to become bisphosphate by using 2 ATP
2. Heroes bisphosphate splits into 2 Triose phosphate
3. 2 molecules of TO oxidised to 2x pyruvate
   Net gain of 2 reduced NADH and 2 ATP

Question 7

Write an equation to summarise glycolysis

Answer 7

Glucose + 2NAD + 2ATP + 2P -> 2 pyruvate + 2NADH + 2ATP + heat