Chapter 12: Respiration

Question 1

What is meant by ‘respiration’?

Answer 1

Respiration refers to the process of breaking down glucose to provide energy for the cell

Plant and animal cells release the energy stored in glucose

Converting that energy into ATP an immediate source

The energy powers biological processes

Question 2

What is the equation for respiration?

Answer 2

C₆H₁₂O₆ + 6O₂ — 6CO₂ + 6H₂O + energy

Question 3

What are the 2 types of respiration?

Answer 3

The 2 types of respiration are aerobic and anaerobic respiration

Question 4

True or False: Both aerobic and anaerobic respiration produce ATP

Answer 4

True. Although anaerobic respiration produces less ATP than aerobic

Question 5

Aerobic respiration occurs in which conditions and produces what?

Answer 5

Aerobic respiration occurs when oxygen is present/available and produces:

CO₂ + water + energy

Question 6

Anaerobic respiration occurs in which conditions and produces what?

Answer 6

Anaerobic respiration occurs when there is no oxygen and produces:

CO₂ + ethanol/lactate + energy

Question 7

What are the stages of respiration?

Answer 7

The stages of respiration are:

For aerobic:

1. Glycolysis
2. the Link Reaction
3. the Krebs Cycle
4. Oxidative phosphorylation

For anaerobic:

1. Glycolysis
2. Alcoholic/Lactate fermentation

Question 8

What is glycolysis?

Answer 8

Glycolysis is the first stage in both aerobic and anaerobic respiration

Site: cytoplasm of plant cells

Does not need oxygen - anaerobic process

Pyruvate is made from glucose

One 6-carbon molecule of glucose is split/converted into 2x 3-carbon molecules of pyruvate

Question 9

Which stage in respiration is shared by aerobic and anaerobic respiration?

Answer 9

Glycolysis

Question 10

Describe what happens in glycolysis.

Answer 10

Glucose is phosphorylated to make it more reactive (lowers activation energy for following enzyme controlled reactions)

• 1 molecule of ATP is hydrolysed
• Glucose becomes glucose phosphate
• Another ATP is hydrolysed
• Glucose phosphate becomes hexose biphosphate
• Hexose biphosphate splits into 2 molecules of triose phosphate

Each triose phosphate is oxidised to pyruvate by enzyme controlled reactions in which 2 molecules of reduced NAD and 4 molecules of ATP are formed/released

• TP is oxidised (hydrogen is removed)
• Forms 2 molecules of pyruvate
• and 2 molecules of ATP
• The hydrogen released is picked up by NAD
• Forming 2x reduced NAD

There is a net gain of 2 ATP molecules because 2 were used up at the start

Question 11

What happens to the 2 molecules of reduced NAD made from glycolysis?

Answer 11

The two molecules go to oxidative phosphorylation.

Question 12

What happens to the 2 molecules of pyruvate made in glycolysis?

Answer 12

The 2 molecules of pyruvate go to the Link reaction and are actively transported into the matrix of the mitochondria

Question 13

What is the Link Reaction?

Answer 13

The second stage of aerobic respiration

Question 14

Describe what happens in the Link reaction?

Question 15

What is the Krebs cycle?

Question 16

What Is the Purpose of Oxygen in Aerobic Respiration?/The role/ The importance of oxygen in aerobic respiration?