3.2 Respiration

Question 1

Why is energy required

4 Points

Answer 1

• obtain nutrients,
• synthesise materials for growth (cell division) and repair
• provide energy for movement and metabolism and eliminate wastes
• maintain body temperature

Question 2

What type of energy do cells use?

Answer 2

All cells use chemical energy

• Chemical energy is the energy stored in the bonds that join atoms together in molecules of organic molecules such as glucose, fats and proteins
• When the molecule is broken apart, the energy of these bonds is released

Question 3

What is ATP

Answer 3

Adenosine Triphosphate

Stores immediately useable energy in the chemical bonds

When a cell needs energy for a chemical reaction, the high-energy chemical bonds attaching the last phosphate group are broken releasing stored energy

Converts to ADP

Question 4

What is the difference between ATP and ADP?

Answer 4

Number of phospate Groups

ATP = 3 phosphate groups

ADP = 2 phosphate groups

Question 5

How is ADP made?

Answer 5

When energy is produced during respiration the energy is used to attach the phosphate group back onto the ADP molecule

Question 6

What is produced when Glucose is broken down?

Answer 6

The breakdown of glucose results in three products:

• Carbon dioxide
• Water
• Energy in the form of ATP

Question 7

How efficient is the reaction?

Answer 7

Only 40% of the chemical energy released from the breakdown of glucose ends stored in the bonds of ATP.

The rest is lost as heat.

Question 8

What is 1st stage of Cellular respiration

Answer 8

Glycolysis

Question 9

What is 1st stage of Cellular respiration

Question 10

What is 2nd stage of Cellular respiration

Answer 10

Aerobic Respiration (when oxygen present)

OR

Anaerobic Respiration (without oxygen)

Question 11

Glycolysis

Where does it occur?

Answer 11

In the cytoplasm of the cell

Question 12

Does Glycolysis requrie oxygen

Answer 12

No

This is a common stage to both aerobic and anaerobic respiration.

The amount of energy that can be harvested from the glucose depends on whether oxygen is present

Question 13

What happens in Glycolysis?

Answer 13

Glycolysis :

• Splits Glucose → 2 Pyruvate molecules
• Converts 2 ADP → 2 ATP (net)

Question 14

Aerobic Respiration

Where does it happen?

Answer 14

Occurs in the mitochondria

Within the inner membrane called the cristae, which provides a large surface area for the reactions to take place

Question 15

Aerobic Respiration

What is the outcome?

Answer 15

36-38 molecules of ATP

General simplified chemical formula is:

C₆H₁₂O₆ + 6 0₂ → 6 CO₂ + 6 H₂O + 36~38 ATP

Question 16

Anaerobic Respiration

Answer 16

Pyruvate passes into the anaerobic pathway also known as fermentation

The pyruvate molecules undergo fermentation into either:

• Lactic acid (in most animals)
• Alcohol & Carbon Dioxide
  (in most plants, and microorganisms such as yeast and bacteria)