Section 4 - Respiration & Gas Exchange

Question 1

What is respiration?

Answer 1

Process of transferring energy from glucose. It happens in every cell of your body

Question 2

How is the product of respiration used?

Answer 2

• The product of respiration is ATP which stores energy for many cell processes.
• If energy needed molecules of ATP are broken down and release energy.

Question 3

Aerobic respiration

Answer 3

• Happens when there is plenty of oxygen
• Most efficient way to transfer energy from glucose: produces 32 molecules of ATP per molecule of glucose

Question 4

Aerobic respiration word equation

Answer 4

glucose + oxygen -> carbon dioxide + water

Question 5

Anaerobic Respiration

Answer 5

• Happens when your doing vigorouse exercise
• Releases less energy per glucose molecule (2 ATP molecules produced)
• Glucose is only partially broken down so lactic acid is also produced

Question 6

Anaerobic respiration in Animals:

Answer 6

Glucose -> lactic acid (+energy)
Lactic acid is removed from muscles by blood flow

Question 7

Anaerobic respiration in Plants:

Answer 7

Glucose -> ethanol + carbon dioxide (+ energy)

Question 8

Breathing in:

Answer 8

1. Intercostal muscles + diaphragm contract
2. Thorax volume increases
3. Decreases the pressure

Question 9

Breathing out:

Answer 9

1. Intercostal muscles + diaphragm relax
2. Thorax volume decreases
3. Air is forced out

Question 10

What are alveoli?

Answer 10

millions of air sacs located in the lungs where gas exchange happen

Question 11

Gas exchange

Answer 11

1. Blood passing next to the alveoli returnes from the rest of the body so they contain CO2
2. Oxygen diffuses out of the alveolus into the blood and CO2 diffuses out of the blood into the alveolus to be breathed out
3. When blood reaches body cells oxygen is released from red blood cells diffuses into body cells
4. At the same time CO2 diffuses out of the body cell into the red blood cells

Question 12

Alveoli characteristics:

Answer 12

• Huge number of them so gives lungs large surface area
• Alveoli have very thin walls so diffusion happens faster
• Great blood supply to mantain high concentration gradient
• Walls are permeable

Question 13

Problems of smocking tobacco:

Answer 13

1. damages walls inside alveoli reducing surface area. This leads to emphysema
2. Damages the cilia in your lungs and trachea. This hairs catch dust and bacteria before they reach the lungs. Chest infections are more likely
3. Carbon monoxide reduces amount of oxygen blood can carry. Increases risk of coronary heart disease