Human gas exchange - Paper 1 and 2

Question 2

What do both types of respiration produce?

Answer 2

ATP (energy)

Question 3

What are the main differences between anaerobic and aerobic respiration?

Answer 3

• Aerobic requires oxygen, anaerobic does not
• aerobic provides more energy than anaerobic because glucose is not fully broken down in anaerobic, so much less energy is released

Question 4

What is the word equation for aerobic respiration in living organisms?

Answer 4

glucose + oxygen → carbon dioxide + water + ATP (energy)

Question 5

What is the balanced chemical equation for aerobic respiration in living organisms?

Answer 5

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP (energy)

Question 6

What is the word equation for anaerobic respiration in plants and in animals?

Answer 6

Glucose –> Lactic acid + Carbon Dioxide + ATP (energy)

Question 7

What happens during ventilation? (inhalation and exhalation)(include what happens to the diaphragm and intercostal muscles)

Answer 7

INHALATION:
-External intercostal muscles contract, internal intercostal muscles relax.
-rib cage moves up and out
-diaphragm is pushed downwards (flattens and contracts)
-volume inside the thoracic cavity increases
-pressure inside the thoracic cavity decreases (as it is lower than the atmosphere) as air moves into the lungs
EXHALATION:
-External intercostal muscles relax, internal intercostal muscles contract
-rib cage moves down and in
-diaphragm relaxes into its domed shape, pushing up into the lungs
-volume inside the thoracic cavity decreases
-pressure inside the thoracic cavity increases, as it is higher than the atmosphere as air moves out of the lungs

Question 8

How are the alveoli adapted for gas exchange by diffusion between air in the lungs and blood in the capillaries?

Answer 8

• thin permeable walls which minimises diffusion distance between air and blood
• moist lining in which the gases dissolve before they diffuse across the cell membranes
• a large surface area- there are 100s of millions of alveoli in a human lung, giving a large surface area
• high concentration gradients for the gases because blood is continually flowing though the capillaries along the alveoli, delivering excess CO2 and taking additional O2, and because of the ventilation of the lungs which refreshes the air in the air sacs

Question 9

what is the word equation for anaerobic respiration in plants?

Answer 9

glucose -> ethanol + carbon dioxide + ATP (energy)