Respiration and gas exchange

Question 1

Reasons we respire

Answer 1

• Contracting muscles so that we can move
• Linking amino acids to make proteins
• Cell division to repair damaged tissues and grow.
• To move substances around the body through active transport
• Transmitting nerve impulses
• Produce constant heat inside the body.

Question 2

Aerobic respiration

Answer 2

The chemical reactions in cells that use oxygen to break down nutrient molecules to release energy

Question 3

Anaerobic respiration

Answer 3

Chemical reactions in cells that break down nutrient molecules to release energy, without using oxygen

Question 4

Aerobic respiration equation

Answer 4

glucose + oxygen = carbon dioxide + water

C6H12O6 + 6O2 = 6CO2 + 6H2O

Question 5

Anaerobic respiration equation

Answer 5

glucose = alcohol + carbon dioxide
C6H12O6 = 2C2H5OH + 2CO2

Question 6

Characteristics of surfaces

Answer 6

• Thin to allow gas pass through easily
• Close to an efficient transport system
• Large surface area
• Good supply of oxygen

Question 7

Pathway to the lungs

Answer 7

The air that we breathe in enters the nose or mouth, flows through the throat (pharynx) and voice box (larynx) and enters the windpipe (trachea). The trachea divides into two hollow tubes called bronchi then it enters the alveoli

Question 8

Goblet cells

Answer 8

Goblet cells are a type of intestinal mucosal epithelial cell, they make a liquid which contains water and mucus which evaporates into the air in the nose and moistens it

Question 9

Cilia

Answer 9

cilia are found in the lungs, respiratory tract, they help to keep the airways clear of mucus and dirt, allowing us to breathe easily and without irritation.

Question 10

Inspiration

Answer 10

Breathing in, in this process the:

• muscles of the diaphragm is pulled downwards which increases the volume in the thorax
• It pulls the rib cage upwards and outwards
• since the volume has no pressure air rushes through the trachea and bronchi to the space

Question 11

Expiration

Answer 11

Breathing out, in this process:

- muscles of the diaphragm relaxes and it comes back to its original position which decreases the volume of the thorax

Question 12

Oxygen debt

Answer 12

Oxygen debt occurs when the body reaches a state of anaerobic respiration during intense exercise. When a person engages in high levels of physical activity, the body cannot distribute oxygen to the cells at a sufficiently rapid pace to keep up with the oxygen demand. This results in an oxygen deficit as the cells continue to produce energy but need additional oxygen to process the lactic acid produced during the process.