Chapter 10: Respiration

Question 1

What is the word equation for aerobic respiration

Answer 1

Glucose + oxygen —> Large amount of energy + water + carbon dioxide

Question 2

What is the word equation for anaerobic respiration

Answer 2

Glucose —> Small amount of energy + lactic acid

Question 3

What is the definition of aerobic respiration?

Answer 3

It is the breakdown of food substances in the presence of oxygen

Question 4

What is the definition of anaerobic respiration?

Answer 4

It is the breakdown of food substances in the absence of oxygen

Question 5

Explain why breathing increases?

Answer 5

1) As levels of exercise increases, muscular contractions increases
2) This increases the demand of energy by muscle
3) This increases the rate of aerobic respiration, increasing the demand of oxygen and glucose
4) This increases breathing rate and heart rate to enable more oxygen uptake and to reach the muscles

Question 6

Explain the breathing after exercise / high amount of lactic acid

Answer 6

1) If the oxygen uptake is insufficient for the demand of energy of muscular contractions, the muscle incurs an oxygen debt
2) It undergoes anaerobic respiration, releasing a little extra energy and producing lactic acid
3) Accumulation of lactic acid can lead to muscle cramps / soreness
4) After exercise, lactic acid is removed from the muscles and transported to the liver to be oxidised. Oxygen uptake remains high as it repays the oxygen debt

Question 7

What is the order of the human respiratory system?

Answer 7

Larynx, trachea, bronchus, bronchiole, alveoli

Question 8

Explain the characteristics of the alveoli

Answer 8

1) The walls of the alveolus is one-cell thick : So there is shorter diffusion distance for exchange of gases for faster rate of diffusion of oxygen into the blood

2) There is a thin film of moisture in the inner walls of the alveolus : So oxygen can dissolve in it and diffuse into the blood

Question 9

Name the chemicals in tobacco smoke

Answer 9

Nicotine, carbon monoxide, tar

Question 10

Explain the effects of nicotine in tobacco smoke

Answer 10

Nicotine :
1) Addictive drug, causes the release of hormone adrenaline which increases blood pressure and heart rate
2) Increases blood clot : Increases risk of blood clots in the arteries which leads to CHD

Question 11

Explain the effects of carbon monoxide in tobacco smoke

Answer 11

Carbon monoxide :
1) Combines irreversibly with haemoglobin to form carboxyhaemoglobin which reduces the ability of blood to transport oxygen
2) Increases the rate of fatty deposits in the inner walls of the arteries which leads to increased CHD : Narrows the lumen of the arteries and leads to increase in high blood pressure

Question 12

Explain the effects of tar in tobacco smoke

Answer 12

Tar :
1) Causes uncontrolled division of cells which leads to increased risk of cancer in the lungs

Question 13

Describe the gas exchange of oxygen in the alveoli

Answer 13

Gaseous exchange of oxygen
1) Oxygen concentration is higher in the alveolar air than in the blood
2) Oxygen dissolves into the thin film of moisture lining the inner surface of the alveoli and diffuse into the blood capillaries
3) It combines reversibly with haemoglobin to form oxyhaemoglobin

Question 14

Describe the gas exchange of carbon dioxide

Answer 14

Gaseous exchange of carbon dioxide :
1) Carbon dioxide concentration is higher in the blood than in the alveolar air
2) Carbon dioxide diffuse from the blood into the alveolus
3) Is forced out of the lungs through exhalation

Question 15

Describe the gas exchange in respiring tissue

Answer 15

Gas exchange in respiring tissue :
1) Oxygen concentration is lower in the respiring tissues than in the blood
2) Oxyhaemoglobin releases oxygen which diffuses into the tissue cells through the capillary wall

Question 16

Name the diseases caused by tobacco smoke

Answer 16

Chronic bronchitis, emphysema, lung cancer

Question 17

Explain chronic bronchitis

Answer 17

1) The epithelium lining the airways is inflamed
2) There is excessive secretion of mucus
3) The cilia lining the airways are paralysed
4) Dust particles and mucus cannot be removed
5) Air passages becomes blocked, making breathing difficult
6) Persistent coughing to clear airways in order to breath, increasing risk of lung infection

Question 18

Explain emphysema

Answer 18

1) The partition walls of the alveoli breaks down due to violent coughs
2) This reduces the surface area for gaseous exchange
3) The lungs lose their elasticity and becomes inflated with air
4) Breathing becomes difficult, can result to severe breathlessness and wheezing

Question 19

Explain lung cancer

Answer 19

1) Uncontrolled division of cells producing outgrowths or lumps of tissue