Topic 4 Respiration (from 2.34)

Question 1

What is ATP?

Answer 1

‘Energy currency’ of cell - the form in which energy is released

• needed for muscle contraction, active transport, protein synthesis + cell division

Question 2

What is the function of mitochondria?

Answer 2

1. Site of aerobic respiration

2. Release energy

Question 3

What is the word equations for aerobic respiration?

Answer 3

Oxygen + glucose -> carbon dioxide + water

Question 4

What is the symbol equation for aerobic respiration?

Answer 4

6O2 + C6 H12 O6 -> 6CO2 + 6H2O

Question 5

What is the word equation for anaerobic respiration in animals?

Answer 5

Glucose -> lactic acid

Question 6

What is the word equation for anaerobic respiration in plants?

Answer 6

Glucose -> ethanol + carbon dioxide

Question 7

When is anaerobic respiration used?

Answer 7

When oxygen is not available/ cannot be supplied fast enough for energy requirement

Question 8

What happens during anaerobic respiration?

Answer 8

• incomplete breakdown of glucose produces lactic acid in muscles
• after exercise, lactic acid needs to break down into co2 and h2o
• this occurs by reacting lactic acid with oxygen
• > amount of oxygen needed = oxygen debt, which is why there must be a fast supply of highly oxygenated blood to muscles even after exercise
• > explains why heart + breathing rate remain high after vigorous exercise

Question 9

Why is anaerobic respiration not as useful to cells as aerobic respiration?

Answer 9

• lactic acid is made, build up of this causes pain + muscle fatigue
• less energy released as breakdown of glucose is incomplete
• oxygen debt builds up, as lactic acid must be oxidised into co2 and h2o

Question 10

Plants + fungi, like yeast, respire anaerobically to release ethanol + carbon dioxide. How is this useful?

Answer 10

Can use ethanol in fermentation to produce alcohol for beer + wine

Can utilise the co2 of yeast to make bread

Question 11

What colour is hydrogen carbonate indicator in high co2 levels, atmospheric, and low co2 levels?

Answer 11

Yellow

Red

Purple

Question 12

What are 3 chemicals in cigarettes?

Answer 12

1. Nicotine
2. Tar
3. Carbon monoxide

Question 13

What is tar?

Answer 13

Carcinogen

Question 14

What is nicotine and how does it affect the body?

Answer 14

1. Increases heart rate
2. Narrows blood vessels, leading to increased blood pressure and atherosclerosis
3. Addictive

Question 15

How does carbon monoxide affect the body?

Answer 15

1. Binds irreversibly to haemoglobin -> carboxyhaemoglobin - reducing capacity of blood to carry oxygen
2. Leads to increase in breathing frequency + depth in order to get to same amount of oxygen into blood
3. Circulatory system has to pump blood faster -> increases risk of chd and strokes

Question 16

Why is lung cancer an effect of smoking?

Answer 16

1. Carcinogenic chemicals cause DNA in cells to mutate + divide uncontrollably forming a tumour
2. Symptoms include cough, chest pain and coughing blood

Question 17

What happens to cilia as a result of smoking?

Answer 17

1. Cells lining trachea + bronchi produce sticky mucus which traps dirt + bacteria
2. Cilia move mucus up and out of lungs
3. Heat and chemicals from cigarette smoke paralyse cilia so smokers more likely to get lung infections

Eg bronchitis + emphysema

Question 18

What is emphysema?

Answer 18

1. Walls of alveoli are broken down, elasticity reduced so collapse
2. Reduces surface area
3. Less gas exchange = reduced oxygen in blood
4. Short of breath, coughing, wheezing

Question 19

What is bronchitis?

Answer 19

1. Cilia damaged by smoke + chemicals
2. Causes inflammation of bronchi + bronchioles
3. Production of mucus by goblet cells in trachea increases but can’t be removed
4. Build up of mucus causes infections (traps bacteria)
5. Hacking cough, sore throat, headache

Question 20

Why should you not smoke during pregnancy?

Answer 20

• lack of oxygen given to baby

- affects baby’s growth + development

Question 21

Investigate the release of carbon dioxide in humans?

Answer 21

1. Half fill 2 test tubes w lime water
2. Insert rubber bungs
3. Two holes in each bung - one connected to capillary tube and the other a t tube that you breathe into (look at diagram in cp book)

The test tube where the t tube is in the lime water will turn cloudy as this is the one you are exhaling into

Question 22

Investigate the effect of exercise on breathing? CORRMMS

Answer 22

C - intensity of exercise

O- will test on humans of same gender + age who are all moderately active (SSS)

R1- will test range of mild - high intensity exercise

R2- test each three times by doing 15, 30, 45 star jumps in a minute

M1 - count how many breaths test subject takes in minute w stopwatch (m2) after exercising

Question 23

Explain the effects of exercise on breathing and heart rate

Answer 23

1. Heart/breathing rate increases
   - > faster transport of glucose + oxygen to muscle cells and removal of carbon dioxide and lactic acid
2. Arteries supplying muscles dilate -> more blood flow
3. Increase sweating -> faster release of heat from body to prevent enzymes denaturing