Respiration And Gas Exchange

Question 1

Aerobic respiration- with oxygen

Answer 1

Word: glucose + oxygen—> carbon dioxide + water

Question 2

Anaerobic respiration- without oxygen

In animals-
(In plants and fungi-)

Answer 2

In animals- glucose—-> lactic acid

In plants and fungi- glucose—-> carbon dioxide + ethanol

Question 3

Explain aerobic respiration:

Answer 3

1) When you are walking slowly you don’t need a lot of energy and so you do not need a lot of oxygen for respiration.
2) The lungs can easily take in enough oxygen and the heart can easily pump enough oxygen to muscle cells in the legs.

Question 4

Explain anaerobic respiration:

Answer 4

1) when you run, more energy is needed and so you have to breathe faster and the heart beats quicker so more oxygen reaches the muscles
2) but it is difficult to get enough oxygen to the muscles and the muscle cells begin to respire anaerobicly
3) toxic lactic acid builds up

Question 5

But you still breathe quickly when you stop running….?

Answer 5

1) you do not need a lot of energy when you stop running, but you still breather quickly
2) thesis time the EXTRA oxygen is used to oxidise and remove TOXIC lactic acid .
3) when all the lactic acid has gone, breathing returns to normal.

Question 6

MEASURING THE RATE OF ANAEROBIC RESPIRATION IN YEAST method one

• liquid paraffin…
• waterbath…
• limewater…
• to find the rate of respiration…
• however, the v…

Answer 6

Liquid paraffin- prevents oxygen entering the mixture, so conditions remain anaerobic

Waterbath- keeps the temperature constant

Limewater- turns the cloudy white, showing that bubbles contain co2

Find r of r- could the no. Of bubbles produced in a minute

However- volume can vary, 1 big could be same as 5 small

Question 7

MEASURING THE RATE OF ANAEROBIC RESPIRATION IN YEAST method two

*to achieve a more…

Answer 7

-to a hive a more accurate result, the volume of co2 gas per minute is measured

Question 8

Why was no more carbon dioxide made after 2 days of it respiring anaerobicly

Answer 8

1) the glucose (sugar) had run out

2) the yeast cells had been killed by the accumulating ETHANOL

Question 9

Equation for rate of respiration?

Answer 9

Rate of respiration= volume of gas

Produced/ time taken to make the gas

Question 10

Aerobic respiration chemical equation:

Answer 10

C6H12O6 + 6O2 —-> 6CO2 + 6H2O

Question 11

Explain anaerobic respiration in animals:

Answer 11

1) in animals, muscles may start to respire anaerobicly during vigorous exercise
2) a lot of oxygen is required to release a lot of energy for the exercise being carried out
3) but oxygen is not delivered to the cells quickly enough and lactic acid builds up, causing stiffness

Question 12

Explain anaerobic respiration in plants:

Answer 12

(After heavy rain)

1) The soil becomes waterlogged and oxygen cannot reach the roots (by diffusion) from the surrounding air.
2) If the soil does not drain, the cells of the roots may start to die because of the toxic ethanol that builds up

Question 13

Inhaled air passes through the filling parts:

Answer 13

1) windpipe
2) bronchus
3) bronchiole
4) alveolus

Question 14

Explain gas exchange:

Answer 14

1) when air reaches the alveoli, oxygen diffuses into the blood and carbon dioxide diffuses into the alveolar space.
2) for this to happen there must be a concentration gradient between the alveolar space and the blood

Question 15

How is the rate of diffusion increased?

Answer 15

1) the walls of the alveoli are only one cell thick. There is only a small distance to travel.
2) the walls of the capillaries are only one cell thick
3) the capillaries which take up the oxygen are very close to the alveolar wall
4) the alveoli walls are lobed to create a large surface area
5) there are many alveoli o create a large surface area