gas exchange

Question 1

flying muscles respire anaerobically and products accumulate. suggest how this affects the supply of oxygen of oxygen to the flying muscles.

Answer 1

Lactate builds up [1 mark]
It lowers their water potential [1 mark]
The water from the tracheoles moves into the cells by osmosis [1 mark]
Allowing oxygen in the tracheoles to diffuse directly into the cells [1 mark]
The diffusion pathway has been shortened [1 mark]

Question 2

explain the results of this graph

Answer 2

More air is required in the tracheal system when oxygen concentration is low
Increased rate of opening helps to increase the airflow through the tracheal system

Question 3

suggest why it would beneficial for no stomata on upper surface

Answer 3

Stomata could become blocked by drops of rain/water which would reduce gas exchange
/ uptake of carbon dioxide; [1 mark]
The stomata will be in direct sunlight which will increase water loss/evaporation
/transpiration;

Question 4

explain how young tadpoles are able to get oxygen without developed gills

Answer 4

Gas exchange/diffusion of oxygen takes place across the body surface / skin of the
tadpoles; [1 mark]
The diffusion pathway/distance is short OR they have a large surface area:volume ratio;

Question 5

why no conclusion of table

Answer 5

No information about the mean rate of oxygen uptake for adult toad; [1 mark]
So cannot compare all of the stages in Table 1; [1 mark]
There is no statistical information provided OR there is no test/t-test/comparison of the
standard deviations OR there has been no measure of significant differences; [1 mark]

Question 6

how does inspiration occur (full process)

Answer 6

external intercostal muscles contracts , moving rib cage up and out,
diaphragm contracts also.
Decrease pressure, and increases volume in thorax cavity.
air moves down pres. gradient.

Question 7

how to compare leaves of different species

Answer 7

five of each plant species

Question 8

why stomata close

Answer 8

prevents water loss through evaporation thru stomata and maintains water content in cells

Question 9

how oxygen reaches capillaries

Answer 9

air enters through nose, trachea, bronchus bronchioles down the pressure gradient and diffusion gradient across the alveolar epithelium

Question 10

fire breather question

Answer 10

less elascity means less recoil

Question 11

Answer 11

talk about co2 uptake

eg 1) shows all co2 uptake