Gaseous exchange in flowering plants

Question 1

Gaseous exchange in flowering plants

Answer 1

Gaseous exchange occurs in the leaves, stems androots of plants bydirect diffusion between theintercellular air spaces and all the cells in these organs that are in contact with the air spaces

Question 2

stomata and lenticels

Answer 2

Gasesdiffuse between the atmosphere and the air spaces through the stomata of leaves and the lenticels ofbark covered stems and roots.

Question 3

lenticels

Answer 3

small areas of loosely packed cells.

Question 4

THE GASEOUS EXCHANGE SURFACE IN PLANTS

Answer 4

The walls and membranes of all the cells inside the leaves, stems and roots of plants form the gaseous exchange surface.

Question 5

GRAPH SHOWING THE MOVEMENT OF GASES IN A LEAF

respiration occurs when in a leaf

Answer 5

respiration occurs all the time, as a plant/leaf is a living organism, if it is a non photosynthesising organ such as a stem or root respiration still occurs

Question 6

GRAPH SHOWING THE MOVEMENT OF GASES IN A LEAF

night

Answer 6

During the night, only respiration occurs. Oxygen diffusesin andcarbon dioxide diffusesout

Question 7

GRAPH SHOWING THE MOVEMENT OF GASES IN A LEAF

dawn

Answer 7

As dawn approaches photosynthesis begins and its rate gradually increases. The compensation pointis reached when the rate of photosynthesis equals the rate of respiration. At this point, there is no net movement of gases in or out of leaves

Question 8

GRAPH SHOWING THE MOVEMENT OF GASES IN A LEAF

during the day

Answer 8

During the day, the rate of photosynthesis is greater than the rate of respiration. Carbon dioxidediffuses in and oxygen diffuses out

Question 9

GRAPH SHOWING THE MOVEMENT OF GASES IN A LEAF

dusk

Answer 9

At about dusk a second compensation point occurs as the rates of photosynthesis and respiration become equal once more.

Question 10

large surface area

Answer 10

Leaves are broad, thin and numerous, and stems and roots have a branching SYSTEM creating a large surfacearea compared to the volume

Question 11

thin

Answer 11

Cell walls and membranes are extremely thin. as opposed to alveoli and gill lamallae whose walls are only one cell thick

Question 12

moist

Answer 12

All the cells are covered with a thin layer of moisture.

Question 13

Transport system
between the
surface and body
cells

Answer 13

Direct diffusion occurs between the air and the cells due to the large surface area to volume ratio