Gas Exchange Flowering plants

Question 1

DIFFUSION IS

Answer 1

the movement of molecules from an area of high concentration to an area of low concentration

Question 2

diffusion drives the process of

Answer 2

gas exchange

Question 3

respiration and photosynthesis rely on the exchange of (2)

Answer 3

oxygen and carbon dioxide

Question 4

what cells respire

Answer 4

all living cells

Question 5

in respiration, The cells use ____ in respiration so the concentration is always ____ inside the respiring cells

Answer 5

oxygen
low

Question 6

in respiration, carbon dioxide diffuses from _____ the leaf to ____ the leaf so from ___ concentration to a ____ concentration

Answer 6

inside

outside

high

low

Question 7

plant cells can only photosynthesize when

Answer 7

there is enough sunlight

Question 8

process of photosynthesis needs the uptake of ____ and release of ____

Answer 8

carbon dioxide

oxygen

Question 9

concentration is low in photosynthesizing cells because

Answer 9

cells use carbon dioxide in photosynthesis so go from outside to inside ( high to low)

Question 10

in photosynthesis oxygen diffuses from

Answer 10

a high concentration ( inside the leaf) to a low concentration (outside)

Question 11

oxygen goes from ___ the leaves to ____ the leaves in photosynthesis

Answer 11

inside to outside

Question 12

why is there hardly any CO2 in the leaf in photosynthesis

Answer 12

because it is used up a lot

Question 13

how does oxygen diffuse out the leaf

Answer 13

through the stomata

Question 14

photosynthesis only happens during the

Answer 14

day

Question 15

plants respire

Answer 15

all the time

Question 16

why do plants respire all the time

Answer 16

to get the energy they need to live

Question 17

during the day, plants make ____ oxygen by photosynthesis than in respiration.

so they _____ oxygen

Answer 17

more

release

Question 18

during the day, plants ___ __ more carbon dioxide than they produce so ____ ___ carbon dioxide (photosynthesis)

Answer 18

use up

take in

Question 19

at night plants only

Answer 19

respire

Question 20

so during the night plants release ____ and take in ____

Answer 20

take in oxygen

release carbon dioxide

Question 21

how are leaves adapted for efficient gas exchange structure/outside (3)

Answer 21

• short diffusion distance (thin)
• large surface area (flat)
• stomata (allowing diffusion )

Question 22

adaptations of the internal leaf structure (5)

Answer 22

• air spaces Air spaces to allow gas movement around the loosely packed mesophyll cells
• Many stomata in the lower epidermis open in sunlight to allow gas movement in and out of the leaf
• Thin cell walls allow gases to move into the cells easily
• Moist air which gases can dissolve into for easier movement into and out of cells
• the close contact between the cells and the air spaces allows efficient gas exchange for photosynthesis and respiration

Question 23

3 key gases for leaf gas exchange

Answer 23

• CO2
• oxygen
• water vapour

Question 24

when is water vapour released

Answer 24

respiration and transpiration

Question 25

when is oxygen released

Answer 25

photosynthesis

Question 26

when is carbon dioxide released

Answer 26

respiration

Question 27

where are the stomata found

Answer 27

between the guard cells

Question 28

when do stomata close

Answer 28

when the guard cells lose water ( by osmosis) to the epidermal cells

Question 29

what are stomata

Answer 29

little holes or spaces found between 2 guard cells on the lower epidermis of the leaf

Question 30

guard cells are responsible for

Answer 30

opening and closing of stomata pore which controls gas exchange and water loss

Question 31

what does the stomata pore control

Answer 31

loss of water and gas exchange

Question 32

are stomata open in the night, why

Answer 32

no because they’re open when there is plenty of water and sunlight

Question 33

what does the guard cell control

Answer 33

The guard cells control the opening and closing of the stomata

Question 34

during the daytime plants …

Answer 34

respire and do photosynthesis

Question 35

if plants respire during the night, it means there is ( movement of gases)

Answer 35

this means that there is a net movement of oxygen into the plant and a net diffusion of carbon dioxide out of the plant during the nighttime

Question 36

at low intensities, the rate of photosynthesis is ____ to rate of respiration

meaning that the net movement of gases is

Answer 36

equal

This means that there is no net movement of oxygen or carbon dioxide in either direction

Question 37

PRACTICAL EFFECT OF LIGHT ON GAS EXCHANGE IN PLANTS

Answer 37

• Measure out 20 cm3 hydrogencarbonate indicator into 4 boiling tubes
• Put some cotton wool into each boiling tube
• Label the boiling tubes A-D and set them up as follows:
• Tube A - No leaf (control tube)
• Tube B - Place a leaf in the tube and leave in the light
• Tube C - Place a leaf in the tube and wrap it in aluminium foil to block out the light
• Tube D - Place a leaf in the tube and wrap it in gauze to allow partial light
• Put a LID into the top of each tube
• Leave all 4 tubes in the light for 30 minutes

Question 38

what should the results of the practical be

Answer 38

Tube A- should remain orange/red to show There has been no net movement of CO2

Tube B- will turn purple as there is less carbon dioxide than atmospheric levels

Tube C- will turn yellow as carbon dioxide levels increase above atmospheric levels

Tube D- no net change in carbon dioxide levels and the indicator remained orange/red