Gas Exchange & Transpiration

Question 1

What is transpiration?

Answer 1

The net movement of water up the xylem to the stomata in the leaf, wherby the water vapour is removed via evaporation

Question 2

increasing the light intensity increases the rate of transpiration why

Answer 2

more light opens more stomata

Question 3

What are the 3 factors that increase the rate of transpiration?

Answer 3

Wind, Light, temperature

Question 4

How does higher light intensity affect transpiration?

Answer 4

greater transpiration rates, because plants open their stomata in response to light, allowing water vapour to escape from the leaves.

Question 5

During the day , are the stoma open or closed?!?

Answer 5

Open

Question 6

What effect do wind speeds have on transpiration?

Answer 6

It increases it

Question 7

How is the spongy mesophyll adapted to its function?

Answer 7

The spongy mesophyll has lots of air spaces meaning that it increases the surface area to volume ratio to increase the diffusion carbon dioxide.

Question 8

What is the word equation for Photosynthesis?

Answer 8

Carbon Dioxide + Water -> Oxygen + Glucose

Question 9

What factor reduces the rate of transpiration?

Answer 9

Humidity

Question 10

How does higher humidity affect transpiration?

Answer 10

the transpiration rate decreases as It is easier for water to evaporate into dryer air due to the Prescence of a high to low concentration gradient

Question 11

What happens to the stomata when hydrated and dehydrated

Answer 11

The stomata will open when hydrated, and closed when dehydrated.

Question 12

State all four factors that affect the rate of transpiration in a plant

Answer 12

• Temperature
• Light/CO2
• Humidity
• Wind

Question 13

Explain how guard cells open

Answer 13

Guard cells become turgid, opening to stomate and allowing gases to enter and exit the leaf

Question 13

what is the adaptation of the spongy mesophyll layer for gas exchange

Answer 13

lots of air space to increase the surfaces area for more diffusion of co2

Question 14

what is the name of the indicator that shows if carbon dioxide is present

Answer 14

Hydrogen carbonate indicator

Question 15

what is the middle part of the structure of the leaf called and way has is it adapted for photosynthesis.

Answer 15

The middle part is called the mesophyll, the pallisade mesophyll contains lots of chloroplats meaning more abosrbtion of light meaning more photosynthesis. The spongy mesophyll contains air spaces, allowing gases to move easier, meaning faster rate of diffusion of CO2, meaning faster rate of photosynthesis.

Question 16

How many waxy cuticle layers are there?

Answer 16

2

Question 17

What indicator is used to measure transpiration?

Answer 17

Hydrogen-carbonate indicator

Question 18

Why does the shoot need to be cut at an angle when measuring the rate of transpiration?

Answer 18

Increase surface area to reduce air bubbles into the Xylem

Question 19

Why are leaves thin?

Answer 19

Leaves are thin to create a short diffusion pathway for gases so that the diffusion of gases in and out of the leaf are much quicker.

Question 20

What are the two types of measuring the rate of transpirtaion in a leaf?

Answer 20

• mass potometer
• bubble potometer

Question 21

What does the xylem transport and to where?

Answer 21

Water and dissolved mineral ions from the root to the leaves

Question 22

By what process does water move from the soil to the root hair cell?

Answer 22

Osmosis

Question 23

What is the factor that decreases the rate of transpiration the more there is?

Answer 23

humidity

Question 23

Why does humidity lower the rate of transpiration?

Answer 23

Because there is a higher - and growing - concentration of water molecules on the outside of the leaf than inside

Question 46

what is the word equation for photosynthesis?

Answer 46

Carbon dioxide + water -> glucose + oxygen