Transport In Plants

Question 1

How would stomata vary between plant environments

Answer 1

The amount, position, size and distribution of stomata vary between plants depending on the environment they live in and therefore water requirement

Question 2

How are the stomatal openings regulated to reduce water loss

Answer 2

Turgidity of guard cells change in relation to light intensity and availability of water to regulate stomatal openings

Question 3

How is water in leaves regulated

How does water enter the leaf then leave

Answer 3

When photosynthesis occurs glucose is produced creating a concentration gradient (in the guard cells)
This allows water to enter the leaves by osmosis
This makes the guard cells turgid and stomata opens, fully allowing exchange of gases and water loss

Question 4

Where in a plant contains the reproductive organs required to make seeds

Answer 4

The flower🌷

Question 5

Function of xylem

Answer 5

Transports water and soluble mineral salts from root hair cells to leaves (transpiration) to replace water lost by evaporation and photosynthesis

Question 6

Function of phloem

Answer 6

Allow the movement of food substances eg.sucrose around the plant (translocation)

Question 7

How can translocation be used in plants

Answer 7

Sucrose,a food substance is transported to storage organs (usually in the roots) and converted into starch

Or it may be sent to growing regions such as buds

Question 8

What are xylem and phloem defined as

What sort of system do they have with leaves

Answer 8

They are transport tissues

They form a continuous system of tubes from roots to leaves

Question 9

What is transpiration

What is the transpiration stream ‘powered’ by

Answer 9

The movement of water and minerals from the soil throughout the whole plant

Transpiration is powered by the evaporation of water from the stomata

Question 10

Explain how water moves through the plant through transpiration

Answer 10

Water evaporates from internal leaf cells through the stomata
Water passes by osmosis from xylem to leaf cells (pulling water up)
Water enters xylem from root tissue to replace water moving upwards
Water enters root hair cells by osmosis to replace water which has entered the xylem

Question 11

What are minerals in the soil carried as

Answer 11

Carried as dissolved ions

Absorbed and carried in the transpiration system

Question 12

Describe the xylem vessel

Answer 12

Hollow tubes made from dead plant cells

The cellulose cell walls are thickened and strengthened with a waterproof substance

Question 13

What is the hollow centre of xylem called

Answer 13

A lumen

Question 14

Describe phloem cells

Answer 14

Long columns of living cells able to move sugars up and down the plant

Question 15

What is the movement of sugars translocated by phloem cells

Answer 15

Phloem cells are able to translocate sugars UP and DOWN the plant

Question 16

Function of roots

Answer 16

Anchor plant in the ground and absorb water and minerals

Question 17

How are root hair cells adapted to absorb water

Answer 17

Large surface area

Question 18

What factors affect the rate of transpiration

Answer 18

Light 🔆- more light increases rate of photosynthesis so transpiration increases
Air movement🌪- transpiration increases as air movement increases
Temperature🌡- higher temperature increases rate of photosynthesis so transpiration increases
Humidity💭- increased humidity decreases rate of transpiration

Question 19

How does increased light increase transpiration rate

Answer 19

Increased light intensity increases rate of photosynthesis
This draws up more water from the transpiration stream
This maintains a high concentration in the spongy mesophyll

Question 20

How does increased temperature increase transpiration rate

Answer 20

Increased temperature increases kinetic energy of molecules

This removes water vapour quicker

Question 21

How does decreased humidity decrease transpiration rate

Answer 21

Humidity lowers water vapour concentration outside the stoma and maintaining concentration gradient

Question 22

How can the location of stomata vary depending on different climates

Answer 22

Plants living in arid climates often have fewer stomata with no stomata on the upper surface as the heat from sun increases evaporation here

Question 23

What would you use to measure rate of transpiration and how

Answer 23

A potometer
Put shoot in test tube with bung to prevent water evaporating
As plant transpires it takes up water from test tube to replace what it has lost, air bubble moves
The distance bubble moves can calculate transpiration in a time period

Question 24

Transpiration and water loss are inevitable consequences of photosynthesis

How is water passed out of the leaf

Answer 24

The stomata allows water molecules to pass out of the leaf