Plant transport

Question 1

Where do plants absorb water from?

Answer 1

From the roots

Question 2

What is the transport system made up?

Answer 2

A tissue called xylem and phloem

Question 3

What does phloem transport?

Answer 3

Phloem transports sucrose and amino acids from the leaves where they are made to other parts of the plant

Question 4

Describe the features of the xylem.

Answer 4

It is made of hollow dead cells joined end to end

the end walls have disappeared so a long open tube is formed

Question 5

Where do xylem vessels run from?

Answer 5

From the roots, up through the stem and branch out into every leaf

Question 6

What do xylem not contain?

Answer 6

Cytoplasm and nucleus

Question 7

What are the xylem walls made up of ?

Answer 7

Made of cellulose and lignin.

Question 8

What is lignin?

Answer 8

Lignin is very strong so xylem vessels help to keep plants upright

Question 9

What is wood made up of?

Answer 9

Lignified xylem vessels

Question 10

Describe the features of the phloem.

Answer 10

They are made of many cells joined end to end. They have sieve plates which have small holes in them- sieve tube elements

Question 11

What direction do minerals travel in a xylem?

Answer 11

One way

Question 12

What direction do organic molecules travel in the phloem?

Answer 12

Two way

Question 13

What is a root cap?

Answer 13

At the very tip of the root hair cells. It is a layer of cells that protects the root as it grows through the soil.

Question 14

What adaptation do root hair cells have?

Answer 14

They have a large surface area to increase the the rate of absorption

Question 15

How do they absorb water?

Answer 15

By osmosis

Question 16

How do they absorb ions?

Answer 16

By active transport

Question 17

What is the function of the root hairs?

Answer 17

To absorb water and minerals from the soil. Water moves into a root by osmosis.

Question 18

Describe how water is absorbed by the root hair cell.

Answer 18

The water in the soil is normally a more dilute solution so water diffuses into the root hair, down the concentration gradient and through the partially permeable surface membrane.

Question 19

How does water travel up the xylem?

Answer 19

The pressure at the top of the vessels is lowered, while the pressure at eh bottom stays high.

Question 20

How is the pressure at the top of the xylem vessels reduced?

Answer 20

It happens because of transpiration

Question 21

What is transpiration?

Answer 21

Loss of water vapor from plant leaves by evaporation of water at the mesophyll cells followed by diffusion of water vapor through the stomata.

Question 22

What is the transpiration stream?

Answer 22

The flow of water through a plant, from the roots to the leaves via the xylem vessels.

Question 23

Describe the attractive forces in the xylem vessels

Answer 23

The attractive forces between the water molecule result in cohesion. These forces are greater than the forces trying to separate them, so the transpiration stream is pulling thin columns of water molecules, which resist the tendency to break apart.

Question 24

What increases the rate of evaporation?

Answer 24

The many air spaces inside the leaf means that there is a large surface area of wet cells.

Question 25

What do stomata do?

Answer 25

They allow water vapor to diffuse easily out of the leaf

Question 26

What do the stomata reduce?

Answer 26

Reduces water potential inside the leaf which encourages more water to evaporate from the surfaces of the mesophyll cells

Question 27

What is the rate of transpiration?

Answer 27

The rate at which a plant takes up water depends on the rate of transpiration- the faster a plant transpires the faster it takes up water

Question 28

What is a potometre?

Answer 28

Records how fast the air/ water meniscus moves along the capillary tube- you can compare how fast the plant takes up water.

Question 29

Describe the effect of temperature on transpiration.

Answer 29

On a hot day water will evaporate quickly from the leaves of a plant. Transpiration increases as the temperature increases

Question 30

Describe the effect of humidity on transpiration.

Answer 30

Humidity means the moisture content of the air. The higher the humidity, the less water will evaporate from the leaves. This is because there is not much of a diffusion gradient for the water between the air spaces inside the leaf, and the wet air outside it. Transpiration decreases as humidity increases

Question 31

Describe the effect of wind speed on transpiration.

Answer 31

On a windy day water evaporates more quickly than on a still day. Transpiration increases as wind speed increases

Question 32

Describe the effect of Light intensity on transpiration.

Answer 32

In bright sunlight, a plant may open to supply plenty of CO2 for photosynthesis. More water therefore will evaporate from the leaves.

Question 33

What is the direction of water movement in a plant?

Answer 33

Root hair- cortex- xylem- leaf - stomata

Question 34

What happens if the plant is in short supply of water?

Answer 34

The plant will close its stomata, decreasing the rate of transpiration.

Question 35

What happens if the leaves too much water loss?

Answer 35

The plant wilts because cells lose water by osmosis and become flaccid

Question 36

What is translocation?

Answer 36

The movement of sucrose and amino acids in phloem from regions of production to regions of storage or to region of utilization in respiration or growth.

Question 37

What can carbohydrates be made into?

Answer 37

Amino acids, proteins

Question 38

What is a source?

Answer 38

The part of the a plant from which sucrose and amino acids are being trans located- leaves

Question 39

What is the sink?

Answer 39

The part of the plant to which they are being trans located such as roots and flowers

Question 40

What do the flowers use sucrose for?

Answer 40

To make fructose for when fruits are developing

Question 41

What would act as a sink when it is a bud?

Answer 41

The leaves.