Transport in Plants

Question 1

Transport needed for

Answer 1

Provides materials for photosynthesis, respiration, growth, reproduction

Question 2

Water transport-route

Answer 2

enters via root hairs using osmosis

moves with diffusion to grund tissue and xylem

Question 3

Root hair adaptions for absorbing water

Answer 3

Thin walls
Large surface area-lots of root hairs
Dont have cuticle

Question 4

Mechanisms to transport water against gravity

Answer 4

Root pressure: as water enters xylem builds up pressure that pushes water up.
Transpiration: as water evaporates more water is pulled up to the leaf.

Question 5

Transpiration

Answer 5

Loss of water through leaves

Question 6

Methods of controlling transpiration

Answer 6

1. Cuticle- waxy surface. Doesnt let water through. upper surface as more exposed.
2. Location of stomata- small holes where water leaves the leaf. Lower side of leaf-less exposed
3. Shape of stomata

Question 7

Shape of stomata

Answer 7

2 guard cells- change shape to open/close stoma. water gets into cells by osmosis and they curve to reveal stoma. When they lose water they shrink and the gap between them closes the stoma.

Question 8

Function of Stomata

Answer 8

Gas exchange (CO2 in, O2 out)

Question 9

Why is CO2 needed?

Answer 9

needed for photosynthesis.

Question 10

Where does photosynthesis take place

Answer 10

Spongy Mesophyll cells

Question 11

How does CO2 get into the cells?

Answer 11

Diffuses through the stomata from the atmosphere. Diffuses into the air spaces and then into mesophyll cells

Question 12

Factors that control opening/closing of stomata

Answer 12

Daylight- Open- photosynthesis taking place, allows CO2 in. Low levels of CO2 in air spaces. Stomata opens to let more in.
Darkness-Closed- photosynthesis not occuring, no CO2 used, high concentration in air spaces. Closed to reduce water loss and CO2 intake.

Question 13

Conditions where stomata close during the day

Answer 13

If plant has lost too much water
If temperature too high.
In dry conditions stomata remain closed which means photosynthes cant take place and food crops die.

Question 14

The amount of CO2 absorbed is used to

Answer 14

tell us the rate of photosynthesis
However CO2 is also produced by respiration. So true rate of photosynthesis is CO2 taken in by stomata and CO2 formed in respiration

Question 15

Fate of Photosynthesis products

Answer 15

Oxygen- diffuses into air spaces and out stomata. Some used in respiration
Glucose- carbohydrate made by photosynthesis. Provides energy for respiration. Stored as starch (mesophyll cells) Converted into sucrose.

Question 16

Importance of stored starch

Answer 16

Important in diet of leaf eating animals. eg. horses, cattle etc.

Question 17

Use of glucose converted to sucrose

Answer 17

Enters phloem sieve tube cells and transported through plant.

Question 18

What is phoem sap?

Answer 18

The glucose that is converted to sucrose.

Question 19

Function of minerals

Answer 19

Calcium- Make cell walls

Magnesium- Makes chlorophyll

Question 20

How minerals enter plant

Answer 20

Dissolved in water. Requires energy so is called active transport.

Question 21

Cohesion

Answer 21

Similiar molecules sticking together. eg. water sticks to water.

Question 22

Adhesion

Answer 22

Different molecules sticking together. eg. water sticking to Xylem walls

Question 23

Cohesion Tension Model

Answer 23

Transpiration-column of water under tension- Cohesion replaces the water mol. by pulling up the next one- felt down length of column- tension pulls to great heights against gravity- causes column to stretch-cohesive and adhesive forces keep together.
Lignin in walls keeps xylem from collapsing in.