Transport And Coordination In Plants

Question 1

What does the transport system in plants enable plant to do ?

Answer 1

• enables leaves to receive water for photosynthesis
• mineral ions needed to convert the products of photosynthesis into useful substances
• once these are formed these are transported to other parts of the plant like growing points and storage areas

Question 2

What does xylem do?

Answer 2

• transports water and mineral irons from the roots to the leaves

Question 3

What are nitrate ions needed for in a plant ?

Answer 3

To make amino acid’s and proteins

Question 4

What are magnesium ions needed for in a plant ?

Answer 4

To make chlorophyll

Question 5

What is xylem made up of ?

Answer 5

Thick walled vessels, they are dead cells containing no cytoplasm - they are completely hollow and arranged end to end

Question 6

Which way does water and mineral ions move in xylem ?

Answer 6

From ROOTS to SHOOTS

Question 7

What are the walls of xylem thickened with ? And what does this do ?

Answer 7

Lignin, which makes them
• waterproof
• very strong - stops cells collapsing inwards
• give stems support

Question 8

What does phloem transport ?

Answer 8

It transports sucrose and amino acids from the leaves to the growing points or storage areas

Question 9

What cells do phloem consist of ?

And why ?

Answer 9

Living cells, as tubes have cytoplasm in the walls, as cells need to be kept alive to transport the substances

Question 10

How is sucrose and amino acid’s transported ?

Answer 10

Active transport

Question 11

What is sugar converted into in the leaves ?

Answer 11

Sucrose, as the sugar made in photosynthesis is converted to sucrose for transport through the Phloem to the growing tips

Question 12

What direction do the fluids move in the phloem ?

Answer 12

Both directions

Question 13

What are the cell walls made of in the phloem tube ?

Answer 13

Cellulose

Question 14

How is water uptaked ?

Answer 14

By the roots by the root hair cells

Question 15

How is water absorbed by the root hair cell ?

Answer 15

• plants take in water from the soil through the root hairs
• The hairs increase the surface area of the roots epidermis
• The long thin outer projection penetrate between the soil particles reaching the soils water
• this water has some solutes dissolved in it but the concentration is much lower than the concentration of solutes inside the root hair cell. The soil water has a higher concentration of water molecules and water will enter the cell by osmosis
• this dilutes the contents of the cell increasing its concentration of water molecules. Water will then move from the root hair cell into the cortex cells of the root
• this gradient is maintained as water is constantly being taken up by the xylem

Question 16

How are mineral ions uptaken ?

Answer 16

By active transport and diffusion

Question 17

What is transpiration?

Answer 17

The evaporation of water from the surface of the leaf

Question 18

What is the transpiration stream?

Answer 18

Transpiration causes water to be pulled up by the xylem in the stem and roots in a continuous flow known as the transpiration stream

Question 19

Where does the water leave during transportation?

Answer 19

Through the stomata

Question 20

Where does the water vapour in transportation evaporate between ?

Answer 20

The water leaves the mesophyll and evaporate into that space between spongy Mesophyll

Question 21

What are the four functions of the transpiration stream ?

Answer 21

• to carry mineral ions to the leaves
• to keep heard your pressure high in the leaf cells, holding the leaves up
• evaporation cool the leaves
• transpiration is inevitable as the stomata has to be at least partly open to allow O2 and CO2 to diffuse freely

Question 22

What are the five factors that affect the rate of transpiration?

Answer 22

• temperature
• humidity
• wind speed
• water supply
• light intensity

Question 23

How does temperature affect the rate of transpiration?

Answer 23

• on a hot day, water will evaporate quickly from the leaves of the plant. Therefore transpiration will increase if temperature increases.

Question 24

How does humidity affect the rate of transpiration?

Answer 24

• very humid air contains a great deal of water vapour- therefore it can only except a small amount of water from the leaf, so transpiration slows down
• in dry at the diffusion of water vapour from the leaf to the atmosphere will be rapid. Transpiration increases if humidity decreases

Question 25

How does windspeed affect the rate of transpiration?

Answer 25

• in still air, the region around the transpiring leave will become saturated with water vapour, so that no more can I escape from the leaf - causing transportation to slow down
• in moving air, the water vapour will be swept away from the leaf as fast as it diffuses out. This will speed up transpiration
• transpiration therefore increases as wind speed increases

Question 26

How does light intensity affect the rate of transpiration?

Answer 26

• light itself does not affect evaporation, but in daylight the stomata is open to supply carbon dioxide for photosynthesis, this allows more water to diffuse out of the leaves and into the atmosphere

Question 27

How does watersupply affect the rate of diffusion?

Answer 27

• if water is in short supply, and the plant is losing water by transpiration faster than it is being taken up by the roots, then the plant will start to wilt
• before this happens the stomata starts to close, therefore reducing transpiration and delaying wilting

Question 28

What is a tropism ?

Answer 28

The growth of a plant to water directional stimulus

Question 29

What is phototropism ?

Answer 29

The growth of a plant towards light

Question 30

What is positive phototropism ?

Answer 30

The growth of a plant towards light E.g. Stem

Question 31

What is negative phototropism ?

Answer 31

Growth of a plant away from the light e.g. roots

Question 32

What is Geotropism ?

Answer 32

Is the growth away from gravity

Question 33

What is positive Geotropism ?

Answer 33

The growth with the direction of gravity e.g. Roots

Question 34

What is negative Geotropism ?

Answer 34

Is the growing upwards of a plant away from gravity

Question 35

What is translocation ?

Answer 35

The movement of sugars around the body

Question 36

Where is auxin produced?

Answer 36

In the growing tip

Question 37

How does a plant grow towards the light?

Answer 37

• The growing tip grows towards the light as auxin is produced in the growing tip, light destroys auxin on the sunny side, so auxin diffuses over to the Shady side
• auxin accumulates on the Shady side this causes increased cell elongation. Therefore the growing tip leans/grows towards the sun