transport in plants

Question 1

what does the xylem transport

Answer 1

water and mineral ions

Question 2

what does the phloem transport

Answer 2

sucrose and amino acids

Question 3

describe the features of the xylem

Answer 3

• dead cells ( no obstruction from organelles )
• continuous column
• walls are thickened with Lignin ( waterproof and strong to prevent collapsing )
• movement in one direction only ( roots to shoots )

Question 4

describe the features of the phloem

Answer 4

• companion cells ( keeps phloem alive )
• sieve plates between each cell ( allows things to flow through
• movement happens in both directions

Question 5

definition of translocation

Answer 5

sugars made during photosynthesis are transported through the phloem to growing points and turned into starch

Question 6

definition of transpiration

Answer 6

the loss of water by evaporation from the surface of the plant

Question 7

list 4 things that affect transpiration

Answer 7

light, humidity, temperature and wind speed

Question 8

how does wind speed affect transpiration

Answer 8

wind blows water molecules away, this increases the water potential gradient therefore the rate of transpiration increases

Question 9

how does temperature affect transpiration

Answer 9

having a higher temperature means water molecules have more kinetic energy meaning more movement, increasing the rate of transpiration

Question 10

how does humidity affect transpiration

Answer 10

more humidity means more water molecules outside the plant, meaning transpiration will slow as the it decreases the water potential gradient

Question 11

how does light affect transpiration

Answer 11

more light means more photosynthesis occurring which means more CO2 is needed so the stomata is open which results in water loss and an increase in the rate of transpiration

Question 12

describe a transpiration stream

Answer 12

• water moves into root hair cells by osmosis
• water is pulled up the xylem
• water is lost as it evaporates
• water is replaced creating a transpiration stream

Question 13

how are root hair cells adapted to take in water and minerals

Answer 13

• thin walls ( short diffusion distance )
• large surface area
• low water concentration so water can move in by osmosis

Question 14

how is the leaf adapted for gas exchange

Answer 14

• broad thin leaf increases SA
• spongey mesophyll has gas pockets so gases can diffuse
• stomata which enable gases to diffuse in and out

Question 15

effects of deforestiation

Answer 15

soil erosion, leaching, disturbing evapotranspiration, balance of O2 and CO2