Transpiration And Translocation

Question 1

what is transpiration

Answer 1

the evaporation of water from plants

Question 2

where is water carried thorough in a plant

Answer 2

in the xylem tube which are vessels from the roots to leaves

Question 3

what are the features or adaptations of xylem tubes

Answer 3

• thick side walls and rings of lignin
• dead cells have no cytoplasm
• lack of cell walls between cells
• tiny pores

Question 4

what does the lignin do

Answer 4

keeps it strong

Question 5

what are the features or adaptations of phloem tubes

Answer 5

• holes in ends of cell walls
• pores
• very small amount of cytoplasm

Question 6

how does transpiration happen

Answer 6

• water travels up xylem tubes like a suction system
• water travels to leaves
• unbroken chain of water molecules held together by weak forces of attraction between molecules
• as water from leaves evaporates, more is drawn into the roots

Question 7

what factors impact the rate of trnaspiration

Answer 7

• light intensity
• temperature
• air flow or wind speed

Question 8

why is water important for a plant (2)

Answer 8

• plants wilt as water sustains a plants structure. if little water, plant cant stand up properly
• it helps photosynthesis be done in its optimum conditions,like controlling temp of plant

Question 9

how do you measure the rate of transpiration

Answer 9

• with a potometer

- it measures the movement of a bubble in a capillary tube

Question 10

how does poor air flow affect the rate of transpiration

Answer 10

• if air flow if poor, water vapour just surrounds leaf and doesnt move away
• this means that there is a high concentration of water particles outside the leaf as well as inside
• so diffusion doesnt happen quickly

Question 11

how does light intensity affect the rate of transpiration

Answer 11

• the brighter the light, the greater the transpiration rate
• stomata begin to close as it gets darker
• as photosynthesis cant happen in the dark, so stomata dont need to be open to absorb CO2
• when stomata are closed, very little water can escape

Question 12

what is translocation

Answer 12

the movement of sugars in a plant

Question 13

what happens in translocation

Answer 13

• plants make sucrose from glucose after photosynthesis
• its transported via translocation in the sieve tubes in the phloem
• companion cells actively pump sucrose into and out of the sieve tubes

Question 14

what are xylem tubes made up of

Answer 14

dead cells joined end to end with no walls between them and a hole in the middle

Question 15

what is the transpiration stream

Answer 15

the movement of water from the roots, through the xylem and out of the leaves

Question 16

what is a phloem tube made up of

Answer 16

columns of elongated living cells with small pores in the end walls to allow stuff to flow through

Question 17

what is the function of the phloem tube

Answer 17

to transport food substances (mainly sucrose) made in the leaves to the rest of the plant for immediate use or for storage

Question 18

what does translocation require

Answer 18

• energy from respiration

- as the transport goes in both directions

Question 19

how does good air flow or quick wind speeds affect the rat of transpiration

Answer 19

• if there is good air flow, rate of transpiration increases
• because the water is swept away
• which maintains a low concentration of water particles in the air outside the leaf
• so diffusion from the leaves happens quickly, from an area of high concentration to an area of low concentration

Question 20

how does temperature affect the rate of transpiration

Answer 20

• the warmer it is, the faster transpiration happens
• when its warm the water particles have more energy
• to evaporate and diffuse out of the stomata

Question 21

how do you measure the rate of transpiration suing a potometer

Answer 21

distance moved / time taken

Question 22

what is water uptake by the plant directly related to

Answer 22

• water loss from the leaves

- as the xylem tube is a continuously flowing source of water

Question 23

why do xylem tubes have thick walls and rings of lignin

Answer 23

• to form rigid tubes that wont burst or collapse

- and provide support

Question 24

why do xylem tubes have dead cells with no cytoplasm

Answer 24

to form an empty tube for water to flow through

Question 25

why do xylem tubes lack cell walls between cells

Answer 25

so that water flow is not slowed down

Question 26

why do xylem tubes have tiny pores in cells

Answer 26

to allow water to enter and leave xylem vessels

Question 27

why do phloem tubes have holes in the end of cell walls

Answer 27

to allow liquids and minerals to flow from one sieve cell to next

Question 28

why do phloem tubes have pores

Answer 28

to have holes which sucrose solution can be pumped through

Question 29

why do phloem tubes have small amounts of cytoplasm

Answer 29

so there is more room for the central channel