plant transport

Question 1

what is the function of xylem

Answer 1

to transport water and mineral salts from the roots to leaves

Question 2

what is the 4 types of cell in xylem

Answer 2

tracheid, xylem vessels, parenchyma and fibres

Question 3

describe what the tracheid are/do/ have

Answer 3

they hv a smaller diameter than xylem vessels and pointed ends
they have pits to allow water to flow
they transport water in-between cells

Question 4

describe what xylem vessels are/do/ have

Answer 4

long tubes that join end to end

lignin for strength and permeability

Question 5

what does parenchyma and fibres do

Answer 5

parenchyma- store food

fibres- support

Question 6

what are the adaptations of xylem vessels and tracheid

Answer 6

lignin- strength & prevents food entry
open ends to allow water flow
pit to allow mineral salt and water pass through
open ends join to form hollow tubes - water and mineral salt pass sideways

Question 7

what is the function of phloem

Answer 7

to transport products of photosynthesis from leaf to storage and growing areas

Question 8

what are the 4 types of cells in phloem

Answer 8

sieve tubes, companion cells, parenchyma and fibres

Question 9

describe what sieve tubes are

Answer 9

they have no nucleus and are dead cells
long cells that join end to end with no lignin
sieve plate lets substances pass through

Question 10

what is companion cells

Answer 10

have nucleus and help sieve tubes
produces mitochondria
provide protein and energy

Question 11

describe root pressure

Answer 11

high concentration of ms in cell, active transport from soil to cell. lower wp in cell so osmosis. causes root pressure

Question 12

adaptation of root

Answer 12

has root hair cells which is just elongated cytoplast to increase surface area
has root cap to protect root

Question 13

describe the pathway of water

Answer 13

soil - root- root hari-cortex- cell -xylem - leaf

Question 14

describe the pathway of water

Answer 14

soil - root- root hair-cortex- cell -xylem - leaf

Question 15

compares villus and root hair

Answer 15

similarities
both use active transport
absorb nutrients
have structures to increase surface area
differences
root hair absorb water and ms but villus absorb amino acid
root use AT to get nutrients but villus use diffusion
root hair has cytoplasm, nucleus and vacuoles but villus has lacteal and vein

Question 16

why is root pressure not enough to bring water up the stem

Answer 16

it is insufficient to over come forces of gravity

Question 17

what are the 2 types of forces in capillary action and their meaning

Answer 17

cohesive- between water molecules

adhesive- between water molecules and vascular vessels

Question 18

why do we need transpiration pull

Answer 18

capillary action is only enough to pull upwards the xylem vessel but not enough to pull to leaves

Question 19

how does transpiration occur

Answer 19

there is excess water is mesophyll cells
the temp rises due to sunlight intensity
water evaporates
concentration of water vapor in atmosphere in air space is higher than atmosphere
water will diffuse out of the lead into atmosphere

Question 20

define transpiration

Answer 20

loss of water vapour due to the evaporation of water in the mesophyll cell followed by diffusion of water vapour through stomata

Question 21

what is transpiration pull

Answer 21

force that pulls water vapour up from the xylem vessels into mesophyll cells

Question 22

describe how the force of transpiration pull is made

Answer 22

the cell has low wp
adjacent cell has higher wp so osmosis
draws water up the xylem vessels

Question 23

what is the importance of transpiration

Answer 23

maintain turgidity
cool temp - use heat to change liquid to gas
water uptake

Question 24

what happens if there is too much transpiration

Answer 24

wilting occurs

Question 25

what does leaves do to avoid too much transpiration

Answer 25

roll inwards t reduce SA and hv less water loss

Question 26

why is too much transpiration a bad thing

Answer 26

they cant carry out biochemical reactions

Question 27

what do you use to measure rate of transpiration

Answer 27

potometer

Question 28

what are the 2 ways to measure rate of transpiration

Answer 28

distance travelled by bubble/ fixed time | measure time for bubble to travel fixed distance

Question 29

what is the assumption of potometer

Answer 29

volume of water loss from potometer is equal to volume of water transpired

Question 30

how to set up potometer

Answer 30

``` place potometer in water place plant and rubber topper lift apparatus up to get 1 bubble measure distance open reservoir to restart ```

Question 31

what are the limitation of potometer

Answer 31

not all water taken up will be transpired | use for photosynthesis and absorbed by cells to maintain turgidity

Question 32

what are the other uses of potometer other than measuring rate of transpiration, and how do you manipulate them

Answer 32

effect on light intensity: distance of lamp effect of air movement: speed of fan effect of number of leaves: remove leaves one by one

Question 33

what are the 6 factors that affect rate of transpiration?

Answer 33

humidity, air movement, light intensity, temperature, number of stomata and water supply

Question 34

how does humidity affect rate of transpiration

Answer 34

lower the humidity, the faster the rate less water vapour outside, so steeper gradient faster diffusion so faster rate

Question 35

how does air movement affect rate of transpiration

Answer 35

more air movement, faster rate air will move water vapor away from the leaves lower concentration outside and thus steeper gradient increases transpiration rate

Question 36

how does light intensity affect rate of transpiration

Answer 36

higher light intensity, higher rate of transpiration stomata opens wider so more co2 and water vapour go out light intensity simulates stomata to open

Question 37

how does temperature affect rate of transpiration

Answer 37

higher temp higher rate more kinetic energy to evaporate and diffuse out the stomata rate of photosynthesis is higher, so more water is drawn up the stem so more water in air spaces

Question 38

what is source

Answer 38

region of production

Question 39

what is sink

Answer 39

region of storage area of places where used for growth and respiration

Question 40

how does translocation change in potato leaves during changes of seasons

Answer 40

in summer, leaves are source bc photosynthesis, tubers and stem becomes sink in winter, leaves fall out so tubers, which stored starch becomes source and leaves became sink

Question 41

how does development of seed and translocation change

Answer 41

when developing, leaves are source and sink so seed store sucrose is from of starch in cotyledon when they germinate seed becomes source

Question 42

list some adaptation to reduce transpiration rate

Answer 42

hairy leave- less air movement less stomata, less evaporation waxy cuticle- longer distance to travel for diffusion small leaves- reduce surface area rolled leaves- trapped air inside has higher humidity