plant transport Flashcards

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1
Q

what is the function of xylem

A

to transport water and mineral salts from the roots to leaves

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2
Q

what is the 4 types of cell in xylem

A

tracheid, xylem vessels, parenchyma and fibres

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3
Q

describe what the tracheid are/do/ have

A

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

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4
Q

describe what xylem vessels are/do/ have

A

long tubes that join end to end

lignin for strength and permeability

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5
Q

what does parenchyma and fibres do

A

parenchyma- store food

fibres- support

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6
Q

what are the adaptations of xylem vessels and tracheid

A

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

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7
Q

what is the function of phloem

A

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

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8
Q

what are the 4 types of cells in phloem

A

sieve tubes, companion cells, parenchyma and fibres

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9
Q

describe what sieve tubes are

A

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

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10
Q

what is companion cells

A

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

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11
Q

describe root pressure

A

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

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12
Q

adaptation of root

A

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

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13
Q

describe the pathway of water

A

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

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14
Q

describe the pathway of water

A

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

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15
Q

compares villus and root hair

A

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

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16
Q

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

A

it is insufficient to over come forces of gravity

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17
Q

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

A

cohesive- between water molecules

adhesive- between water molecules and vascular vessels

18
Q

why do we need transpiration pull

A

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

19
Q

how does transpiration occur

A

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

20
Q

define transpiration

A

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

21
Q

what is transpiration pull

A

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

22
Q

describe how the force of transpiration pull is made

A

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

23
Q

what is the importance of transpiration

A

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

24
Q

what happens if there is too much transpiration

A

wilting occurs

25
Q

what does leaves do to avoid too much transpiration

A

roll inwards t reduce SA and hv less water loss

26
Q

why is too much transpiration a bad thing

A

they cant carry out biochemical reactions

27
Q

what do you use to measure rate of transpiration

A

potometer

28
Q

what are the 2 ways to measure rate of transpiration

A

distance travelled by bubble/ fixed time

measure time for bubble to travel fixed distance

29
Q

what is the assumption of potometer

A

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

30
Q

how to set up potometer

A
place potometer in water 
place plant and rubber topper 
lift apparatus up to get 1 bubble 
measure distance 
open reservoir to restart
31
Q

what are the limitation of potometer

A

not all water taken up will be transpired

use for photosynthesis and absorbed by cells to maintain turgidity

32
Q

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

A

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

33
Q

what are the 6 factors that affect rate of transpiration?

A

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

34
Q

how does humidity affect rate of transpiration

A

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

35
Q

how does air movement affect rate of transpiration

A

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

36
Q

how does light intensity affect rate of transpiration

A

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

37
Q

how does temperature affect rate of transpiration

A

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

38
Q

what is source

A

region of production

39
Q

what is sink

A

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

40
Q

how does translocation change in potato leaves during changes of seasons

A

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

41
Q

how does development of seed and translocation change

A

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

42
Q

list some adaptation to reduce transpiration rate

A

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