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A Level Biology : Content > Topic 4B : Resources From Plants > Flashcards

Topic 4B : Resources From Plants Flashcards

1
Q

cell wall

A

a rigid structure that surrounds plant cells and its made of cellulose

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2
Q

function of cell wall

A

support the plant cell

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3
Q

middle lamella

A

the outermost layer of the cell made of calcium pectate

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4
Q

function of middle lamella

A

adhesive layer, sticking adjacent plant cells together giving the plant stability

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5
Q

plasmodesmata

A

channels in the cell walls that link adjacent cells together

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6
Q

function of plasmodesmata

A

allow transport of substances and communication between cells

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7
Q

pits

A

regions of the cell where the wall is very thin

they are arranged in pairs (pit on one cell is lined up with pit in the adjacent cell)

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8
Q

function of pits

A

allow transport of substances between cells

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9
Q

chloroplast

A

flattened structure surrounded by double membrane and has thylakoid membranes inside

has grana(stacked thylakoid membrane) which are linked by lammae

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10
Q

function of chloroplast

A

site of photosynthesis

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11
Q

amyloplast

A

small organelle enclosed by a membrane which contains starch granules

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12
Q

function of amyloplast

A

storage of starch grains and also convert starch back to glucose for release when plants requires it

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13
Q

vacuole

A

vacuole is a compartment surrounded by tonoplast

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14
Q

function of vacuole

A

vacuole contains cell sap which is made of water,enzymes, minerals and waste producers

vacuoles keep the cell turgid and are involved in breakdown and isolation of unwanted chemicals in the cell

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15
Q

name the membrane that surrounds the vacuole

A

tonoplast

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16
Q

function of tonoplast

A

tonoplast controls what enters and leaves the vacuole

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17
Q

xylem vessels

A

long, tube-like structures formed from dead cells joined end to end found in bundles

cells are longer than wide and they have hollow lumen and no end walls making it uninterrupted tube allowing water and mineral ions to pass through the middle easily

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18
Q

function of xylem vessels

A

transport water and mineral ions up the plant and provide support

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19
Q

name the substance that thickens the walls of xylem vessels

A

lignin

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20
Q

sclerenchyma fibres

A

made of bundles of dead cells that run vertically up the stem

longer than wide and have hollow lumen and have end walls

have thickened walls by lignin

more cellulose than other cells

no pits

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21
Q

function of sclerenchyma fibres

A

provide support

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22
Q

phloem tissue

A

formed from cells arranged in tubes

includes sieve tube elements and companion cells

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23
Q

function of phloem tissue

A

transport organic solutes mainly sugars (translocation)

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24
Q

structure of sieve tube elements

A

living cells joined end to end to form sieve tubes

sieve parts are end walls that have lots of holes

no nucleus

very thin layer of cytoplasm (cytoplasm of adjacent cell is connected through the holes in the sieve tubes)

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25
Q

function of companion cells

A

carry out living functions for both themselves and their sieve tubes eg they provide the energy needed for active transport of solutes

26
Q

vascular bundles

A

when xylem vessels group together with phloem tissue in the stem

27
Q

name the two polysaccharides that starch is made up from

A

amylose and amylopectin

28
Q

structure of amylose

A

long unbranched chain of alpha glucose

angles of the glycosidic bonds give it a coiled structure making it compact so good for storage and you can fit more in small place

29
Q

structure of amylopectin

A

long branched chain of alpha glucose

side branches allow enzymes that break down the molecule to get at the glycosidic bonds easily so glucose can be released quickly

30
Q

function of starch

A

main energy storage material in plants and store excess glucose as starch

31
Q

is starch insoluble in water

A

yes

so doesn’t cause water to enter cells by osmosis making it good for storage

32
Q

function of cellulose

A

main structural component pf cell walls due to its strength which is a result of many hydrogen bonds found between parallel chains of microfibrils

high tensile strength pf cellulose allows it to be stretched without breaking which makes it possible for cells to withstand turgor pressure

stops plant cells from bursting when too much water enters by osmosis

33
Q

structure of cellulose

A

polymer consisting of long chains of beta glucose joined together by 1-4 glycosidic

to form 1-4 glycosidic bonds between beta glucose molecules, the glucose molecules must be rotated to 180 degrees to each other

these inversions keep it from coiling and it results in a long straight chain

hydrogen bonds form between hydroxyl groups on parallel chains

34
Q

what do plants require to perform functions efficiently

A

water and inorganic ions (minerals) which are absorbed through the root hairs on the root and travel up in xylem vessels

35
Q

why is water important for plants

A

required for photosynthesis

acts as a transport medium for minerals

maintains turgidity through pressure in cell vacuoles

regulates temperature so enzymes can work at optimum rate

36
Q

why are magnesium ions important for plants

A

required for chlorophyll production

this provides the green colour of stems and leaves essential for photosynthesis

37
Q

why are nitrate ions important for plants

A

plants would be unable to synthesise DNA, proteins and chlorophyll (nitrate ions required for enzymes)

essential for growth and production of fruit and seeds

38
Q

why are calcium ions important for plants

A

for important cell wall components

require calcium ions for proper growth

39
Q

clinical trials

A

when drugs first need to be teates for effectiveness and side-effects before sold to general public which avoids exposing the public to drugs that may pose a risk to their health

40
Q

what was digitalis used to treat

A

swelling caused by heart failure (dropsy)

41
Q

digitalis soup

A

different versions of foxglove treatment containing different concentration of digitalis

42
Q

why dis withering use different concentrations of digitalis

A

foxglove is poisonous to humans so he had to find the most effective concentration without poisoning the patient

43
Q

stages before clinical trials

A

modelling potential effects of drug using computers

drug tested on human tissues in a laboratory

44
Q

phase one of clinical trials

A

involves small group of healthy individuals to determine how the body reacts to the drug, side effects and correct dosage that should be taken

45
Q

phase two of clinical trials

A

done on larger group of patients (non-healthy who require the drug) to determine effectiveness of the drug

46
Q

phase three of clinical trials

A

comparing drug to existing drugs to see of it works any better

large number of patients split into two groups, each of which received either new drug or existing one

47
Q

during what stage of clinical trials do placebos take place

A

2

48
Q

explain how placebos are used

A

patients are split into two groups - one will receive the drug and the other group will be given a placebo, which looks exactly like the drug but contains no active ingredients.

the patients are not told which group they are in which this provides a way for scientists to determine whether the drug actually works.

49
Q

placebo effect

A

this is where a patient will show improvements in their health due to the belief that they are receiving the drug

50
Q

during what stage do double blind studies occur

A

2 or 3

51
Q

double blind studies

A

neither the patient nor the doctor knows which patient is receiving the drug or the placebo reducing the effect that attitude of either doctors or patient may have on the results.

52
Q

conditions required for bacterial growth to occur

A

nutrients to provide them with materials needed to grow and respire

those that respira aerobically will need oxygen supply

temperature and pH must be not too high or too low to allow enzymes that control metabolic processes to function optimally

53
Q

antimicrobial

A

substance either kills microbes or prevent their growth

54
Q

what are plant fibres made of

A

long tubes of plant cells

55
Q

give two reasons why plant fibres are strong

A

the arrangement of cellulose microfibrils in the cell wall

secondary thickening of cell walls

56
Q

arrangement of cellulose microfibrils in the cell wall

A

cell wall contains cellulose microfibrils in a net-like arrangement which gives plant strength

57
Q

the secondary thickening of cell wall

A

Pectin acts as a glue in middle lamella jining cells together therefore secondary cell wall produced when structural plant cells have finished growing which is ticker than the normal cell wall and usually has more lignin.

58
Q

give two advantages of using plant fibres rather than oil-based plastics to make rope

A

more sustainable as less fossil fuel is used up and crops can be regrown to maintain supply for future

biodegradable so they can be broken down by microbes

plants easier to grow and process than extracting oil making it also cheaper and easier for developing countries

59
Q

give a advantage of using plant fibres rather than oil-based plastics to make rope

A

they are generally not as strong as ropes made of plastic

60
Q

give advantage of using starch rather than oil to make plastics

A

more sustainable than making them from oil as less fossil fuel is used up and crops from which starch came from can be regrown

61
Q

name two other products other than rope that can be made from plants

A

bioplastics

vehicle fuel eg bioethanol

62
Q

explain why the production of fibres from nettles is more sustainable fibres produced from crude oil

A

crude oil is non renewable while nettles are renewable

nettles can be replanted after harvest

crude oil produces produces plastic which is non degradable while nettles are degradable

A Level Biology : Content (18 decks)

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