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biology igcse > questions revise > Flashcards

questions revise Flashcards

1
Q

in mitosis, State the structures that will form between the nuclei so that the cell divides into two cells.

A

cell membrane and cel wall

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2
Q

role of progesterone

A

maintain lining of uterus

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3
Q

describe role of lh

A

stimulates ovulation

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4
Q

explain why carbon dioxide is used in galsshouses

A

carbon dioxide is reactant needed for photosynthesis
increases rate of photosyntehsis
more glucose is produced
co2 is limiting factor outside glasshouse
-more growth of plants/ increased yield

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5
Q

state advantages of biofuels against fossil fuels

A

renewable resource/ finite
doesn’t cause climate change/ greenhouse gases/ global warming
conserves fossil fuels
produces photosynthesis, thus uses co2
less likely to cause acid rain

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6
Q

what are disadvantages of soil erosion

A

can cause landslides
reduction of transpiration of plants, can cause floods
desertification
change rainfall pattern
destroys habitats
decreases nutrients available for animals consumption
can cause species extinction
damage growth of plants

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7
Q

what are disadvantages of intensive livestock production

A

spread of disease quick to wild populations
deforestation for room for livestock
increase in relesion of co2/ greenhouse gases
use of pesticides
use of monoculture to provide food
lack of biodiversity
destruction of habitat

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8
Q

explain how tooth decay happens

A

-food such as sugar remains in teeth
-bacteria use food, breaks it down into sugars, to use for respiration
-acid is produced
-dissolves enamel
-dentine is exposed, which is soft tissue

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9
Q

describe and explain function of molars

A

physical digestion
grinds/chews food
increases surface area of food
for amylase action

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10
Q

explain how vasoconstriction reduces heat loss

A

less heat is lost by radiation or convection by air, less blood flows through surface of skin less heat is lost from blood to surrounding reducing heat lost from organism

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11
Q

outline effects of large scale deforistation on soil

A

soil erosion, happens, flooidng increases, less absoprtion of water by plants, loss of nutrients in soils, can cause land slides

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12
Q

outline effects of large scale deforistation on rivers

A

increases water present in rivers, more nutrients present in rivers

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13
Q

explain the importance for the enviornment of developing technologies for recylcing materials such as those found in drink cartons

A

microplastics can be consumber by aquatic life, plastic is a limted resource, recycling it causes less deforestation, and also uses less energy than making paper.

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14
Q

why were cells immersed in 1.8% salt solution diameter decrease

A

solution has lower water potential then cells
water moves by osmosis out of the cell unto solution across a partially permeable membrane
from high concentration to low concentration

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15
Q

why was there no change in diameter of red blood cells immersed in 0.9% salt

A

water potential same in cell and solution

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16
Q

state uses of water in a plant

A

prevents wilting by providing tugor pressure
translocation
reactant in photosynthesis
as a solvent

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17
Q

describe what is meant by an adaptive feature

A

inherited feature, makes an organism more adaptable and fit for evniornment it is in, higher chance of survival and reproduction

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18
Q

what is the spongy layer also known as

A

spongy mesophyll

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19
Q

what adaptation in the spongy mesophyll make hydrophytes fit for enviornment

A

large and many air spaces, reduces density of leaf, leaf floats on surface of water, makes it more accesible to light, carbon dioxide and gas exchange for photosynthesis

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20
Q

parkinsons disease affects neurones in brain hat are responsible for movement suggest and explain effect of parkinsons disease on a persons movement

A

movement is slower, slower reflexes, fewer vesicles, fewer neurotransmitters in vesicles, less neurotransmitters released into synaptic clef, fewer diffuse through synaptic clef, fewer bind to receptor proteins

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21
Q

explain how shape of receptor proteins is determined

A

sequence of bases in gene/ dna determines sequence of amino acids, used to build the protein and determine its shape

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22
Q

what is the role of protein carriers in membranes

A

carry particles accros partially parmeable membrane during active transport, against concentration gradient, eg. move magnesium ions accross membrane

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23
Q

why is not all oxygen produced in leaf released

A

some used in respiration and some remains in air spaces

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24
Q

describe role in chlorophyll in photosynthesis

A

absorbs light, synthesises glucose, converts light energy into chemical energy

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25
Q

describe ways in which the circulatory system of fish is different from circulatory system of a mammal

A

fish is single circulation, carries blood in lower pressure, one atrium and one ventricle only, only deoxygenated blood pumped by heart

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26
Q

explain advantages of a double circulatory system

A

prevents mixing of oxygenated and deoxygenated blood ;
blood able to flow at high pressure (to the body) ;
efficient / fast, supply of, blood / glucose / oxygen / nutrients ;
efficient / fast, removal of, waste / carbon dioxide / urea / lactic acid ;
allows efficient filtration in kidneys (for excretion) ;
to allow / maintain, a high, metabolic rate / rate of respiration ;
lower pressure, in pulmonary circuit / to lungs ;
to prevent damage to, delicate tissue / capillaries, in lungs ;
allows more time for gas exchange ;

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27
Q

state ways in which a baby can acquire immunity

A

vaccination, infection of disease, passive immunity across placenta, injection of antibodies

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28
Q

sepal function

A

protects flower bud

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29
Q

what does the pollen release during process leading to fertilisation

A

enzymes, to break down ovary and be able to penetrate ovary

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30
Q

outline advantages and disadvantages of self pollination

A

ad- more pollination, doesnt rely on pollinators, less pollen produced
dis-less variation, fewer individuals survive, more competition between plants, more succeptable to diseases, less adaptable to changes in enviornment

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31
Q

how is upper epidermis adpated to its function

A

thin and transparent, allows penetration of sunlight

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32
Q

how is capillary adapted for its function

A

small lumen
short diffusion distance
slows down blood flow
gaps between cells
thin one cellthick membrane
diffusion of oxygen

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33
Q

function of cartilage in breathing system

A

prevents airway from collapsing
located in trachea
makes airway open

34
Q

explain the effect of exercise on rate and depth of breathing

A

more oxygen needed to release energy
muscle contraction
energy fro muscle cells
quickly provides oxygen and glucose to cells
increased evel of co2 in blood
detected by brain
brain sends impulses to diaphragm
adrenaline released
quickly remove co2 from blood

35
Q

what does hair help in thermoregulation

A

when erect it traps air which acts as an insulator

36
Q

state why bacteria are useful in biotechnology

A

reproduce assexually
reproduce quickly
small
simple requirements to grow
same genetic code as other organims
lack of thical concerns
contain plasmids

37
Q

strrucutres both animal and bacterial cell share

A

dna
cell membrane
ribosome
cytoplasm

38
Q

explain why in a fermenter population will decrease after a while

A

lack of resources/ nutrients
build up of toxic materials such as co2
more deaths than births
increased competition
built up of pressure

39
Q

describe meaning of adaptation

A

result from natural selection
over many generations
make organism more fit for survival and reproduction, more likely to survive

40
Q

adaptations visible in plants in deserts

A

thick stem, corrugated stems, spikes (reduce surface area for transpiration)

41
Q

state and explain effect on stomata on increasing humidity of room

A

stomata take longer to close
guard cells do not lose water
guard cells stay turgid, take longer to become flaccid and close the stomata
less water will diffuse out as water vapour
gradient of diffusion is less steep due to humidity and water vapour on the outside of the plant

42
Q

explain how protein is made by a cell

A

uses energy
order of amino acids determined by base sequence in mrna
dna unzips revealing sequence of bases, mrna copies complementary bases, forming a template
mrna moves from nucleus to cytoplasm
ribosome is responsible for protein synthesis
ninds amino acids together to form a protein, using mrna as a template

43
Q

state types of cell membrane proteins

A

carriers
receptor proteins
maltase/ enzymes

44
Q

how can antibiotic resistence be decreased

A

education about antibiotic resistence
ingest les antibiotics
development of new antibiotics
improving detection of pathogen
vaccinated / population has reached herd immunity
isolating infected individuals

45
Q

explain how bacteria become resistant to antibiotics

A

random mutations occur in some bacteria
genetic variation in ability of bacteria to survive antibiotic treatment
bacteria with resistance, survive and reproduce
pass on resistant, gene to offspring
increase in frequency of resistant gene
to natural selection- become more adapted for environment

46
Q

state features present in all prokaryotes

A

no cell wall, circular dna, cell membrane, cytoplasm, ribosome, unicelular

47
Q

what is the name of the fifth trophic level

A

quaternary consumer

48
Q

outline how energy in primary consumers i used to produce biomass in secondary consumer

A

-primary consumers contain chemical energy
-energy is transferred to, secondary consumers, after having eaten primary
-food particles of primary consumer are digested to make energy for respiration
-energy released is used for, growth
-energy is used for, protein synthesis

49
Q

explain why it is more efficient for humans to eat crop plants than livestock that fed on crop plants

A

-plants are at a lower trophic level
-energy transfer along food chain is inefficient
-energy lost in respiration / heat
-more material that is lost as, faeces in longer food chains
-energy lost inexcretion / urine

50
Q

suggest why oxygen and water are required for germination

A

oxygen aerobic respiration
water is a solvent
water used for turgor pressure

51
Q

in a menstrual graph which hormone is at its highest in day 14 and which other is also high but not as much

A

highest= FSH
high=LH

52
Q

how should you draw concentrations of progesterone in a menstrual cycle day concentration of hormone graph

A

progesterone low unti day 14, where it increases up to day 21 where it then decreases again

53
Q

where in the body are goblet cells found

A

small intestine (villi)
trachea lining
bronchi
bronchioles

54
Q

describe and explain how structure of villus adapted for function

A

-microvilli
-increase surface area (fast absirption of nutrients)
-epithilium lining thin
-diffusion of nutrients
-good supply of blood
-good supply of blood to maintain steep concentration gradient
-enzyme production
-lacteal absorbs fats

55
Q

state features of amphibians that distinguish them from all other vertebrates

A

moist skin
eggs laid
-gas exchange occurs through skin
-larva have gills and adults have lungs
-two stage life cycle

56
Q

what can increase mutation rate

A

ionising radiation
chemicals

57
Q

explain risks to a species if its population size decreases

A

reduction in genetic variation
harder to find mate- decreases reproduction
can lead to extinction
inbreeding
increase i frequency of recessive alleles

58
Q

how can you tell double circulatory system is one

A

passes through heart twice before one complete circuit/ before reaches all vital organs
2 separate blood circuits, pulmonary and systematic circuit

59
Q

why does vein has a large lumen

A

provide less resistance for blood flow, and carry larger volume of blood

60
Q

what happens when suspensory ligments are permenantly over streched and you must focus on distant objects

A

ciliary relax, suspensory try to stretch but cant
lens remains wide instead of stretched doesn’t change angle of refraction

61
Q

Discuss the disadvantages of genetically modifying rice plants to produce beta-carotene

A

reduces biodiversity
ethical concerns
seed expensive to purchase
unknown long term side effect to consumers
risk of cross contamination to other rice plants

62
Q

State the name of the type of pathogen penicillin is used to treat.

A

bacteria

63
Q

List nutrients that need to be added to a fermenter to produce penicillin.

A

glucose
water
amino acids
ions

64
Q

Explain why the nutrients are sterilised (step 2) before they are added to the fermenter

A

stops growth of microogranisms

65
Q

state steps of producing pencillin

A

1 is reproduction mitosis of penicillium
2 inoculation in a fermenter
3exponential growth of organism penicillium in fermenter
4 sampling to check when penicillin is ready
5 penicillin is, a byproduct of maximum growth/ fermentation
6 cells / product / penicillin, are removed
7 purification of penicillin
8 idea of packaging of penicillin

66
Q

Suggest how the scientists would identify the presence of the HbS allele in tissue
samples.

A

analysing dna base sequence

67
Q

Mutations are always inherited in single-celled organisms that reproduce asexually but are not always inherited in organisms that reproduce sexually explain why

A

mutations are found in the DNA ;
asexual reproduction offspring are, genetically identical to parent
(so) any existing mutations (in parent DNA) will be inherited
sexual reproduction (usually) involves two parents
mutation will only be in one of the parents
mutation will only be in some of the gametes
meiosis does not result in genetically identical cells

68
Q

Describe how acid rain destroys forests.

A

lowers pH / acidifies soil
causes leaching
burn / corrode / damage , leaves
affects ability of roots to absorb mineral ions
lack of magnesium ions, causes lack of chlorophyll produced, limits photosyntheiss that be performed
lack of nitrate ions cause lack of protein, affect plants growth

69
Q

Suggest why amphibians are vulnerable to pollutants such as acid rain

A

adapted to a different pH
moist / permeable, skin
large surface to volume ratio
may have gills which are, fragile / thin
lays (unshelled) eggs in water
part of the life cycle / larval stages, only exist in water

70
Q

Describe how countries have reduced acid rain.

A

flue gas desulfurisation, in power stations / chimneys
reduce use of coal-fired power stations
use alternative / renewable, energy sources
catalytic converters
low sulfur fuel
recycling / reusing / reducing, plastic / less plastic waste burnt

71
Q

Suggest how the carbon dioxide concentration in a glasshouse can be enriched.

A

carbon dioxide gas cylinders used

72
Q

what are some adaptation of motor neurones

A

axons / long, to transmit (impulse), over (long) distance / 
fast / direct connection ;
2 (many) branches to connect to, other / relay, neurones / 
cells / effector / muscle ;
3 mitochondria to (release energy), for, transmission of
impulse / protein synthesis / active transport / making or
releasing (neuro)transmitters ;
4 vesicles to, carry / hold / release, chemicals / 
(neuro)transmitters (into synapse) ;
5 receptor (molecules), to ensure unidirectional transmission / 
to allow signal to be received by next neurone

73
Q

which organ is secreted from small intestine and acts in the epithelial lining
of the small intestine

A

maltase

74
Q

Discuss the negative impact on the natural environment of using chemicals, other than fertilisers, in modern farming methods.

A

kill / harm, non-target species (in natural environment) ;
example of specific impact from harm of non-target
species ;
loss of biodiversity / disrupt food chains ;
bioaccumulation / bioconcentration / biomagnification ;
ref to resistant organisms or super, bugs / weeds ;
pollute / destroy / AW, non-target / named, area / habitat ;
(antibiotics cause) antibiotic-resistance ;

75
Q

describe process of treating water or sewage

A

removal of, large pieces of waste
coagulation / clump suspended particles
settling of, (insoluble) particles
digestion / decomposition by bacteria / fungi
aeration tank
(water) treated with, chlorine /
distillation / collection of water from evaporator

76
Q

differences between 5 kingdoms

A

prokarayote- no nuclues, uni cellular, has cell wall not made of cellulose, heterotroph
fungi- made of hyphae, multicellular, has cellwall, heterotophs,
protocist- unicellular, heterotroph or autotroph,
animal- multicellular, no cell wall, has nucelus, heterotroph
plant- multicellular, has cell wall, autotroph, has nucleus

77
Q

different animal groups

A

molluscs, vertebrates, arthropods, annelids, cnydarians

78
Q

differnet plant groups and distinguishing features

A

ferns- no flowers, germinate, underground stems and roots, complex leaves, have spores (reproduce)
flowering plants-pollen, ovule, seed, fruit, leaves, aerial stems

79
Q

different vertebrate groups

A

all contain backbones
mammals, reptiles, fish, birds, amphibians

80
Q

distinguishing feautres of each vertebrate group

A

mammals- fur, warm blooded, external ears, produce milk,internal fertilisation
reptiles- 4 limbs, scales, lungs, cold blooded, internal fertilisation
fish- scales, gills, streamlined shape, cold blooded, external fertilisation, lay eggs
birds- beak, wings, feathers, internal fertilisation, warm blooded
amphibians- 2 life cycles, larva have gills, adults have lungs, moist skin,

biology igcse (25 decks)

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