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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
describe ways in which the circulatory system of fish is different from circulatory system of a mammal
fish is single circulation, carries blood in lower pressure, one atrium and one ventricle only, only deoxygenated blood pumped by heart
26
explain advantages of a double circulatory system
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 ;
27
state ways in which a baby can acquire immunity
vaccination, infection of disease, passive immunity across placenta, injection of antibodies
28
sepal function
protects flower bud
29
what does the pollen release during process leading to fertilisation
enzymes, to break down ovary and be able to penetrate ovary
30
outline advantages and disadvantages of self pollination
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
31
how is upper epidermis adpated to its function
thin and transparent, allows penetration of sunlight
32
how is capillary adapted for its function
small lumen short diffusion distance slows down blood flow gaps between cells thin one cellthick membrane diffusion of oxygen
33
function of cartilage in breathing system
prevents airway from collapsing located in trachea makes airway open
34
explain the effect of exercise on rate and depth of breathing
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
what does hair help in thermoregulation
when erect it traps air which acts as an insulator
36
state why bacteria are useful in biotechnology
reproduce assexually reproduce quickly small simple requirements to grow same genetic code as other organims lack of thical concerns contain plasmids
37
strrucutres both animal and bacterial cell share
dna cell membrane ribosome cytoplasm
38
explain why in a fermenter population will decrease after a while
lack of resources/ nutrients build up of toxic materials such as co2 more deaths than births increased competition built up of pressure
39
describe meaning of adaptation
result from natural selection over many generations make organism more fit for survival and reproduction, more likely to survive
40
adaptations visible in plants in deserts
thick stem, corrugated stems, spikes (reduce surface area for transpiration)
41
state and explain effect on stomata on increasing humidity of room
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
explain how protein is made by a cell
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
state types of cell membrane proteins
carriers receptor proteins maltase/ enzymes
44
how can antibiotic resistence be decreased
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
explain how bacteria become resistant to antibiotics
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
state features present in all prokaryotes
no cell wall, circular dna, cell membrane, cytoplasm, ribosome, unicelular
47
what is the name of the fifth trophic level
quaternary consumer
48
outline how energy in primary consumers i used to produce biomass in secondary consumer
-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
explain why it is more efficient for humans to eat crop plants than livestock that fed on crop plants
-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
suggest why oxygen and water are required for germination
oxygen aerobic respiration water is a solvent water used for turgor pressure
51
in a menstrual graph which hormone is at its highest in day 14 and which other is also high but not as much
highest= FSH high=LH
52
how should you draw concentrations of progesterone in a menstrual cycle day concentration of hormone graph
progesterone low unti day 14, where it increases up to day 21 where it then decreases again
53
where in the body are goblet cells found
small intestine (villi) trachea lining bronchi bronchioles
54
describe and explain how structure of villus adapted for function
-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
state features of amphibians that distinguish them from all other vertebrates
moist skin eggs laid -gas exchange occurs through skin -larva have gills and adults have lungs -two stage life cycle
56
what can increase mutation rate
ionising radiation chemicals
57
explain risks to a species if its population size decreases
reduction in genetic variation harder to find mate- decreases reproduction can lead to extinction inbreeding increase i frequency of recessive alleles
58
how can you tell double circulatory system is one
passes through heart twice before one complete circuit/ before reaches all vital organs 2 separate blood circuits, pulmonary and systematic circuit
59
why does vein has a large lumen
provide less resistance for blood flow, and carry larger volume of blood
60
what happens when suspensory ligments are permenantly over streched and you must focus on distant objects
ciliary relax, suspensory try to stretch but cant lens remains wide instead of stretched doesn't change angle of refraction
61
Discuss the disadvantages of genetically modifying rice plants to produce beta-carotene
reduces biodiversity ethical concerns seed expensive to purchase unknown long term side effect to consumers risk of cross contamination to other rice plants
62
State the name of the type of pathogen penicillin is used to treat.
bacteria
63
List nutrients that need to be added to a fermenter to produce penicillin.
glucose water amino acids ions
64
Explain why the nutrients are sterilised (step 2) before they are added to the fermenter
stops growth of microogranisms
65
state steps of producing pencillin
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
Suggest how the scientists would identify the presence of the HbS allele in tissue samples.
analysing dna base sequence
67
Mutations are always inherited in single-celled organisms that reproduce asexually but are not always inherited in organisms that reproduce sexually explain why
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
Describe how acid rain destroys forests.
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
Suggest why amphibians are vulnerable to pollutants such as acid rain
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
Describe how countries have reduced acid rain.
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
Suggest how the carbon dioxide concentration in a glasshouse can be enriched.
carbon dioxide gas cylinders used
72
what are some adaptation of motor neurones
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
which organ is secreted from small intestine and acts in the epithelial lining of the small intestine
maltase
74
Discuss the negative impact on the natural environment of using chemicals, other than fertilisers, in modern farming methods.
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
describe process of treating water or sewage
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
differences between 5 kingdoms
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
different animal groups
molluscs, vertebrates, arthropods, annelids, cnydarians
78
differnet plant groups and distinguishing features
ferns- no flowers, germinate, underground stems and roots, complex leaves, have spores (reproduce) flowering plants-pollen, ovule, seed, fruit, leaves, aerial stems
79
different vertebrate groups
all contain backbones mammals, reptiles, fish, birds, amphibians
80
distinguishing feautres of each vertebrate group
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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