4 Flashcards
(107 cards)
1
Q
what is a population
A
a group of interbreeding individuals of same species found in an area, various populations within a habitat make up a community
2
Q
what is a ecological niche
A
the way an organism exploits its environment- all species sharing a habitat have different niches
if two species occupy a habitat and share the same niche they will have to compete directly with each other
3
Q
what is a species
A
a group of organisms morphology, physiology and behaviour which can interbreed to produce fertile offspring, and which are repoductively isolated (place,time,behaviour) from other species
4
Q
adapted
A
specialised to suit the environment in which the organism lives
5
Q
behavioural, anatomical and physiological adaptations
A
behavioural= any acions of an organism that help them to survive and reproduce, a change in behaviour to increase its survival chances
phsiological= features of the internal workings of organims that help them survive and reproduce. Changes is the internal biochemical functioning of the oranism in response to a stimulus
anatomical=structures we can see when we observe or dissect an organism
6
Q
steps of natural selection
A
a population of organisms shows genetic diversity/variation due to having a variety of alleles caused by mutation
environmental conditions change causing a change in selection pressure
natural selection reduces the reproductive efficiency of some individuals as an allele previously of no particular advantage now becomes favorable so organisms with allele are more likely to survive and reproduce
their offspring more are more likely to have allele
over many gens the frequency of these alleles increase, so it becomes more common in the population
7
Q
what is a gene pool
A
consists of all alleles of all the genes present in a population
8
Q
HW equation (pt1)
A
p+q=1
p=frequency of dominant allele in a gene pool
q=frequency of recessive allele in gene pool
9
Q
working out allele frequency assumptions for a gene with only two alleles
A
do later
10
Q
what is evolution
A
a change in allele frequency in a pop over time- natural selection contributes to the evolution of a species
11
Q
HW equation (pt2)
A
p^2=frequency of homozygous dominant individuals
2pq=frequency of heterozygous individuals
q^2=frequency of homozygous recessive individuals
12
Q
what does the ability of a population to adapt to new conditions depend on
A
strength of selction pressure, size of gene pool, reproductive rate of the organism
13
Q
how can a new species arise- sepciation
A
reproductive isolation of two populations of same species will result in the accumulating different allele frequecies as over time two groups will become less like each other as they respond to different selction pressures and random mutations accumulate- difference great enough they may no longger be able to breed and produce fertile offspring
allopatric(geographically isolated)- reproductively isolated from physical barriers
sympatric(isolated by other means within the same area)- different mating times, courting ritals, difference in gentalia
14
Q
what is biodiversity
A
variety of living organisms in an area
variety of species that belong to every different group of organisms
15
Q
binomial system
A
first part is genus- shared by all closely related species
second part is the species the genus belongs to
16
Q
taxonomic heirarchy
A
kingdom- animalia, Plantae, Fungi, Protoctista, Prokaryotae
phylum
class
order
family
genus
species
17
Q
kingdoms
A
animalia- multicellular eukaryotes that are heterotrophs- obtain energy as organic molecules by ingesting material from other organisms, no cell walls, have a nucleus
plantae-multicellular eukaryotes that are autotrophs, have a cell wall made of cellulose
fungi-multicellular eukaryotes that are heterotrophs that absorb nutrients from decaying matter after external digestion, can be single celled, saprtrothic- leaches food from other organisms/decaying matter
protoctista- eukaryotes that are photosynthesise or feed on organic matter from other sources - single celled
prokaryotae-bacteria and blue green bacteria, no nucleus or membrane bound organelles
18
Q
molecular phylogeny
A
phylogeny- study of evolution of a particular species or group
mp- study of the genetic and heridatry molecular differences- such as dna, rna or amino acids to analyse an organisms evolutionary relationships
19
Q
why is molecular phylogoney more accurate then observing characteristics
A
conversion evolution- unrelated species may have similar traits or phenotypes due to the adaption of similar conditions, DNA is not effected by the environment so similar DNA=similar inheritance/ancestors
20
Q
what is taxonomy
A
placing organisms into groups based on observable shared features
each taxon share a common evolutionary ancestor- making them more closely related
21
Q
Chromista
A
life cycles include motile cells with ‘tinsel’ like flagellum- kelp
22
Q
Carl woese
A
developed phylogenic trees showing evolutionary relationships between bacteria based on molecular differences
found some prolaryotes differ to each other in RNA sequences
called archea that do not use all of a genetic code for a protein, meaning their genes contain unused sections, also has no peptidoglycans in cell wall, membrane lipids differing to that of euks and bacteria
23
Q
3 domains
A
universal phylogenetic tree based on 3 domains: archea, bacteria, eukaryota
phylogenetic tree-repersent the evolutionary relationships based on best existing evidence
24
Q
what is genetic diveristy and why it it useful in an ecosystem
A
genetic diversity= a measure of genetic variation in a species, number of alleles in a gene pool
in all organisms that reproduce sexually, every individual has a unique combination of alleles, greater variety of genotypes the more genetically diverse a population is- allows population to adapt to changing conditions so is able to be conserved
25
sources of genetic variation
Mutations – mutations resulting from changes to the base sequence of DNA, or from chromosomal mutations, can result in the generation of new alleles.Some alleles of a gene can be lethal, resulting in the death of the organism.Some alleles can be beneficial, and then passed on to offspring.
Crossing-over – crossing over during prophase I of meiosis results in changing the inheritance patterns of alleles, and sometimes even leading to new alleles being formed.
Gene flow – sometimes new members can move into a region, leading to breeding between different populations. If you added many British Dogs to an environment of African Dogs, the genetic diversity in the African population would rise.
26
what is an endemism
Endemism is when a species is only found in a particular place. These species are unique to their area and will not be found anywhere else.
27
diversity index
D=probability of 2 random individuals being from the same species
N=total number of organisms of all species
n=total number of organisms in one particular species
28
what is the heterozygosity index
proportion or % genes present in the heterozygous form
no heterozygotes/no of individuals in a population
29
how to conduct a breeding prograamme of a species
Small amount of individuals in a species resulting in a small gene pool with low genetic diversity. Captive breeding will increase population ; studbooks /records kept of breeding programme. (zoos) select mates with inter-zoo exchange of animals for breeding to prevent inbreeding which results in an inbreeding depression. Breeding of genetically different indivduals to avoid genetic drift. IVF used to encourage breeding. measuring genetic diversity with DNA profiling
30
what is species richness
way of measuring biodiversity
counting up number of species present in a given habitat
not number of indviduals within a species
benefits: promotes biodiversity, encourages competion which therfore promotes evolution, large gene pool aids survival
31
human imapcts on biodiversity
negative
deforestation-ruins habitats which could lead to extinction due to removal of resources and shelter, soil erosion as root hold soil in place leading to wind at water removing soil nutrients
intorduction of alien species
pesticides and herbicides- reduces biodiversity due to the killing of organisms
fertilisers and eutriphication- carried by rain water to nearby bodies of water, lead to a spike in nitrogen, ammonia, and other nutrients in the water, causes aquatic plants to grow rapidly-removes o2 from water- but toxic to many aquatic animals
selective breeding-loss of genetic diversity- reduced gene pool within speices- Loss of genetic diversity in domesticated plants and animals makes them easily susceptible to diseases that can wipe out large numbers of plants and animals, resulting in severe food shortages.
positive
conservation-
32
what is species eveness
measurment of the number of indviduals within a species
if all species has the same abundance of individuals then species eveness is high
benefit: not a domimcae of one species that outcompetes others, species less likely to go extinct, higher codependence between species
33
2 ways of measuring gentic diversity
direct= DNA sequencing to determine bases in a segjment of DNA and thus determines which alleles are present
indrectly= DNA cut into fragments then seperated using electrophoresis- diff allels produce fragments of diff lengths
34
effects of interbreeding with other species
increases gene pool as it intorduces new alleles into the population
35
why 2 species may not interbreed
reproductive isolation ;
2. different breeding times;
3. do not recognise {courtship displays / songs
/ eq} ;
4. physically incompatible eg genitalia
36
gene pool
(the total of) all the alleles in a {population
37
allele frequecy
the {proportion of / number of times occurring /eq} for one allele within a {gene pool
38
structures in plant cells that are not in animal and their functions
chloroplasts-site of photosynthesis- contain stacks of thylakoid mebrane called gana
rigid cell wall made of cellulose
amyloplasts- storage vacuoles in cytoplasm holdign strach
large central vacuole
tonoplasr-vacuolar membrane
parenchyma-plant tissue found throughout plant- places a support role, fill spaces between more specialised tissues and may have specialised funtions
39
cell wall
plant's strength comes from thin cellulose walls -Formed by condensation of beta glucose,every other beta glucose is inverted ,Long unbranched chains-straight, 1,4 glycosidic bonds,1000-10000 glucose units, fibrous , insoluble and indigestible
Microfibers and microfibrils are strong threads that are made up of cellulose chains joined together by hydrogen bonds and provide structural support in plant cells to prevent lysis-wound in a helical arrangement around cell and stuck together with a polysaccharide glue (hemicelluloses and pectins bind both to surface of cellulose and each other holding microfibrils together)-microbfrils within a matrix of hemicelluloses and pectins makes cell wall very strong
middle lamella-layer between cell walls of adjacent cells cementing them together-pectin acts as a cement here to hold cells together
40
plasmodesmata
narrow fluid filled channels that cross the cell walls
makes continuos cytoplams
cell walls fully permable to water and solutes
some places cell wall thin becaise only first layer of cellulose deposited-results in pit in cell wall where plasmodesmata often located
41
slcerenchyma
columns of cells with stiffend (lignified) cell walls tp provide support
42
vascular bundle
contains xylem vessels and phloem sive tubes- sclerenchyma fibres on outside of bundle
43
xylem vessels
large cells with thick cell walls form a collum of cells acting like a tube for transport of water and mineral ions
cell walls have to be waterproof by lignin (polymer)- imprgnates the cellulose cell wall and as cells become lignified the entry of water and solutes into them is restricted- same time tonoplast breaksdown and there is autolysis of cell content-cell organelles, cytoplasms and cell surface membrane broken down by the action of enzymes and are lost, leaving dead empty cels
end walls between the cells of the columns or become highly perforated- continuos tubes from roots to leaves- cellulose microfibrils and lignin in cell walls of xylem vessels give them great strength
44
how is water transported through xylem vessels
water evaporates from leaves-majority from substoaml cavities in the leaves- water diffuses out stomata down a diffusion gradient-water leaving leaf by transpiration is replaced by water absorbed through the roots
surface of cells in leave covered in water, evaporates casuing a high conc of water vapor which diffuses out leaf through stomata, water moves by osmosis from adgacent ceels, reaches xylem- pullinng tension effect
minute channels between the cellulose microfibrils in the cell walls act as tiny cappillaries- draw up water by capillary action which is caused by surface tension between the water and the capillary walls. Thousands of minute capillary like channels in the cell walls inside the leaves produce a massive pull on water behind them-water moves up the xylem vessels and through the cell walls within leaf in continuos stream-transpiration stream
energy for moving water through a palnt comes from sun, heats and evaporates water from cells lining substomatal cavity-water under tesnion fro evaporation and is pulled up-water bonded by hydrogen bonds
45
what else do xylem transport
mineral ions-nitrate ions for making of amino acids, magnesium ions-chlorphyll, calcium ions-cell wall and membrane
46
transport in phloem
translocation
sucrose and amino acids produced in leaves by photosynthesis
bidirectional
companion cells perform metabolic funtions that maintain sieve tubes
products of photosynthesis move out of cells they are produced in and pass through cells until they arrive in transfer cell next to sieve tubne-parenchyma-actively transport products into sieve tube
photosynthetic products actively unloaded from phleom sieve tubes in the parts of plant where sugars are being used-sinks
source-where photosynthesis occurs/stored sugars
lloading of solutes to phloem increases solute conc which draws water into the sieve tube by osomosis from adjacent xylem tubes-increases hydrostatic pressure inside the lumen-at sinks solutes are unloaded lowering conc in tube-water moves back into xylem through osmosis lowering pressure- diff in pressure between loading and unloading sites causes mass flow along sieve
47
xylem and sclerenchyma for support
sclerenchyma and xylem lined with lignin providing support
48
phloem sieve
collums of cells- alive unliked dead xylem- nucleus and most cell contents disintergrate during development- leaves most of cell as liquid filled space- end walls of each sieve tube cell contains holes aligned with neighbouring cells-sieve plates
role is to provide a channel for translocation to take place so cellular contnets kept to a minimum meaning it doesn't have the anility to carry out aerobic respiration so companion cells required to supply ATP
49
why hybrids more genetically diverse than their parents
genotype made up of the different alleles in each of the two populations as a result of each {population / species} being adapted to live in different environmental conditions. there will have been different mutations in each population . alleles from different {species } will mix / hybrids receive alleles from both { species } ;
50
how a large plant species may lead to formation of two speices
original population increasing in size and spreading into a wider diversity of {habitats / eq}. Mutations in different areas of population ; leading to diversity in flowering times / eq (and) other plant features / eq ;
Spreading over a large areas also lead to reproductive isolation and a restriction in gene flow as only reproducing with the plants around them
different environmental factors in each region ; each region has different selection pressures leading to natural selction as plants adapt to environmental conditions of differnt regions; survival and breeding ; change in allele frequencies (over time) ; (leads to) differences between gene pools
51
uses of plant fibres and why
uses:clothing, rope, floor coverings, paper
why:long and thin, flexible, strong
52
phases of bacteria growth over time
lag- cells adjusting to conditions
exponetial growth- cells dividing exponetially at fastest rate possible for conditions
stationary-growth limited by lack of food, build up of toxins, changing ph-balance between cell division and cell death
death- number of cell deaths greater than cells formed
53
bacterial growth conditions
sufficnet nutrients
optimum temp and ph for metabolic processes to take place normally
no build up of toxic waste products
sufficent o2 if bacteria relies on aerobic respiration
54
william withering foxglove
poisonus- dizziness, vomiting, hallunactions and heart failure from irregular heartbeat
used to treat dropsy-oedema-accumilation of fluid in body tissues-fast heart beat a signs as increase in bp
withering made a soup contain foxglove - trial and error with effects of different concentrations- recording side effects of digitalis
increased dose until patient experince diarrhoea and vomiting and then reduced it slightly
55
modern day drug testing
pre clinical testing- animal studies and lab studies on isolated cells and tissue cultures to see effectiveness of compound
phase 1- small group of volunteers told about the drug and given diff doses-normally healthy, determines whether compund is being absorbed, distributed, metabolised and excreted by the body in way predicted in lab- determine afe dosage
phase 2- small group of volunteer patients are treated to test effectiveness
phase3-large group of patinets selected and divided into groups. one given compind being tested other placebo and if existing treatment that used instead of placebo, neither patient nor doctor knows who is having compound under investigation and who isn't- double blind radomised controlled trial- gather data for statistic tests, find rare side effects, compare effectiveness with placebo or previous drug
56
what are seeds adapted for
to protect embryo
aid dispersal
provide nutrition for new plant
57
dicotyledons
in most the embryo absorbs the stored nutrients from the endosperm and the food is stored in the seed leaves which swell to fill seed
58
gelatinisation of starch
starch granules are heated up in water and suddenly swell, absorb water and thicken the liquid- mixture can be cooled allowing bonds to form between the starch molecules stiffening the fabric
if starch is chem cross linked before it under goes gelatinisation then partivle are formed that can be dried- when rehydrated these particles can take up large amounts of water
59
strach foam
temp of gelatinising depends of conc of water-higher the less there is , if pressure raised at the same time the starch forms a plastic mass;if pressure suddenly released starch puffs into an extended structure- foam packaging and corn snacks- packaging used instead if oil based plastics
60
biodisel
produces less sulphur dioxide then disel and less co2 taking into account the carbon taken in by plants to produce it
61
plant based products and sustainablity
carbon dioxide release in theory level to that carbon removed from atmosphere when crop grown-no net change
land us change from food crops to biofuel crops-agricultural waste and non food crops used instead
neede to consider the source of plant product, and the nergy used and pollution created during the production and transport
biodegradeable- most bacteria involved in process require o2 so if burried deep in landfill won't be biodegraded
62
small planet problems for biofuels
cultivate a large proportion of the planet's surface for food, not enough left for biofuels and other plant materials-replacing rainforests
some plant alternatives don't have desirable qualities or may require the consuption of as much or more energy in production, transport
growing population and consumption
63
captive breeding programme aims
increase population size
maiantain genetic diversity within captive population
reintoriduction
64
genetic drift
small population some of the alleles may not get passed onto offspring purely by chance, reducing genetic diversity decreasing chance of survival
65
factors effecting survival after reintro
how well prepared
number of viable mates
avalibility of food
presence of predators
inter/intra species competition
66
seed banks
to conserve seed samples from threatened species to conserve genetic diversity and biodiversity
small samples unlikely to damage a wild population as plants produce large numbers of seeds
seeds small and easy to store and can survive in a desiccated state for years
kept in dry and cool conditions- -20c, sample taken out and germinated on agar plates to ensure survival in storage conditions- tests every 10 yrs
seed collections used for research, habitat restoration and species reintroduction
advans: cheaper to store than grow, little labour, large amounts can be stored, less atmospheric requirments, less likely to be damaged by disease or natural disaster
disadv: testing can be expensive and time consuming, difficult to get smaples from remote locations
67
endosperm
when stored food in the seed remains outside the embryo in storage tissue called endosperm- common in monocotyledons
68
in situ and ex situ
in situ-conservation management applied on site
ex situ- off sitge (zoos and seed banks)
69
purpose of zoos
scientif research
conservation
captive breeding programme- endagered species carefully bred to increase gentic diversity and population size- diversity kept through exchange of organisms from other programmes to intoriduce new alleles into the population and preventing inbreeding
reintroduction programme
70
stud book
shows history and location of all captive animals
provide raw data ypon which breeding plans are based
advises on which animials should or should not breed and on the movement of animals between zoos to maximise genetic diversity and prevent inbreeding
71
inbreeding depression
causes the frequency of homozygous genotypes to risewith loss of heterozygote- individuals inhereting recessive alleles from both parents- harmful effects- smaller, unfit, not live as long, produce fewer eggs
72
flowering plants fertilisation
ovule fertilised by nucleus from pollen grain- outer layers of ovule become lignified froming a seed
73
uses of starch
adhesives,paints,textiles,plasters,insulating material,toilayeries
74
oil based plastics not sustainable
burning fossil fuels contributes to a net increase in atmospheric carbon dioxide concentration
oil reserves will run out
non biodegradeable waste
75
need for nitrate ions
amino acids or proteins
involved in synthesis of DNA, ATP, nucleic acid
affects plant gowth and seed + fruit production
76
need for calcium ions
found in cell walls
required for plant growth
77
role of middle lamella after mitosis
produced between adjacent new cells
middle lamella holds the cell walls together
78
role of plasmodesmata
cytoplasmic connection that allows transport of materials and communication between cells
79
why do seeds store food in form of starch
1,6 glycosidic bonds means making polymer branched means it can be readily hydrolysed and supplies energy more quickly than other glucose polymers like cellulose
starch is insoluble so is broken down into glucose and/or maltose which is soluble so can be transported to cells for respiration
80
why magnesium ions essential for plant fibres
essential in production of chlorophyll
chlorophyll is necissary to produce glucose during photsynthesis
glucose needed to produce cellulose for cell walls
81
how are seeds for seed banks chosen
1. from different plants / eq ;
2. to provide genetic variation / eq ;
3. X-rayed ;
4. to check for { viability / viable embryos
/ eq } ;
82
how involvement of multiple zoos in a captive breeding programme promotes genetic diversity
1. idea that one zoo is a small
population / small gene pool / low
genetic diversity / may have been
closely related / eq ;
2. captive breeding will increase
population ;
3. studbooks /records kept of breeding
programme / eq ;
4. (zoos) select mates ;
5. inter-zoo exchange of animals for
breeding / eq ;
6. idea of the need to prevent inbreeding- stopping the development of homozygous recessive indviduals who are unfit and may carry genetic disorders
;
7. idea of avoiding genetic drift ;
8. use of { IVF / AI / use of
surrogates } ;
9. process for measuring genetic
diversity described, e.g. DNA
profiling / eq ;
83
how seed banks ensure long term conservation of seeds
1. details of assessment of seed viability e.g. only
select seeds with a living embryo, use of X ray (to
detect embryo presence) / eq ;
2. idea of {cleaning seeds / surface sterilisation / eq} ;
3. idea of drying (of the seed) ;
4. idea of storing at low temperatures ;
5. idea of regularly testing viability (during storage of
seed) ;
6. idea of what to do if viability decreases, e.g. if less
than 75% germinate collect fresh seed for storage
84
what conditions are seed banks chosen to have and why
1. dry and cold -
2. to {prevent/reduce} enzyme
activity ;
3. to prevent germination of seeds ;
4. to prevent microbial growth /
decay/decomposition of seeds ;
85
problems a species may face when reintroduced
1. idea of habitat as a factor, e.g. loss of
habitat / wider range of habitats / eq ;
2. availability of { prey / food
3. competition with other members of species (for
resources) ;
4. competition with other species (for
resources) / eq ;
5. effect of eating { poisoned prey- if refrenced in question
6. presence of { predators / hunters } / eq ;
7. preparation for living in the wild improves
chance of survival / if reliant on humans
would not survive ;
8. idea of too few to be a viable breeding
population ;
9. idea of presence of disease ;
86
need for magnesium ions
chlorophyll production
pigment used for photosynthesis
87
intraspecific vs interspecific
Interspecific occurs between individuals of different species.
Intraspecific occurs between individuals of the same species.
88
what is tensile strength and how is it calculated
the pulling force the fibre can withstand before it breaks
force/cross sectional area of fibre
89
why a protected reserve is better tahn a captive breeding programme (problems with a captive breeding programme)
1. idea of less {stress / trauma /
discomfort / depressed /eq} (for
the animals) ;
2. idea that animals are more likely
to breed in natural environment ;
3. idea that animals may require
large areas ;
4. idea that problems of releasing
animals back into the wild is
avoided eg habituation ;
5. idea that {disease is less likely /
disease will not wipe out
population} ;
6. idea of allowing (natural)
{interspecific relationships /
communities} to exist ;
7. idea of allowing (natural)
{intraspecific relationships /
family / social / eq}
{structure/ behaviour} ;
8. (because) large numbers of
animals needed / wider gene pool
/ eq ;
9. idea that (natural) {diet / food /
eq} available ;
90
Suggest why seed germination is tested at regular intervals.
1. idea that checking {seed viability /
germination success / eq } ;
2. allows new seeds to be produced / eq ;
3. idea that stored seeds may need replacing
e.g. due to decay / death ;
91
effect of global warming on plant species
1. { loss / eq } of (existing) species / extinction ;
2. idea of changes in distribution (of plants / species) ;
3. idea of changes in {numbers / size / growth / eq } (of plants
/ species) ;
4. idea that there will be changes in rainfall patterns ;
5. idea of a change in growing seasons ;
6. idea that temperature may become too hot for some species
OR credit a link made between temperature and enzyme
activity ;
7. idea of increased carbon dioxide results in more
{photosynthesis / GPP / NPP / biomass / eq} ;
8. idea of fall in pH in {oceans / rivers / eq} ;
92
importance of conserving endangered plants
conservation of genetic diversity / genetic variation /biodiversity
extinction
aesthetic reasons
plants may be useful e.g. as medicines
other animals depend on these plants as a source of food /habitat
93
middle lamella
consists of polysarcharides as well as calcium (calcium pectate) and magneisum ions
94
Why vaccine used when not passing clinical trials
Large number of people dying
Healthy people in close contact
Side effects not worse than disease
Help reduce spread
95
Why placebo makes valid results
Provides control for comparison
Therefore ensuring that the drug is causing effect
96
Why double blind trial makes valid results
Bc neither doctor nor patient knows who has been given the actual drug which therefore ensures that bias is removed from trial
97
Benefits of seed bank
Prevents species from becoming extinct
Conserves species with potential medical properties
Safeguarding genes potential of being useful- drought resistance, pest resistance, disease resistance
Allows reintroduction of species in future
Conserves genetic diversity
Protected from natural disasters, climate change, deforestation
98
Why bloodstream optimal for bacteria
Ideal ph and warm conditions for high reaction rate
Glucose for respiration
Amino acids for growth
99
Role zoos play in conservation
Protection for poaching, hunting and allow treatment
Captive breeding programme to increase population and prevent inbreeding
Reintroduction
Research- developing genetic database
100
why clinical trials better than wirthing
safer- pure drug used rather tahn an extract, tested on cells instead on humans first, regulated by legislation
valid- placebo for comaprison, double blind for lack of bias, other factirs such as lifestyle taken into account
relaible- more people, results taken in statistically
101
Captive breeding vs protection of habitats
Cb increase population, conserves gd, protected from poachers and deforestation
Cb animals show behaviour that may make them unable to compete in wild, lack of infraspecific inferspecific relationships, passage of human disease to captive pop
102
why phloem havce less mitochondria
CC has many mitochondria whereas the ST has { few / none } the role of the ST is to provide a channel, so cellular contents are kept to a minimum so the ST has { limited / no } ability to carry out (aerobic) respiration , { ATP / energy } is supplied to the ST from the CC
103
ions experiment
use of similar, healthy plants grown in the same conditions up to the start of the experiment-control of the growing environment, e.g. light intensity, temperature
use of growth medium with an adequate concentration of all other necessary ions- control
grow plants in different defficancies
measurement of an appropriate specified dependent variable, over the same growing period for all plants
data collection from at least five plants at each defficancy, used to calculate mean values
104
zone of inhibtion
shows no bacteria growth in area
therefore this indicates how effective the extracts were at killing or inhibiting the growth of the bacteria
105
why clinical better then foxglove trials
(Safer) • because pure drug used rather than extract (1) • due to pre-testing on {cells / animals} before testing on humans (1) • because regulated by legislation (1)
(More valid)
because a placebo is used as a comparison (1)
because modern testing may involve double-blind trials (1)
because controlling {factors / variables / eq} tested cohort e.g. age, lifestyle (1)
(More reliable)
because more people are tested (1)
because results are analysed statistically (1)
106
why seeds preserved
(seeds from different plants of the same species) ensures {genetic diversity / a large gene pool / genetic variation} (1) • therefore greater chance of {survival/adaptation} (1) • (if the plants are reintroduced) {conditions may have changed / may be a different habitat} (1)
107
why increasing tempo increases rate of germination
increase in (spring) temperature increased germination for
all three species (1)
• (because) there is more (kinetic) energy and more
(frequent) collisions between substrate and enzyme (1)
• (therefore) starch is { broken down / hydrolysed } faster (1)
• greater supply of glucose increases the rate of respiration
(1)
ALLOW { lipids/proteins } broken
down faster
EXP
(3)
Q
