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topic 4 Flashcards

1
Q

species richness

A

the number of species in a habitat

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2
Q

biodiversity

A

variety of species in a habitat
variety of alleles in a population

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3
Q

diversity index

A

higher index, greater biodiversity
record number of species and the number of individuals of each species

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4
Q

describe how the scientific community critically evaluates new theories

A

communicating theory to specific community
peer review
checking of evidence to ensure its validity

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5
Q

explain the relationship between the structure and functions of a granum in photosynthesis

A
  • granum is formed from many layers of thylakoid membranes to increase surface area
  • thylakoid membranes contain chlorophyll to absorb light
  • electron carrier molecules in thylakoid membrane involved in ATP production
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6
Q

how are nitrate ions transported from the root to the leaves

A

through the xylem in water

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7
Q

monomer that makes cellulose

A

beta - glucose
Every other molecule is inverted
6 carbons

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8
Q

how are monomers in cellulose held together

A

by 1,4 glycosidic bonds in an unbranched chain
Alternative monomers are inverted

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9
Q

why do seeds need magnesium ions

A

magnesium is needed to make chlorophyll
because chlorophyll is required for photosynthesis
because shoots need chlorophyll to carry out photosynthesis to grow
(produce glucose during photosynthesis whcih is needed to produce cellulose for cell walls)

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10
Q

plant tissue that has lignin in its cell walls and the position

A

xylem on inside of vascular bundle. sclerenchyma on outer side of vascular bundle

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11
Q

role of middle lamella when plant cell completes mitosis

A

produced between adjacent new cells
because the middle lamella holds cell walsl together
Contains calcium pectate

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12
Q

effect of magensium defficiency on plants

A

limits production of chloroplasts
lack of glucose due to less photosynthesis
plant leaves may be yellow and plants may be small

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13
Q

why does sieve tube element not require RER and ribosomes

A

no transcription/mRNA so ribosomes not required for translation
no proteins will be synthesised to be processed in ER

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14
Q

polygenic meaning

A

a characteristic showing variation
caused by multiple genes at different loci

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15
Q

explain how epigenetic chanegs affect development of tissues in embryo

A

dna is wrapped around histones
histone modification affects binding of rna polymerase
methylation of dna affects transcription of genes
therefore gene expression is altered

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16
Q

difference between organ and tissue

A

tissue made up of one type of cell
organ made of different tissues

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17
Q

decisions society had to make about embryonic stem cells

A

they are totipotent
source of them has to be considered
moral issues as embryos destroyed
research establishments to be regulated

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18
Q

totipotent

A

a cell that has the ability to differentiate into all cell typesd

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19
Q

how do cells become specialised

A

chemicals cause some genes to be activated
only atcivated are transcribed producing specific mrna
mrna translated to produce specific proteins. this determines cell structure
causing cell modification/different types of cells being produced

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20
Q

amylopectin

A

alpha glucose

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21
Q

bonds between cellulose molcules in microfibril

A

hydrogen

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22
Q

role of middle lamella

A

produced between adjacent new cells becasue they hold cell walls togethr

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23
Q

starch

A

Polysaccharide made from alpha glucose
Monomers in the chains joined by 1.4 glycosidic links
Contains amylopectin which is branched, so it is rapidly hydrolysed
Insoluble so has no osmotic effect
Branches are joined to chains by 1,6 glycosidic links
Contains amylose which is coiled making starch making

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24
Q

sieve tube

A

provide a channel

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25
positions in stems of schlerenchyma fibres and xylem vessels
schlerenchyma fibres on the outsid eof vascular bundels xylem vessels on the inside of vascular bundeles
26
what contains nucelus
companion cell
27
the wall of the sieve tube contains
microfibrils, pectin, cellulose
28
if cells arent totipotent
some genes have already been aciutvated/deactivated so cant specialsie
29
as we grow older
fewer mesenchymal stem cells to replace cells in tissues
30
stem cells
undifferentiated cell that can give rise to sepcialsiec cells that can divide to produce more cells
31
Why use stem cells from patient than donor
Genetically identical cells to patient No risk of rejection Less risk of infection No need to take immunosuppressant drugs
32
Difference between pluripotent and totipotent
Totipotebt can give rise to any cell Pluripotent can not give rise to extra embryonic tissues Only totipotent cells can give rise to other totipotent cells Totipotent cells can give rise to an entire human being while pluripotent cells can’t
33
Explain why a second sperm cell cannot fertilise the egg cell.
cortical reaction thickening/hardening of zona pellucida so sperm cells cannot reach egg cell membrane
34
Explain why DNA is replicated before mitosis begins
to ensure daughter cells are genetically identical to ensure diploid number of chromosomes in eac daughter cell
35
Describe how each gamete receives only one allele of each gene.
homologous chromosomes are separated from one another sister chromatids are also separated from one another spindle fibres pull the chromatids to opposite poles of the cell
36
Describe how the acrosome is involved in the digestion of the zona pellucida
membrane of acrosome fuses with plasma membrane of sperm releasing enzymes by exocytosis
36
Explain how large numbers of cells with the same phenotype can be produced in a tissue.
phenotype is determined by genotype and effect of environment mitosis produces cells with the same genotype
37
Describe one advantage and disadvantage of using ropes made from plant fibres rather than ropes from oil-based plastics
Advantage - being sustainable Disadvantage - less strong
38
Describe two aseptic techniques that should be used when working safely with bacteria
Boiling culture medium before use ‘Flaming’ of the instruments Keeping lids off for the minimum time Disinfecting the bench
39
Explain why some bacteria can grow rapidly in skin wounds
The temperature is warm, increasing the rate of reactions in bacteria Availability of energy source from blood Availability of water for bacterial cell functions Oxygen availability is good, allowing aerobic respiration
40
Explain how breeding programmes in zoos maintain genetic diversity of captive populations
Animals are selected to prevent breeding between closely related individuals A stud book is used to select individuals for mating Exchange of animals between zoos
41
Explain why healthy volunteers were give different doses of the drug or placebo
Check for side effects Different doses to determine safe dose Placebo to make sure that any side effects described were due to the drug
42
Compare modern clinical trials with William Withering when he tested digitalis soup
Both trials used different doses William withering didn’t use healthy volunteers and this drug trial did William withering did not use a placebo while his trial did
43
Describe how clinical trials of a vaccine would be conducted.
healthy volunteers are given the vaccine to test for side effects they are tested for presence of antibodies to the virus a group of people at risk of contracting the disease is given the vaccine the number of people who develop the viral disease are monitored
44
justify the use of vaccine, if clinical trials have not been done
large numbers of people died health workers are in close contact with people suffering from the disease side effects of the vaccine will not be worse than contracting the disease vaccinating immediate family will help to reduce the spread of disease if health workers were vaccinated they could care for more people
45
suitable conditions for keeping seeds in a seed bank.
cold and dry
46
Describe how aseptic techniques are used when handling bacterial cultures.
working near a bunsen burner to provide a convection current sterilising work surfaces sterilising equipment with heat limiting time containers are open
47
Explain the role that a placebo has in producing valid conclusions
provides a control group for comparison ensuring that the active ingredient is causing the effect
48
Explain the role that a double blind trial has in producing valid conclusions
neither doctors nor patietns know who has been given the actual drug bias has been removed
49
Explain why the agar plate was incubated at 25 °C.
allow bacteria to multiply without encouraging pathogenic organisms
50
Describe roles that zoos play in animal conservation
Protection - from hunting, poachers, vet care Repopulation - increase numbers, breeding programmes, release back into wild Education - conservation Role in research - improving health
51
Explain advantages of drying seeds before storage
Extends storage time of seeds Because drying prevents germination of seeds Prevents damage to seeds
52
Benefits of conserving seeds
Prevent species from becoming extinct Conserves genetic diversity Protected from effects of climate change Ensures future food security Conserving species with medical properties Safeguarding genes that may prove useful in the future Allow reintroduction of species
53
Explain why bacteria are able to multiply in bloodstream when they enter body
Warm conditions/water/glucose/ideal pH available Suitable temperature/pH for bacterial enzymes Glucose used for respiration Amino acids used for growth
54
Advantage of washing seeds
Washing with disinfectant will kill any microorganisms
55
Why use of fibres from plants is sustainable
More plants can be grown Plants are renewable source Available to future generations
56
Inbreeding effect on genetic diversity
Increases genetic diversity Introduction of new alleles
57
Explain how two species may have risen from a common ancestor
Mutation leads to variation within the population Species with better adaption survive to reproduce Giving rise to population with differing allele frequency Populations become reproductively isolated
58
Explain how molecular phylogeny shows populations are reproductively isolated
Comparing differences in DNA comparison of amino acid sequences Greater differences number, more likely they are reproductively isolated
59
Heterozygosity index
Measure of genetic diversity within a species
60
Species
Group of organisms that can interbreed to produce fertile offspring
61
Explain how Hardy Weinberg equation shows natural selection occurring in the population
The equation shows allele frequency in a population If natural selection is occurring there would be a change in allele frequency over timr
62
Effect of calcium ion deficiency
Without calcium for the middle lamella new leaves cannot grow fully
63
Lignin
Strength and waterproofing
64
Why starch must be broken down before it can be used by cells
Produce glucose Which is transported easily/soluble/used in respiration
65
Companion cells
Contain nucleus
66
Why are plant fibres strong
Cell wall made of strong cellulose microfibrils in a net like arrangement Secondary thickening, cell wall which is thicker and has more lignin
67
Why is plastic material only partially sustainable
Starch comes from plants that can be regrown Not 100% starch so some oil-based products needed
68
what happens during telophase
spindle fibres break aparrt chromosomes decondense nuclear envelope forms two separate sets of chromosomes
69
the importance of nitrate ions for plants
used to mkae amino acids makes DNA if lacking,growth is reduced
70
how does dna methylation affect thr activation of a gene
methyl groups attahced to dna prevents transcription transcription factors cannot bind to dna deactivating a gene
71
compare and contrast the sturcture of unfertilised egg cell with zygote
both contain mitochodnria/rer in the cytoplasm both possess cell cytoplasm/cell membrane unfertilised egg has a haploid nucleus whereas zygote has a diploid nucleus unfertilised egg cells contains cortical granules
73
Ecosystem
All the organisms living in a particular area
74
Habitat
Place where an organism lives
75
Population
All the organisms of one species in a habitat
76
Community
All the organisms of different species that live in the same habitat and interact with each other
77
What happened to bare rock to allow growth of trees
- rock colonised by pioneer species - break up the rock Dead plants add organic matter as they decompose Trees able to grow as soil becomes deeper and can retain more water
78
Test for comparison
T test
79
What infection control practices have hospitals introduced
Hand wash Doctors not to wear long sleeves Disinfection of beds/surfaces Isolation/quarantine of infected patients
80
explain how microorganisms in soil break down stems
- stems contain starch or cellulose - enzymes are secreted by microorganisms they break down glycosidic bonds which releasse glucose that is used by microorganisms in respiration
81
describe how mineral ions are taken up by root hair cells
low to high conc. through carrier proteins, active transport
82
explian how protection of hotspots can affect global biodiveristy
prevents extinction loss of these species will decrease global biodiversity
83
which population is more likely to adapt to changing conditions
the population with more genetic diversity frequency of allele increases more likely to have an allele that gives advantage those with advantageous allele survive and reproduce
84
Role of products of LDR in Calvin cycle
ATP used to convert GP to GALP Reduced NADP converts GP to GALP

biology (13 decks)

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