things i have got wrong Flashcards

(65 cards)

1
Q

what does the medulla oblongata send to the SAN

A

impulses (not signals)
sends MORE than normal to increase heart rate

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2
Q

what are ribosomes made from

A

RNA
amino acids

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3
Q

structure of glycogen

A

made from monomers of alpha glucose
1,4 and 1,6 glycosydic bonds
highly branched

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4
Q

describe the cotransport mechanism

A

Na+ binds to carrier/channel protein and carrier molecule
protein changes tertiary structure to allow Na+ and carrier to enter cell
Concentration gradient is maintained by Na+/K+ pump
With use of ATP

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5
Q

what happens if the CSM of plants is disrupted

A

may lose ions which can lead to cell death

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6
Q

why does temperature need to be constant when measuring something to do with plants

A

so rate of diffusion is constant
so kinetic energy is constant

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7
Q

describe the process of phagocytosis

A

pathogen is engulfed and enclosed in a phagosome
phagosome fuses with lysosome
pathogen is destroyed by hydrolytic enzymes
proteins of pathogen are processsed and displayed on CSM

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8
Q

how does too much sodium in the blood lead to a build up of tissue fluid

A

lower water potential of tissue fluid
so less water returns to the capillary by osmosis at the venule end

higher blood pressure
so more fluid pushed out at arteriole end

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9
Q

how do bacteria reproduce

A

divide by binary fission
circular DNA is replicated
cytoplasm divides to produce 2 daughter cells
each with a single copy of the circular DNA

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10
Q

how are proteins denatured

A

breaks hydrogen/ ionic bonds between R groups

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11
Q

why are extracellular proteases important

A

to hydrolyse/ digest protein
so amino acids can be absorbed for growth

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12
Q

why are diproteases important in the gut

A

to hydrolyse the peptide bond
as amino acids can cross the cell membrane

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13
Q

what is the reaction for ATP synthesis

A

ADP + Pi —> ATP + H2O

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14
Q

why is it better to use 2 antibiotics at the same time

A

unlikely that bacteria will be resistant to both antibiotics
one antibiotic won’t kill all bacteria
resistant bacteria will reproduce to create more resistant bacteria

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15
Q

Describe how presentation of a virus antigen leads to the secretion of an antibody against this virus antigen

A

TH cells bind to antigen on the antigen-presenting cell (e.g phagocyte)
TH cell stimulates specific B cell
B cell divides by mitosis
to form plasma cells which release the specific antibody

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16
Q

what are three comparisons of genetic diversity

A

The (base) sequence of DNA
2. The (base) sequence of mRNA
3. The amino acid sequence (of proteins)

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17
Q

adaptations of the tracheal system for efficient gas exchange

A

Tracheoles have thin walls so short
diffusion distance to cells

Highly branched/large number of
tracheoles so short diffusion distance to
cells and larger surface area for gas exchange

Tracheae provide tubes full of air so fast
diffusion

Fluid in the end of the tracheoles that
moves out (into tissues) during exercise to increase the space in tracheoles available for oxygen to move in so faster diffusion through the air to the gas exchange surface

Body can be moved (by muscles) to move
air so maintains diffusion/concentration
gradient for oxygen/carbon dioxide

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18
Q

why is more oxygen needed for animals which move a lot

A

they have a higher metabolic rate
so use more oxygen for aerobic respiration
to release heat

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19
Q

how to make an experiment reliable

A

random sampling
calculate standard deviation from the mean then do T test
use a large sample

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20
Q

what is the use of fatty acids/ amino acids in the mitochondria

A

can be oxidised to produce ATP

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21
Q

what happens if there are more individuals in a population

A

more intraspecific competition

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22
Q

what is the benefit of having more muscle fibres

A

more mitochondria so more ATP
less anerobic respiration
less lactate
so can exercise for longer

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23
Q

what happens if the light-dependent reaction is inhibited

A

less NADPH
less ATP
less GP converted into TP

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24
Q

explain allopatric speciation

A

population becomes reproductively isolated
gene pools are separate
eventually can’t breed to produce fertile offspring
change in frequency of alleles
disruptive selection

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25
what happens if you reduce the amount of acetylcholine esterase in the body
more acetyl choline is available to bind to receptors and allow Na+ to flow into a neurone and initiate an action potential
26
why would DNA probing not be suitable to identify a mutation with a short base sequence
the sequence will be found elsewhere so false positives may occur
27
describe how a nerve impulse causes the release of the neurotransmitter from the presynaptic knob
causes Ca2+ channels to open so Ca2+ enters the presynaptic knob by facillitated diffusion causes vesicles to fuse with the presynaptic membrane
28
do viruses have ribosomes
no
29
what is one difference between a virus and bacteria
viruses have a capsid but bacteria have a cell surface membrane
30
what does a big range show when testing durgs etc.
works well on some individuals but not others
31
what does a P value over 0.05 show
results are not statistically significant there is more than a 5% probablity that results are due to chance
32
how does siRNA work
binds to mRNA with complementary base sequence to prevent translation
33
why might siRNA not prevent translation entirely
more mRNA than siRNA
34
how is water returned from the tissue fluid to the blood
plasma proteins remain in the blood and create a low water potential so water moves into blood from tissue fluid by osmosis down a water potential gradient some returns to blood via lymphatic system
35
precautions when doing disection (4)
use sharp scalpel disinfect hands disinfect surfaces wear safety goggles
36
how can an arteriole restrict blood flow into capillaries
muscle contracts narrows arteriole (vasoconstriction when cold)
37
what does semilunar valves being closed show
ventricle muscle is relaxed no backflow into ventricles
38
what does AV valves being open show
atria contracts blood moves from atria to ventricles
39
why would bloodflow not increase in the aorta even if pressure in the left ventricle is increasing
semilunar valve is closed no pressure gradient (yet)
40
what are 3 featires a virus ALWAYS has
capsid, attachment proteins, genetic material
41
why are viruses non-living
no cell membrane, can't reproduce outside a host cell
42
why does the xylem need to be a continuous tube
allows unbroken water column cohesion from H bonds between water molecules evapouration creates tension
43
structure of chromosomes
when visible they are seen as 2 sister chromatids joined at a centromere
44
how is variation increased
independent segregation of homologus chromosomes crossing over between homologus pairs
45
how does oxygen uptake indicate metabolic rate
it shows rate of aerobic respiration which produces ATP
46
explain the counter current principle
blood and water flow in opposite directions so a steeper concentration gradient is maintained so diffusion occurs along the whole length of the lamellae
47
how does oxygen move from alveoli to blood
moves through alveolar epithelium then through epithelium of capillary
48
when would a median be used
small sample size or anomolies present
49
when would a specialised transport mechanism not be needed
short diffusion pathway
50
what does heat treatment (hot or cold) effect
active transport
51
how is carbon dioxide converted into sucrose
in photosynthesis
52
how should a new drug be tested
on a few different mammals then on healthy humans then on humans with the disease
53
how does HIV replicate (once it is inside the host cell)
reverse transcriptase makes a DNA copy of HIV RNA this is inserted into a chromosome transcription makes functional RNA translation makes all the viral proteins virus particles are assembled then released from the cell
54
what is a fungal cell wall made from
chitin
55
why might biomass be measured instead of number of plants
plants are too small to count
56
aseptic techniques
disinfect surfaces (not sterilise) use sterile equipment
57
what would increased kinetic energy cause in plants
rate of transpiration to increase
58
what creates a longer diffusion distance
more cells
59
mutagenic agent definition
something which increases the chance of DNA base sequence mutation
60
at which stage of the cell cycle does it technically become 2 cells
telophase
61
why would an animal with the wrong number of chromosomes be sterile
too many chromosomes homologus chromosomes can't pair meiosis can't occur
62
how is chromosome number halved during meiosis
homologus chromosomes pair 1 of each pair is pulled to daughter cells
63
explain crossing over
homologus pairs associate chiasmata form equal lengths of non-sister chromatids are exchanged producing a new combination of alleles
64
why should you do random sampling
to avoid bias, so results are reliable
65
why would a control be used
to show the effect of no (whatever is removed) to show the effect of only (whatever is not removed)