why large animals need large SA V
large / active, organisms have high(er), demand for oxygen / need to remove CO2 ; small(er), surface area to volume ratio / SA:V / surface area:volume ; surface area too small / distance too large / diffusion takes too long (to supply needs) ;
describe and explain adaptations of the gas exchange susteems
epithelium short (diffusion) distance ;
capillaries
delivers carbon dioxide (to be removed from blood) / carries oxygen away (from alveoli) ; short (diffusion) distance ;
diaphragm / intercostal muscles
ventilation / supply of oxygen (to alveoli) / removal of carbon dioxide (from alveoli) ;
mny alveoli to increase SA across which O2 AND CO2 diffuse
inspiration
diaphragm (contracts / flattens and) moves downwards ; intercostal muscles contract to move ribs, up / out ; increase volume of thorax ; reduce pressure inside thorax ; to below atmospheric pressure/creates pressure gradient / AW ;
single circulatory system:
blood passes through the heart once for each, circulation / circuit / cycle, of the body
closed circulatory system:
the blood is maintained inside vessels ;
source
site where, sucrose / sugars / assimilates, loaded (into phloem) / AW ;
sink
site where, sucrose / sugars / assimilates, unloaded / removed (from phloem) / AW ;
2
when park removed from tree, phloem removed oo, if a omplete ring of bark removed, th e tree swells abouve the cut. why
sugars) cannot pass the cut / AW ;
decrease water potential ; water moves into cells ;
(damage triggers) increased cell division ; to produce cells to store sugars ; cut causes, gall / infection ;
(A / goblet cells)
release mucus / AW ;
(mucus) traps, dust / particles / named particle ;
ciliated cell
/ B / cilia, wave / waft / move, mucus ;
to, top of trachea / back of mouth / AW ;
fuction of smooth muscle int eh bronchsu
to constrict the bronchus / AW ;
why capp and alveoli close
short, distance / path / AW ;
(so that) diffusion / concentration, gradient is, high / steep ; high rate of, (gas) exchange / diffusion ;
why alvreoli wall has elastic fibres
recoil / expel air / prevent bursting ;
why water loss by transpiration unavaoidable
stomata (open to) allow, gaseous exchange / carbon dioxide in / oxygen out / AW ;
(gaseous exchange) for photosynthesis ; (photosynthesis) essential for plant to, gain energy / make sugars ; some water lost through cuticle ;
xerohystes
reduce water (vapour) potential gradient / diffusion gradient ;
[A 1] hairy leaves ; trap water vapour / moisture ;
[A 2] stomata, in pits / sunken ; pits trap, water vapour / moisture ;
[A 3] rolled leaves / presence of hinge cells ; reduce surface area OR (rolled leaves) trap water vapour / moisture ;
[A 4] high solute concentration in cells ; reduces water potential inside leaf cells ;
[A 5] thick(er) cuticle ; (which is) waterproof / (relatively) impermeable ;
[A 6] small leaves / needles ; smaller surface area ; [A 7] fewer stomata ; reduces diffusion (of water vapour) ;
[A 8] stomata close, during the day ; reduces diffusion (of water vapour) ;
[A 9] most stomata on lower surface ; less exposure to sun OR cooler OR reduces diffusion (of water vapour) ;
why xylem lignified
Functions: F1 (lignin), strengthens / thickens, the (xylem) wall ;
F2 waterproofing (wall) / AW ;
F3 (improving) adhesion of water (molecules) ; F4 (spiral) pattern allows flexibility / stretching / movement; 2 max
ACCEPT support only if in specific context of supporting the xylem wall ACCEPT waterproofs cell
DO NOT ACCEPT adhesion and cohesion when used together Flexibility / stretching must ref, pattern of lignin laid down i.e. spirals
Explanation: E1 prevents collapse of xylem ; E2 (water) under tension / at low pressure / negative pressure; E3 reduces (lateral) loss of water, through wall ; E4 increases capillarity / AW ; E5 prevents stem breaking / AW ; in
fuction of the pits in the xylem
(pits) allow water to move, in / out / between, vessel(s) ; to bypass blockage ; supply water to other, tissues / (other types) cells / parts of plant ;
tissue found in the lungs
squamous epithialial
organ
(organ is) a collection of tissues / named tissues ; (working together) to carry a out a particular function
function of glycoprotein
1 (acting as) antigens ; 2 identification / recognition, (of cells) as, self / non-self / AW ; 3 cell signalling / described ; 4 receptor / binding site, for, hormone / (chemical) signal / (medicinal / named) drugs ;
5 ref. to receptor / binding site / trigger, on transport proteins / AW ; 6 cell adhesion / to hold cells together (in a tissue) ; 7 attach to water molecules (to stabilise membrane / cell)
ways that artery wall is diff to vein wall
Arteries have:
no valves ; endothelium / tunica intima, folded / AW ; more / thicker, muscle / elastic tissue / tunica media ; more / thicker, collagen / tunica externa ;
how hydrostatic pressure generated in the heart and why it falls as blodd moves from heart
contraction of ventricle, wall / muscle ;
more, (smaller) vessels / named vessels ;
(vessels) have larger, total lumen / cross sectional area ;
reduced resistance to blood flow ;
arteries, stretch / expand ;
loss of, fluid / plasma, from capillaries ;
2
why, when measuring vital capacity with the spirometer, us a nose clip
to ensure all air breathed comes from chamber OR to prevent, escape of air / entry of air, through nose ;
ACCEPT air may be breathed in or out through nose ACCEPT ensures breathes through mouth
make results invalid
why, when measuring vital capacity with the spirometer, us a nose clip
to ensure all air breathed comes from chamber OR to prevent, escape of air / entry of air, through nose ;
ACCEPT air may be breathed in or out through nose ACCEPT ensures breathes through mouth
make results invalid
procustions to take when using a spirometer
use (medical grade) oxygen / fresh air ;
Note question relates to measuring vital capacity ACCEPT ensure there is enough oxygen / air
disinfect mouthpiece ; ACCEPT change / wash mouthpiece
ref. to health of subject ; e.g. asthmatics
ref to correct functioning of equipment ;
why single cell nah need specialised exchange
large surface area to volume ratio ;
small so demand for, O2 / CO2, is low ;
idea of: diffusion (alone) is adequate to meet needs ;
fetal o2 diss curve
1 fetal haemoglobin has a higher affinity (for oxygen) ( than adult haemoglobin) ;
2 (fetal Hb) takes up oxygen in low(er) partial pressure of oxygen ;
3 placenta has low partial pressure of oxygen ;
4 at low partial pressure of oxygen / in placenta, adult (oxy)haemoglobin will dissociate / AW ;
benefits of bohr shift to actively respiring cells
1 (actively respiring tissue) needs / requires, more oxygen ;
2 for aerobic respiration / to release more energy ;
3 (actively respiring tissue produces) more CO2 ;
4 haemoglobin involved in transport of CO2 ;
5 less haemoglobin available to combine with O2 ;
6 (Bohr shift) causes more oxygen to be released
how water move from root to leaf
1 water moves into xylem down water potential gradient ;
2 root pressure / high (hydrostatic) pressure at bottom of xylem ;
3 water vapour loss / transpiration / evaporation, at leaves / top of plant ; 4 (creating) low (hydrostatic) pressure at top of xylem ;
5 water, under tension / pulled up (in a continuous column) ; 6 cohesion between water molecules / described ;
7 adhesion of water molecules to xylem / described ; 8 capillary action / described ;
9 water moves up (xylem / stem) by mass flow ; 10 from high(er) (hydrostatic) pressure to low(er) (hydrostatic) pressure / down (hydrostatic) pressure gradient ;
how histamine stimulates so=mooth muscle contraction
1 (histamine), binds / attaches, to, receptor / glycoprotein ;
idea of : 2 in / on, plasma / cell surface, membrane (of muscle cell) ;
3 complementary (shape) ;
4 triggers response / causes effect, inside cells ;
action of histamine and explain them
stimulates so=mooth muscle contraction
1 (histamine), binds / attaches, to, receptor / glycoprotein ;
idea of : 2 in / on, plasma / cell surface, membrane (of muscle cell) ;
3 complementary (shape) ;
4 triggers response / causes effect, inside cells ;
and makes capillary walls more permeable idea of : 1 more tissue fluid formed / increase in volume of tissue fluid ;
2 increase pressure in tissue ;
3 swelling / inflammation / oedema;
4 (more) white blood cells pass into tissues ;
5 larger molecules / (named) proteins , pass into tissue fluid
process of trainspiration
In the leaf: idea of : 1 water loss (from leaf) is replaced ;
2 via, apoplast / symplast / vacuolar, pathways ;
3 down water potential gradient / AW ;
4 (lost water replaced) by water from the xylem ;
In the xylem: 5 (loss of water) causes, low / negative, (hydrostatic) pressure (at top / in leaf) OR creates pressure gradient ;
idea of : 6 water moves, from higher pressure to lower pressure / down pressure gradient ;
7 under tension / pulled up / drawn up ;
8 by mass flow ;
9 cohesion / attraction, between water molecules ;
idea of : 10 column / stream / chain, of water (molecules) ;
transpiration
evaporation / loss of water vapour ;
from, aerial parts of plant / leaf / leaves ;
via stomata ;
why plants survive longer if ends of stem removed immediately before placed in water
Ref to : bubbles / air (present / being removed) ;
(blockage) in xylem ;
restore (continuous) column of water (in xylem) ;
explan how the diff cells and tissures make gas ex so effective
C1 thin / squamous, epithelium ; C2 thin endothelium (of capillary) ;
F1 (provides) short diffusion distance / described ;
F2 ref to surfactant (from epithelial cells) , reducing surface tension / preventing alveoli collapsing ;
C3 blood / red blood cells / erythrocytes ;
F3 transports (named) gas(es) , to / from , exchange surface / alveoli ; C4 diaphragm / intercostals , muscles ;
F4 (maintains / creates) diffusion / concentration , gradient ;
C5 ciliated epithelium / goblet cells / ciliated cells ; F5 idea of: protection from / removal of , dust / bacteria / pollen / spores ;
C6 cartilage ; F6 hold airway open ;
C7 smooth muscle
F7 constrict / control diameter of , airway / blood vessel ;
C8 elastic , fibres / tissue ; F8 for recoil / aiding ventilation ;
C9 macrophage / neutrophil ; F9 engulf / destroy pathogens or protect from infection ;
why left ventrivcle thicker
left ventricle
1 (more muscle to create) more force ;
2 (needs to create) higher pressure ;
3 push blood against greater , resistance / friction ;
4 (left ventricle) pumps blood further / pumps blood to all parts of body / supplies systemic circulation
how changes in pressure of the heart closes the AVV aka bicuspid valve
1 ventricular systole or ventricle , wall / muscle , contracts ;
2 (ventricular contraction) raises ventricular pressure ;
3 (ventricular pressure) higher than atrial pressure ;
4 idea of (pressure / movement of blood, generated by ventricular contraction) pushes valve shut ;
5 chordae tendinae prevent inversion ;
two adaptations of the sieve tube that enables massflow to occur
1 elongated elements ;
2 elements , joined end to end / form column ;
3 sieve plates / pores in end walls / perforated end plates / sieve pores ;
4 little cytoplasm / cytoplasm pushed to cell edges / thin (layer of) cytoplasm ;
5 no nucleus / few organelles ;
descried the process of phloem loading
1 active transport of, hydrogen ions / protons / H+ , out of companion cells ;
2 creates , hydrogen ion / concentration / diffusion , gradient ;
3 (facilitated) diffusion (of H+) back into companion cells ;
4 sucrose / assimilates , move in with hydrogen ions ;
5 by cotransport / through cotransport protein ;
6 sucrose / assimilates , (diffuse) through plasmodesmata (from companion cell to sieve element) ;
7 into sieve, tube / element ;
how steep con grad maintained in the lungs
EITHER D1 (continuous) blood flow (in the capillaries) ;
E1 to, bring in (more) carbon dioxide / take away (more) oxygen ;
OR
D2 oxygen combines with haemoglobin ; E2 to keep concentration in, blood / plasma, low ;
two advantages of keeping blood inside blood vessels
maintain / high(er), (blood) pressure ;
increase rate of, flow / delivery ; flow can be, diverted / directed / AW ;
how walls of artery enable it to withstand pressure and maintain pressure
to withstand pressure wall is thick ; (thick layer of) collagen ; (wall / collagen) provides strength ;
endothelium, corrugated / folded ;
idea of: no damage to, endothelium / artery (wall) (as it stretches) ;
max 3 to maintain pressure (thick layer of) elastic tissue / elastic fibres / elastin ; to cause recoil / return to original size ;
(thick layer of) smooth muscle ; narrows / constricts, lumen / artery ;
why water loss unavoidable during the day
1 2
3 4 5
6 7
stomata are open ; allow, gaseous exchange / entry of carbon dioxide / exit of oxygen ;
for photosynthesis ; water vapour leaves (the leaf) ; down a water (vapour) potential gradient ;
high(er) temperatures (during the day) ; causes greater evaporation / some water vapour loss through leaf surface all the time
pulse
fluxtuations in heart rate
changes in pressure of blood as it flows throught eh circulatory sustem from aorta to veins
marks for pressure change: pressure drops, as distance from heart increases ;
greatest / rapid / significant, pressure drop while blood is in the arteries ; pressure, constant / does not drop, in veins ;
marks for amplitude of fluctuations: fluctuation / AW, decreases from aorta to arteries ;
no fluctuation in, capillaries / veins ;
use of comparative figures with unit ;
why important that pressure changes as blood flow from aorta to capp
blood flows into larger number of vessels ;
(total) cross-sectional area of the arteries is greater than the aorta ; (total) cross-sectional area of the capillaries is greater than the, aorta / arteries capillary (wall) is, thin / only one cell thick ; (high pressure would) burst / damage, capillary (wall) ; reduce chance of, tissue fluid build up / oedema
expiration
between B & C expiration:
1 (external) intercostal muscles / diaphragm, relax ;
2 rib cage / ribs, move down OR diaphragm, moves / pushed, up ; 3 volume of, thorax / chest cavity / lungs, drops / decreases ; 4 pressure inside, thorax / chest cavity / lungs, increases ; 5 above, external / atmospheric, pressure ; 6 air leaves down pressure gradient ; 7 (elastic) recoil of alveoli ;
describe phloem active loading
1 hydrogen ions / H+ / protons, pumped out of companion cells ; 2 increases, hydrogen ion / H+ / proton, concentration (gradient) (outside companion cell) ;
3 hydrogen ions, re-enter / flow back into, companion cells ; 4 sucrose / sugar, moves with hydrogen ions / AW ;
5 down concentration gradient ; 6 ref. cotransporter proteins / cotransport(ation) ; 7 by facilitated diffusion ;
8 sucrose / sugar, diffuses into sieve tube (element) ;
9 through plasmodesmata ;
why delay netweem atria excitation and ventricular excitation
(to allow time) for the atria to (fully) contract ;
to allow (time for), atria to empty / blood to move / ventricles to fill ; so that ventricle(s) do not contract, too early ;
why is wave of excitation carried tot the apex
so that (ventricular) contraction starts at, apex / base / bottom ;
to push blood upwards OR into/ towards, (named) arteries ;
complete / efficient, emptying of ventricles ;
need for cartilage in the trachaea
(provides) strength / support, to keep, it / trachea / airway, open OR (provides) strength / support, to prevent collapse ;
during, inspiration / inhaling / breathing in ;
volume of, chest cavity / thorax / lungs, increases ;
low(er) / negative, pressure in, trachea / thorax / lungs
why xylem needs ignin
provides, strength / support ;
to keep, it / the vessel / the tube, open OR prevent collapse of, vessel / tube ;
(because) transpiration produces, tension / negative pressure ;
to waterproof the, cell / vessel / tube / wall ;
(so) cell, dies / content decays ;
to create a hollow, tube / vessel OR to create a continuous column / allow unimpeded flow ;
to limit lateral flow of water ;
ref to adhesion (between water molecules and wall) ;
where can water be lost from th plant
aerial parts of the pant
cuticle
how aveoli adapted fro gas ex
- wall is one cell thick for short(er) diffusion, distance / pathway ;
- squamous, cells / epithelium , provide short diffusion distance / pathway ;
- elastic so, recoil / expel air / helps ventilation ;
- create / maintain, concentration gradient / described ;
- large number (of alveoli) provide large(r) surface area ;
- small size (of alveoli) provide large(r) surface area to volume ratio ;
- (cells secrete) surfactant to maintain surface area ; max 4
babies lungs
lungs not, functioning / filled with air ;
blood / haemoglobin, is, not oxygenated in the lungs / oxygenated in placenta ;
(therefore) pulmonary circuit / lungs, bypassed ;
think of the ballon model of the lungs, why do the ballons expand?
1 volume, inside / of, jar increases ;
2 pressure inside, jar / balloons, decreases ;
3 to below pressure in atmosphere ;
4 (therefore) air, moves / pushed / forced, into, balloons / glass tube ;
what is tidal volume
volume of air, inhaled / exhaled ;
in, one / each, breath ;
during, steady / regular, breathing ;
how could the teacher use the ballon model to show tifal volume
up / down, movements (of rubber sheet / band) ;
idea of: small / steady / regular, movements (of rubber sheet) ;
what is vital capacity
the maximum volume of air ;
inhaled / exhaled, in one breath ;
how could the teacher use the ballon model to show vital capacity
idea that pulled down on rubber, sheet / band, as far as possible and pushed up as far as possible ;
why tissue fluid doesn’t contain rbc?
gap(s) between endothelium cells (too) small ;
(erythrocytes) too large / cannot change shape (much) ;
to, fit / move / pass, between (endothelium) cells OR through, gaps / pores / fenestrations;
describe the rle of haemoglobin in oxygen transportation
1 (haemoglobin has) high affinity for oxygen ;
2 oxygen binds to haemoglobin in, lungs / alveoli / high pO2 ;
3 oxyhaemoglobin ;
4 oxygen released, in tissues / where needed / where pO2 is low / where respiration is occurring
how are the HC03- made in the RBC
1 carbon dioxide, enters / diffuses into, erythrocytes ;
2 (carbon dioxide) combines / reacts, with water ;
3 correct ref to carbonic anhydrase;
4 forms carbonic acid ;
5 (carbonic acid) dissociates to form hydrogencarbonate ions and, hydrogen ions / protons ;
high co2 con in the blood reduces o2 transported by haemoglobin. what is this effect called and why does It happen?
1 Bohr (effect / shift) ;
Explanation (any 2 of the following marks)
2 reduces affinity (of Hb) for oxygen ;
3 formation of haemoglobinic acid / hydrogen ions interact with haemoglobin ;
4 prevents, fall in pH / build-up of H+, in cells OR provides buffering effect ;
5 alter, structure / shape, of haemoglobin ;
6 more oxygen released where, needed / more respiration / carbon dioxide concentration high ;
7 CO2 binds to haemoglobin forming carbaminohaemoglobin
adaptations of the companion cell
many / large, mitochondria ;
plasmodesmata (between companion cell and sieve tube) / described ;
many ribosomes / extensive RER ;
many proteins in the, plasma / cell surface, membrane ;
explain the significance between rate of diffusion and the SA V for large plants
arge plants) have a, small / low, SA : VOL ratio ;
idea of diffusion too slow (to supply requirements) ;
idea of need transport system (for water / minerals / assimilates) ;
idea of need (special) surface area for, gaseous exchange / uptake of minerals
squamous epithelium
short(er) diffusion, distance / path ;
good blood supply
high/ large / steep, concentration gradient OR removes oxygen (from lung surface) / brings carbon dioxide (to lung surface);
good ventilation
high / large / steep, concentration gradient OR supplies oxygen (to alveoli) / removes carbon dioxide (from alveoli) ;
large number of alveoli
large(r) surface area ;
new growth in a stem or trunk comes from the cambium. that is situated between the xylem and the phloem vessels. why would tree branches grow from the stump
this is where cambium / meristem / xylem / phloem / vascular bundle, is found ;
mitosis/cell division, occurs in cambium (to produce new cells for growth) ; new cells, differentiate / specialise, (into xylem and phloem) ; xylem supplies water for, (cell) elongation / (cell) growth ; phloem supplies, sugars / assimilates, for, energy / growth /respiration
lenticels allow gases to diffuse into the living tissues of the trunk of a tree. why are they not found in ;arge mutlicell animals?
allow oxygen to reach, cells / tissues (under bark) ;
for (aerobic) respiration ;
animals transport oxygen in, blood / circulation / transport system ; plants do not transport (much) oxygen in transport system ;
idea that (oxygen not supplied from leaves as) stomata only open in day / no leaves in winter ;
why use fetal haemoglobin to treat sickle cell anaemia?
(fetal) haemoglobin may not crystallise (much) (at low pO2) ;
red blood cells do not change shape ;
(fetal) haemoglobin can pick up more oxygen at low pO2 (than sickle haemoglobin);
idea that more oxygen, transported / delivered (around body) ;
how do susbstances enter the tissue fluid?
iffusion ;
from high concentration to low concentration / down concentration gradient;
(hydrostatic) pressure in capillary high(er than in tissue fluid) ; capillary (walls) leaky / described ;
fluid / plasma, forced out (of capillary) OR fluid / plasma, moves, from higher pressure to lower pressure / down pressure gradient ;
(as the fluid / plasma moves out) glucose / oxygen / small molecules, leave with, fluid / plasma ;
distinguish between transpiration and the transpiration stream
transpiration loss of water vapour / evaporation of water ; from, aerial parts of plant / leaves / stomata ;
transpiration stream movement of water (up xylem vessels) ; from roots to, leaves / air surrounding leaves ;
adapatations of the granum / grana / granal stack / thylakoid stack ;
1 contain , (named) pigment (molecules) / photosystems ;
2 contain , (named) electron carriers / ETC / ATP synth(et)ase ;
3 idea that has a large surface area (in a small volume) for , light absorption / light dependent reaction(s) / light dependent stage / electron transport ;
why theoretical rate of photosyntheses nort achieved at high light intensities
at high light intensity other (named) factor becomes a limiting factor ;
2 idea that temperature becomes limiting as , Calvin cycle / light independent reaction , involves enzymes / relies on kinetic energy of molecules ;
3 idea that CO2 (concentration) becomes limiting as it is required for , Calvin cycle / light independent reaction / formation of (named) Calvin cycle compound / reaction with RuBP / fixation by Rubisco ;
how leaf of plant adapted to living in shade is different to other plants
shade leaf will have 1 large(r) / more , chloroplast(s) / (palisade) mesophyll ;
2 more , grana / thylakoids (in chloroplast) ;
3 large(r) surface area (of leaves) ;
describe the secretion of insulin from beta cell
1 glucose , respired / phosphorylated / metabolised , to produce ATP ;
2 ATP , blocks / closes , potassium ion channel(s) and potassium ions / K+ , build up (inside cell) / cannot leave ;
3 (voltage-gated) calcium ion / Ca2+ , channels open and calcium ions / Ca2+ , enter (cell by diffusion) ;
4 (more) calcium ions / Ca2+ , resulting in , movement of vesicles to membrane / exocytosis / described ;
why dpoes cell still secrete insulin even after no futher gloucose intake
1 (continues to be secreted) as long as blood / plasma , glucose (concentration) , remains high / is higher than normal ;
2 (sufficient) ATP is still present and so K+ channels remain closed ;
3 (exocytosis) still being triggered by , calcium ions / Ca2+;
2
why does aerobic respiration yield fewer atp than thoretical
1 some ATP used to (actively) transport pyruvate (into the mitochondrion) ;
2 some ATP used to (actively) transport H(+) from (reduced) NAD , formed in glycolysis / into the mitochondrion ;
3 some energy released in ETC , is not used to transport H+ (across inner membrane) / is released as heat ;
4 not all the H+ movement (back across membrane) , is used to generate ATP / is through ATP synth(et)ase ;
5 not all the, reduced NAD / red NAD / NADH , is used to feed into the ETC ;
explain why the incomplete breakdown of glucpse in anerobic respiration produces less ATP than aerobic respiration
1 glycolysis / conversion of glucose into pyruvate , occurs ;
2 produces 2 molecules of ATP (net) ;
3 (only) substrate level phosphorylation (occurs) ;
4 oxygen not available as final electron acceptor ;
5 pyruvate / ethanal , used to regenerate NAD for glycolysis (to continue) ;
6 (Krebs cycle and) electron transport chain / chemiosmosis / oxidative phosphorylation , do not occur ;
why is uncertain diagnosis of kidney failure more common in over 65s
uncertain diagnosis because idea that older people may have more complex medical problems
how does the peri differ in its function from the artificial membrane in a dialysis machines used in haemodialysis?
it can perform , active transport / facilitated diffusion ;
why does the dialysis fluid used in peri contain dextrose solution not just water alone
1 idea that (dialysis is replicating function of kidney and) part of kidney’s function is to remove (excess) water from blood ;
2 (dextrose / sugar) reduces , water potential / (of dialysis fluid) or (dextrose / sugar , solution) has a lower , water potential / (than water) ; 3 water moves from blood (into dialysis fluid) by osmosis or prevents water moving into the blood (from dialysis fluid) by osmosis ;
4 (if it was water alone) cells would , swell / burst ;
why patients receiving perineal need the Peri df replaced 4times a day but Haemo only need treatment 3 times a week
1 peritoneal dialysis can remove less (named) waste (than haemodialysis) ;
2 idea that in haemodialysis dialysis fluid is constantly , refreshed / changed (but not in peritoneal dialysis) ;
3 haemodialysis uses counter-current flow ;
4 idea that haemodialysis maintains concentration gradient or in peritoneal dialysis the concentration gradient , reduces / is lower ;
5 (in peritoneal dialysis) the fluid reaches equilibrium with the blood
type of cell from which rbc are formed and where is cell is located
stem / erythropoietic , cell(s) and bone marrow ;
outline the ways in which the structures of a sensory neurone are similar
both have
1 dendrite(s) ;
2 an axon ;
3 a cell body with a , nucleus / named organelle ;
4 myelin sheath / myelinated / (covered with) Schwann cell / nodes of Ranvier ;
5 voltage-gated channels / sodium-potassium (ion) pump
what effect does sweating habe on the bofy
1 evaporation will , have a cooling effect / reduce (body) temperature ;
2 heat , taken from / supplied by , the body / blood / skin , is , needed / used for , evaporation ;
3 idea that water has a high latent heat of , vaporisation / evaporation
why does shivering happen duing fever?
idea that to increase body temperature as it is lower than the ‘new’ set-point (even though body is hot) ;
hypothermia is when someones core body temp is lowered. alcohol causes vasodiltion, why shouldn’t you give them alchohol
1 vasodilation results in more blood nearer to the skin surface ;
2 idea that will lose (even) more heat / further heat loss (from body) / body temperature decreases further ;
3 (named) organ(s) will not be able to maintain , function / metabolism ;
primary photosynthetic pigment in PS1 and PS11
chlorophyll A
accessory pigment
chlorophyll b / xanthophyll(s) / carotenoid(s) / ( / beta-) carotene
advantages of having a range of accessory pigments
able to , absorb / use , a range of / different / more / other , (light) wavelengths /
two different polysaccs that can be made from the end products of the light independent stage of photosynthesis
starch / amylose / amylopectin and cellulose
why is the pacian corpusvle a transducer
it converts energy (mechanical) into , another / different , form of energy (electrical)
why does deformation of the plasma membrance of the tip of the neurone casue the membrance to become more permeable to Na+
idea that deformation of membrane will allow more Na+ through because
1 (the increased pressure) causes sodium (ion) channels to open ;
2 (temporary) gaps / holes / spaces , appear , between the phospholipids / in the bilayer ;
why are action potentials all or nothing
if the , stimulus is not strong enough / threshold (value) is not reached / depolarisation (of membrane) is insufficient , then , it / an action potential , is not , generated / AW
how is the strength and intenstitty of a stimulus communicated to the brain
1 idea that it is represented by the frequency of the action potentials ;
2 high , frequency / rate (of generation) , of action potentials shows , a strong / an intense , stimulus ; ora
2
why aren’t AP made by the PC when you wear clothes
action potentials not generated because
1 sodium (ion) channels (remain) open / resting potential not re-established ;
2 idea of ions being in the wrong place for correct ion movement (across membrane) ;
outline the roles of the synapses in the nervous system
1 allows , neurones to communicate / cell signalling ;
2 ensure transmission (between neurones) in one direction (only) ;
3 allows , convergence / impulses from more than one neurone to be passed to a single neurone ;
4 allows , divergence / impulses from a single neurone to be passed to more than one neurone ;
5 idea that filters (out) , ‘background’ / low level , stimuli or ensures that only stimulation that is strong enough will be passed on ;
6 prevents fatigue / prevents over-stimulation ;
7 allows many low level stimuli to be amplified ;
8 idea that presence of inhibitory and stimulatory synapses allows impulses to follow specific path ;
9 permits , memory / learning / decision making ;
why shouldn’t you eat 8hrs before a blood test?
idea that time needed , to restore normal (blood) glucose concentration / for insulin to act (fully) ;
suggest reasons for someone having a high resting blood glucose level
patient might have had a drink containing sugar ● patient was nervous and secreted adrenaline ● other medication interferes with glucose levels ● patient’s haemoglobin does not bind effectively with glucose (e.g. anaemia / sickle cell)
how glucagon is involved in regulation of bgc in a person who is able to regulate their bgc correctly
when blood glucose concentration decreases
1 (glucagon) released by the , alpha / , cells in , islets of Langerhans / pancreas ;
2 promotes / AW , conversion of glycogen to glucose / glycogenolysis , in , liver / muscle / effector , cells ;
3 ref gluconeogenesis / described ;
4 ref conversion of triglycerides to (free) fatty acids / lipolysis / increased use of fatty acids in respiration ;
5 negative feedback , reduces / inhibits , the secretion of glucagon ;
6 glucagon , reduces / inhibits , insulin secretion ;
when to give a glucagon injection?
if blood glucose falls , extremely / dangerously / too / very , low ;
2 if patient , cannot produce (enough) glucagon / produces little glucagon ;
3 idea that glucose source cannot be taken by mouth ;
difuctional alpha cells
dysfuction glycagon receptors
a chemical that transfers a nerve impulse from one neurone to another
acetylcholine
which liver cells lead to the regernation of the liver and what type of cell division do they use
hepatocytes
and
mitosis / mitotic (division) ;
why are parasties that live in mammal blood(that contains oxygen) adapted to respire anerobically
1 idea that parasites have little access to oxygen ;
2 (inaccessible because) little oxygen dissolved in plasma / oxygen not very soluble (in plasma) ;
3 (inaccessible because) idea that oxygen is , combined with haemoglobin / contained in red blood cells ;
4 idea that haemoglobin has greater affinity for oxygen than parasite (pigment) ;
differences between the two types of fermentation
in animals A1 pyruvate is , converted / reduced , to , lactate / lactic acid ;
A2 can be reversed as no , atoms lost / other product formed ;
A3 lactate dehydrogenase available to reverse the reaction ;
in yeast Y1 pyruvate converted to ethanol (in 2 steps) and carbon dioxide / CO2 ;
Y2 cannot be reversed as , carbon dioxide is / atoms are , lost ;
Y3 (de)carboxylase enzyme cannot reverse the reaction
type of drug misued by athletes
ANABOLIC steriods
how the LofH of a animal that lives in dry places is diff to that of one that does not
It is longer.1 more (sodium and chloride) ions pumped , out of ascending limb / into medulla ;
2 builds up greater water potential gradient ;
3 allows , reabsorption / removal , of more water from , collecting duct / M ; therefore small amount of concentrated urine.
Describe how smoking could cause changes in alveoli
named component of cigarette smoke (correctly linked to a stated problem) ;
tar, hydrogen cyanide, carbon monoxide (but NOT in context of Hb), ammonia, sulphur dioxide destroy / paralyse , cilia ; mucus not removed ;
tar over-active goblet cells / extra mucus produced ;
(accumulation of mucus) leads to , infections / bronchitis ;
neutrophils / phagocytes / macrophages / monocytes (invade) ; secrete , enzyme / elastase ; elastin / elastic fibres , digested / destroyed ; low(er) level of , elastase inhibitor / antitrypsinase ; alveoli fail to recoil ;
constriction of (terminal) bronchioles ; (so) coughing / forced expiration , causes alveoli to burst ; reduced surface area ;
Emphysema is a form of chronic obstructive pulmonary disease (COPD).
Describe two signs or symptoms of emphysema
shortness of breath / shallow breathing / strained breathing / hard to breathe out / wheezing ; barrel chest ; fatigue / extreme tiredness / cannot exert themselves ; pulmonary hypertension / high blood pressure to lungs ; enlargement of right side of heart ; heart failure / congestive cardiac failure / fluid buildup in lungs ; cyanosis / skin with blue tinge ;
Emphysema is described as a chronic disease.
Suggest the meaning of the term chronic
long term / lifelong / persistent ; slow onset / takes time for the symptoms to show ; (usually) degenerative / gets (progressively) worse
Name two diseases associated with obesity
1 coronary heart disease / CHD / atherosclerosis / angina / coronary thrombosis / myocardial infarction / heart attack / cardiac arrest / cardiovascular disease / stroke ;
2 (osteo)arthritis ; 3 (Type 2) diabetes ; 4 high blood pressure / hypertension ; 5 gallstones ; 6 cancer ;
compare the processes of excretion and secretion.
excretion (metabolic) waste or toxin / harmful or substance is to be removed from body or does not use vesicles urea / carbon dioxide / water / bile pigment /
secretion useful product or used in cell communication (e.g. to target tissues) or released from glands (ducts or ductless) or uses vesicles or remain in body hormone / enzyme / antibodies / mucus / bile salts / neurotransmitter /
but both requires ATP or (involved in) homeostasis or (compounds) produced by cell(s) / produced by metabolism / need to cross membrane / need to move through membrane / need to leave cell / (may be) transported in blood
Although carbon dioxide and water are products of aerobic respiration, the equation is an over-simplification of the process.
State and explain one way in which this equation is an over-simplification
glucose is not the only substrate / there are other substrates ; named alternative substrate ; or ATP is produced / energy is released ; (by) substrate level / oxidative, phosphorylation ; or ATP / energy, required ; (for) phosphorylation / glycolysis ; or is not a single step reaction / other steps involved / other products / other intermediates ; named stage(s) / named intermediate compound(s) ; or enzymes are involved ; dehydrogenation / decarboxylation / oxidative phosphorylation / named (respiratory) enzyme ; or coenzymes / NAD, involved ; oxidative phosphorylation / link reaction / Krebs cycle / glycolysis ; or glucose does not, combine / react , (directly) with oxygen ; (oxygen) used in oxidative phosphorylation / is final electron acceptor / is final hydrogen acceptor ;
Explain how Type 1 diabetes is caused
unable to produce (enough) insulin / do not secrete insulin / produces ineffective insulin ; insulin-producing cells / beta cells / islets of Langerhans, not functioning (correctly) / damaged / destroyed / attacked ;
by (body’s own) immune system / by (body’s own) antibodies / auto-immune disease ; (idea of) family history / genetic / hereditary ; (condition can be) triggered by , virus / environmental factor ;
Describe three factors that increase a person’s risk of developing Type 2 diabetes
increasing age / older / ageing / more prevalent over 40 ; (idea of) family history / genetic / hereditary ; (more common in) males ; (more common in) some ethnic groups / African / Afro-Caribbean / Asian / Hispanic / Oceanic ; obese / overweight / fat around abdomen ; high / frequent, intake of , sugar / highly processed food / high GI food ; lack of physical activity / sedentary lifestyle ; high blood pressure ; excessive alcohol intake ;
In anaerobic conditions, pyruvate does not proceed to the link reaction.
Describe the fate of pyruvate during anaerobic respiration in an animal cell and explain the importance of this reaction.
(pyruvate / F) converted to lactate ;
F / pyruvate , accepts hydrogen (atoms) ;
hydrogen from , reduced NAD / reduced E ; (catalysed by) lactate dehydrogenase ;
no, oxygen / O2 , to act as (final), hydrogen / electron, acceptor ; (so) link reaction / Krebs cycle / ETC, cannot take place ;
NAD / E, regenerated / recycled / able to be re-used ; allows glycolysis to continue / pyruvate continues to be made ;
limited / small amount of / some, ATP can be produced
Suggest how the seal is adapted to respire for such a long time underwater
large nostrils (open) to take in air ;
(when submerged) nostrils close / nose closes , to , keep air in / stop air from escaping ;
lungs / airways , have high (vital) capacity ;
links to respiration idea that seal , has low(er) metabolic rate / has low(er) respiratory rate / has low(er) energy requirements / uses (relatively) little ATP ;
able to respire anaerobically for a long time / more glycolysis ; large supplies of NAD (to accept H) ; (this) prevents , build-up of lactate / lowering of pH ; idea that (seal) tolerates lactate / removes lactate quickly ; idea that (seal) tolerates high CO2 concentration ; idea that (seal) tolerates low pH / has more pH buffers ; synoptic / inference idea that blood diverted from certain regions / certain regions have reduced metabolic activity ; idea that has plenty of , haemoglobin / red blood cells / myoglobin (as oxygen source) ; idea that haemoglobin has a higher affinity for oxygen / dissociates less readily / dissociation curve shifted to left ;
Suggest why an increase in temperature results in an increase in the speed of conduction
increased kinetic energy / KE so, ions diffuse, across (axon) membrane / into neurone / into cell / between nodes / along neurone, more quickly or faster movement of (neurotransmitter) vesicles / exocytosis (of neurotransmitter) or neurotransmitter diffuses more quickly across,
synapse / synaptic cleft or neurotransmitter (ACh) broken down by enzyme (acetylcholinesterase) more quickly ;
faster diffusion of ions leads to, faster depolarisation or shorter duration of action potential or shorter refractory period or faster repolarisation ;
As the temperature continues to increase, it reaches a point at which the conduction of the impulse ceases. Suggest why.
ion, channels / pumps, disrupted / denatured / no longer function ; fluidity of, membrane / phospholipid / bilayer, disrupted ; (named) synaptic enzymes denatured ;
Outline the events following the arrival of an action potential at the synaptic knob until the acetylcholine has been released into the synapse.
calcium channels open ;
Ca2+ / Ca++ / calcium ions , enter / diffuse into, acetylcholine / ACh / neurotransmitter, in vesicle(s) ;
(synaptic) vesicles move towards presynaptic membrane ; vesicles fuse with membrane ; release acetylcholine, by exocytosis , into synaptic cleft ;
Name the process by which the fluid passes from the glomerulus into the renal tubule.
ultrafiltration
Name the tissue that lines the proximal convoluted tubule.
(cuboidal) epithelium / epithelial ;
Suggest why it is necessary to add an anticoagulant to the blood in haemodialysis
so that clots don’t form, while in the (dialysis) machine / during dialysis ;
Suggest why no anticoagulant is added to the blood towards the end of a dialysis session.
idea of allowing blood to clot normally after treatment
State the process by which molecules and ions, other than water, will move from the blood into the dialysate.
(simple) diffusion
Suggest why the direction of flow of the blood and the dialysate is opposite in haemodialysis
idea that it, maintains diffusion gradient / maintains concentration gradient / maximises diffusion gradient / maximises concentration gradient / allows maximum removal of waste / allows maximum rate of diffusion / AW ;
Name the pigment at the reaction centre of photosystems I and II
chlorophyll a ;
Suggest one benefit of anaerobic respiration to an organism
idea that ATP produced / energy released ;
idea that recycles NAD / NAD can be used again ;
allows , glycolysis / description of glycolysis , to take place / to continue
name of hydrogen acceptor after glycolysis pyruvate anaerobic respiration in mammals
pyruvate
name of hydrogen acceptor after glycolysis anaerobic respiration in yeast
ethanal
is CO2 made in anaerobic respiration in mammals
no
Triose phosphate is a compound that is central to the metabolism of this cell.
Explain how the three reaction pathways glycolysis ;
Calvin cycle / light-independent stage (of photosynthesis) ;
Krebs cycle ;
3 are able to work independently of each other in the same leaf cell.
take place in different , parts / organelles , of the cell or compartmentalisation / reactions separated by membranes ;
W / glycolysis , in cytoplasm ;
X / Calvin cycle , in , chloroplast / stroma (of chloroplast) ;
Y / Krebs cycle , in , mitochondrion / matrix (of mitochondrion) ;
State the products of oxidative phosphorylation.
ATP / adenosine triphosphate ; water / H2O ; (oxidised) NAD / FAD ;
Osmoregulation is a key feature of homeostasis and maintains the water potential of the blood within certain limits. This is achieved by the action of anti-diuretic hormone (ADH).
(a) Explain the likely effect on the blood cells if the water potential of the plasma was allowed to increase significantly.
water potential / , of plasma / outside cells , would be higher than that of the (blood) cells ;
water would enter (blood) cells ;
blood cells , swell / (might) burst / lyse
ADH does not stay in the blood indefinitely Suggest where ADH is removed from the blood and describe what then happens to the ADH molecule.
in , liver / hepatocytes ;
hydrolysis / acted on by protease ;
deamination / amine group removed / formation of ammonia / formation of NH3 ;
ornithine cycle / formation of urea / formation of CO(NH2)2 ;
amino acids / keto acids , used in (named) metabolic pathway ;
how ADH or urea is dealt with as a small molecule in kidney ;
(ultra) filtered from blood / moves from blood into nephron ;
(because) small molecule ;
urea not (all) reabsorbed / ADH not reabsorbed / (ADH or urea) present in urine ;
excreted ;
Outline the hormonal and nervous mechanisms involved in the control of heart rate.
adrenalin(e) increases , heart rate / stroke volume / cardiac output ;
cardiovascular centre in medulla oblongata ;
idea of nervous connection to , SAN / sino-atrial node ; (which) controls frequency of waves of , excitation / depolarisation ;
vagus / parasympathetic , nerve decreases heart rate ; accelerator / sympathetic , nerve increases heart rate ;
high blood pressure detected by , stretch receptors / baroreceptors ; low blood pH / increased levels of blood CO2 , detected by chemoreceptors ;
(receptors) in , aorta / carotid sinus / carotid arteries ;
Describe the way in which an endothermic animal, such as a mammal, normally prevents its body temperature from decreasing when the external temperature decreases.
peripheral / skin , thermoreceptors / (heat) receptors , stimulated (by decrease in external temp) ; (impulses sent to / blood temperature monitored in ) hypothalamus / sensory cortex ;
vasoconstriction of , arterioles / small arteries , to reduce heat loss ;
(prevents heat loss by) radiation / conduction / convection ;
increased , metabolic rate / metabolism / respiration , to generate heat (energy) ; (release of) adrenaline / thyroxine ; shivering / (involuntary) muscle spasms , to generate heat (energy) ;
erector / hair , muscles raise , (skin) hair / fur , to trap , air / heat ;
A pregnancy testing kit contains a testing ‘stick’ to detect a hormone in the urine.
Explain how the stick detects this pregnancy hormone
(testing for) human chorionic gonadotrophin / hCG ; hormone small so can pass from blood into filtrate (at Bowman’s capsule) ;
monoclonal / immobilised , antibodies / immunoglobulin , on stick ; antibodies attached to , marker / dye ; hormone , binds / complementary , to antibody ; (triggers) appearance of colour / line becomes visible ;
AVP ;
3
Discuss the fate of triose phosphate (TP) in the Calvin cycle
regenerates / produces , ribulose bisphosphate / RuBP ; so cycle can continue / for (further) CO2 fixation / to combine with CO2 ;
formation of (named) , sugar / glucose / hexose / sucrose / starch / cellulose ;
formation of (named) , fat / triglyceride / lipid / fatty acids / glycerol / amino acids / protein / nucleic acids / nucleotides ;
10x TP for RuBP and 2x TP for production or most TP used to produce RuBP and the rest for production
photorespiration
oxygen used and carbon dioxide , produced / excreted ;
(only) occurs in the light / light (energy) required or uses , (same) photosynthetic enzyme / Rubisco or involves Calvin cycle ;
describe and explain the likely effect on photosynthesis of an increase in the oxygen concentration
reduces (rate of) photosynthesis / increases (rate of) photorespiration ;
less Rubisco available for CO2 / more oxygen competing with CO2 for Rubisco / more O2 binding to Rubisco O 2 outcompetes CO2 for Rubisco ;
less CO2 , fixation / for Calvin cycle ; CO2 given off ;
less , glycerate 3-phosphate / GP / TP , produced ; less RuBP , regenerated / formed ;
Suggest an explanation for the differences observed in blood glucose concentration:
(i) between starch and sucrose,
starch contains (only) glucose and sucrose contains , 50% glucose or glucose and fructose ;
by hydrolysis , starch releases more glucose / sucrose releases less glucose
Suggest an explanation for the differences observed in blood glucose concentration: between starch and cellulose.
both starch and cellulose are (only) made of glucose ;
starch , is digestible / can be broken down and cellulose , is indigestible / cannot be broken down ;
(named) enzyme present for starch digestion / no (named) enzyme present for cellulose digestion
explain how a person with Type 2 diabetes could control the condition by modifying their diet
low / decrease , starch ;
as starch has the greatest effect on blood glucose conc. ;
increase / include , cellulose / fibre / roughage / fat / protein / meat , as no effect on blood glucose ;
some / medium amount of , sugars / sucrose / lactose ;
idea of limiting , sucrose / lactose / fat / protein , as causes an increase in insulin and will make cells less responsive (to insulin)
glycogen vs glucagon
glycogen carbohydrate OR polysaccharide
role of compound storage OR to provide glucose (when blood glucose conc. falls) OR can undergo glycogenolysis
site of production liver OR hepatocytes
glucagon
hormone OR polypeptide OR protein
role of compound
binds to cell receptor OR causes conversion of glycogen to glucose OR stimulates glycogenolysis OR increases (blood) glucose concentration
site of production
pancreas OR islets of Langerhans OR alpha / α , cells
Suggest why MS is described as an auto-immune condition
attacked by the body’s (own) immune system ;
(immune system) mistakes / treats / recognises , body cells / neurones / myelin , as , ‘foreign’ / non self ;
correct ref. to , antibodies / (named) phagocytes / (named) B lymphocytes / (named) T lymphocytes
Explain why this damage to the mylein sheath leads to a loss of sensation
damage to) myelin / sheath / Schwann cell(s) ; removes / has less , insulation ;
interferes with / slows / stops , conduction of , (nerve) impulse / action potential or slows / stops / prevents , saltatory conduction / described ;
occurs , in sensory neurones / towards brain / towards CNS / from sensory organ / from receptor
Explain what is meant by the term homeostasis
1 idea of maintaining (relatively) stable internal , environment / state ; 2 within (narrow) limits / within (narrow) range / about a set point ;
3 even though environment is changing
Describe how negative feedback is used to control blood glucose concentration.
cells / cells / receptors , detect , change / increased / decreased , in blood glucose (concentration) ;
2 if high(er) glucose (concentration) , beta / , cells (in pancreas) release insulin ;
3 (increased) uptake / absorption , of glucose by , liver / muscle / effector , cells ;
4 enters through glucose transport proteins (in cell surface membrane) ;
5 glucose converted to glycogen / glycogenesis ;
6 increased (use of glucose in) , respiration / ATP production ;
7 if low(er) glucose (concentration) , alpha / , (in pancreas) cells release glucagon ;
8 (increased) conversion of glycogen to glucose / glycogenolysis ;
9 (increased) conversion of other compounds (amino acids / lipids) to glucose / gluconeogenesis ;
10 glucose leaves cells , by facilitated diffusion / through glucose channels ;
Name the organ that produces urea
liver
It has been observed that the urea content of urine is relatively high when a person eats an excessive amount of protein in their diet.
Suggest why a high intake of protein in the diet will be likely to result in a high concentration of urea in urine.
(high intake of protein) leads to a large amount of amino acids ;
2 (excess) amino acids cannot be stored ;
3 amino acids deaminated or amine group / NH2 , removed / converted to ammonia ;
4 (large amount of) ammonia enters ornithine cycle (for conversion to urea) ;
5 increased , blood / plasma , concentration of urea (leads to more urea in , filtrate / urine) ;
6 high concentration of , amino acids / urea , in blood increases water absorption from urine
answer cyclic photophosphorylation only (C)
or
• non-cyclic photophosphorylation only (N)
or
• both cyclic and non-cyclic photophosphorylation (B)
-ATP is produced
-an electron leaves photosystem I
electrons are passed along an electron carrier chain
electrons leave both photosystem I and photosystem II
an electron from a water molecule replaces the electron lost from the photosystem
the same electron returns to the photosystem
B B B N N C
State the stage or stages of aerobic respiration during which:
(i) carbon dioxide is produced
link reaction and Krebs cycle ;
State the stage or stages of aerobic respiration during which:oxygen is used
oxidative phosphorylation
Explain how the glomerulus is able to perform its function
1 afferent arteriole , has diameter greater than that of / is wider than , efferent arteriole ;
2 build up of / high , hydrostatic / blood , pressure ;
3 endothelium / wall , of , capillary / glomerulus , has , (small) pores / fenestrations ;
4 (these allow) ultrafiltration
Suggest the effects of complete kidney failure on the composition of the blood
if kidney cannot filter so substances remain in blood 1 increase / high , in urea ; 2 increase / high , in , (named) ions / (named) salts ; 3 increase / high , in water ; 4 AVP ;
OR
if problems cause substances to be lost indiscriminately 5 decrease / low , in , protein / blood cells ; 6 decrease / low , in , (named) ions / (named) salts ; 7 decrease / low , in , glucose / amino acids / vitamins ; 8 decrease / low , in water ;
One way of treating a person with kidney failure is by giving them a kidney transplant.
Explain the need for close matching of the donated kidney to the recipient.
if not closely matched
1 donated kidney will be recognised as , foreign / non-self ;
2 antigens / glycoproteins , (on donated kidney) will be different ;
3 causing rejection ;
4 (response) by immune system ;
5 use of immuno-suppressant drugs ;
6 ref to need for suitable size in specific case (e.g. if recipient is a small child
State one way in which:
(i) the structure of a motor neurone differs from that of a sensory neurone
the motor neurone - structure the cell body is at (one) end of the , neurone / cell or the cell body is in , brain / spinal cord / CNS or dendrites connected (directly) to cell body or long(er) axon or no dendron or axon , connects to / ends at , effector / motor end plate ;
State one way in which: the function of a motor neurone differs from that of a sensory neurone
the motor neurone - function carries , impulse(s) / action potential(s) , from , brain / spinal cord / CNS / relay neurone or carries , impulse(s) / action potential(s) , to , effector / muscle / gland
Describe and explain how the resting potential is established and how it is maintained in a sensory neurone.
pumping / active 1 sodium-potassium pump , uses ATP / uses energy / by active transport / (pumps) actively ;
2 pumps / actively moves , sodium ions / Na+ , out of , cell / axon / neurone , and , potassium ions / K+ , in ;
passive / diffusing 3 K+ , diffuse / move / flow / leak , (freely) back out (of cell) ;
4 membrane less permeable to Na+ / fewer Na+ channels open , so fewer Na+ , diffuse / move / flow / leak , back in ; ora
5 voltage-gated (Na+) , channels closed ;
6 AVP ;
Comment on the relationship between the strength of a stimulus and the resulting action potential
1 idea that only stimuli , that reach / are greater than , threshold value / -50mV , produce an action potential ; ora
2 (when stimulated) action potential either occurs or does not / all-or-nothing (law) ;
3 idea that the action potential is the same (magnitude / size) , no matter how strong the stimulus / even if strength of stimulus increases ;
4 idea that a strong stimulus produces many action potentials (in rapid succession)
Explain what might happen to a person if the liver did not break down insulin
blood glucose (concentration) would fall , too low / below normal level ;
2 idea that glucose would continue to be taken up by , cells / liver / muscle (results in low blood glucose) or idea that glucose is continually converted into glycogen / would store too much glucose as glycogen ;
3 (mitochondria eventually) cannot , release enough energy / generate enough ATP (as less available glucose in blood) ;
4 coma / death ;
5 AVP ;
Alcohol (ethanol) is oxidised in the liver. If a person has a high alcohol intake, it will result in the production of excess reduced NAD.
(i) Excess reduced NAD in the liver cells will influence some metabolic pathways by:
• inhibiting the conversion of lactate to pyruvate • inhibiting fatty acid oxidation • promoting fatty acid synthesis.
Using this information and the information in Fig. 2.1, suggest the consequences for liver metabolism if a person has a regular high alcohol intake.
build-up of lactate / prevention of pathway S , poisons / kills , (liver) cells ;
2 disruption of enzymes as a result of low pH ;
3 idea that lack of substrate / fatty acids not available , for respiration ;
4 lack of (oxidised) NAD for (metabolic) reactions ;
5 (some) deamination / ornithine cycle / pathway P / breakdown of (named) hormones / pathway R , cannot occur ;
6 build-up of fatty acids / more fatty acids present , resulting in , fat deposits in (liver) cells / fatty liver / cirrhosis
State precisely where in the liver cell the excess reduced NAD can be re-oxidised.
crista(e) / inner mitochondrial membrane
The chloroplast contains fat droplets, as shown in Fig. 3.1. These act as a reserve of raw material for the chloroplast.
Suggest what this raw material might be used for in the chloroplast
for membrane formation or phospholipid / cholesterol / glycolipid , for membrane ;
fatty acid / (named) pigment , synthesis ;
describe how light is harvested in the chloroplast membranes
(primary & accessory) pigments , are in / form a(n) , photosystem / complex / antenna complex ;
2 photon / light energy , absorbed by pigment (molecule(s)) ;
3 electron , excited / moves to higher energy level / delocalised , and returned to pigment ;
4 (energy / photon) passed from one pigment to another ;
5 (energy / photon) passed to , reaction centre / chlorophyll a / P680 / P700 / PS I / PSII / primary pigment ;
6 range of / accessory , pigments allow range of wavelengths to be absorbed ;
process(es) beginning with g that produce glucose
gluconeogenesis and glycogenolysis ;
process(es) beginning with g that have glucose as a starting point
glycolysis and glycogenesis ;
The blood in the glomerulus has a high ………………………………………………. pressure,
which forces small molecules, such as glucose and …………………………………………….. ,
out of the glomerulus and into the lumen of the Bowman’s capsule. This process is
known as ……………………………………………… .
In the proximal convoluted tubule, the glucose, most of the ……………………………………….. and
some of the salts are reabsorbed into blood ………………………………………………. that surround
the nephron at this point.
hydrostatic ;
water / urea / amino acids / vitamins / small proteins ;
ultrafiltration ;
water ;
capillaries / vessels
State precisely where the cells that detect a decrease in the water potential of the blood plasma are found.Name the cells that detect this decrease.
((walls of) blood vessels in) hypothalamus
osmoreceptor(s)
Name the part of the adrenal gland that releases aldosterone
cortex
Suggest and explain what effect the action of aldosterone will have on the secretion of ADH.
water potential of , plasma / blood , will , decrease / become more negative ;
(ADH secretion) will increase ;
Complete the table below by stating three differences in the structure of motor and sensory neurones.
M:S cell body in CNS
cell body , not in CNS / in PNS ;
2 cell body at end (of neurone)
cell body , not at end / in middle (of neurone)
;
3 dendrites connect directly to cell body
dendrites do not connect directly to cell body or dendrites at the end(s) of , dendron / axon
;
4 long(er) axon short(er) axon ; 5 dendron absent / no dendron dendron present ; 6 ends at motor end plate starts at / connects to , (sensory) receptor
When an impulse is not passing along a neurone, a resting potential of ………………. mV is
established. When the neurone is stimulated, it causes ……………………………………………….. of
the cell surface membrane. This will not generate an action potential unless it is large enough
to exceed the …………………………………… …………………………………… .
A neurone will either conduct an action potential or not; this is described as the
……………. - ……….. - ……………………………………. law.
Action potentials all have the same …………………………………… . The only way in which the
intensity of a stimulus can be interpreted is by the ……………………………………………. of the
action potential.
- 60 to -70 ;
2 depolarisation ;
3 threshold potential / threshold value ;
4 all or nothing ;
5 size / magnitude ;
6 frequency ;
Explain how emphysema could result in fatigue
less ventilation / Idea of difficulty in exhaling due to less recoil / small surface area for gaseous exchange / less oxygen entering capillaries / less oxygen entering blood ;
2 less oxygen (reaching cells) for , (aerobic) respiration / oxidative phosphorylation ;
3 (so) less ATP produced ;
4 idea of increased acidity (as CO2 / lactate builds up) interfering with / affects , enzymes / respiratory metabolism
In Type 2 diabetes, the target cells do not respond correctly to the insulin produced when there is an increase in blood glucose concentration.
Suggest why fatigue may occur in a person with Type 2 diabetes who is not taking medication.
1 not enough / less , glucose uptake into cells ;
2 not enough / less , glucose / substrate , for , respiration / ATP production ;
3 glucose not , stored as / converted to , glycogen
Certain heart conditions result in a weak and irregular heart beat.
Suggest how a weak and irregular heart beat could result in fatigue
1 idea of slow rate of / sluggish , blood flow or low(er) blood pressure ;
2 less / irregular amount of , oxygen (reaching cells) for , (aerobic) respiration / oxidative phosphorylation ;
3 less glucose (reaching cells) for respiration ;
4 (so) less ATP produced ;
5 idea of increased acidity (as CO2 / lactate builds up) interfering with / affects , enzymes / respiratory metabolism
Describe the different ways in which the pancreas acts as both an endocrine and an exocrine gland.
endocrine H1 hormone(s) released directly into blood ; H2 beta / β , cells , secrete / produce / release , insulin ; H3 alpha / α , cells , secrete / produce / release , glucagon ;
H4 islet / and , cells , detect / monitor , blood glucose concentration ; 3 max exocrine E1 fluid / juice / secretion / enzymes , released into duct ;
E2 (release triggered by) nervous / hormonal , stimulation ; E3 pancreatic secretions into , gut / small intestine / duodenum ; E4 alkaline / pH 8 / (sodium) hydrogen carbonate ; E5 containing 2 named enzyme(s) ;
Describe the features of the glomerulus and Bowman’s capsule that allow them to perform their function effectively
ultrafiltration ;
2 afferent arteriole is wider than efferent arteriole ;
3 high blood pressure in glomerulus / high(er) hydrostatic pressure in glomerulus (than in Bowman’s capsule) ;
4 idea that endothelium / wall of capillary , has gaps to , allow / prevent , passage (of substances / cells) ;
5 idea that basement membrane stops removal of , large molecules / cells ;
6 podocytes / epithelial cells of Bowman’s capsule , have (finger-like) projections / processes ;
7 (projections) ensure gaps to allow passage (of substances)
Nephritis is a condition in which the tissue of the glomerulus and proximal convoluted tubule becomes inflamed and damaged.
Suggest two differences in the composition of the urine of a person with nephritis when compared to the urine of a person with healthy kidneys
1 (large) protein / amino acids , present ;
2 blood (cells) present ; 3 glucose present ;
4 more water present / more dilute ; 5 more , ions / salts / electrolytes , present ; 6 (more) vitamins present ; 2
a) State the precise location where each of the following biochemical processes take place:
(i) the production of glucocorticoids in the body
adrenal cortex ;
a) State the precise location where each of the following biochemical processes take place: chemiosmosis within an animal cell.
inner mitochondrial membrane / crista
Light strikes a molecule of chlorophyll a in photosystem I, providing it with enough energy so that it loses an electron. This electron is passed along a series of electron carriers and then returns to a molecule of chlorophyll a in photosystem I. As the electron loses energy, ATP is formed.
cyclic photophosphorylation
Outline how the first neurone communicates with the second neurone across the gap
(named) neurotransmitter / acetylcholine , released from pre-synaptic / first , cell / membrane ;
2 diffuses across , gap / cleft / synaptic cleft or reaches second , neurone / cell / membrane , by diffusion ;
3 attaches to , receptors / binding sites of sodium channels , on post-synaptic membrane / membrane of second cell ;
4 neurotransmitter / acetylcholine , broken down (in cleft) ;
Outline the importance of the junctions between neurones in the functioning of the nervous system.
ensures movement of , impulse / action potential , in one direction (only) ;
2 integration or one neurone can , connect to / receive impulses from / transmit impulses to , many neurones ;
3 allows summation ;
4 idea that filters out , ‘background’ / low level , stimuli or ensures that only stimulation that is strong enough will be passed on;
animals that are able to regulate and maintain their core body temperature within narrow limits;
endotherm(s) ;
the increase in the diameter of the lumen of an arteriole to allow more blood to flow through
vaso)dilation
Name a hormone that increases the metabolic rate and so generates heat.
/ adrenaline;
Name the part of the brain where the thermoregulatory centre is located
hypothalamus
Which part(s) of the nephron corresponds to each of the statements
walls are impermeable to water
glucose is reabsorbed into the blood
ADH acts on the walls
contains podocytes
most of the water is reabsorbed into the blood
ascending (limb of loop of Henle proximal convoluted tubule / collecting duct / distal convoluted tubule Bowman’s capsule / renal capsule proximal convoluted tubule
With reference to Fig. 2.1, explain the role of the loop of Henle in the production of urine
2
3 4
5
6
7
role of loop of Henle is to cause a decrease in water potential in / establish water potential gradient going down , medulla ; (as) in ascending limb active transport outwards of , solutes / (sodium and chloride) ions ;
(walls of) descending limb permeable to water ; water removed from descending limb ;
water potential of tissues surrounding collecting duct is low(er) than fluid inside it ; water removed from , filtrate / urine (in collecting duct) ;
State the precise location of the electron transport chain in the cell.
crista(e)
Name the hydrogen acceptor in yeast anaerobic respiration
ethanal ;
Explain why anaerobic respiration pathway is important for the plant cell
releases NAD , to accept more H / to be reduced again / so glycolysis can continue or allows (some) ATP to be generated (in glycolysis) ;
2 (some ATP available) for named cellular process ;
products of yeast anaerobic respiration
ethanol and carbon dioxide
Paraquat is a weedkiller. It binds with electrons in photosystem I.
Suggest how paraquat results in the death of a plant.
1 prevents photophosphorylation ; 2 cyclic and non-cyclic ;
3 no / less , ATP / reduced NADP , for , light-independent stage / Calvin cycle / GP to TP ;
4 no (named) substrate made for respiration
Name the endocrine tissue in the pancreas that is responsible for secretion of hormones
islet(s) of Langerhans ;
secretion of insulin from a pancreatic cell is controlled.
Insulin secretion is stimulated when the blood glucose concentration increases ;
Glucose enters the pancreatic cell through channel proteins. The glucose
enters the 2 glycolytic / glycolysis pathway and ATP
is produced.
The increase in ATP causes ATP-controlled potassium ion channels to close
and the cell membrane becomes depolarised ;This results in the opening of voltage-gated calcium ion channels and the concentration of this ion inside the cell increases.
The increased concentration of these ions causes the secretion of insulin from
the cell by the process of 5 exocytosis
State where in a pancreatic cell insulin molecules are synthesised
ribosome / rough endoplasmic reticulum / RER ;
explain the difference in the speed of conduction of an action potential along the length of a myelinated neurone and a non-myelinated neurone.
in myelinated neurones
1 conduction faster in myelinated neurone ; ora
2 depolarisation / action potential , can only occur where (voltage-gated / Na(+)) channels present ;
3 idea that myelinated neurones have long(er) sections with no, (voltage-gated / Na(+)) channels present ;
4 ion , movement / transfer , can only take place at the gaps / nodes ; ora
5 longer local circuits / fewer local circuits ; 6 saltatory conduction / action potential jumps from node to node ;
State where the core body temperature is monitored
thermoregulatory centre in) hypothalamus
Explain how each of the following adaptations help the animal to control its body temperature.
(i) Elephants have large, thin ears that they move backwards and forwards when hot.
large surface area (to lose heat) ; (thin) so , blood flows / (named) blood vessel are , close to the (skin) surface (to lose heat) ; (movement) increases air movement over , skin / surface (to lose heat)
Penguins living in cold climates have ‘shunt’ blood vessels. These shunt vessels link arterioles carrying blood towards their feet with small veins that carry blood away from their feet.
blood loses less heat because , less blood flows to feet / warm blood diverted from arterioles to veins
or less blood flows to feet so core body temperature maintained
Explain the changes in fluid composition from blood to filtrate to urine
1 large molecules / proteins / blood cells , cannot , leave blood / enter the filtrate or (named) small molecules can , leave blood / enter filtrate;
2 endothelium / fenestrations / basement membrane , prevents , large molecules / erythrocytes , reaching , renal / Bowmans capsule ;
3 all glucose / glucose completely , reabsorbed at the , proximal convoluted tubule / PCT ;
4 all amino acids / amino acids completely , reabsorbed at the , proximal convoluted tubule / PCT ;
5 (some / not all) ions , reabsorbed / move into blood (at any part of , nephron / tubule) ;
6 urea / ion , concentration increases (between filtrate and urine) because , movement (of urea / ion) into tubule / water removed
Suggest what a high concentration of creatinine in the blood plasma indicates about kidney function. Give a reason for your answer
idea that (high creatinine concentration indicates) reduced function because , less filtration / low GFR
Discuss, whether it is ethical for live donors to be used as a source of kidneys for transplantation
eneral 1 idea that people should have a right to choose (freely) what to do with their kidney ;
perceived donor advantages 2 idea that donors / donors’ families , can benefit from money raised (by selling a kidney) ; 3 people can donate a kidney to family member ; 4 idea that people can donate without payment ;
perceived donor disadvantages 5 idea of exploiting people’s poverty ; 6 idea of exploitation of , children / minors ;
recipient issues 7 idea that people should receive transplants irrespective of wealth ; 8 idea that it is wrong that recipients are being charged excessively
Name one hormone which will increase the heart rate
adrenaline / epinephrine / noradrenaline / norepinephrine
State one way in which the nervous system decreases the heart rate
impulses along parasympathetic nerve / impulses along vagus nerve / nerve endings releasing acetycholine ;
a product of the light-dependent reaction that is not used in the light-independent reaction.
oxygen
