OCR A old spec Flashcards
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