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95 Cards in this Set

  • Front
  • Back

The curve is steepest in the region marked X on the graph. Explain how the steepness of thecurve in region X helps the tissues in a mammal function more efficiently.

small drop of ppO2 (dont do this in exam)

large amount of oxygen dissociates easily

tissues can respire aerobically

aerobic respiration more efficient

than anaerobic (prevents lactic acid build up)

What is the advantage of an increasing partial pressure of carbon dioxide in a muscle?

more oxygen released

at same partial pressure of oxygen

needed for aerobic respiration

Explain the importance of the position of the dissociation curve of fetal haemoglobin

higher affinity of oxygen; absorbed from mother

becomes fully saturated at low ppO2

. Explain howthis curve indicates the worm’s adaptation to its environment.

lives in environment where low ppO2

allows Hb to become fully saturated at lower ppO2

Xylem vessel

transports water/ mineral ions

sieve tube element

Transport of organic molecules/SUCROSE/ amino acids/ products of photosynthesis

not glucose

Companion cell

Makes proteins/ ATP/ release energy

not make/ produce energy

function of lignin?

supports/ strengthens/ prevents

xylem vessel from collapsing when water sucked along it

adhesion of water molecules

aids movement of water upwards

Movement of water

Water is absorbed into the root mainly through the root hairs. Its movement through theapoplast is prevented by the Casperian strip in the endodermis. Movementthrough the symplast pathway is aided by the plasmodesmata. The water is pulledupwards by the transpiration pull and this is possible by large cohesive forces between the water molecules and adhesion forces between the watermolecules and the hydrophilic lining of the cells.

Give three other properties of respiratory surfacescommon to all organisms.

short diffusion pathway

large surface area



concentration gradient

respiratory surface in inseccts

tracheole in contact with tissue

Advantages of using a tracheal system for gas exchange

fast (oxygen 200,000 x faster than blood)
no respiratory pigment; reduced water loss

oxygen supplied directly to tissue; no transport system required

Describe and explain the process of inspiration in a mammal.

intercostal muscles contract

ribs upwards and outwards

diaphragm contracts/ flattens

volume increases

pressure decreases

below atm pressure

(air drawn in)

State the difficulties aquatic organisms face, compared to terrestrial organisms, inobtaining oxygen from water.

water contains less oxygen than air

diffusion rate slower

dense/ viscous medium more difficult to pump

why is countercurrent flow more efficient

concentration gradient maintained over entire distance travelled by water over gills

suggest two reasons why terrestrial animals rely on internal fertilisation

increased chance of fertilisation

gametes independent of water for movement

fertilised egg can develop inside protective layer

gametes dont dehydrate

advantages of sexual reproduction


allows a development of a resistant stage in lifecycle

seeds, spores, larvae allow dispersal

cons of sexual reproduction

slow form of reproduction (needs two individuals)
some variations not as successful as parent type/ mutations more common

Suggest three reasons why the flowering plants have been so successful in the colonisationof the land.

life cycle rapid; food store in seed allows rapid growth of embryo; enables to survive long periods of time

protection by resistant outer layer

leaf fall, recycling of nutrients, link with animals, no need of water for fertilisation

describe theory of evolution as put foward by Charles Darwin

Darwin recognised species evolved over time

explain adaptive radiation

evidence= similar morpholgically to common ancestor

similar proteins

so similar DNA

fossil evidence

what is ventilation

the process of moving the respiratory medium over the respiratory surface

What organelles are present in guard cells but not in the other epidermal cells ofa leaf


Explain the mechanism by which light causes the opening of stomatal pores.

potassium ions pumped into guard cell

by active transport

starch to malate

WP in guard cell decreases

water moves in by osmosis down WP gradient

turgor increases, as cells expand, they bend as inner walls thicker than outer

What environmental factor could account for the displacement of the curve fromA to B

increased carbon dioxide

significance of Bohr shift

oxygen dissociates more easily at lower ppO2

why are llamas curve to left of human?

at low partial pressures of oxygen

Hb has greater affinity to oxygen

able to absorb more oxygen from environment

how are homologous structures used as evidence for evolution

suggest shared common ancestory

advantage of asexual reproduction

colonise area quickly

internal fertilisation

fusion of gametes

with femal body

using intromittent organ

no reference to zygote

mode of nutrition



Describe how the stomach of P is adapted to its diet (ruminant)

cud mixed with ceullulase secreting bacteria

allows cud to be regurgitated and further chewing

allows water to be re-absorbed

rumen=1st chamber, hosts microorganisms

some absorption of fatty acids

Suggest why certain areas of carnivores stomach are larger

to provide room to store meat

until killing of prey next time

long time between feeding...

blood vessels in sub mucosa

transport dissolved products of digestion to liver (via hypatic portal vein)

lymphatic vessels in sub mucosa

transport lipids

nerves in s.m.

coordinates muscular contraction for peristalsis

control secretion

brunners glands

secretion of enzyme

state best technique for working out the relationships between the descendants ofthe orignal finch

comparing DNA

(DNA hybridisation) cytochrome C

not gel electrophoresis

In a similar diagram of a human gut these features would be intermediatebetween those shown. Give a reason for this

humans omnivores

Suggest a reason for refection

gives more time to absorb nutrients (eat poo)

Cows feed in a similar way to rabbits but do not show refection.Explain this difference.

cows have four more stomachs

food is regurgitated for chewing of cud

additional stomachs for fermentation

Name three structural features of fish gills which make them efficient gaseous exchangeorgans

large surface area



good blood supply

advantage of countercurrent flow

concentration maintained along whole of gill plate

blood saturation reaches higher level

Describe the function of the hydrogen ions produced in the red blood cell andexplain its importance in muscle tissue

dissociate oxygen from oxyhaemoglobin

needed for aerobic respiration by muscle

explain function of chloride shift

to maintain electrical neutrality of rbc

Describe and explain the difference in the transpiration rate at 0800hrs compared with1600hrs

increased rate of transpiration

increased temperature/ other factor

not light

what is meant by cohesion?

strong attraction of water molecules exert on one another

what creates tension

water evaporating through stomata at top of column are replaced from below

and because of cohesion, this creates an upward force (tension) throughout the column

how is root pressure generated?

active transport of ions into root xylem

water drawn in by osmosis at foot of xylem

osotic pressure

What is the role of the intercostal muscles in the thorax of a mammal?

move ribs/enlarge thorax

Give two advantages to a mammal of having internal lungs

reduce heat loss

reduce water loss

protection (by ribs)

where are villi present?



where is the site of mechanical breakdown of food



what connects with the bile duct?


where do microorganisms secrete vitamins?

large intestine

where does carbohydrate digestion tak eplace?




where are brunners glands found

duodenum, secrete alkaline fluid

main region of water absorption

large intestine

where does protein digestion begin


visible features anthropods have in common


jointed limbs

segmented body

significance of myoglobing

oxygen store

high affinity to oxygen

used when muscle is working very hard

how do parasties survive without a digestive system?

absorption of host nutrients

over parasites body

why do parasited produce large numbers of offspring

high mortality

what is meant by term source

region where photosynthate produced


region where photosynthate used

importance of closure of spiracles

prevents excessive water loss

explain lifcycle of parasite

eggs eaten by pigs

tapeworm eggs in muscle

undercooked meat eaten, containing eggs

explain why cynaide prevents stomatal pores from opening

cynaide is a respiratory inhibitor (stops ATP)

prevents active transport of potassium ions into guard cell

stae and explain adapatations of hydrophytes

large air spaces for buoyancy

stomata on upper surface to allow gas exchange with air

thin cuticle as little water vapour loss

little xylem as surrounded by water

air spaces in stems allow diffusion of gases

why does aortic pressure not reach 0

where as ventricle does

aortic (semilunar) valve closes

preventing backflow

ventricle diastole

how does hydrolysis of lipds increase ph

xreates fatty acids

increase pH

main sites of digestion?



small intestine

main sites of absorption?

small intestine

large intestine

explain why human digestion system is divided into specialised regions

diffwewnt regions carry out differnt function (enzyme optima)...


lives in or on another organism

deriving benefit

whilst causing harm to host

describe one theory that would explain how water moves up stem of leafy shoot

water vapour lost from leaves by transpiration

causes tension on water molecules

cohesive forces between water molecules

adhesive forces between water molecules and xylem vessels

water molecules pulled up xylem vessel

explain full reasons for max and min pressure in left ventricle and aorta

contraction of left ventricle causes a surge in blood pressure

pressure drops when left ventricale relaxes

pressure in aorta does not decrease to zero as of closing of aortic, semi lunar valves

elastic recoil of arteries maintains blood pressure

role of lymph vessel

remove excess tissue fluid


Autotrophs use {(simple) inorganic molecules / carbon dioxide andwater} to synthesise {(complex) organic compounds / named organiccompound

eg Plant / named Plant / Algae / Bacteria must be qualified bychemosynthetic;


Saprobionts {secrete enzymes onto the food outside the body / feedby extracellular digestion} and absorb ( or e.q.) the (soluble)products (by diffusion); NOT ingestBacteria / Fungi / or named

vessels found on surface of heart?

Coronary;Supplies oxygen / blood to the heart muscle / wall / tissue / cells ORcorrect function for vein;

valves replacement

Valve {exposed to / works at} a higher pressure (in left ventricle)/{Right ventricle pumps blood at / valve A exposed to} lowerpressures (to lungs);

what would happen to flow of blood if valve is damaged?

Blood leaks back (from ventricle) to atrium

) Breathlessness

how do fish overcome problem of water?

Water is forced over the gill by {ventilation mechanisms / pressuredifferences / continuous swimming};Unidirectionally / one way flow;Countercurrent flow of blood and water / or description of;{Diffusion / concentration} gradient is maintained or description of;over the entire gill surface;High affinity Hb;

importance of epithelium?

Microvilli:Increase SA for diffusion / uptake of molecule / digestion (ofmolecules);11Mitochondria:(Synthesis of) ATP for active transport;

explain how endodermis carries out its function of uptake of water and mineral ions into plant

Waterproof / Casparian strip / band / suberin;Blocks the apoplast pathway;Selective uptake / Active uptake / transport of minerals (byendodermis cells);Into symplast pathway;Active transport of minerals into pericycle;Water follows by osmosis;Water and minerals move into xylem vessels;

Describe three properties that all respiratory surfaces must possess and explain whythey must have them.

Thin – small diffusion distance;Accept small diffusion distance/ pathwayLarge surface area- (large contact with air) for diffusion/ gasexchange/ OWTTE;Moist- allow gases to dissolve/ gases go into solution (to crossmembrane); Not diffuse intoPermeable-to allow gases to pass through (the respiratorysurface);NOT blood supply

Give two reasons why gills do not function effectively on land.

They dry out/ unable to remain moist/ lose water; 2They clump together (because of surface tension.)/ collapse/lie on top of each other;

State the function of(i) sieve tube cells [1](ii) companion cells.

{Translocation/ movement/ transport/ carry NOT flow} of{products of photosynthesis/ sucrose/organic compounds/sugars/ amino acids}/ description of source to sink/translocation;1(NOT nutrients/ other named sugar/ named ions)(ii) Carry out {metabolism/respiration} /to supply (sieve cells) with{energy/ATP}/ contain mitochondria for {ATP/ active transport};NOT contain organelles that the sieve cells do not have/ notloading sieve cell

Describe two features of an amniote egg

Fluid filled cavity (surrounded by a membrane);{Protective/ hard/ leathery} {shell/ outer covering/ coat};(embryo within) yolk sac/ food store/ yolk for nutrition/ owninternal nutrient supply;

The development of embryos takes place internally in mammals. List three ways inwhich this is an advantage over externally laid eggs.

(the young are retained) for a {considerable/ longer} time in themother’s womb or uterus;(The embryo is) nourished there from {the mother’s bloodsupply /the placenta}/ {unlimited nutrients/ OWTTE};Protection – qualified;The young are {born in a relatively advanced state ofdevelopment/ well developed/ more advanced growth inwomb}; [Any 3]NOT parental care/ ref to number of offspring

Give an account of the sequence of events that takes place during the digestionand absorption of a meal containing carbohydrate and protein.

n buccal cavity/ mouth;B teeth (and tongue) {mechanically/ physically} break down food/to provide large surface area;C (Saliva added from) salivary glands;D (saliva) contains mucus to lubricate;E Amylase substrate is starch, product is maltose/ disaccharides;F Stomach adapted for protein digestion/ protein digestion{starts/ begins} in stomach/ proteins are partially digested inthe stomach;G Produces hydrochloric acid/ low pH in stomach;H Peptidase/Pepsin’s substrate is {protein/ polypeptides},products are {polypeptides/peptides};reject ref to other enzymesI Small intestine (is adapted to) completes (protein/carbohydrate) digestion/ Description of {disaccharide/polpeptide} digestion in small intestine;J Named enzyme produced by small intestine;K Two named enzymes produced by pancreas;L correct reference to endo- exo- peptidases;M Absorption takes place in the ileum/small intestine;N Villi / microvilli increase surface area;O Glucose/ monosaccharides/ products are absorbed bydiffusion and active transport;

Name the original source of energy that moves water through a plant.


where is the main site of lipase production


Explain how the jaw and teeth shown above are adapted for this mode ofnutrition herbivore

{large/ridged/WM shape} {molars/premolars} for grinding;{diastema/space with no teeth/ gap between teeth} toassist with {chewing/ (tongue to) manipulate food/ cud};{well developed/ sharp/ long} incisors for {biting/ cutting/slicing/ tearing} (vegetation);loose articulation/ jaw moves in a {horizontal/ circular}plane;3maxVery small/ no canines;open roots to allow continuous growth of molars;

Explain how the gut of this mammal is adapted for digestion.

Four chambered stomach (NOT four stomachs) / rumen/large caecum;Contain cellulose digesting bacteria/ have cellulaseproducing bacteria; NOT cellulose eating bacteriaLong gut {to allow extra time for digestion of cellulose/cellulose harder to digest};Cud is regurgitated for further chewing;