Topic 1 (Heart & Lungs)

Structure of the mammalian heart

1. idea that there are four chambers ; 2. correct reference to relative position of atria and ventricles ; 3. idea of left and right sides separate / septum ; 4. reference to muscular nature of walls ; 5. reference to cardiac muscle ; 6. idea of relative thickness of ventricle (walls) ; 7. correct reference to position of {atrioventricular valves / eq} ; 8. correct reference to position of semilunar valves ; 9. reference to position of {tendons / tendinous cords / papillary muscles / eq} ; 10. correct reference to position of {aorta / pulmonary artery} ; 11. correct reference to position of {vena cava / pulmonary vein} ; 12. correct reference to coronary arteries ; 13. reference to {SAN / Sino Atrial Node / pacemaker/ AVN /Atrioventricular Node / Purkinje fibres /Purkyne fibres / Bundle of His/eq } ;

Why many animals have a circulatory system

1. idea that {it overcomes limitations of diffusion / it is involved in transport / heat transfer} ;

Animals need a heart and a circulatory system.

1. idea that the heart has to pump blood a long way around the body of the animal ; 2. (therefore) blood needs to be (pumped) at high pressure / eq; 3. blood vessels are needed to contain the blood / reference to closed circulation / eq ; 4. idea of double circulatory system ; 5. capillaries needed to ensure that all parts of animal are close to blood supply/ eq ; 6. idea of need for a circulation to {provide oxygen / remove carbon dioxide / other correct named substance} ; 7. idea of {oxygen / glucose} needed as {high metabolic rate / high rate of respiration; eq} 8. idea that a circulatory system is needed to overcome limitations of diffusion / eq ;9. reference to low surface area to volume ratio ; 10. idea that circulatory system helps regulation of body temperature ;

Circulatory system and efficient gas exchange

1. idea that one side (of heart) transports blood to the lungs other to the body ; 2. comment on blood pressures e.g. lower to lungs, higher to body3. separation of oxygenated and deoxygenated blood / eq ; 4. idea that moving blood helps to maintain a concentration gradient ;5. idea that a { steep / eq } concentration gradient gives a { fast / eq } rate of diffusion ;6. idea of { network / lots / eq } of capillaries ;7. large surface area of capillaries / eq ;8. idea that large surface area increases the rate of diffusion ;9. idea that capillaries have very thin walls ;10. idea that diffusion is fastest over small distances ;11. idea that no {organs / cells / tissues } are far away from blood / capillaries cover alveoli / eq ;12. Reference to mass flow generated by heart / supply of O2 to body cells maximised ; 13. idea of need for a good supply of oxygen as (mammals are) {very active / high rate of metabolism / warm blooded / eq} ;14. idea that efficiency is related to double circulation ;

The heart requires oxygen and glucose to function

Oxygen supply to the cardiac muscle

1. Correct reference to the coronary circulation; 2. Via the coronary artery; 3. From the aorta; 4. Reference to capillaries (within) cardiac muscles; 5. Reference to {red blood cells / haemoglobin} {carrying / releasing} oxygen;

Glucose and its purpose in the heart

1. Glucose is {a monosaccharide / soluble / doesnt need to be digested} / eq; 2. Glucose can be quickly absorbed into the blood stream; 3. Can pass into muscle (cells); 4. Can be used for respiration; 5. To provide energy; 6. For (muscle) contraction;

Mammals have a heart and circulatory system whereas a single cell organism (e.g. flatworm) does not.

1. Flatworm has a large surface area : volume ratio / converse; 2. Diffusion {sufficient / effective} for flatworms {needs / eq} / converse;3. Mammal {has higher metabolic rate / is warm blooded / eq} / converse;

Double circulatory system advantage to mammals1. Separation of deoxygenated and oxygenated blood ; 2. (Therefore) better {oxygenation of blood / oxygen supply to tissues} ; 3. Maintains different pressure to lungs and rest of body / eq ; 4. Mammals have a high (er) demand for oxygen ; 5. Idea of repressurisation ;

Double circulation is important in maintaining high pressure of oxygenated blood in the arteries1. Reference to blood in the lungs / reference to oxygenation of blood; 2. Reference to {narrow / extremely long} capillaries;3. Results in {low pressure / loss of pressure} of blood (when it emerges from the lungs); 4. Not enough pressure to get through rest of {capillary network / the body}; 5. Pumping the blood again {raises / restores} lost pressure OR provides extra boost of pressure / reference to second pump; 6. Higher pressure in system

Advantages of human circulatory system over single

1. blood flows {faster /at higher pressure / eq} (to the body) ;2. blood flows {slower /at lower pressure / eq}to the lung ;3. idea that this reduces risk of damage to lungs;4. correct ref to more efficient {exchange /transport} of gases / eq ;

Mammalian heart is divided into a right side and a left side

1. idea that it keeps oxygenated and deoxygenated blood separate ; 2. idea that this results in as much oxygen as possible being carried to the {tissues / cells } ; 3. reference to different pressures in each side / need for different pressures explained ;

Insects do not need blood vessels to transport its blood around the body (open circulatory system)

1. correct ref to large surface area to volume ratios ; 2. idea that (all) {cells / eq} are very close to the {blood / heart} ; 3. idea that diffusion is fast enough for exchange of {nutrients / gases / waste} ; 4. idea of low metabolism ;5. idea that movement of blood back into the heart is fast enough (to return blood back into the heart) ;

Daphnias heart and gas exchange 1. Idea that blood carries {oxygen / carbon dioxide} ; 2. Idea that blood moving maintains concentration gradient ; 3. Reference to mass flow ; 4. Idea that organs have large surface area to volume ratio

Closed circulatory system and open circulatory system

1. closed circulatory system = blood vessels2. to generate high blood pressure3. open circulatory system = no blood vessels 4. all cells are close to heart so diffusion is fast enough for exchange of nutrients

Mass flow

1. mass transport of liquids

Cardiac cycle 1. sequence of events from one beat to the next beat / eq; 2. reference to {contraction / systole} and {relaxation / diastole}; 3. correct detail of sequence e.g. atrial systole ventricular systole diastole / approx 30% of time spent in systole and 70% in diastole; 4. correct detail of electrical regulation of cardiac cycle/eq;

Coronary circulation1. From aorta ; 2. Coronary artery ; 3. Supplies {blood / oxygen / glucose / nutrients / named nutrient} to heart {muscle / tissue / myocardium} / correct reference to removal of {waste products / named waste product} by (cardiac vein) coronary circulation ; 4. Returns to right atrium;

Atrial systole

1. Ventricles relaxed;2. Atria contract;3. Volume of chamber decreases and pressure increases;4. (pressure) opens atrioventricular valve; 5. Blood is pushed into ventricles;6. Ventricular pressure / chamber volume increases; 7. as the ventricles receive the ejected blood from the contracting atria;

Ventricle systole

1. ventricle (muscle) contracts; 2. higher pressure in ventricles relative to atria; 3. (pressure) closes atrioventricular valve; 4. higher pressure in ventricles relative to the {aorta / pulmonary artery / arteries}; 5. (pressure) opens the semilunar valve; 6. blood forced into the {aorta / pulmonary artery / arteries};

Ventricular diastole / Atrial diastole:

1. Ventricles and atria relax;2. Higher pressure in pulmonary artery and aorta force SL valves shut to prevent backflow into ventricles; 3. Blood returns to the heart and atria fill again;4. due to higher pressure in the vena cava and pulmonary vein;5. atrial pressure increases;6. ventricles continue to relax, so pressure falls below the pressure of the atria;7. (so) AV valves open;8. Blood flows passively (not pushed by atrial contraction) into ventricles from the atria;9. Atrial contraction occurs and process is repeated

Ventricles diastole and systole blood pressure

1. pressure increases as blood forced into ventricle during atrial systole; 2. pressure increases during (initial) ventricular systole/eq; 3. (due to) reducing volume of ventricle (causing pressure increase); 4. pressure starts to decrease due to blood into artery / loss of blood from ventricle; 5. decreases during diastole / eq; 6. (due to) increasing volume (of chamber);

Difference in pressure between right ventricle and left ventricle

1. Right ventricle pumps blood to lungs ; 2. Left ventricle pumps blood all around the body ; 3. Correct reference to relative thickness of ventricular walls ; 4. Correct reference to pressure in relation to lungs / body / e.g. more pressure needed to pump blood round body / converse OR less resistance to blood flow in lungs / converse; 5. blood from (left ventricle) has to divide between more capillaries / eq;

Difference in pressure between left ventricle and aorta1. Reference to closure of semilunar valve ; 2. Elasticity / eq of aorta wall ; 3. Recoil (in aorta) maintains pressure ;4. Reference to refilling / relaxation of ventricle ;

Explanation When the ventricles relax/refill the semilunar valve will close causing the pressure to drop The elasticity of the aorta walls and recoil in the aorta will maintain the same pressure throughoutLeft ventricle structure and valves aid in its function

1. {Valves} close; 2. (To) prevent backflow (of blood); 3. Reference to {contraction / systole} of ventricle; 4. Thick (muscular) wall / more muscle; 5. Provides high {pressure / force / eq}; 6. To pump blood through {systemic circulation / round body / eq}; 7. Reference to elasticity of {aorta} (to accommodate blood expelled from ventricle) / eq;

Roles of the atrioventricular (bicuspid and tricuspid) valves during the cardiac cycle

1. valves {separate / eq} atria from ventricles ; 2. open during atrial {systole / contraction } / eq ; 3. so that blood can pass through to ventricles / eq ; 4. closed during ventricular {systole / contraction} eq ; 5. to prevent {blood being forced back / backflow / eq} (up into atria) / to maintain pressure in ventricles ; 6. open during diastole / eq ; 7. so that ventricles can start to fill up (as atria are filling) ;

Role and location of Semilunar valve

1. {base / eq} (of aorta) ; 2. prevents backflow (of blood into heart / ventricles) / eq ; 3. during { diastole / atrial systole } / eq ;

Importance of valves in preventing wrong directional flow of blood

1. Valves only open one way;2. Dependant on the relative pressure of the heart chambers;3. if pressure > behind valve, its forced open;4. once bloods flown through the valve, pressure is greater in the front of the valve;5. (which) forces it shut, preventing blood from flowing back into the chamber/backflow

A. Artery B. VeinC. Capillary Artery

Tunica media or middle coat containssmooth muscle fibrescollagen Elastic fibres.

Adaptation structure

1. thick {wall / layer} of (smooth) muscle / thick elastic {layer / wall}; allows artery to expand (elastic recoil) / withstand pressure from the pulse of blood / eq; 2. collagen (fibres); Provide {strength / support } / prevents bursting ; Idea that they enable artery to withstand high blood pressure / eq ;3. smooth lining; prevent resistance to blood flow / eq; 4. small lumen / eq; to maintain high pressure / eq;

Structure of arteries relating to function

1. Muscular walls;2. Contain elastic tissue;3. Endothelium/inner lining is folded and can expand;4. These features enable effective control and regulation of high blood pressure

Aorta, major artery has elastic fibres

1. {middle layer of wall of vessel / eq } / tunica media / in the muscle layer ; 2. reference to allows { stretching / recoil / description} ; 3. to prevent damage (of the aorta) / eq / {to maintain the pressure of the blood / eq } ;

Advantages of coronary artery branching from aorta

1. Blood at high pressure; 2. High concentration of oxygen / eq; 3. High concentration of glucose / eq;

Consequences of narrow lumen in artery

1. narrowing leads to higher blood pressure; 2. increases risk of {further damage to the artery wall/ aneurysm} 3. platelets stick to damaged wall; 4. correct reference to mast / foam cells / inflammatory response;5. triggers blood clotting process / eq;

Vein

Describe how blood is moved through veins

1. (skeletal) muscle contracts / eq; 2. squeezes vein / named vein; 3. blood forced in both directions (away from squeezed area) / eq; 4. (one way) valves present (in veins); 5. one way flow / prevent backflow / eq; 6. reference to role of thorax e.g. pressure changes during inspiration / expiration / breathing; 7. lower pressure in {heart / atria} during {diastole / eq};

Capillary

Adaptation1. {squamous / pavement / flattened /thin / eq } cell / endothelium; 2. Wall (only) one cell thick; 3. small lumen present /(capillary) small diameter; 4. pores present / gaps present / eq;

Function Force fluid out to form tissue fluid at arterial end1. High {hydrostatic / blood} pressure; 2. Which is higher than {solute potential gradient / eq} / correct osmotic effect described; 3. (Plasma forced out) through {pores / gaps} in capillary wall; 4. The fluid is forced out of the capillary into the intercellular space;

Function of tissue fluid1. For transport / eq of, solutes/ nutrients / molecules, to / from, cells / tissues ; 2. Movement of waste products

Accumulation of tissue fluid and swelling 1. Blocked lymph vessels / high blood pressure / {low solute potential / high water potential} in blood / loss of plasma proteins / damage to tissue / histamine / eq;

What is this swelling called?1. Oedema

Factors that could cause oedema1. Increased blood pressure / hydrostatic pressure / hypertension / increased capillary permeability / decrease in plasma protein / colloidal osmotic pressure / protein / amino acid deficient diet / blocked lymphatic vessels / faulty valves in lymphatic vessels ;

NOTE:1. proteins are large (molecules); 2. cannot pass through capillary wall / eq;

Structural differences between arteries and veins

Insects not needing blood vessels

1. Larger surface area to volume ratio;2. Diffusion efficient;3. (because) cells are very close to blood/heart;4. idea of low metabolism ;5. idea that movement of blood back into the heart is fast enough (to return blood back into the heart) ;

Why is Daphnia a suitable organism?

1. Heart is visible / transparent organism / reference to ethical issues / eq;Daphnia needs a heart and circulatory system

1. Very active / high metabolic rate; 2. Supplies oxygen / removes CO2; 3. Slow diffusion 4. Low SA/V ratio / eq;

Sequence of blood clot1. platelets stick to damaged wall of artery / eq; 2. thromboplastin released (from damaged tissue/platelets); 3. correct reference to Ca2+ / Vit. K; 4. prothrombin (plasma protein) converted to thrombin (enzyme); 5. fibrinogen (soluble plasma protein) converted to fibrin (insoluble strands of protein); 6. fibrin mesh traps blood cells forming a clot;

Blood clot and coronary artery1. Lack of blood to {cardiac / heart} muscle; 2. So lack of {oxygen / glucose} / ischaemic / anaerobic / eq; 3. Muscle stops working / damaged / cells die; 4. Pain / angina / lactic acid build up; 5. insufficient energy release for contraction/ damage to heart muscle/Myocardial infarction / heart attack;

Explained: Blood contains oxygen/glucose which is required for the muscles to stay functioning. A blood clot, at the coronary artery, stops the flow of blood to the heart. This causes the muscle to stop working/die which leads to lactic acid build up (from anaerobic respiration) and eventually a heart attack.Blood clot and stroke1. idea of {reduced blood flow / bleeding} ; 2. {less/no} {oxygen /glucose} (reaches brain) ; 3. idea of {less/no} (aerobic) respiration ; 4. idea of {less / no} ATP produced ; 5. idea that brain needs lots of {energy / ATP} to function ; 6. lactic acid produced (from anaerobic respiration); 7. lactic acid {inhibits enzymes / toxic / eq };

Atherosclerosis/Atheroma

1. damage to {endothelial cells / epithelial cells /cells lining artery (wall)} ; 2. reference to inflammatory response ; 3. reference to (accumulation of) white blood cells in (damaged area) ; 4. {build up / eq} of cholesterol (in damaged area) ; 5. reference to build up of {calcium salts / fibrous tissue / fibrin / platelets} ; 6. reference to formation of {atheroma / plaque} ; 7. reference to {loss of elasticity (of artery) / narrowing of lumen} / eq ;

Thrombosis

1. (Blocks) coronary artery / artery supplying heart muscle / tissue / cells; 2. Reduces blood supply3. Reduces oxygen / glucose supply (to heart muscle / tissues / cells); 4. less oxygen; anaerobic respiration; 5. build up of {lactic acid / lactate} (causes pain);

Factors making atherosclerosis develop CHD1. narrowing of the arteries ; 2. thrombosis / blood clot ;Arteries and atherosclerosis 1. Higher (blood) pressure / more chance of damage to endothelium;Plaque1. Consists of fatty deposits2. Plaque forms due to damage to the endothelial cells

Factors effecting CVD1. gender 2. smoking 3. genes / inheritance / eq4. stress 5. high LDL level / LDL to HDL ratio / high blood cholesterol 6. reference to inappropriate diet such as high {salt / fat / cholesterol / calorie} intake / eq7. high alcohol intake 8. obesity 9. lack of exercise / eq Dietary factors that increase CHD1) high {salt / sodium} 2) high cholesterol 3) high saturated fat / high trans-fat 4) high calories 5) high alcohol 6) low fibre / low NSP 7) low antioxidants / low vitamin C / low vitamin E ;

High Blood Cholesterol High Blood PressureSmoking

1. Fatty deposition in artery walls / plaque formation;2. Atheroma formed; 3. Increased blood pressure; 4. Lumen of (coronary) arteries narrowed / reduced elasticity of artery wall / eq; 5. Correct reference to LDLs;1. Damage to (lining of) arteries; 2. Risk of aneurysm / damaged lining (of arteries) rupturing; 3. Increased risk of blood clot blocking coronary arteries; 4. Correct reference to inflammatory response;1. Increases blood pressure; 2. Increases risk of aneurysm; 3. Less antioxidants / more free radicals; 4. Increases {number / activation} of platelets; 5. (Leading to) increased risk of blood clot blocking coronary arteries;

Age 1. older increases risk, {arteries {become less elastic / more easily damaged / blood pressure increases} with (increase in) age ; Gender 1. {women less likely to develop CVD than men / oestrogen offers some protection to women against CVD } (pre menopause) / eq ;

HDLS

1. Mainly protein;2. Activate more cholesterol receptors on the liver, so more is brought in (where cholesterol is recycled);3. Reduces total blood cholesterol when level is too high4. Opposite for LDLs - with LDLs being mostly lipid

Diet and CHD1. High intake of {saturated fat / animal fat / example of fat / cholesterol}; 2. Atherosclerosis / description of deposition inside arteries; (smaller lumen/damaged arteries)3. (Which leads to) reduced {blood flow / oxygen / eq) to heart muscle / increased blood pressure (in coronary circulation) / reference to thrombosis; 4. High {salt / Na+} intake; 5. High blood pressure / hypertension; 6. (Which leads to increased) {risk / eq} of {heart attack / heart failure / myocardial infarction};

High fat diet and inactivity

1. idea of energy imbalance ;2. idea of individual becoming {overweight /obese / eq } ;3. idea of increased blood pressure ;4. idea of obesity leads to diabetes (a CVD risk factor) ;5. idea of increased (blood) {cholesterol / LDL levels / LDL to HDL ratio} ;6. idea of {damage to endothelium / overloading of receptors} ;7. formation of { atheroma / plaque / atherosclerosis } / eq ;8. idea of {loss of elasticity of artery / narrowing of lumen / eq } ; (NOT NARROWING OF ARTERIES)

Genetic - inheriting a greater risk of developing cardiovascular disease.

1. has gene(s) which increase chance of developing CVD / eq; 2. named example of gene (e.g. SRY, APOE4, AZE, MTHFR); 3. genes do not necessarily mean you will develop the disease /eq; 4. {other risk factor / named risk factor}also contributes to chance of developing CHD;

Obesity and coronary heart1. Higher cholesterol levels; 2. Fatty deposits in arteries / atheroma / plaques / reference to atherosclerosis; 3. Higher blood pressure; 4. Risk of damage to (coronary) arteries; 5. Risk of blood clot blocking coronary artery6. Risk of type II diabetes;

Alternative mark scheme - Smoking on increasing risk of CVD

1. Carbon monoxide;2. Joins with haemoglobin to form carboxyhaemoglobin;3. Reduces amount of oxygen transported;4. Reduces oxygen available to tissues;5. {Heart muscle / tissues / cells} unable to respire;

6. Less antioxidants / more free radicals; 7. Antioxidants protect cells from damage;8. (so) the artery walls are more likely to become damaged;9. Increases {number / activation} of platelets;

10. Nicotine;11. Increases stickiness of platelets;

12. (Leading to) increased risk of blood clot blocking coronary arteries;13. (leading to) atheroma formation14. Increases blood pressure; 15. Increases risk of aneurysm; Allow description of atheromas for two for marks MAX.

Suggest how ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II.Angiotensin II causes blood vessels to constrict.

1. inhibits the enzyme (that catalyses the conversion); 2. by active site-directed inhibition / eq; 3. inhibitor {is a similar shape to the substrate } / blocks active site; 4. by non active site-directed inhibition; 5. inhibitor attaches to enzyme at point other than active site / eq; 6. (and) causes active site to change shape;

Drugs in treating CVD

ANTIHYPERSENITIVES:1. Reduces blood pressure;2. Decreases risk of {atheromas / blood clots} forming;3. Diuretics;4. Increases urine production so decreases amount of blood5. Beta-blockers;6. Reduces strength of heart beat; 7. Vasodilators;8. Widens blood vessels; BENEFITS: Work in different ways so can be given in combination; Blood pressure can be monitored, so efficiency can be checked; RISKS: Palpitations / Fainting / Headaches / Drowsiness / Allergic reaction

PLANT STATINS:1. Stanols / Sterols;2. Reduce blood cholesterol;3. Reduces amount absorbed by the gut; BENEFITS: Reduces risk of CVD; RISKS: Reduces risk of absorption of vitamins;

ANTICOAGULANTS:1. Reduces blood clotting;2. Artery walls less likely to get damaged; BENEFITS: Treat people with CVD / blood clots; No new ones can form; RISKS: Excessive blooding occurs when injured; Fainting / allergic reactions / osteoporosis;

PLATELET INHIBITORY DRUGS:1. Prevents platelets from clumping;2. Reduces chances of blood clotting;3. Reduces chance of blood vessels being blocked; BENEFITS: Treat those with blood clots / CVD; RISKS: Rashes / nausea / liver function problems / constant bleeding

Cholesterol in our bodies ensures that we stay healthy1. Cell membrane structure2. (steroid) hormone production 3. Bile salt production4. Vitamin D production in the skin;LDL and heart disease1. High (LDL) cholesterol in blood circulation; 2. Increases the likelihood of {deposits / plaques / atheroma} on arterial wall; 3. Narrows arteries / blocks arteries / restricts blood flow; 4. Hardens arteries / makes arteries less elastic; 5. Reference to atherosclerosis; 6. Increases risk of {CHD / blood clots / angina / heart attack / eq};

Low cholesterol diet may not lower blood cholesterol level1. cholesterol synthesized by the body; 2. further detail e.g. made in liver / cholesterol made from saturated fats; 3. genetic factors; 4. further detail e.g. hypercholesterolaemia / number of LDL receptors;

Risk factor 1. Anything that {affects / raises} the chance of harm / eq;

Reduce the development of heart disease 1. {people more aware of the dangers / better health education} / appropriate named example /eq ; 2. less stress /eq ; 3. {better / more} screening / eq ; 4. better treatments / eq ; 5. more exercise being taken / eq ; 6. changed diet / less obesity / eq ; 7. less alcohol intake / eq ; 8. decrease in smoking ; 9. change in population genetics / eq

Alveoli and gas exchange1. Alveoli or capillary walls / epithelium / lining are thin / short distance between alveoli and blood; 2. Many alveoli / alveoli walls folded provide a large surface area; 3. Many capillaries provide a large surface area; 4. ref. to increased diffusion / decreased diffusion distance / eq; 5. Of {respiratory gases / oxygen / carbon dioxide}; 6. {transport of (respiratory) gases (ventilation) / movement of blood (circulation)} maintains diffusion gradient;7. (So) fast diffusion;

Structure of lungs and gaseous exchange 1. alveoli one cell thick / thin (epithelium) ; 2. {walls / endothelium } of capillaries { one cell thick / thin} ; 3. Alveoli covered with capillaries / eq ; 4. idea of short (diffusion) distance ; 5. reference to diffusion ; 6. idea of large surface area provided by {alveoli / capillaries} ; 7. idea that concentration gradient maintained by {ventilation / breathing /eq } ; 8. ref. to large numbers of red blood cells OR idea that oxygen combines with haemoglobin ; 9. idea that concentration gradient maintained by blood flow ; 10. {reference to / description of} Ficks Law ; Diffusion rate is proportional to the surface area

How humans achieve efficient gas exchange

1. One cell thick/thin (not thin membrane)/flattened cells for faster diffusion/shorter diffusion pathway; 2. Large surface area for faster diffusion; 3. Ventilation to maintain a diffusion/concentration gradient;

Single cell organism gas exchange (lives in water)1. (gas exchange) occurs through the {cell membrane / phospholipid bilayer} ; 2. idea that the membrane is thin ; 3. oxygen enters cell (from water) / eq ; 4. carbon dioxide leaves cell (into water) / eq ; 5. {O2 / oxygen / CO2 / carbon dioxide} are {small / non-polar} (molecules) ; 6. reference to diffusion ; 7. {reference to / description} (suitable) concentration gradient ; 8. reference to large surface area (to volume ratio) ;

Structure of a triglyceride 1. made of C, H, O; 2. glycerol / propan (1, 2, 3) triol; 3. three fatty acids; 4. correct location of ester {bond / link};

Formation & Breaking of triglycerides

1. Made from single glycerol molecule;2. 3 molecules of fatty acids;3. Ester bonds form between the fatty acid & glycerol;4. Water molecule produced for each fatty acid;5. Broken up by hydrolysis ;6. Water molecule added;7. To break up each ester bond;

Products of the hydrolysis of triglycerides

1. Fatty acids;2. Glycerol;

The type of fatty acid

1. (mono)unsaturated;

Difference between saturated and unsaturated lipids

1. Unsaturated contain one or more (C=C) double bonds / eq;

How the physical properties of triglyceride is affected by a double bond1. Softer / more likely to be liquid / less densely packed molecules / eq;2. unsaturated / eq are {liquid at room temperature / lower melting point} whilst saturated / eq solid at room temperature;

Saturated lipidsUnsaturated lipids

Found in animal fatsFound in plants

Single bonds in hydrocarbon tailsSome double bonds (which causes a kink in the chain)

Melt at higher temperaturesMelt at lower temperatures

Function of lipids in mammals FunctionDetail

Energy stores;{More than / twice as much as) carbohydrate OR Insoluble / compact / minimise mass OR Subcutaneous / adipose / blubber;

Protection / mechanical insulation;Around {organs / named organ} OR Reference to adipose tissue OR Ear wax giving protection against infection;

Waterproofing;Of skin / fur / feathers / insect cuticle / ear wax OR Hydrophobic / insoluble / repels water;

Electrical insulation;Reference to myelin sheath / nerve cells / neurones / axons / dendrons OR Non-polar;

Heat insulation;Subcutaneous / adipose / blubber OR Prevents heat loss from body;

Buoyancy;Less dense than {water / muscle};

Making beeswax;Formation of honeycomb;

Membrane fluidity;Reference to cholesterol;

Cell membrane structure;Reference to phospholipids;

Reference to hormones;As steroids;

Source of metabolic water;Reference to respiration OR Desert adaptation

Saccharides

1. Monosaccharaides one sugar molecule2. Disaccharides two sugar molecules joined by condensation3. Polysaccharides many sugar molecules joined by condensation

Role of starch 1. store energy in plants

Structure and function of starch

1. Contains amylose and amylopectin;

2. Amylose (not a mark) :3. Long and unbranched chains;4. 1-4 glycosidic bonds;5. coiled structure;6. (so) compact;7. (so) can fit more in a small space;

8. Amylopectin (not a mark) :9. (long), branched chains;10. (has) 1-4 and 1-6 glycosidic bonds;11. side branches which can be broken down quickly;12. Insoluble;13. so water doesnt cause it swell via osmosis

Structure and function of Glycogen

1. Amylopectin;2. 1-4 and 1-6 glycosidic bonds;3. many/lots of side branches;4. (so) glucose can be released quickly;5. Insoluble;6. (so) doesnt swell by osmosis;7. Large molecule so can store lots of energy

Structural difference between starch and glycogen1. glycogen has side branches only / more side branches; 2. starch composed of two components / amylose and amylopectin;

Glycogen is used as a storage molecule1. Compact / eq; 2. {Polymer / eq} of glucose; 3. Can be (easily) hydrolysed / can be broken down to release energy; 4. Insoluble / does not affect osmosis / eq; 5. Will not diffuse out of cells / will remain in cells;

Starch and glycogen are both storage molecules in cells.1. compact therefore large numbers of molecules can fit in a small space / eq 2. insoluble therefore osmotically inactive / eq 3. large molecule therefore remains within cells / cannot pass through membranes / contains a lot of energy 4. easily hydrolysed when required for energy /eq

Give an account of the structure and functions of lipids, including triglycerides and phospholipids.Contain carbon, hydrogen and oxygen ; Insoluble (in water) / hydrophobic ;Triglycerides consist of glycerol plus three fatty acids ; Joined by condensation reactions / formation of ester bonds ; Correct reference to saturated and unsaturated fatty acids ; Phospholipids consist of glycerol plus two fatty acids and a phosphate group ; Reference to non-polar/hydrophobic tails/fatty acids and polar/hydrophilic heads/phosphates of phospholipids ; Correct orientation of phospholipids, in cell membrane / phospholipids bilayer ; Role of phospholipids in cell membrane (fluidity/permeability etc) / role of surfactants ;Energy stores ; Reference to energy from fats / oils, compared with carbohydrates ; (mechanical) protection / packing qualified ;Insulation qualified (either electrical or thermal) ; Buoyancy ; Qualified reference to waterproofing / protection against entry of pathogens in plants ;

Water is an effective molecule for transporting other molecules around living organisms1. idea that water is a solvent ;2. idea that water is {slightly charged / dipole /polar / eq} ;3. idea that {polar molecules / ions / eq} can dissolve in water ;4. idea that water is {viscous / fluid / eq} ;5. idea of water as a liquid assists mass flow6. correct reference to cohesion / adhesion ;

Water molecules are dipolar 1. Charge is not equally distributed throughout molecule / one part is positive and the other part is negative};2. Hydrogen (atoms) have (slight) positive charges; 3. Oxygen (atom) has a (slight) negative charge ;

High heat capacity of water for organisms in water

1. Idea that a lot of {energy / heat} is needed to change temperature ;2. Temperature of their {environment / habitat} does not {fluctuate / change} much / reference to {thermostable / thermobuffer}; 3. Reference to effect on metabolic {rate / reactions};

Causation:

when a change in one variable is responsible for a change in another variable / eq ; Correlation:

(relationship between two variables such that) a change in one of the variables is reflected by a change in the other variable / eq ;

M.H