1

Question 1

what is CVD

Answer 1

diseases of heart circulation- main forms of CVD are coronary heart disease

Question 2

why larger organisms don’t just rely on diuffusion for circulatory system and what do they use instead

Answer 2

as organisms size increases: surface area to vol ratio decreases, diffusion distance increases, metabolic rate increases making diffusion isnufficent as it is not quick enough for organisms requirements
instead rely on mass transport system to move substances efficently over long distances by mass flow, all particles in liquid move in one direction through tubes due to difference in pressure- circulatory system- heary and circulation which moves substances around body and allows exchange of substances to take place

Question 3

what is double circulatory system

Answer 3

birds and mammels
RV of heart pumps deoxygenated blood to lungs,oxygenated blood returns to heart to be pumped a second time to rest of bod by LV
blood going to rest of body pushed at higher force to give birds and mammels higher metabolic rate as substances for matbolic processes delivereed more rapidly

Question 4

structure of heart

Answer 4

made up of cardiac muscle
right side recieves deoxygenated blood and pumps it to lungs whilst left side recieves oxygenated blood and pumps it to body
four chambers: right and left atria + right and left ventricles
four main blood vessels: pulmanory vein-from lungs to left atria, aorta-from LV to body, vena cava- from body to RA, pulmanory artery- from RV to lungs
AV vlaves-seperates atria from ventricle
valve tendons- prevent AV valves from turning inside out from pressure
septum-prevents oxygenated and dexoygenated blood from mixing
conarary arteries- wrapped around body to supply cardiac muscles with oxygen
cardiac muscles- thicher on LHS as needs to push blood with more forces

Question 5

ventricular systole

Answer 5

Ventricles contract from base of the heart upwards, increasing pressure in ventricles
Pressure forces open semilunar valves
Pushes blood up and out through the pulmonary arteries and aorta
Pressure of blood against av valves in ventricles closes them preventing backwards into atria

Question 6

circulatory system in unicellular organisms

Answer 6

due to large surface area to voulme ratio oxygen, co2 and digestive products move around by diffusion- movement of molecules or ions from a region of high conc to a region of low conc by random movement of molecules- fast enough to meet unicellular organisms requirments

Question 7

what is an open circulatory system

Answer 7

insects and other animal groups
blood ciculates in large open spaces- simple heart pumps blood into cavities surrounding the animal’s organs- subs diffuse between blood and cells
when heart relaxes blood is drawn back into heart from cavity through small valved openings

Question 8

closed circulatory system

Answer 8

all vertebrates
blood enclosed in tubes-blood vessels
causes high blood pressure as blood forced along fairly narrow channels-blood travels faster making it more efficent
arteries to arterioles to capillaries(come into close contact with most cells in body where subs exchanged beyween blood and cells) blood returns to heart venules then veins

Question 9

what is a single circulatory system

Answer 9

fish
heart pumps deoxygenated blood to gills, gaseous exchange in gills; diffusion of co2 from blood into water and o2 from wtaer into blood, blood leaving gillsflows around rest of body then to heart

Question 10

what is a transport medium

Answer 10

fluid in which substances are carried (blood)
blood plasma mainly water and contains dissolved substances such as digested food molecules, o2 and co2
proteins, amino acids,slats, enzymes, hormones, urea are other subs transported by plasma
red blood cells,white blood cells and platelets
tranfers energy around body for regulation of body temp

Question 11

structures of blood vessels

Answer 11

walls of both arteries and veins contain collagen which makes them strong and durable as well as elastic fibres that allow them to strech and recoil
arteries:narrow lumin,thicker walls,more collagen+smooth muscle for them to constrict and dilate + elastic fibres, no valves
veins:wide lumin,thinner walls,less collagen+smooth muscle+fewer elastic fibres,valves
capillaries, 10um lumen, one cell thick walls

Question 12

How does blood move through vessels

Answer 12

systole-blood forced into arteries and their elastic walls stretch to accomidate blood, thick artery walls can withstand pressure
diastole-elasticity of artery walls cause them to recoil behind blood, helping push blood forwards and smoothing blood flow
blood flows more smoothly in the cappilaries due to narrow lumens causing more of blood to be slowed due to friction with walls- allows exchange between blood and surrounding cells through one cell thick walls- ensure rapid diffusion between blood and surrounding cells
heart has less of a direct effect on blood flow in veins- flows steadily without pulses as under low pressure- assited by the contraction of skeletal muscles during movement of limbs and breathing, low pressure in thorax when breathing helps draw blood back into heart, black flow prevented by semilunar valves
heart does not obtain o2 and nutrients from blood inside heart due to diffusion distance - supplied through cornary circulation which includes coronary arteries and coronary veins

Question 13

Atrial systole

Answer 13

Blood under low pressure flows into the left and right atria from pulmonary veins or vena cava
As atria fills pressure against atrioventricular valves pushes them open and blood leaks into ventricle
Atria walls contract forcing more blood into the ventricles

Question 14

Cardiac diastole

Answer 14

Atria and ventricles relax
Elastic recoil of the relaxing heart walls lowers pressure in atria and ventricles
Blood under high pressure in the pulmonary arteries and aorta is drawn towards ventricles due to change in pressure gradient
Semilunar valves closed
Coronary arteries fill during diastole
low pressure in atria helps draw blood into heart from veins

Question 15

what happens during atherosclerosis

Answer 15

the endothelium, delicate layer of cells that line inside of artery and sperates blood flow from muscle wall, becomes damaged and dysfunctional (high blood pressure putting extra strain on cells or toxins in blood like nicotine)
breaching of inner lining of artery causes an inflammatory response where white blood cells leave blood vessels and move into artery wall- cells accumulate chems from the blood, particularly cholesterol cauising the build up a fatty deposit atheroma
calcium stalts and fibrous tissues also build up at site resulting in a swelling called a plaque on inner wall of artery-build up of fibrous tissue means artery will lose some elasticity and harden
plaques cause lumen to become narrower making it diffiuclt for the heart to pump blood around the body and can lead to a raise in blood pressure- build up of a positive feedback=plaques lead to a raise in blood pressure and raised blood pressure makes it more likely that futher plaques will form as damage in endothelial tissue in other areas become more likely

Question 16

what is atherosclerosis

Answer 16

disease thatleads to conary heart diseas and strokes-fatty depositis block an artery directly or inclease the chance of it being blocked by blood clotting
in conary arteries results in myocardial infarction
arteries supplying blood to brain results in stroke as it causes damage or death to cells in brain

Question 17

why do only arteries get atherosclerosis

Answer 17

fast flowing blood in arteries is under high pressure so there is a significant chance ofdamage to the walls- low pressue in veins means less likely damage to walls

Question 18

why is the septum in the heart important

Answer 18

without it deoxygenated blood would mix with oxygenated blood therefore reducing the concentration of oxygen in the blood circulating in the body which means there is less oxygen available for cells for aerobic respiration

Question 19

blood clotting process

Answer 19

when platelets comes into contact with damaged vessel wall they change from a flaterned disc to spheres with long thin projections
their cell surface changes causing them to stick to exposed collagen in the wall and each other to form a temporary plug, whilst releasing subs that activaye more platelts
contact between blood and collagen stimulates a cascade of changes
platelets and damaged tissues release the protein thromboplastin triggering the clotting cascade
thrombo and clotting factors present in plasma (Ca2+ and vitamic K) triggers the conversion of inactive prothrombin wich is a protein into thrombin which is an enzyme
thrombin catalyses the conversion of the soluble plasmaprotein, fibrinogen, into the insoluble fibrin
a mesh of fibrin(network of fibres) forms that traps more platelets and red blood cells to form a clot- fibrinogen is globular and fibrin is fibrous

Question 20

what is a risk

Answer 20

the probability of occurrence of some unwanted event or outcome’

Question 21

why is blood clotting necissary

Answer 21

blood clot seals the break in the blood vessel and limits loss and prevents entry of pathogens through any open wounds

Question 22

what happens inside the arteries to cause blood clotting

Answer 22

atherocsclerosis and the endothelium is damaged, the platelets come in contact with damaged surface and exposed collagen- triggering clottig cascade

Question 23

conary heart disease

Answer 23

narrowing of conary arteries limits amound of oxygen rich blood reaching the heart muscle- may result in chest pain called angina- heart muscles need to respire so respire anaerobically
if fatty plaque in the conary artery ruptures, collagen is exposed which leads to rapid clot formation- blood supply may be blocked completely- heart muscles are ischaemic (without blood)-muscle cells starved with o2 for that long they will be permenatley damaged - heart attack or myocardial infraction

Question 24

stroke

Answer 24

supply of blood to brain interrupted/blocked

Question 25

why overestimate a riskinvoluntary

Answer 25

involuntary not natural unfamiliar dreaded unfair very small

Question 26

why blood clotting can lead to heart attack

Answer 26

1. prevents oxygen reaching the heart {muscle / cells / tissue / eq} ; 2. prevents (aerobic) respiration ; 3. (cardiac) muscle { unable to contract / dies / eq } ;

Question 27

what is LDL

Answer 27

bad chlosterol

Question 28

Explain how atherosclerosis can result in damage to heart muscle.

Answer 28

narrowing of lumen of conary arteries which blood flow to cardiac muscles therfore reducing amount of oxygen these muscles are recieving for aerobic respiration causing a build up of lactic acid from anaerobic respiration

Question 29

how arteries structure benefit their function

Answer 29

-elastic fibres-allow stretching to accommodate higher pressure / allow recoil to maintain pressure and push blood -folded endothelium-allow stretching to accommodate higher pressure -(smooth) muscle - muscle can {contract / exert pressure / eq}- when contract vessel constricts, making lumen narrower and increasing resistance raisng blood pressure, if smooth muscle relaxes the lumen dilates so peripheral ressiatnce is reduced -reference to smooth endothelium - reduce {friction / resistance to blood flow / -narrow lumen-to maintain (high) blood pressure ; -collagen-avoids rupture / damage

Question 30

what detremines blood pressure

Answer 30

contact between blood and walls of blood vessels causing friction which impedes flow of blood- peripheral resistance

Question 31

why is blood pressure lower in arterioles and cappillaries then in arteries

Answer 31

offer a greater total surface area than arteries, resisting flow more, slowing down the blood and causing blood pressure to fall

Question 32

what is a oedema and what is it a sign of

Answer 32

fluid building up in tissue causing swelling high blood pressure,kidney or liver disease, resticted body movement

Question 33

how is an oedmea formed

Answer 33

arterial end of cappilary blood under pressure forces fluids and small molecules in plasma through tiny gaps between cells into intercellular space froming tissue fluid-interstital fluid -cells abosorb nutrients and oxygen from tissue fluid and give out waste blood cells and larger proteins stay inside the capillary;too large tissue fluid drains into a network of lymph capillaries which returns the fluid to the blood via lymph vessels which empties into vena cava, and some returns back to capillaries via osmosis blood pressure rsing above normal means more fluid forced out of capillaries- fludi accumulates within tissue causing oedema

Question 34

features of a good study

Answer 34

clear aim-a clearly stated hyphothesis or aim, design of study must be appropriate to the stated hypothesis or aim and produce results that are valid and relaible representative sample-selected from the wider population that study's conclusions will be applied to-selection bias occurs when those who participate in a study are not representative of the target population, differnces in people asked to take part must be considered- non particpating may be employeed and lifestyle differs to that who is un-employed and has time to take part, minamise number of people who drop out after study begins valid and reliable results-datat measuring what it is supposed to, surveys lead to over or under estmiations, reliable way to collect results- able to be repated and get similar results, controleld and taken into account variables, clearly defined disease diagnosis sample size-large enough to produce results that could of not occured by chance- large samples means more accurate estimates for wider population can be calculated controlling variables-recorded effects of all variables that could be correlated with disease

Question 35

risk factors for cvd

Answer 35

high bp obesity blood chloesterol and other dietary factors smoking inactivity genetic inheritance

Question 36

fats

Answer 36

as well as supplying energy also provide a source of essential fatty acids-fatty acids body needs but cannot synthesis- need to be consumed to avoid deficiency

Question 37

measuring obesity and overweight

Answer 37

bmi= mass kg/height2 waist circumfrence: hip cicumfrence- didviding waist by hip

Question 38

causation vs correlation

Answer 38

Correlation describes an association between variables: when one variable changes, so does the other. A correlation is a statistical indicator of the relationship between variables. These variables change together: they covary. But this covariation isn’t necessarily due to a direct or indirect causal link. Causation means that changes in one variable bring about changes in the other; there is a cause-and-effect relationship between variables. The two variables are correlated with each other and there is also a causal link between them.

Question 39

what is chloesterol

Answer 39

a short lipid molecule essential for good health-vital component of cell membranes, steriod sex hormones and some growth hormonesmade from chloesterol made in liver from saturated fats and also obtained in diet- saturated fats; eggs meat and dairy products

Question 40

why need balanced diet

Answer 40

constant supply of energy for metabolic process in body- basal metabolic rate

Question 41

how is cholesterol transported in blood

Answer 41

not soluble in water- to be transported in water is combined with proteins to form soluble lipoproteins

Question 42

what is LDL

Answer 42

low density lipoproteins made in the liver triglycerides from fats in our diet combine with cholesterol-more than in hdl- and protein to form LDLs which transport the ch to body cells contain more triglycerides with saturated fatty acids circulate in bloodstream and bind receptor sites on cell mebranes before being taken up by cells where ch is involved in maintance and synthesis of cell membranes excess LDLs pverload these membrane receptors resulting in high blood ch levels- may be deposited in artery walls forming atheromas

Question 43

HDLs

Answer 43

high density lipoproteins higher % of protein and less ch compared to LDLs tris+ch+proteins transport ch from body tissues to liver where they are broken down- lowers blood ch levels and helps removes fatty plaque of atheroma

Question 44

how are HDLs and LDLs associated with unsaturated and saturated fats

Answer 44

staurated fat in diet increases LDL and HDL- but greater LDL unsaturated decreases LDL and HDL levels

Question 45

why mammals need heart and circulatory system

Answer 45

the heart has to pump blood a long way around the body of the mammal, so therefore blood needs to be (pumped) at high pressure through contractions of heart..blood vessels are needed to contain the blood in a closed circulation. Mammals have a double circulatory system where seperation of flow of blood to lungs to get oxygenated and a return to heart to be pumped around the body.capillaries needed to ensure that all parts of mammal are close to blood supply need for a circulation to {provide oxygen / remove carbon dioxide } ; {oxygen / glucose} needed as {high metabolic rate / high rate of respiration / eq} ; diffusion not meeting the requirements of the mammal as low surface area to volume ratio circulatory system helps regulation of body temperature ;

Question 46

why age and gender asked when calculating probabilty of developing cvd

Answer 46

1. age effect qualified e.g. older increases risk, {arteries {become less elastic / more easily damaged / blood pressure increases} with (increase in) age ; 2. gender effect qualified e.g. {women lesslikely to develop CVD than men / oestrogen offers some protection to women against CVD } (pre menopause) / eq ;

Question 47

how structure of aorta realtes to function

Answer 47

1. Idea that there is a {thick wall / lots of collagen / thick layers / thick tunica media / eq} ;- Idea that it needs {to avoid rupture / to withstand high pressure/ eq} ; 2. {elastic / muscular / eq} {layer / fibres / wall/ eq} ;- Control the flow of blood / maintain blood pressure / elastic recoil/ eq ; 3 smooth endothelial wall / eq -to reduce {friction / resistance / eq} ; 4. semi lunar valve present -to prevent backflow (during diastole) ; 5. large lumen - idea of accommodating large volumes of blood /eq ; 6. branches - to supply blood to different parts of the body (including coronary arteries) / eq ;

Question 48

why is bigger sample better

Answer 48

1. idea that it makes the {results / data / study} {representative / reliable} ; 2. idea that there are {many potential risk factors / large variation between individuals}; 3. idea that side effects more likely to show up ;

Question 49

why test for CVD need to be over a long period of time

Answer 49

{CVD is not an immediate disease / side effects may take time to become apparent / need to see if drug works over a long time}

Question 50

advantages of a double circulatory system over a single

Answer 50

1. blood flows {faster /at higher pressure / eq} (to the body) ; 2. blood flows {slower /at lower pressure / eq} to the lung ;

Question 51

ways to reudce risk of CVD

Answer 51

1. idea that the woman could reduce her {energy / eq} intake ; 2. {weight/ BMI} decreases if her energy expenditure greater than intake / eq ; 3. diet should have reduced cholesterol levels / eq ; 4. cholesterol has been associated with {high blood pressure / atherosclerosis / eq} ; 5. diet should have reduced saturated fat / eq ; 6. reduces blood {cholesterol /LDL} / eq ; 7. idea that the woman could increase the amount of exercise she took ; 8. weight decreases if energy expenditure is greater than her intake / exercise helps maintain a healthy heart /reduces blood pressure / eq ; 9. idea that if the woman smoked she should reduce it ; 10. smoking {reduces oxygen uptake / increases stickiness of platelets / increases blood pressure / increases risk of atheroma / eq} ; 11. idea that diet should have reduced salt ; 12. high salt associated with high blood pressure ; 13. idea of moderate alcohol intake ; 14. high alcohol associated with high blood pressure ;

Question 52

genes and CHD and CVD

Answer 52

inheritance of genes can cause changes in body leaidng to raises in blood pressure- can be resulted of multiole genese interacting or a mutation apolipoprotein gene cluster associated with CHD- apolipoproteins roles in stabilisng the structure of LP and recognising receptors involved in lipo uptake on the plasma membrane

Question 53

types of apolipoproteins

Answer 53

APOA- major protein in HDL helps removal of chloesterol to liver for excretion APOB- main protein in LDL- tranfers chloesterol from blood to cells APOE-major compenent in HDL and very LDL involved in the removal of excess chol from blood to the liver

Question 54

role of salt

Answer 54

high intake can cause kidney to reatin water- higher fluid levels in the blood results in evaluated bp

Question 55

alcohol

Answer 55

raises bp, contributes to obesity and can cause irregular heart beats excess results in direct tissue damage especially in liver- which process carbs, fats and proteins and detoxification

Question 56

reduce risk of CVD

Answer 56

no smoking mainatin resting bp og 140/85 mmHg mainatin low chol levels low BMI and waist to hip ratio regular exercise moderate use of alcohol

Question 57

ACE inhibitors- antihypertensive drugs

Answer 57

reduce synthesis of angiotensin II- hormone that causes vasoconstriction of blood vessels- prevents hormone being produced from inactive angiotensin I side effects: dry cough, dizziness from lapid lowering of BP, abnormal heart rhythm and reduction in function of kidney

Question 58

calcium channel blockers- antihypertensive drugs

Answer 58

block calcium channels in the msucle cells in lining of arteries- for muscles to contract calcium must pass through these channels into muscles cells- prevents contraction of muscles lowerinf bp side effects: headaches, dizziness, swollen lugs from fluid build up, abnprmal heart rhythms, flushing red in face and conctipation

Question 59

how diet battles cvd

Answer 59

energy balance reduces saturated fats more polyunsaturated fats reduce chol reduced salt more polysaccharides not starch- lower blood chol fruits and veg- contain antioxidants

Question 60

platelet inhibatory drugs

Answer 60

reduces risk of blood clotting- make platelets less sticky reuding likelhood of clot aspirin can cause risk of stomach bleeding

Question 61

anticoagulant

Answer 61

warafrin- interfers with production of vitamin K reducing risk of blood clotting risk of bleeding

Question 62

smoking affects on CVD

Answer 62

carbon monoxide binds with haemglobin in rbc instead of o2, reduces supply of o2 to cells- increase heart rate as body reacts to provide more o2 nictoine stimulates the production of adrenaline- increases heart rate and causes conctriction of arteries and arterioles raisng blood pressure other chems can cause damage to endothelium associated with reduction in HDL

Question 63

inacticity affects on CVD

Answer 63

moderate exercise lowers bp, helps mainatain healty weight, raises HDL levels without affecting LDL levels and reduces chances of developing type 2 diabetes, more likely to survie a heart attack or stroke inactivity can lead to obesity- pressure on blood vessel

Question 64

role of antioxidants

Answer 64

during reactions in the body, unstable radicals result when an atom has unpaired electron- highly reactive and can damage many cell components like enzymes and genetic material- implicated with development types of cancer, heart disease some viatmins like C able to protect against damage-provide hydrogen atoms that stabilise the radical by pairing up

Question 65

role of stress

Answer 65

stress releases adrenaline causing constriction of arteries and arterioles causing raised bp

Question 66

beta blockers- antihypertensive drugs

Answer 66

reduce frequency of heart contractions and make them less powerful by blocking of response to heart hormones may increase risk of diabetes

Question 67

diuretics- antihypertensive drugs

Answer 67

increase vol of urine produced by kidney riding body of excess fluids and salts- decrease in blood plasma vol and cardiac output lowering bp diziness, nausea, muscle cramps

Question 68

statins

Answer 68

inhibt an enzyme involved in production of LDLs by liver- reduces overall chlosteral level reducing risk of atheroma tiredness, disturb sleep, feeling sick, vomiting, diarrhoea, headaches, muscle weakness

Question 69

effects a large quantity of unsaturated lipoprotein

Answer 69

it will increase blood chloesterol as it is an unstaurated lipoprotein meanining it is an LDL which have a higher propotion of saturated fats and chloesterol than protein ldl tranporst chloesterol to cells where they bind to receptors on cell surface membrane, if there is an overload ldl will acumulate in blood casuing an increase in blood chloesterol levels

Question 70

health risks as a result of high BMI

Answer 70

high bp leading to damage to endothelium, which will start proscess of atheroscloroisis as inflamatory repsonse causes wbc to move in accumulating chlosterol,firborus tissues and calcium salts casuing formation of fatty plaque that narrows lumen of arteries futher increasing bp- this will lead to heart disease if present in conoaray arteries as narrowing of lumen means lower conc of oxygen reaching cells in cardiac muscle for respiration leading to cell death, same process cold happen in arteries leading to the brain resulting in a stroke there could also be joint damage due to increase body mass leading to damage of cartalige

Question 71

why lowering blood cholesterol levels reduces risk of CVD

Answer 71

less cholesterol (in blood) to build up on artery wall when damage to endothelium meaning less likely to develop atherosclerosis which results in narrowing of arteries, ischemia, decrease in flow of blood (to heart)

Question 72

why a larger sample size is better for experiments

Answer 72

1. idea that it makes the {results / data / study}{representative / reliable} ; 2. idea that there are {many potential risk factors / large variation between individuals}; 3. idea that side effects more likely to show up ;

Question 73

similarties and differences between double and single circulatory systek

Answer 73

sims: both have a fluid medium, heart pump and blood vessels to carry blood differnces: deoxygentaed blood and o2 blood sepertaed in heart by 4 chambers and in single blood not sperated and there are only 2 chambers, blood enters heart 2x per ciculation and once in single, sing less effective at tranporting oxygen and removing co2 from lungs, pressure lower in sing to not damage gills

Question 74

what is correlation

Answer 74

association or relationship with no casual link

Question 75

why larhger body mass= less oxygen consumption for repiration

Answer 75

smllaer sa to vol ratio means less repsiration needed for heat loss

Question 76

dpania experinet control variables

Answer 76

Temperature – measure temperature with thermometer. Carry out in same place Volume of solutions – use same number of drops on Daphnia each time Stress of Daphnia – try to minimise stress of Daphnia (explained in Ethical Considerations section) Size of Daphnia – try to pick Daphnia of around the same size for repeats Time to acclimatise – leave Daphnia in caffeine solution for same amount of time to acclimatise (e.g. 5 minutes)

Question 77

vitamin c practical method

Answer 77

Pipette 1cm³ of 1% blue DCPIP into a conical flask .Fill up a burette with the first type of fruit juice to be used and take a note of the start value. Use the burette to slowly add the fruit juice to the DCPIP drop by drop. Swirl the contents of the conical flask with one hand whilst controlling the tap with the other. Close the tap as soon as the DCPIP loses its blue colour and note the end value .Work out how much volume of the fruit juice was needed to decolourise the DCPIP and note this down in an appropriate table. Repeat this procedure for the other fruit juices available. Repeats can be carried out 2 times to obtain mean results.

Question 78

vitamin c controls

Answer 78

Temperature – measure temperature with thermometer. Carry out in same place Concentration of DCPIP – 1% solution used each time Volume of DCPIP – 1cm³ of DCPIP solution used each time Shake each tube same number of times (e.g. 3 times) Same end point colour – until the blue colour of DCPIP just about disappears

Question 79

how to calculate vitmain c content

Answer 79

Mass of vitamin C to decolourise 1cm³ of DCPIP = 10mg × volume of vitamin C used Mass of vitamin C in fruit juice sample = mass of vitamin C to decolourise 1cm³ of DCPIP × volume of sample required to decolourise 1cm³ of DCPIP

Question 80

daphnia experiment method

Answer 80

1. Dilute the caffeine solution with distilled water to produce several different concentrations. 2. Place some cotton wool (to restrict movement) on a cavity slide. Add one large water flea. 3. Use filter paper to absorb the water around the flea. 4. Then use a dropping pipette to add a few drops of distilled water to the slide-Do not use a coverslip to prevent conditions from becoming anoxic. 5. Use a stop clock to time a minute and record the number of heartbeats. 6. Repeat the experiment, replacing the distilled water with a caffeine solution.

Question 81

effects of having a high BMI

Answer 81

high blood pressure causes damage to endothelium (1) • atherosclerosis leads to narrowing of lumen of arteries (1) • heart disease as a result of narrowing of coronary arteries (1) • stroke as a result of reduced blood flow to brain (1) • joint damage caused by increased body mass leading to damage of the cartilage (1) • type 2 diabetes caused by reduced sensitivity of insulin receptors

Question 82

correlation

Answer 82

Correlation shows an association or relationship but no causal link