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A Level Biology > Lifestyle, Risk and Health > Flashcards

Lifestyle, Risk and Health Flashcards

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1
Q

Define an open circulatory system

A

Blood circulates in large open spaces

  • A simple heart contracts to pump blood into cavities surrounding the organs
  • Substances will diffuse into and out of the cells
  • When the heart relaxes blood will be drawn back to the heart
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2
Q

Define a closed circulatory system.

A

Blood is enclosed within vessels, generating higher pressure, travels in one direction and faster as it is forced along narrow channels.
Blood travels from arteries to arterioles to capillaries and returns by venules to veins.

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3
Q

Define a single circulatory system.

A

Blood flows through the heart once each complete circuit of the body.

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4
Q

Define a double circulatory system.

A

Blood flows twice through the heart for each complete circuit. Right ventricle pumps deoxygenated blood to the lungs, left ventricle pumps oxygenated blood round the body. Leads to a high metabolic rate.

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5
Q

What are the properties of water that make it a good transport medium?

A

Water is polar as hydrogen is slightly positive and oxygen is slightly negative which forms hydrogen bonds and therefore forming a dipole. Other polar substances, as well as ionic and hydrophilic substances, can easily dissolve in water.

The specific heat capacity of water is very high to maintain homeostasis.

Water has a high boiling point due to the hydrogen bonds.

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6
Q

Describe the structure of an artery.

A

Narrow lumen, thick walls (withstand), more collagen (maintain), smooth muscle (maintain) and elastic fibres ( expand and recoil), endothelium layer (reduce friction)

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7
Q

Describe the structure of a vein.

A

Wide lumen, thin walls, valves to prevent backflow.

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8
Q

Describe the structure of a capillary

A

Endothelium is one cell thick, small lumen.

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9
Q

Describe atrial systole.

A

High pressure. Atria fill with blood from the Vena Cava/Pulmonary Vein. Atrioventricular valves open. Blood flows into the ventricles. Atria contract.

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10
Q

Describe ventricular systole.

A

High pressure. Ventricles fill with blood. Semi-lunar valves open, atrioventricular valves close. Ventricles contract.

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11
Q

Describe diastole.

A

Low pressure. Atria and ventricles relax. Semi-lunar valves close. Coronary arteries fill.

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12
Q

Describe atherosclerosis.

A

The endothelium becomes damaged. There is an inflammatory response causing white blood cells to move into the artery wall. A fatty deposit (atheroma) builds up. Calcium salts and fibrous tissues build up, causing a plaque. The artery loses elasticity, narrows and hardens. Causes a rise in blood pressure and dangerous positive feedback.

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13
Q

Describe the consequences of atherosclerosis.

A

Increases chance of blood clots blocking the artery. Cells are permanently damaged. May result in heart attack, stroke, tissue death or gangrene. An artery may burst due to build up of blood.

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14
Q

Describe the effects of Coronary Heart Disease.

A

Narrowed coronary arteries may lead to angina. Heart muscle lacks oxygen and has to respire anaerobically. Arteries blocked and are ischaemic (not enough blood flowing). If muscle cells are starved of oxygen for too long it results in an infarction.

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15
Q

Describe the effects of a stroke.

A

If the supply of blood is interrupted, a stroke will happen. Blood clots blocking arteries may cause a stroke.

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16
Q

Describe the clotting cascade reaction.

A

Platelets release the protein thromboplastin. This activates an enzyme which catalyses prothrombin into thrombin in the presence of Vitamin K and Ca2+ ions. This then catalyses soluble fibrinogen into insoluble fibrin. Fibrin traps platelets and red blood cells to form a clot.

Platelets in contact with damaged vessels become spheres instead of flattened discs. They stick to exposed collagen.

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17
Q

Describe risk perception.

A 
People will overestimate risk if:
it is out of their control
it is unnatural
it is unfamiliar
it is dreaded
it is unfair
or if the risk is very small.
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18
Q

Describe some risk factors of CVD.

A 
Age
Heredity
Physical environment
Social environment
Lifestyle
Behavioural choices.
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19
Q

What must a study have?

A

A clear aim
A representative, large sample
Controlled variables
Valid and reliable results.

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20
Q

What is used to measure blood pressure?

A

A sphygomanometer.

21
Q

Describe oedema.

A

Fluid builds up in tissues leading to swelling. Higher blood pressure leads to more fluid being forced out of capillaries.

22
Q

How are disaccharides formed?

A

Monosaccharides are joined together in a condensation reaction, producing water. They are joined by a glycosidic bond. They can be split by hydrolysis.

23
Q

Describe the formation of starch.

A

Starch is made up of amylose, which is an unbranched chain, 1,4 glycosidic bonds and is cooked into a spiral, and amylopectin, which has side branches and 1,6 glycosidic bonds. Starch is low solubility in water and compact.

24
Q

Describe the formation of glycogen.

A

Made up of alpha glucose. Has numerous side branches allowing rapid hydrolysis. 1,4 and 1,6 glycosidic bonds. Stored in liver and muscles. Used by bacteria, fungi and animals as an energy store.

25
Q

Describe triglycerides.

A

Insoluble in water but soluble in organic solution.

Made up of a glycerol backbone and three fatty acid tails, linked by ester bonds in a condensation reaction producing three molecules of water.

26
Q

Describe the difference between saturated and unsaturated hydrocarbons.

A

Saturated hydrocarbons have the maximum number of hydrogens. They are straight, long chains with no double bonds. Solid at room temperature.

Unsaturated hydrocarbons have double bonds, causing links in the chain, preventing it from packing closely together. Liquids at room temperature. Hydrogenation can saturate, addition of hydrogens, uses a nickel catalyst.

27
Q

Describe low-density lipoproteins.

A

Triglycerides, proteins and cholesterol combine. Transports cholesterol to body cells. May be deposited in artery walls.

Excess LDLs overload membrane receptors.

28
Q

Describe high-density lipoproteins.

A

Triglycerides with a higher percentage of protein and a lower percentage of cholesterol. Transports cholesterol from body tissue to the liver, where it can be broken down. Lowers blood cholesterol levels and reduces plaques formed from atherosclerosis.

29
Q

Describe smoking as a risk factor.

A

Carbon monoxide binds to haemoglobin instead of oxygen, reducing the supply to cells, increasing heart rate.

Nicotine produces adrenaline, increases heart rate, causes arteries and arterioles to construct, raises blood pressure.

Chemicals in smoke damage endothelium of arteries.

Linked with reduced HDL.

30
Q

Describe the benefits of exercise.

A

Halves the risk of CHD.

Raises HDL cholesterol.

Reduces development chance of Type 2 diabetes.

31
Q

Describe salt as a risk factor.

A

More salt in the blood, more water into the blood, increase blood pressure

32
Q

Describe stress as a risk factor.

A

Releases adrenaline, arteries and arterioles constrict, raises blood pressure.

33
Q

Describe alcohol as a risk factor.

A

Leads to an irregular heartbeat, direct tissue damage, increases risk of CVD.

Moderate consumption linked with raised HDL levels.

34
Q

Describe ACE inhibitors.

A

Antihypertensives.

Reduces synthesis of angiotensin II which causes vasoconstriction.

Reduces vasoconstriction which lowers blood pressure.

35
Q

Describe calcium channel blockers.

A

Antihypertensives. Block calcium channels in muscle cells.

36
Q

Describe diuretics.

A

Increases volume of urine. Decreases blood plasma volume and cardiac output, lowers blood pressure.

37
Q

Describe statins.

A

Inhibits an enzyme producing LDLs.

38
Q

Describe the use of aspirin as an anticoagulant.

A

Reduces the stickiness of platelets and the likelihood of clot formation.

39
Q

Describe the use of warfarin as an anticoagulant.

A

Interrupts production of Vitamin K and the synthesis of factors involved in clotting.

40
Q

Define basal metabolic rate.

A

The amount of energy used, per day, whilst at rest.

41
Q

Which two monosaccharides make sucrose?

A

Glucose and fructose.

42
Q

Which two monosaccharides make maltose?

A

Glucose and glucose.

43
Q

Which two monosaccharides make lactose?

A

Glucose and galactose.

44
Q

Describe obesity indicators.

A

BMI.

Waist to hip ratio.

45
Q

What is the calculation for waist to hip ratio.

A

Waist circumference divided by hip circumference.

46
Q

DCPIP vitamin C experiment

A

1) Liquid extract
2) Titration from DCPIP in burette to solution in the beaker
3) Using DCPIP
4) Solution goes blue
5) Calibration curve

47
Q

LDL

A

Brings cholesterol from the liver to the body cells, contain high levels of cholesterol

48
Q

HDL

A

From the body cells to the liver, contains low levels of cholesterol.

49
Q

Effect of caffeine on Daphnia heart rate.

A

Place Daphnia on cavity slide. Replace pond water with distilled water. Leave to acclimatise. Count heart rate under microscope for 30 seconds. Multiply by 2. Repeat with more Daphnia. Repeat with different concentrations of caffeine (5).

As caffeine increased, heart rate increased.

A Level Biology (14 decks)

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