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Biology Edexcel Alevel > Topic 1 > Flashcards

Topic 1 Flashcards

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1
Q

What is a CVD and give examples

A

CVD is a disease affecting heart and circulation
Stroke and CHD

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2
Q

What is mass flow (larger organism)

A

Particles in a liquid move in one direction due to change in pressure

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3
Q

Define open circulatory system

A

Simple heart pumps blood between cavities, substances diffuse between blood and cells. When relaxed blood drawn back.

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4
Q

Define closed circulatory system

A

1)Blood leaves heart under pressure and flows along arteries to capillaries
2)Substances exchanged
3)After capillaries blood returns to heart via veins

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5
Q

Single circulatory system

A

Blood only passes past heart once for each complete circuit

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6
Q

Double circulatory system

A

—> Right ventricle-deoxygenated blood flows to lungs to receive oxygen
—>Left ventricle-oxygenated blood flows to rest of body to give oxygen

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7
Q

Why is water a good transport medium (liquid transporting ions/molecules)

A
  • easily dissolves molecules that are polar (hydrophilic) and molecules held by ionic bonds
  • it has a high specific heat capacity and is a liquid at room temperature as it has strong H+ bonds.
  • Water is polar as one end is positive (H+) and the other negative (O-) forming a dipole.
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8
Q

Structure of arteries (blood away from heart)

A

-Thick wall (withstand high BP)
-Smooth walls (ease blood flow)
-Elastic walls (recoil blood)
-endothelium cells (Lower friction)
-narrow lumen

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9
Q

Structure of vein (blood to heart)

A

-Thin walls
-Valves (stop back flow of blood)
-Wide lumen
-Little smooth/elastic muscles

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10
Q

Structure of Cappilaries

A

-Narrow lumen
-One cell thick (for shorter diffusion distance)

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11
Q

Steps of cardiac cycle

A

1)Atrial systle- blood under low pressure flows into left/right aria from pulmonary veins and vena cava. Atria fills up opening AV so blood flows into ventricles.
2)Ventricular systle- Ventricles contract opening SV and blood goes into pulmonary artires ( from right ventricle) and aorta (from left ventricle).
3)Cardiac diastole- atria and ventricles relax and blood from pulmonary arteries and aorta goes back into ventricles closing SV. Conary artires fill and blood is drawn into heart via viens.

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12
Q

Describe atherosclerosis

A

1) Endothelium becomes damaged (i.e by high BP) and there is an inflammatory response
2)White blood cells move into artery walls. Over time there is a build up of cholesterol,calcium and fibres build up and harden leading to atheroma (plaque) forming.
3) Arteries narrow and lose elasticIty so again high BP and there is a positive feedback loop

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13
Q

Why and how does the heart get its own supply of O2

A

Heart is a muscle so needs O2/glucose for aerobic respiration. Conary arteries supply heart with blood (O2)

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14
Q

Risk factors for atherosclerosis

A

-Age (arteries become less elastic)
-Diet (more cholesterol in poor diet)
-High BP (damage endothelium)

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15
Q

Blood clotting (thrombosis) steps

A

1)Platelets and damaged tissue release thromboplastin
2)Thromboplastin activated enzyme that catalyse prothrombin into thrombin (needs to be Vitamin K and calcium for this)
3)Thrombin catalyses fibrogen in fibrin
4)mesh of fibrin traps platelets/red blood cells to form clot

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16
Q

What does ischaemic men

A

Without blood

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17
Q

What is angina

A

Chest pain caused when heart has to respire anerobically at it is starved of O2

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18
Q

What is risk and how can it be overestimated

A

Risk-probability of occurrence of some unwanted event
Can be over/under estimated as:
Involuntary/not natural/unfair/unfamiliar/small

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19
Q

What is correlation

A

When a change in one factor is accompanied by a change in another

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20
Q

What is causation

A

When a change in one factor causes a change in another

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21
Q

What is a cohort study

A

Follow large groups over time. Monitor to see who develops condition and interview to find correlation between risk factors.

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22
Q

What is case control study

A

Group with and without condition interviewed about past histories to work out risk factors.

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23
Q

Features of a good study

A

Clear aim
Good sample size
Control variables
Good sample size

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24
Q

What is high BP known as and how is it measured

A

Hypertension and measured with a sphygmomanometer

25
Q

What is oedema

A

Sign of high BP it’s fluid building up tissue causing swelling

26
Q

How are disaccharides formed

A

Joining of two monosaccharides (simple sugar molecule) in a condensation reaction (removing water), joined by glycosidic bonds. They can be split by hydrolysis (adding water).

27
Q

How is Maltose/Sucrose/lactose (disaccharides) made

A

—>Maltose-Condensation of two glucose molecules
—>Sucrose-Condensation of glucose+fructose
—>Lactose-Condensation of glucose+glactose

28
Q

What are polysaccharides

A

Polymers made up of simple sugar monomers joined by glycosidic bonds into long chains. Act as energy stores as compact with low solubility in water.

29
Q

What is starch made up of

A

Amylose (unbraced chain of glucose join by 1,4 glycosidic bonds) and amylopectin (polymer of glucose with branches joined by 1,4 and 1,6 glycolic bonds)

30
Q

What is glycogen

A

Polysaccharide used by bacteria instead of starch as an energy store. It has many branches (1,4 and 1,6 glycosidic bonds) so rapidly hydrolysed, so energy released quickly . In humans stored in liver and muscle cells.

31
Q

What are lipids

A

Biological molecules only soluble in organic solvent (alcohol)

32
Q

Saturated lipids

A

No double carbon (animal fats)

33
Q

Unsaturated fats

A

One double carbon bond. Melt at lower temperatures as intermolecular forces are weaker. Double bond makes lipid weaker as it created a “kink”.

34
Q

Properties of lipids

A

-waterproof as fatty acid tail hydrophobic
-compact so better energy release than carbohydrates and proteins
-conduct heat slowly so provide thermal insulation

35
Q

What is triglycerides

A

Made of one molecule of glycerol and 3 fatty acids joined by ester bonds in condensation reaction. Used as energy release in plants/animals.

36
Q

How can fats help

A

Provide energy and essential fatty acids that body can synthesise

37
Q

What is Basal metabolic rate

A

Energy needed for essential processes
Higher in: -males
-younger people
-more active people

38
Q

BMI calculation

A

BMI=mass/height^2
-18 or below= underweight
-30 or above =overweight

39
Q

Features of LDLs (bad cholesterol)

A

They bind to cell surface receptors which can become saturated leaving LDLs in the blood. They are associated with atherosclerosis development and be maintained at a low level.

40
Q

Features of HDLs (good cholesterol)

A

They transport cholesterol from body tissue to the liver where they are broken down. HDLs lower cholesterol levels and should be maintained at a low level.

41
Q

How can different types of fat affect HDL and LDL levels

A

—>Saturated fats (bad fat)- increase both LDL and HDL levels but increased LDLs at a higher rate.
—>Unsaturated fats (better fats)-decrease both but decrease LDLs more

42
Q

How can smoking affect circulatory system

A

-Carbon monoxide in smoke binds to haemoglobin (O2 carrying cell), reducing O2 supply to cells. This can increase heart rate.
-Nicotine stimulate release of adrenaline. This increase heart rate and causes arteries to constrict both raising BP.

43
Q

How can moderate exercise decrease risk of developing CVDs

A

-prevent high BP
-maintain good weight
-increase HDL levels

44
Q

What are apolipoproteins

A

Protein component of lipoproteins. Formed in liver and intestines and important in stabilising lipoprotein structure named recognising receptors.

45
Q

Apolipoproteins A mutation

A

Mutation associated with low HDL levels and less cholesterol removal

46
Q

Apolipoproteins B mutation

A

Higher LDL and susceptibility to CVDs

47
Q

Apolipoprotein E mutation

A

APOE is a major proteins in HDLs and vLDLs

APOE4 mutation associated with slower removal of cholesterol

48
Q

How can vitamin c (citrus fruits) help body

A

Antioxidants in Vitamin C provide H+ atoms so they can stabilise free radicals that damage cells by pairing up with free unpaired electron.

49
Q

How can salt increase CVD risk

A

Salt causes kidneys to retain water so there are higher fluid levels in blood leading to high BP

50
Q

How can alcohol increase risk

A

Can result in tissue damage like liver damage, if liver is damaged then glucose and lipid removal from blood is impaired.

51
Q

Describe diuretics (antihypertensive)

A

Increase urine vol, lowering blood vol/pressure therefore lowering BP.
Side effects: nausea/dizziness

52
Q

Beat blockers (antihypertensive)

A

Reduce frequency and power of heart contractions by blocking heart to hormones.
Side effects: increase chance of diabetes

53
Q

ACE inhibitors (antihypertensive)

A

Blocks conversion of angiotensin 1 to angiotensin 11 which cause atrial constriction, reducing BP.
Side effects: coughing/dizziness

54
Q

Use of warfarin as an anticoagulant

A

Interrupts vitamin K production so decrease risk of clot formation. Taking too much can lead to uncontrollable bleeding.

55
Q

Statins

A

Inhibit enzyme that produce LDL.
Side effects: tiredness/headaches

56
Q

Use of aspirin as a platelet inhibitory drug/anticogulants

A

Reduce platelet stickiness so lower chance of clots
Side effects: can cause stomach bleeding as aspirin disturbs stomach lining.

57
Q

Calcium channel blockers (antihypertensive)

A

Block calcium channels in muscle cells reducing muscle contraction and arteries diameter, so frequency/power of heart reduces.
Side effects: dizziness/headaches

58
Q

Type of diet to reduce risk of CVD

A

-energy balanced
-more unsaturated fats
-less salt
-less cholesterol

Biology Edexcel Alevel (8 decks)

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