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Biology Edexcel Alevel > Topic 1 > Flashcards

Topic 1 Flashcards

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
What is oedema
Sign of high BP it’s fluid building up tissue causing swelling
26
How are disaccharides formed
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
How is Maltose/Sucrose/lactose (disaccharides) made
—>Maltose-Condensation of two glucose molecules —>Sucrose-Condensation of glucose+fructose —>Lactose-Condensation of glucose+glactose
28
What are polysaccharides
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
What is starch made up of
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
What is glycogen
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
What are lipids
Biological molecules only soluble in organic solvent (alcohol)
32
Saturated lipids
No double carbon (animal fats)
33
Unsaturated fats
One double carbon bond. Melt at lower temperatures as intermolecular forces are weaker. Double bond makes lipid weaker as it created a “kink”.
34
Properties of lipids
-waterproof as fatty acid tail hydrophobic -compact so better energy release than carbohydrates and proteins -conduct heat slowly so provide thermal insulation
35
What is triglycerides
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
How can fats help
Provide energy and essential fatty acids that body can synthesise
37
What is Basal metabolic rate
Energy needed for essential processes Higher in: -males -younger people -more active people
38
BMI calculation
BMI=mass/height^2 -18 or below= underweight -30 or above =overweight
39
Features of LDLs (bad cholesterol)
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
Features of HDLs (good cholesterol)
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
How can different types of fat affect HDL and LDL levels
—>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
How can smoking affect circulatory system
-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
How can moderate exercise decrease risk of developing CVDs
-prevent high BP -maintain good weight -increase HDL levels
44
What are apolipoproteins
Protein component of lipoproteins. Formed in liver and intestines and important in stabilising lipoprotein structure named recognising receptors.
45
Apolipoproteins A mutation
Mutation associated with low HDL levels and less cholesterol removal
46
Apolipoproteins B mutation
Higher LDL and susceptibility to CVDs
47
Apolipoprotein E mutation
APOE is a major proteins in HDLs and vLDLs APOE4 mutation associated with slower removal of cholesterol
48
How can vitamin c (citrus fruits) help body
Antioxidants in Vitamin C provide H+ atoms so they can stabilise free radicals that damage cells by pairing up with free unpaired electron.
49
How can salt increase CVD risk
Salt causes kidneys to retain water so there are higher fluid levels in blood leading to high BP
50
How can alcohol increase risk
Can result in tissue damage like liver damage, if liver is damaged then glucose and lipid removal from blood is impaired.
51
Describe diuretics (antihypertensive)
Increase urine vol, lowering blood vol/pressure therefore lowering BP. Side effects: nausea/dizziness
52
Beat blockers (antihypertensive)
Reduce frequency and power of heart contractions by blocking heart to hormones. Side effects: increase chance of diabetes
53
ACE inhibitors (antihypertensive)
Blocks conversion of angiotensin 1 to angiotensin 11 which cause atrial constriction, reducing BP. Side effects: coughing/dizziness
54
Use of warfarin as an anticoagulant
Interrupts vitamin K production so decrease risk of clot formation. Taking too much can lead to uncontrollable bleeding.
55
Statins
Inhibit enzyme that produce LDL. Side effects: tiredness/headaches
56
Use of aspirin as a platelet inhibitory drug/anticogulants
Reduce platelet stickiness so lower chance of clots Side effects: can cause stomach bleeding as aspirin disturbs stomach lining.
57
Calcium channel blockers (antihypertensive)
Block calcium channels in muscle cells reducing muscle contraction and arteries diameter, so frequency/power of heart reduces. Side effects: dizziness/headaches
58
Type of diet to reduce risk of CVD
-energy balanced -more unsaturated fats -less salt -less cholesterol

Biology Edexcel Alevel (8 decks)

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