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Biology Edexcel A Alevel > Topic 1 > Flashcards

Topic 1 Flashcards

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1
Q

What is an open circulatory system?

A

A circulatory system that allows the blood to flow out of the blood vessels and into various body cavities so that the cells are in direct contact with the blood.

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2
Q

What is the order of oxygenated blood channels?

A

Arteries, arterioles to capillaries

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3
Q

What is the order of deoxygenated blood channels?

A

Venules to veins

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4
Q

Why are double circulatory systems more efficient?

A

Gives blood returning from the lungs an extra boost, decreasing the time it takes to circulate

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5
Q

What effect does a double circulatory system have on the metabolism?

A

It allows a higher metabolic rate

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6
Q

Is the hydrogen end of water positive or negative?

A

Positive

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7
Q

Is the oxygen end of water positive or negative?

A

Negative

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8
Q

Why is water a useful solvent?

A

Many chemicals dissolve easily in water allowing biochemical reactions to take place.

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9
Q

Which has a larger lumen vein or arteries?

A

Veins

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10
Q

Which blood vessel has thicker walls?

A

Arteries

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11
Q

Which has more collagen, smoother muscles and elastic fibres - arteries or veins?

A

Arteries

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12
Q

What is endothelium?

A

lining of blood vessels

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13
Q

How thick is the endothelium of a capillary

A

Single layer of cells

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14
Q

What happens in atrial systole?

A

Blood is returning to heart from pulmonary vein and vena cava and the atrial ventricular valves open, the atria contract and blood flows into ventricles

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15
Q

What happens in ventricular systole?

A

Both ventricles contract and the atrioventricular valves are pushed shut by pressurised blood.
The semilunar valves in the aorta and pulmonary artery are pushed open.
Blood flows from the ventricles into the arteries.

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16
Q

What happens in diastole?

A

The atria and ventricles relax causing low pressure. The higher pressure in the vena cava and pulmonary veins closes the semi-lunar valves and the low pressure in the atria draws blood

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17
Q

What are the valves between the atria and the ventricles called?

A

Atrioventricular valves

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18
Q

What are the valves between the ventricles and the aorta and the ventricles and the pulmonary vein called?

A

Semi-lunar valves

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19
Q

What is a thrombosis?

A

A blood clot

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20
Q

What is another name for a heart attack?

A

myocardial infarction

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21
Q

What are the five steps of atherosclerosis?

A
  1. Endothelial dysfunction occurs (damaged)
  2. Inflammatory response and atheroma forms
  3. Calcium salts and fibrous tissues build up resulting in a plaque formation
  4. Plaque cause the artery to lose elasticity
  5. The plaque causes the lumen to narrow leading to positive feedback
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22
Q

What is an atheroma made up of?

A

The build up of fatty materials

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23
Q

What happens to platelets when they come into contact with damaged cell walls?

A

They change from flattened discs to spheres with long thin projections and stick to the exposed collagen.

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24
Q

What happens when chemicals by the platelets are released (4)

A
  1. Thromboplastin is released
  2. Thromboplastin activates enzyme that catalyses conversion of prothrombin to thrombin
  3. Thrombin catalyses fibrinogen to fibrin
  4. It traps platelets and red blood cells to form a clot
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25
Q

What happens after thromboplastin is released?

A

Thromboplastin activates an enzyme that catalyses the conversion of prothrombin to thrombin.

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26
Q

What happens when prothrombin is converted to thrombin?

A

Thrombin catalyses fibrinogen to fibrin

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27
Q

What does fibrin do?

A

Forms a mesh and captures more platelets and red blood cells to form a clot.

28
Q

What must be present for prothrombin to turn to thrombin?

A

Vitamin K and Calcium

29
Q

What is thromboplastin?

A

A protein that activates an enzyme

30
Q

What is prothrombin?

A

A protein that is catalysed into thrombin

31
Q

What is thrombin?

A

An enzyme that catalyses fibrinogen into fibrin.

32
Q

What is fibrinogen?

A

A soluble plasma protein that catalyses into an insoluble protein.

33
Q

What is fibrin?

A

An insoluble protein mesh that traps more platelets and red blood cells

34
Q

How can a plaque cause a heart attack?

A

If the plaque ruptures it may block the blood supply causing some areas of the heart to become ischaemic (no oxygen gets to that area of heart muscle which causes it to die)

35
Q

What are the three monosaccharides?

A

glucose, galactose, fructose

36
Q

What are monosaccharides?

A

simple sugar units that provide a rapid source of energy

37
Q

What bonds two monosaccharides together?

A

Glycosylic bonds

38
Q

What are the three di-saccharides?

A

Sucrose, Maltose and Lactose

39
Q

What does glucose and fructose equal?

A

Sucrose

40
Q

What does glucose and galactose equal?

A

Lactose

41
Q

What does glucose and glucose equal?

A

Maltose

42
Q

What reaction creates di-saccharides?

A

Condensation

43
Q

Why do di-saccharides and polysaccharides create a slower release of energy?

A

They have to be broken down first into monosaccharides in order to provide energy.

44
Q

What are the 3 main types of polysaccharide found in food?

A

Starch, cellulose and glycogen

45
Q

What two thing make up starch?

A

Amylose and amylopectin

46
Q

What is amylose composed of?

A

A straight chain that coils into a spiral of glucose molecules

47
Q

What bonds hold amylose?

A

1,4 glycosidic

48
Q

What does amylopectin look like?

A

Side branches from the main chain

49
Q

What bonds hold amylopectin?

A

1, 6 and 1,4 glyosidic

50
Q

What is glycogen and why is it useful?

A

A polysaccharide with many side branches so it can be easily hydrolysed

51
Q

Where is glycogen found?

A

Liver and muscles

52
Q

What makes up a triglyceride?

A

1 glycerol molecule and 3 fatty acids

53
Q

What bonds hold together a triglyceride?

A

Ester bonds

54
Q

What reaction forms the bonds that hold together a triglyceride?

A

Condensation

55
Q

What makes a fat saturated?

A

A fatty acid contains the maximum number of hydrogen atoms

56
Q

What is a key feature of saturated fats?

A

They are solid at room temperature due to strong intermolecular bonds as the fatty acid contains the maximum number of hydrogen atoms

57
Q

Why might the structure of an unsaturated fat be different?

A

Double carbon bonds due to a lack of hydrogen causes kinks, preventing them from packing closely together

58
Q

What do LDL’s do - low density lipids

A

Transport cholesterol to body and bind to receptor cells

59
Q

What happens with an excess of LDL’s

A

They may be deposited in artery walls

60
Q

What do HDLs do?

A

Transport cholesterol back to liver where it is broken down

61
Q

What do statins do?

A

Inhibit enzymes involved in producing LDL’s

62
Q

What are the downsides of statins?

A

Tiredness, muscle ache, headache, nausea

63
Q

What do anti-hypertensives do?

A

Lower blood pressure

64
Q

What are the downsides of anti-hypertensives?

A

Dry cough, dizziness and abnormal heart rhythms

65
Q

What do anti-coagulants do?

A

Interrupt vitamin K, preventing blood clots

66
Q

What do platelet inhibitors do?

A

Reduce the stickiness of platelets

Biology Edexcel A Alevel (15 decks)

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