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Biology Edexcel > Topic 1 > Flashcards

Topic 1 Flashcards

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1
Q

Def Causal relationship

A

a change in one variable brings about a change in another but a strong correlation between 2 variables doesn’t prove a causal link between them.

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2
Q

Characteristics of a Cohort study:

A

Large groups followed over time to see who develops disease
Prospective; at start nobody has disease
Exposure to suspected risk factors recoreded
Expensive
Time consuming

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3
Q

Characteristics case control studies

A

group with disease compared to control group of individuals who do not have disease
retrospecitve

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4
Q

Features of a well designed study

A
  1. Clear: aim hypothesis or question
  2. Representative participants to sample of population results applied
  3. No bias
  4. Sufficient numbers of people
  5. Clearly defined symptoms
  6. Measurements truly reflect what they were trying to measure
  7. Reliable method
  8. Other variables associated with disease taken into account
  9. Timescale suitable to exposure and disease development
  10. Data provides info on what study set out to measure
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5
Q

CVD risk factors (6)

A 
high BP
obesity
smoking
inactivity
genetic inheritance
dietary- blood cholesterol
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6
Q

Def blood pressure

A

measure of hydrostatic force of blood on blood vessel walls.
Highest- arteries
Measured in kilopascal (but in medical practice millimetres of mercury, mmHg).

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7
Q

Factors determining BP (3)

A
  1. Contact between blood and walls of blood vessels (peripheral resistance)
  2. Contraction of smooth muscle = lumen narrower= inc. resistance and inc. bp
  3. arterioles/ arteries constrict due to: loss of elasticity (age), release of hormones (adrenaline), high salt diet.
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8
Q

Odema def

A

Building up of fluid in tissues, causing swelling

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9
Q

Causes odema

A
  1. Arterial end of capillary: blood under pressure, so fluid and small molecules forced through tiny gaps between the cells of the capillary wall, into the inter cellular space. Forms tissue fluid.
  2. Cells absorb nutrients and O2 from fluids, and give out waste
  3. Tissue fluid moves back into capillaries by osmosis.

When BP raised, more fluid forced out into capillaries, which accumulates causing odema

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10
Q

What is 1 calorie

A

quantity of heat required to raise the temp of 1cm3 of water by 1 degree C

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11
Q

General formula: Carbohydrate

A

Cx (H2O)n

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12
Q

Monosaccharide def

A

Single sugar unit- monomer

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13
Q

Dissaccharide def

A

2 single sugar units combined in condensation reaction

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14
Q

3 Monosaccharides

A

Glucose
Galactose
Fructose

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15
Q

When is Maltose produced

A

when amylase breaks down starch (germinating seeds)

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16
Q

3 Dissacharides

A

Maltose
Sucrose
Lactose

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17
Q

3 Polysaccharides

A

Starch
Cellulose
Glycogen

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18
Q

Characteristics Polysaccharides

A

Compact molecules
Low solubility in water

Means they do not diffuse across cell membranes and do not affect concentration of water in the cytoplasm, so do not affect movement of water into or out of cell by osmosis

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19
Q

what are Lipids

A

fats and oils
organic molecules found in every type of cell

Insoluble in water
soluble in organic solvents e.g. ethanol

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20
Q

Saturated, LDL fats def

A

contains max number of hydrogen atoms
Long and straight hydrocarbon chain, with no C=C. This means can pack together closely with strong intermolecular bonds between triglycerides.
Solid at room temp

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21
Q

Unsaturated, HDL fat def

A

Monounsaturated. One C=C in each fatty acid chain.

Polyunsaturated: 2 or more C=C.

Double bonds cause a kink in hydrocarbon chain, which prevent them packing closely together. Inc distance between molecules, weakening intermolecular forces.

Liquid at room temp.

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22
Q

How to make unsaturated fats solid at room temp (saturated)

A

add hydrogen to double bonds.

“hydorgenated” or “trans-fats”

Processed foods

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23
Q

Is cholesterol a lipid

A

yes

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24
Q

Cholesterol def

A

short lipid molecules essential for good health
Vital component of cell membranes with roles in:
cell organisation and functioning

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25
Q

where is cholesterol made and form what

A

liver

saturated fats eg. eggs, meat, dairy

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26
Q

fat provides us with… (3)

A

energy
essential fatty acids the body cannot synthesise
fat soluble vitamins: A, D, E, K

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27
Q

BMI calculation:

A

Body Mass/kg DIVIDED BY (height)2/m2

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28
Q

Waist to hip ratio def

A

continuous, positive correlation, risk of heart attack

Men not over: 0.85
Women 0.90

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29
Q

Waist to hip ratio calculation

A

Waist circumference DIVIDED BY hip circumference

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30
Q

Consequences of obesity

A

increased risk

CHD
High BP
high lipid levels
Type 2 diabetes

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31
Q

what is insulin

A

hormone related to blood glucose levels produced by pancreas.

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32
Q

Type 2 diabetes due to:

A

continuous high Blood glucose levels due to frequent consumption of sugar rich foods can reduce sensitivity of cells to insulin

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33
Q

How is cholesterol (insoluble) transported in bloodstream

A

combines with proteins to form lipoproteins

34
Q

2 types of lipoproteins

A
  1. Low density lipoproteins (LDL)

2. high density lipoproteins (HDL)

35
Q

Characteristics LDLs

A

1) . Triglycerides from fats combine with cholesterol + protein to form LDLs
2) . Transport cholesterol to body cells
3) . Circulate in blood stream and bind to receptor sites on cell membranes before being taken up by the cells, where cholesterol is involved in synthesis and maintenance of cell membranes.

4). Excess LDLs overload membrane receptors = high blood cholesterol levels. LDL deposited in artery walls = atheroma

36
Q

Characteristics: High density Lipoproteins (HDLs)

A
  1. Higher percentage of protein, less cholesterol
  2. Made when triglycerides from fats combine with cholesterol and protein
  3. Transport cholesterol from body tissues to liver - where its broken down. This lowers blood cholesterol levels and helps remove fatty plaques of atherosclerosis
37
Q

Effect of Saturated and unsaturated fats on LDL and HDL cholesterol

A

Unsaturated: Decreases LDL and HDL

Saturated: increases LDL and HDL
Reduces activity of LDL receptors so LDLs not removed from blood

38
Q

Smoking increases:

A

Risk of CVD

39
Q

Affects of smoking on circulatory system: (4)

A
  1. reduced O2 supply to cells: carbon monoxide binds to haemoglobin, reducing O2 supply to cells
  2. Increased BP
    Nicotine stimulates production of hormone adrenaline- which increases HR (inc BP) and constricts arteries + arterioles
  3. Atherosclerosis triggered - chemicals cause damage to artery linings
  4. Linked to reduction in HDL cholesterol levels
40
Q

Effects of moderate exercise:

A

Prevent high BP

Raises HDL cholesterol levels (decreased risk type 2 diabetes)

41
Q

Risk of Heart Attack/ CHD

A 
inactivity
high BP
high blood cholesterol
smoking
hereditary 
obesity
42
Q

What are aplioproteins?

A

Protein component of lipoproteins
formed in liver and intestines
Role in stabilising lipoprotein structure and recognising receptors involved in lipoprotein uptake on the plasma membrane of most cells.

43
Q

Role Aplioprotein A

A

major protein in HDL
Removal of cholesterol to the liver for excretion

Mutations associated with low HDL levels and reduced removal of cholesterol from blood increases CHD risk

44
Q

Role Aplioprotein B (APOB)

A

Main protein: LDL
Molecule transfers cholesterol from blood into cells

Mutations: higher LDL levels, inc CHD

45
Q

Aplioprotein E

A

Component HDL and very low density lipoproteins (VLDLS)
Removal of excess cholesterol from blood to the liver

3 common alleles: produces 3 forms of protein: E2, E3, E4.

APOE4 slows removal from blood, increased risk of CHD

46
Q

What does multifactorial mean

A

Disease is not caused by one factor alone

47
Q

How do unstable radicals result

A

when an atom has unpaired electrons

48
Q

What are radicals

A

highly reactive. can damage cell components including enzymes and genetic material- associated with some types of caner, heart disease and premature ageing

49
Q

What can protect against radical damage

A

vitamins C, E and beta- carotene. They provide hydrogen atoms which stabilise the radical by pairing with its unpaired electron

50
Q

What do antioxidants do

A

stop platelets sticking together

51
Q

what does a diet high in salt do

A

kidneys retain water. Higher fluid levels in blood= elevated BP and inc CVD risk

52
Q

what does stress do

A

release adrenaline; arterioles and arteries constrict, inc BP

overeating
higher alcohol consumption

53
Q

what does heavy alcohol consumption do

A

increased:
BP
Obesity
Irregular HR

Direct tissue damage to liver, brain, heart

54
Q

functions of the liver (2)

A
  1. process fats, proteins, carbs

2. detoxification

55
Q

what does damage to the liver impair? (2)

A

Ability to remove from blood:
glucose
lipids

56
Q

what is moderate drinking associated with

A

higher HDL levels

57
Q

6 ways to reduce CVD

A 
stop smoking
maintain low LDL cholesterol
regular PA
moderate/no alcohol
maintain resting BP below 140/85
Maintain normal BMI and waist to hip ratio
58
Q

3 drugs for high BP

A

ACE inhibitors
Calcium channel blockers
Diurectics

59
Q

what are ACE inhibitors

A

antihyperintensive drugs which reduce synthesis of hormone which causes vasoconstriction of blood vessels (angiotensin II).

60
Q

when is BP medecine required

A

systolic equal or over 160

diastolic 100

61
Q

Side effects ACE inhibitors (4)

A

dry cough
dizziness
abnormal heart rhythm
reduction in kidney function (failure if already have disease)

62
Q

What are Calcium Channel blockers

A

antihyperintensive drugs that block the calcium channels in muscle cells which prevents muscle contraction, meaning blood vessels do not contract, lowering BP

63
Q

Side effects: Calcium channel blockers (6)

A 
headaches
dizziness
swollen ankles due to build up of fluid in legs
abnormal heart rhythm
flushing red in face
constipation
64
Q

What do diuretics do

A

increase volume of urine produced by kidneys, thus ridding body of excess fluids and salt. This decreases blood plasma volume and cardiac output, lowering BP

65
Q

Diuretics side effects (3)

A

Dizziness
Nausea
Muscle cramps

66
Q

Reducing blood cholesterol: (1)

A

Low fat diet

67
Q

What is a cholesterol lowering drug

A

Statins

68
Q

what do statins do

A

inhibit an enzyme involved in production of LDL cholesterol by the liver, decreasing risk of: heart attack and stroke

69
Q

Side effects of Statins (7)

A 
tired
disturbed sleep
feeling sick
vomiting
diarrhoea
headache
muscle weakness

(cancer)

70
Q

How can diet be altered to reduce CVD (6)

A 
energy balanced
reduce saturated fat
Reduced cholesterol
reduce salt
more polyunsaturated fats

more non starch polysaccharides: pectins.
“soluble fibre” lowers cholesterol: fruit, veg, pulses, grain (oats). These are partially digested- leaving a gel which traps cholesterol and prevents its absorption.

71
Q

why are oily fish good

A

contain omega 3 fatty acids which are polyunsaturated and essential for cell functioning, linked to reduction in joint inflammation and heart disease.

72
Q

Why are fruit and veg good

A

Often non starch polysaccharides
antioxidants
plant sterols reduce LDL cholesterol, which competes with cholesterol absorption in intestine.

73
Q

What does aspirin reduce (2) and what is it

A

platelet stickiness
Likelihood of clot formation

platelet inhibitory drug

74
Q

What is warfin and what does it do

A

anticoagulant drug

interferes with vitamin K production, thus affecting synthesis of clotting factors

HOWEVER risk of bleeding can be worse than asprin

75
Q

risks of asprin

A

bleeding in gastrointestinal tract

76
Q

what is mass flow

A

liquid transported in one direction due to difference in pressure

77
Q

Is the hydrogen end of the dipole water positive or negative

A

positive

78
Q

what types of properties does water have

A

solvent and thermal

79
Q

what are the solvent properties of water

A

dipole : chemicals dissolve easily

ionic substances dissolve easily in water (become hydrated) and surrounded by H20 molecules.

Polar molecules dissolves easily in water if hydrophilic (water loving)

Hydrophobic not soluble in water, eg. lipids

80
Q

How are dissolved substances transported in circulatory system

A

blood
lymph systems

Plants:
xylem
phloem

81
Q

Thermal properties of water

A

high specific heat capacity so large amount of energy to break H bonds

Organisms avoid rapid changes in internal temp

Biology Edexcel (8 decks)

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