Topic 1 - lifestyle and risk Flashcards
1
Q
What are the functions of water
A
- It is a solvent - some substances dissolve for biological reactions to take place in a solution
- It transports substances - easier if substance dissolved in a solvent
- The specific heat capacity is very high to maintain homeostasis
2
Q
What is the structure of a water molecule
A
One oxygen, two hydrogen - shared hydrogen pulled towards oxygen so the other side of hydrogen has a slight positive charge. Unshared electrons on the oxygen give it slight negative charge - dipolar molecule
3
Q
What is hydrogen bonding
A
Slight negative oxygen atoms attract slightly positive hydrogen atoms of other water molecules
4
Q
How does water’s dipole nature make it good for transporting substances
A
- Water is very cohesive - attraction between water molecules allows water to flow
- Water is a good solvent - can surround ionic substances
5
Q
Why do single celled organisms not need mass transport systems
A
Materials can diffuse directly across cell membrane due to shorter distance and larger SA:V ratio
6
Q
Why do multicellular organisms have mass transport systems
A
Carry raw materials from specialised exchange organs to body cells and remove metabolic waste
7
Q
Why is the left ventricle thicker
A
More muscular walls to contract more powerfully and pump blood round body
8
Q
What do the atrioventricular valves do
A
Stop blood flowing back into the atria when the ventricles contract
9
Q
Role of the semilunar valves
A
Link ventricles to arteries and stop backflow when the ventricles contract
10
Q
What do valves do
A
Only open one way depending on pressure behind to help blood flow in one direction
11
Q
Features and function of an artery
A
- Carry blood to the rest of the body
- Thick walled, muscular and elastic tissue to cope with high pressure
- Folded endothelium to allow expansion
- Contains collagen to avoid rupture
- Smooth endothelium to reduce resistance
- Elastic fibres stretch to accommodate high pressure and recoil to maintain
12
Q
Features and function of a vein
A
- Take blood back to the heart
- Wider with less elastic and muscle tissue
- Contain valves to prevent back flow
13
Q
Features and function of a capillary
A
- Where metabolic exchange occurs
- Networks increase surface area for exchange
- Walls only one cell thick to allow fast diffusion
14
Q
Explain atrial systole
A
- Atria contract to decrease chamber volume and increase pressure
- Blood pushed into ventricle to cause slight increase in ventricle pressure and volume due to passive filling
15
Q
Explain ventricular systole
A
- Atria relax and ventricles contract to increase pressure and decrease volume
- Pressure higher in ventricles to force AV valves shut and also higher than the arteries so SL valves are forced open so blood forced into arteries
16
Q
Explain cardiac diastole
A
- Ventricles and atria relax. Higher pressure in arteries closes SL valves
- Blood returns to heart and atria fill again due to higher pressure in vena cava and PV. pressure in atria increases and ventricular pressure falls below so AV valves open and blood flows passively into ventricles before atria contract
17
Q
Ethical issues of using invertebrae
A
- Can’t give consent and may be subjected to painful procedures
- However, simpler organisms due to simple nervous system
- Causes distress and suffering by exposure to extreme conditions
17
Q
What do the adjustment knobs do
A
- Coarse - Changes the height of the objective lens
- Fine - adjust focus to see clearer image
18
Q
Explain how atheromas develop
A
- Damage occurs to the endothelium and an inflammatory response occurs - white blood cells accumulate
White blood cells and lipids clump to form fatty streaks - Over time more cells, calcium salts and fibrous tissue build up and harden to form a fibrous plaque (atherosclerosis)
- The plaque partially blocks the lumen and restricts blood flow which causes blood pressure to increase - positive feedback
19
Q
How do atheromas increase risk of thrombosis
A
An atheroma can rupture through the endothelium and damage the artery wall to leave a rough surface
This triggers thrombosis
20
Q
How does a blood clot form
A
- Thromboplastin protein is released from the damaged vessel that exposes collagen
- Along with calcium ions, thromboplastin catalyses conversion of prothrombin into thrombin (an enzyme) in the presence of vitamin K and calcium ions
- Thrombin then catalyses the conversion of fibrinogen to fibrin (insoluble fibres) which tangle together in a mesh and trap platelets
21
Q
How are heart attacks caused
A
Coronary arteries supply oxygen for heart muscle cell respiration
- If it becomes blocked, supply is cut off and heart muscle respires anaerobically (lactic acid can build up)
22
Q
What is a stroke
A
Rapid loss of brain function due to disruption of blood supply to the brain
23
Q
What is deep vein thrombosis
A
Formation of a clot in a vein caused by prolonged inactivity
24
Diet as a risk factor for CVD
- More saturated fats increase blood cholesterol which increases atheroma formation which leads to thrombosis
- High salt increases blood pressure
25
High bp as a risk factor for CVD
Increases risk of damage to the artery walls and atheroma formation, caused by alcohol, stress and diet
26
Smoking as a risk factor for CVD
- Carbon monoxide combines with haemoglobin and reduces amount of oxygen transported
- Nicotine makes platelets sticky so increases blood clot formation
- Decreases antioxidants in the blood which are responsible for cell protection
27
Inactivity as a risk factor for CVD
Increases blood pressure
28
Genetics as a risk factor for CVD
Inheritance of alleles that increase likelihood of high bp or cholesterol
29
Age as a risk factor for CVD
Risk increases with age as plaque builds over time
30
Gender as a risk factor for CVD
Different hormonal levels e.g. oestrogen increases levels of HDL to lower risk
31
What do antihypertensives do
Reduce blood pressure
- Beta blockers - reduce strength of heartbeat
- Diuretics - reduce sodium reabsorbed in blood to reduce water absorbed
- Vasodilators - widen blood vessels
32
Advantages of antihypertensives
- Can be used in combination
- Can monitor blood pressure at home to see if drugs are working
33
Risks of antihypertensives
Side effects: fainting, headaches, palpitations
34
What do statins do
Reduce blood cholesterol by reducing LDL produced in the liver
35
Advantages and disadvantages of statins
Reduce atheroma formation
- Muscle and joint pain, digestive issues, increased diabetes risk, nausea
36
What do anticoagulants do
Reduce blood clotting so less chance of blockage of a vessel
37
Advantages and disadvantages of anticoagulants
Can prevent existing clots from growing and new ones from forming
- Can't get rid of existing ones
- Can cause excessive bleeding, tissue swelling, osteoporosis
38
What do platelet inhibitory drugs do
(type of anticoagulant)
Prevent platelets clumping together so reduce clot formation
39
Describe the role of antioxidants
Vitamins protect against damage to cells from highly reactive radicals
40
How to measure amount of vitamin C in food
Make up vitamin c solutions with known concentrations and measure a set volume of DCPIP (blue to colourless in presence of vitamin C)
Add solution drop by drop and shake, record volume taken to turn colourless
Draw a calibration curve to compare with an unknown solution
41
What is a monosaccharide
Monomer units e.g. glucose has six carbon atoms
42
What are the two types of glucose
Alpha and beta
43
How is the structure of glucose related to its function
It is soluble so can be easily transported
Its chemical bonds contain lots of energy
44
How do monosaccharides join to form a disaccharide
By a glycosidic bond in a condensation reaction when a molecule of water is released. A H of one bonds to an OH of another
The reverse is a hydrolysis reaction
44
Three examples of disaccharides
Maltose - 1-4 glycosidic bond between 2 glucose
Lactose - 1-4 bond between beta glucose and galactose
Sucrose - 1-2 bond between alpha glucose and fructose
45
What is amylose made of
Lots of alpha glucose with 1-4 glycosidic bonds
46
What is amylopectin made of
Alpha glucose with 1-4 and 1-6 bonds with lots of side branches
47
What is glycogen made of
Alpha glucose with 1-4 and 1-6 bonds with more side branches
48
What is the structure and function of starch (a polysaccharide)
The main energy storage in plants (excess glucose)
Amylose - long, unbranched chain of alpha glucose with 1-4 glycosidic bonds. Angles of bonds give it coiled structure to make it compact
Amylopectin - long, branched chain with 1-4 and 1-6 glycosidic bonds. Branches allow enzymes to break bonds easily
Starch is insoluble so doesn’t cause water to enter cells by osmosis so is good for storage
49
What is the structure and function of glycogen
Main energy storage in animals
1-4 and 1-6 glycosidic bonds and loads of side branches to release stored glucose quickly
Very compact so good for storage and insoluble in water so doesn’t cause cells to swell by osmosis
Large molecule to store lots of energy
50
What is a triglyceride
Made of one glycerol and three fatty acids (have long hydrophobic tails made of hydrocarbons) and are insoluble in water
51
How are triglycerides formed
In condensation reactions - fatty acids joined to glycerol with ester bonds. Hydrogen on glycerol bonds to hydroxyl on fatty acid
52
What are saturated lipids
Mainly found in animal fats
No double bonds between carbon atoms in hydrocarbon tails
53
What are unsaturated lipids
Mainly found in plants
Melt at lower temperatures
Double bonds between carbon atoms in tails that cause chain to kink, if they have two or more, the lipid is polyunsaturated
54
How does high saturated fat increase risk of CVD
Increases blood cholesterol level (a type of lipid)
55
What is a high density lipoprotein
Mainly protein
Transport cholesterol from body tissue to liver where it is recycled or excreted
Reduce blood cholesterol when level is too high
56
What is a low density lipoprotein
Mainly lipid
Transport cholesterol from liver to blood where it circulates
Increase blood cholesterol when level is too low
Excess LDL overload membrane receptors
57
How does high LDL cause CVD
More cholesterol increases atheroma formation
