UNIT 1 - Lifestyle, health and risk Flashcards
(93 cards)
1
Q
What are the two main functions of water in living organisms?
A
- Solvent: Substances dissolve in it, most biological reactions take place dissolved in it.
- Transport: If they are dissolved, substances can be transported in water. i.e. glucose, oxygen…
2
Q
What is the chemical structure of water?
A
One atom of oxygen joined to two hydrogen atoms by a pair of shared electrons.
3
Q
How does the chemical structure of water gives it its dipole nature?
A
The shared negative electrons are pulled towards the oxygen (because the oxygen nucleus is more positive).
Therefore, the oxygen becomes partially -ve (delta -) while the hydrogens become partially +ve (delta +).
4
Q
How does the dipole nature of water allow it to form hydrogen bonds?
A
The partially positive hydrogens become atracted to the partially negative oxygens in other water molecules, establishing hydrogen bonds.
5
Q
How does water’s dipole nature dipole nature make it good for transporting substances?
A
- Cohesive: hydrogen bonds between water molecules make them very cohesive so they can flow.
- Good solvent: The dipole nature makes it good for dissolving substances. i.e. Ionic - the negative ion becomes attracted to the H(delta +) while the positive ion becomes attracted to the O (delta -).
6
Q
Why do multicellular organisms need mass transport systems?
A
All cells need energy - most get it from aerobic respiration (glucose+oxygen).
Low SA:Vol ratio. Diffussion isn’t fast enough to deliver raw materials to cells and to remove waste products.
So a mass transport system is needed (circulatory system in mammals).
7
Q
What is A?
A
Aorta
8
Q
What is B?
A
Superior vena cava
9
Q
What is C?
A
Pulmonary artery
10
Q
What is D?
A
Pulmonary veins
11
Q
What is E?
A
Left atrium
12
Q
What is F?
A
Right atrium
13
Q
What is G?
A
Coronary arteries
14
Q
What is H?
A
Right ventricle
15
Q
What is I?
A
Left ventricle
16
Q
What is J?
A
Inferior vena cava
17
Q
What is A?
A
Superior vena cava
18
Q
What is B?
A
Aorta
19
Q
What is C?
A
Pulmonary artery
20
Q
What is D?
A
Pulmonary vein
21
Q
What is E?
A
Left atrium
22
Q
What is F?
A
Right atrium
23
Q
What is G?
A
Atrioventricular valve
24
Q
What is H?
A
Semilunar valves
25
What is I?
Right ventricle
26
What is J?
Inferior vena cava
27
During a dissection, how can you distinguish between arteries and veins?
Arteries are thick and rubbery while veins are much thinner.
28
Why is the wall of the left ventricle thicker than the wall of the right ventricle?
The left ventricle needs to contract powerfully (so more muscle) to pump blood all the way down the body while the right ventricle pumps blood to the lungs, which are nearby.
29
Why do the ventricles have thicker walls than the atria?
Ventricles have to pump blood out of the heart and to the body (or lungs) while the atria only have to push the blood a short distance inside the heart (to the ventricles).
30
What is the function of the atrioventricular valves and why do they have cords?
* Prevent blood from flowing back into the atria when ventricles contract.
* Cords prevent the valves from being forced into the atria when ventricles contract by attaching the valves to the ventricles.
31
What is the function of the semi-lunar valves in the heart?
Prevent blood from flowing back into the heart when the ventricles contract.
32
How do valves (in general) prevent blood from flowing in the opposite direction?
* They can only open one way.
* If there's higher pressure before a valve, it's forced open.
* If there's higher pressure after the valve, teh valve is forced shut.
33
What is the function of the arteries and how are they adapted to their function?
* Carry blood from heart to the rest of the body.
* They are thick-walled and have elastic tissue to cope with the high pressure caused by the heartbeat.
* They also have a thick muscle layer and together with the elastic tissue, helps to regulate pressure.
* The endothelium is folded, allowing the artery to expand, which helps it cope with high pressure.
34
What is A?
Thick outer wall (collagen fibres).
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What is B?
Lumen
36
What is C?
Thick muscle layer and elastic fibres
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What is D?
Folded endothelium
38
What is A?
Thin outer wall
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What is B?
Thin layer of muscle and elastic fibres
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What is C?
Endothelium
41
What is D?
Large lumen
42
What is the function of veins and how are they adapted to their function?
* Carry blood back to the heart.
* Have a wider lumen than arteries.
* Little elastic+muscle tissue since blood is under lower pressure.
* Contain valves to stop blood from flowing backwards.
* Blood flow is helped by contraction of surrounding body muscles.
43
What is the function of the capillaries and how are they adapted to its function?
* Metabolic exchange (exchange of substances)
* Organised into capillary beds to increase SA (therefore inc. diffusion)
* Consist of a one cell thick endothelium (therefore inc. diffusion)
44
What happens during ventricular diastole, atrial systole?
1. Ventricles are relaxed.
2. Atria contract, decreasing the volume and therefore incrasing the pressure.
3. This pushes blood into the ventricles, opening the atrioventricular valves.
4. There's a slight increase in venticular pressure and volume since blood has just entered.
45
What happens during atrial diastole, ventricular systole?
1. Atria relax.
2. Ventricles contract, decreasing their volume and increasing their pressure.
3. Because the pressure is greater in the ventricles than in the atria, the AV valves shut.
4. The pressure is also higher tha in the arteries sosemi lunar valves open and blood is forced out through the aorta and pulmonary artery.
46
What happens during cardiac diastole?
1. Ventricles and atria relax.
2. Higher pressure in arteries causes the valves to shut.
3. Higher pressure in veins causes blood to flow to the atria.
4. As pressure increases in the atria, blood flows passively into the ventricles, causing the AV valves to open.
5. The process then starts again with atrial systole.
47
What is happening in phase A?
Ventricular diastole, atrial systole.
Ventricles relax and atria contract to fill up the ventricles.
48
What is happening in phase B?
Ventricular systole, atrial diastole.
Ventricles contract and atria relax.
therefore the increase in ventricular pressure and decrease in atrial pressure.
49
What is happening in phase C?
Cardiac diastole.
pressure decreases and starts to increase due to passive filling.
50
How long is the cardiac cycle shown in the graph?
0.7 seconds
51
How can the effect of caffeine on the heart rate be tested on daphnia?
1. make a range of caffeine solutions plus a control one without caffeine.
2. Place one daphnia on a cavity slide
3. using a pipette, place a few drops of caffeine solution onto the Daphnia.
4. Place the slide onto the stage of a light microscope and adjust the focus so you can see the beating heart of the daphnia.
5. count the number of heartbeats in 20 seconds multiply this number by three to calculate bpm.
6. Repeat this 10 times with different daphnia but same concentration.
7. Repeat using all the other concentrations + control.
8. Compare the result to see how caffeine affects heart rate.
52
Why do some people believe it is more acceptable to perform experiments on invertebrates?
They are much simpler organisms than vertebrates.
For example, they have a much less sophisticated nervous system, which could mean that they feel little to no pain.
53
How do artheromas form?
1. Damage occurs to the endothelium (i.e. by high blood pressure)
2. Inflammatory response (WBC move into the area)
3. White blood cells and lipids from the blood clump together to form fatty streaks.
4. Over time more blood cells, lipids and connective tissue build up and harden to form a fibrous plaque (artheroma).
5. This partially blocks the lumen of the artery, causing pressure to increase.
54
What is artherosclerosis?
The hardening of the arteries, caused by atheromas.
55
How can atheroma formation lead to thrombosis?
1. An atheroma can rupture the endothelium of an artery, damaging it and leaving a rough surface.
2. This triggers thrombosis - a blood clot is formed.
3. this blood clot can cause a complete blockage of the artery or block a blood vessel elsewhere.
4. The blood flow to tissues supplied by the blocked artery is restricted so less oxygen will reach those tissues, causing heart attack, stroke and other forms of cardiovascular disease.
56
How does a blood clot form?
1. Thromboplastin (protein) is released from the damaged blood vessel.
2. Thromboplastin, along with calcium ions from the plasma triggers the conversion of prothrombin (a soluble protein in the blood) into thrombin (an enzyme).
3. Thrombin then catalyses the conversion fibrinogen (soluble protein) to fibrin (insoluble fibres)
4. Fibrin fibles then form a mesh in which platelets and red blood cells get trapped - forming the clot.
57
How can blood clots cause heart attacks?
1. Cardiac muscle is supplied with blood from the coronary arteries.
2. This blood contains oxygen needed by cardiac muscle cells to carry out respiration.
3. If a coronary artery becomes blocked by a blood clot, an area of cardiac muscle won't recieve blood, ad therefore, won't recieve oxygen, so it won't be able to carry out respiration.
4. This causes myocardial infarction (heart attack).
5. It can cause damage and death of the heart muscle.
58
What is a stroke?
A rapid loss of brain function, due to a disruption in the blood supply to the brain. (can be caused by a blood clot).
59
What is Deep Vein Thrombosis?
The formation of a blood clot in a vein deep inside the body (i.e. leg veins). It is caused by prolonged inactivity and the risk increases with age.
60
What are the lifestyle factors that can increase the risk of CVD?
* Diet high in saturated fats and salt
* High blood pressure (caused by excessive alcohol consumption, stress and diet)
* Smoking
* Inactivity
61
How can smoking increase the risk of CVD?
* Carbon monoxide binds with haemoglobin and reduces the amount of oxygen carried in the blood, therefore less oxygen reaches important tissues such as the cardiac muscle or the brain.
* Nicotine increases the stickyness of platelets, increasing the chance of blood clots forming.
* Decreases the amount of antioxidants in the blood, so more cell damage in the artery walls, which can lead to atheroma formation.
62
How does high blood pressure increase the risk of CVD?
High pressure increases the risk of damage to the artery walls. therefore increasing the risk of atheroma formation.
63
What are the factors beyond control that can increase the risk of CVD?
* Genetics: Some people have alleles that make them more likely to have high blood pressure or high blood cholesterol.
* Age: Risk increases with age, this is partly because plaque build up very slowly over time.
* Gender: Men are x3 more likely to suffer CVD than pre-menopausal women. This may be due to their different levels of hormones. i.e. oestrogen (more present in women) increases levels of HDL cholesterol.
64
What can make a study on CVD more reliable and valid?
* Large and representative sample.
* Control variables
* No bias in data collection
* Repetition
65
How do antihypertensives reduce CVD?
* Contain beta-blockers, which reduce the strength of the heartbeat.
* Contain vasodilators, which widen the blood vessels.
* Include diuretics, which reduce the amount of sodium that's reabsorbed by the blood in the lidneys, so less water is absorbed, and therefore less blood volume.
* All this reduces high blood pressure, so there's less change of damage occuring to the artery walls and therefore less chance of atheromas and blood clots forming.
66
What are the risks/side-effects of hypertensives?
Palpipations, abnormal heart rhythms, fainting, headaches and drowsiness can be caused by too low blood pressure.
Other risks include allergic reactions and depression.
67
How do statins reduce the risk of CVD?
* Statins reduce blood cholesterol by reducing the amount of LDL (bad) cholesterol produced inside the liver.
* A lower blood cholesterol reduces atheroma formation, reducing the risk of CVD.
68
What are the risks/side-effects of statins?
* Muscle and joint pain.
* Digestive system problems
* Increased risk of diabetes.
* Nosebleeds and headaches.
69
How do anticoagulants reduce the risk of CVD?
Anticoagulants (like warfarin and heparin) reduce blood clotting.
Therefore blood clots are less likely to develop at sites of damage in artery walls.
So there's less chance of the artery becoming blocked by a blood clot, therefore reducing the risk of CVD.
70
What are the risks/side-effects of anticoagulants?
If the patient is badly injured and starts to bleed, the lack of blood clotting can lead to excessive bleeding, which in turn can lead to fainting or death.
Allergic reactions, osteoporosis (weakened bones), swelling of tissues.
Can damage the fetus if taken during pregnancy.
71
How do platelet inhibitory drugs reduce the risk of CVD?
Platelet inhibitory drugs like aspirin, are a type of anticoagulant that work by preventing platelets from clumping together to form a blood clot.
Therefore there's less chance of new blood clots being formed.
so there's less chance of a blood vessel becoming blocked by a clot, and therefore less risk of developing CVD.
72
What are the risks/side-effects of platelet inhibitory drugs such as aspirin?
Excessive bleeding
Diarrhoea
Nausea
Liver function problems
73
What is an energy budget?
A term used to describe the amount of energy taken in by an organism and the amount of energy used up by an organism.
74
What happens if there's an imbalance in a person's energy budget?
It will affect the person's weight:
If the energy intake is higher than the output, the excess energy will be turned into fat reserves and so the person will gain weight.
If the energy intake is lower than the output, the needed energy is is obtained from fat reserves, so the person will loose weight.
75
Write the equation for energy budget
energy input - energy output = energy budget
76
What is the recommended daily intake of calories?
2000 for women and 2500 for men
77
What colour change is observed when DCPIP is in presence of vitamin C?
from blue dye to colourless
78
How can you measure the amount of vitamin C in a sample of food?
CALIBRATION CURVE:
* Make up vitamin C solutions of different concentrations.
* Measure out a set volume of DCPIP into a test tube.
* Add one of the vitamin C solutions drop by drop.
* Gently shake the test tube after each drop.
* When the solution turns colourless, record the volume of vitamin C solution that has been added.
* Repeat this procedure and measure an average.
* Repeat this with each concentration of vitamin C.
* Plot a graph of volume of solution, vs concentration of vitamin C.
* This way, you can know the concentration of vitamin C of a solution by knowing the volume of solution needed to turn the DCPIP colourless.
79
What is the chemical structure of alpha glucose?
80
How is the chemical structure of glucose relate dto its function?
Its structure makes it soluble so that it can be easily transported and its chemical bonds contain lots of energy, as its the main source of energy in animal and plants.
81
Describe the structure of maltose
two alpha glucose with 1,4 glycosidic bonds .
82
Describe the structure of lactose
beta glucose and galactose with a 1,4 glycosidic bond.
83
Describe the structure of sucrose
alpha glucose and fructose with a 1,2 glycosidic bond
84
Compare dissacharides with monosacharides in terms of solubility and energy storage
dissacharides are less soluble but their chemical bonds store more energy.
85
Describe the structure of amylose
Long chain of alpha glucose molecules bonded together by 1,4 glycosidic bonds.
86
describe the structure of amylopectin
long chain of alpha glucose molecules bonded by 1,4 glycosidic bonds with branches joined by 1,6 glycosidic bonds to the chain.
87
Describe the structure of glycogen
long chain of alpha glucose molecules bonded by 1,4 glycosidic bonds with branches joined by 1,6 glycosidic bonds to the chain.
Glycogen has even more branches than amylopectin.
88
How is amylose adapted to its function?
Amylose is a long chain and the angles in its 1,4 glycosidic give it a coiled structure, allowing it to be compact and therefore good storage because more can be fitted into a space.
89
How is amylopectin adapted for its function?
Long, branched chain. Its side branches allow the enzymes that break down the molecule to get at the glycosidic bonds easily so that glucose can be released rapidly.
90
What is the composition of starch?
30% amylose
70% amylopectin
91
Is starch soluble? Why is this important?
It is not soluble, otherwise it would cause water to enter to cells by osmosis, which would make them swell.
92
How is glycogen adapted to its function?
* Loads of side branches, so glucose can be released quickly.
* Very compact molecule.
* Insoluble, so doesn't cause cells to swell.
* Its a large molecule, therefore can store lots of energy.
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