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Biology AS Level > Topic 1 - Lifestyle, Health And Risk > Flashcards

Topic 1 - Lifestyle, Health And Risk Flashcards

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1
Q

What are cardiovascular diseases?

A

Are diseases that affect the heart and blood vessels. The main forms of cardiovascular disease are coronary heart disease and stroke.

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2
Q

What is the main purpose of the heart and its circulation?

A

To move substances around the body.

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3
Q

Do unicellular organisms rely on a mass transport system?

A

No, most unicellular organisms where distances are short, substances such as oxygen, carbon dioxide and digestive products move around the organism by diffusion.

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4
Q

What do complex multicellular organisms rely on?

A

On a mass transport system.

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5
Q

What is a mass transport system? Give examples

A

In a mass transport system, all the substances move in the same direction at the same speed by mass flow. Across the range of multicellular organisms found in the living world are a number of mass transport systems, e.g. the mammalian circulatory system and the vascular system of a plant.

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6
Q

What is mass flow?

A

All the particles move in one direction through tubes due to difference in pressure.

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7
Q

Do all animals have only one heart?

A

No, e.g the humble earthworm has five.

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8
Q

What are the two types circulatory systems?

A
  • Open

- Closed

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9
Q

What animals have an open circulatory system?

A

Insects

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10
Q

How does blood circulate in a open circulatory system?

A

(Blood circulates in large open spaces) A simple heart pumps blood out into cavities surrounding the animals organ’s. Substances can diffuse between he blood and cells. When the hearts muscle relaxes, blood is drawn back into the heart through small, valved, openings along its length.

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11
Q

What animals have a closed circulatory system?

A

All vertebrates.

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12
Q

How does a closed circulatory system work?

A

Blood is enclosed in tubes (blood vessels) which generates a higher blood pressure as the blood is forced along fairly narrow channels instead of flowing into large cavities. This means the blood travels faster and so the blood system is more efficient at delivering substances around the body.

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13
Q

Properties of a closed circulatory system?

A
  • The blood leaves the heart under pressure and flows along arteries and then arterioles to capillaries.
  • Extremely large number of capillaries. These come into close contact with most of the cells in the body where substances are exchanged between blood and cells.
  • Blood then returns to the heart by passing through venules and veins.
  • Valves ensure that blood only flows in one direction.
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14
Q

Animals that have a closed circulatory system are …

A

Larger in size and often more active.

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15
Q

What are the two types of closed circulatory systems?

A
  • Single

- Double

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16
Q

What animals have single circulatory systems?

A

Fish

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17
Q

What are the properties of single circulatory systems?

A
  • The heart pumps deoxygenated blood to the gills
  • Gaseous exchange takes place in the gills; there is diffusion of of carbon dioxide from the blood into the water that surrounds the gills and diffusion of oxygen from this water into the blood within the gills
  • The blood leaving the gills then flows around the rest of the body before eventually returning to the heart.
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18
Q

In a single circulatory system how many times does the blood flow through the heart?

A

Once for each complete circuit of the body

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19
Q

What animals have a double circulatory system?

A

Birds and mammals

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20
Q

How does blood flow in a double circulatory system?

A

The right ventricle of the heart pumps deoxygenated blood to the lungs where it receives oxygen. The oxygenated blood then returns to the heart to be pumped a second time by the left ventricle out to the rest of the body.

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21
Q

Why do animals with a double circulatory system have a higher metabolic process?

A

Oxygen and food substances required for metabolic processes can be delivered more rapidly to cells and meet the needs of the organism.

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22
Q

In most animals what is the transport medium?

A

Blood

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23
Q

What is the blood made up of?

A
  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
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24
Q

What does plasma contain?

A

Mainly water with dissolved substances:

  • Digested food molecules
  • Proteins
  • Amino acids
  • Salts
  • Enzymes
  • Hormones
  • Antibodies
  • Urea (the waste product from the breakdown of proteins)
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25
Q

As well as blood transporting dissolved substances and cells, what is its other role?

A

Regulation of body temperature and transfer of energy around the body.

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26
Q

Why is water unusual?

A

It is a simple molecule that is liquid at room temperature.

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27
Q

What is a polar molecule?

A

A polar molecule is a molecule that has an unevenly distributed electrical charge.

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28
Q

Describe the properties of water?

A

It is a polar molecule as it has an unevenly distributed electrical charge. The two hydrogens are pushed towards each other forming a v-shaped molecule. The hydrogen end of the molecule is slightly positive and the oxygen end is slightly negative because the electrons are more concentrated at that end.

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29
Q

What is water also known as?

A

Dipole

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30
Q

Where does a hydrogen bond form?

A

A hydrogen bond forms between to water molecules holding them together. The slightly positive end of the water molecule is attracted to the slightly negative end of surrounding water molecules.

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31
Q

What type of molecules dissolve in water?

A

Dipoles

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32
Q

What substances dissolve easily in water? Give examples

A 
Ionic substance - Sodium chloride - Cl ions attracted to the positive ends of the water molecule whereas the Na ions are attracted to the negative ends of the water molecules, they become hydrated.  
Polar molecules (hydrophilic) become surrounded by water and go into the solution- NH2
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33
Q

Non-polar lipids do not dissolve in water. What do they do so they can?

A

Lipids combine with proteins to form lipoproteins, so that they can dissolve in water.

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34
Q

Is the specific heat capacity of water high or low? Why?

A

It is very high because the energy needed to break the hydrogen bonds needs to be very high. A large energy input only causes a small increase in temperature, so water warms and cools slowly.

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35
Q

What is specific heat capacity?

A

It is the amount of energy in joules required to raise the temperature of 1cm3 of water by 1degree celsius.

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36
Q

Why is it important that water has a high specific heat capacity?

A

This is extremely useful for organisms, helping them to avoid rapid changes in their internal temperature and enabling them to maintain a steady temperature even when the temperature of their surrounding varies considerably. This also means that bodies of water in which aquatic organisms live do not change temperature rapidly.

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37
Q

What is the heart made up of?

A

Cardiac muscle

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38
Q

What is the similarities between veins and arteries?

A

The walls of both vessels contain collagen, a tough fibrous protein, which makes them strong and durable. They also contain elastic fibres that allow them to stretch and recoil. Smooth muscle cells in the walls allows them to constrict and dilate.

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39
Q

What are the key differences between arteries and veins?

A
  • Arteries have a narrow lumen whereas veins have a wide Lumen.
  • Arteries have thicker walls than veins
  • Arteries have more smooth muscle, collagen and elastic fibres
  • Arteries have no valves whereas veins have valves
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40
Q

How does blood move through the arteries?

A

Once systole has occurred, blood is forced into the arteries and the elastic walls stretch to withstand the high pressure. During diastole, the elasticity of the artery walls causes them to recoil behind the blood which helps push the blood forwards.

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41
Q

How does blood move through the arterioles and capillaries?

A

Blood flows more slowly in the capillaries due to their narrow lumen causing more of the blood to be slowed down by friction against the capillary wall. The slower steady flow allows exchange between the blood and the surrounding cells through one cell thick capillary walls. The network of capillaries that lies close to every cell ensures that there is rapid diffusion between the blood and surrounding cells.

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42
Q

How does blood flow through the veins?

A

Blood flows steadily and without pulses in veins where it is under relatively low pressure. In the veins blood flow is assisted by the contraction of skeletal muscle during the movement of limbs and breathing. Low pressure developed in the thorax when breathing in also helps draw blood back into the heart from the veins. Backflow is prevented by pocket valves within the veins.

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43
Q

How is the heart muscle itself provided with a fresh supply of blood?

A

Fresh blood containing oxygen and glucose travels through the coronary arteries (2) to supply the heart and leaves through the two coronary veins.

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44
Q

Describe the cardiac cycle

A

1) (Atrial diastole) Atria fill with blood while the atrioventricular valves are closed.
2) The atrioventricular valves are pushed open by rising blood pressure and the ventricles start to fill with blood. During this time the semilunar valves are closed.
3) The atrial contract forcing remaining blood down into the ventricles.
4) The ventricles contract and atrioventricular valves close. Ventricular contraction forces open semi lunar valves, so that blood is ejected into pulmonary artery and aorta.

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45
Q

What is the lub dub sound made by?

A

Lub - Closing of the atrioventricular valves

Dub - Closing of the semilunar valves

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46
Q

What is atherosclerosis?

A

A disease process that leads to coronary heart disease and strokes.

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47
Q

What can atherosclerosis cause?

A
  • Heart attack (myocardial infarction) it is occurs in the coronary artery.
  • Gangrene and tissue death because of narrowing of the arteries in the legs
  • Arteries can burst because of the blockage
  • A stroke can occur if the blood supply to the brain is restricted or blocked.
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48
Q

How can atheroma lead to atherosclerosis?

A

Atheroma can either block an artery directly or increase its chance of being blocked by a blood clot (thrombosis)

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49
Q

Describe the process of atherosclerosis.

A

1) Endothelium becomes damaged and dysfunctional for some reason.
2) Once the inner lining of the artery is breached there is an inflammatory responses (swelling) white blood vessels move from the bloodstream to the artery wall where they accumulate chemicals from the blood (E.G. particularly cholesterol). Atheroma builds up.
3) On the inner wall of the artery, plaque builds up (hard swelling) as calcium salts and fibrous tissue build up at the site. The fibrous tissue causes a hard swelling because the artery wall loses some of its elasticity.
4) Plaque cause lumen to become narrower making it difficult for the heart to pump blood around the body which can lead to a rise in blood pressure (positive feedback).

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50
Q

What is the endothelium?

A

A delicate layer of cells that lines the inside of an artery and separates the blood that flows in the artery from the muscular wall.

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51
Q

What is an inflammatory response?

A

Damaged cells release chemicals that cause blood vessels to leak fluids into the tissue to cause swelling.

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52
Q

What is cholesterol?

A

A type of fat found in your blood. You need some to be healthy (to help the brain, skin and organs grow) but to much can promote heart attacks and strokes (atherosclerosis).

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53
Q

What is plaque?

A

A semi hardened accumulation of substances from fluids that bath an area.

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54
Q

Why do only arteries get atherosclerosis?

A

The fast flowing blood in the arteries is under high pressure so there is significant chance of damage to the walls. The low pressure in the veins means that there is less risk risk of damage to the walls.

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55
Q

Why does blood clot in arteries?

A

Rapid blood clotting is vital when a blood vessel is damaged. Blood clots seal a break in the blood vessel which limits blood loss and prevents the entry of pathogens.

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56
Q

When is the clotting cascade triggered?

A

Direct contact of blood with collagen within the damaged blood vessel wall triggers a series of complex chemical changes.

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57
Q

Describe the clotting cascade.

A

1) Platelets and damaged tissue release a protein called thromboplastin.
2) Thromboplastin activates an enzyme that catalyses the conversion of the protein prothrombin into an enzyme called thrombin. A number of other protein factors,vitamin K and calcium ions must be present in blood plasma for this conversion to happen.
3) Thrombin catalyses the conversion of the soluble plasma protein, fibrinogen into the insoluble protein fibrin.
4) A mesh of fibrils forms that traps more platelets(Platelets change shape from a flattened disc to a sphere with a long thin projection, sticking to exposed collagen) and blood cells to form a clot.

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58
Q

How can atherosclerosis lead to a coronary heart attack?

A

Narrowing of the coronary arteries limits the amount of oxygen rich blood reaching the heart muscle. If a fatty plaque in the coronary artery ruptures (maybe during exercise when the heart is having to work hard) collagen is exposed leading to a rapid blood clot. The blood to the heart might become completely blocked (ischaemic) and if the affected muscle is starved for too long there will be permanent damage. The large the zone of dead muscle cells the higher the fatality.

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59
Q

What are the symptoms for coronary disease?

A
  • Shortness of breath and angina (First signs)
  • Feeling heaviness, tightness, pain, burning and pressure usually behind breastbone but sometimes in the jaw, arm or neck
  • Women may not have chest pain but may experience unusual fatigue, shortness of breath and indigestion
  • Irregular heart beat (Arrhythmia)
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60
Q

What are the symptoms of a stroke?

A

They appear suddenly:

  • Numbness
  • Dizziness
  • Confusion
  • Slurred speech
  • blurred or lost vision, often only in one eye
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61
Q

Where and why can an aneurysm build up?

A

If a part of an artery has narrowed and become less flexible, blood can build up behind it. The artery bulges as it fills with blood and an aneurysm forms.

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62
Q

How does an aneurysm kill you?

A

Once they burst, the blood lose is often fatal.

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63
Q

What is a risk?

A

The probability of occurrence of some unwanted event or outcome.

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64
Q

When measuring a risk, what must you always quote?

A

A time period.

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65
Q

What factors contribute to health risks?

A
  • Age
  • Heredity
  • Physical environment
  • Social environment
  • Lifestyle and behavioural choices
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66
Q

What are cohort studies? What type of study is it?

A

They follow a large group of people overtime to see who develops the disease and who does not. The type of study is a prospective as at the start none of the participants have the disease.

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67
Q

What is a case-control study? What type of studies are these?

A

A group of people with a disease are compared to a control group of individuals who do not have the disease. Information is collected about the risk factors that have been exposed in the past, allowing factors that may have contributed to the development of the disease to be identified. These type of studies are retrospective. Will only have validity if the two groups are matched for other factors such as age and gender.

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68
Q

In the cohort study the two choices of study are what?

A
  • You have one population and you compare exposure to risk factors, look for correlations and draw conclusions between the group that developed the condition and the group that didn’t.
  • You have two population a group that is exposed to risks and a group that is not exposed to risk factors, then outcomes are compared between the four end groups.
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69
Q

In a case-control study, you have two groups what do you do with them?

A

Take histories of exposure to risk factors in past, compare, look for correlations and draw conclusions.

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70
Q

When conducting a good study, what are the key features?

A
  • Clear aim - Design of study must aid this, producing results that are valid and reliable
  • Representative sample - Must be selected from the wider population that the study’s conclusions will be applied to.
  • Valid and reliable results - Any method used must produce valid results and must be reliable. Results that measure what its supposed to measure.
  • Sample size - Must be large enough to produce results that could not have occurred by chance.
  • Controlling variables - potential effect of variables that could be correlated with the disease should be considered when designing the study.
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71
Q

What are the risk factors for Cardiovascular diseases?

A
  • High blood pressure
  • Obesity
  • Blood cholesterol and other dietary factors
  • Smoking
  • Inactivity
  • Genetic inheritance
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72
Q

What is hypertension?

A

Elevated blood pressure

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73
Q

What is blood pressure?

A

It is the measure of the hydrostatic force of the blood against the walls of a blood vessel.

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74
Q

Where is blood pressure the highest?

A

The pressure is highest in an artery during the phase of the cardiac cycle when the ventricles have contracted and forced blood into the arteries (systolic pressure).

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75
Q

What is systolic pressure?

A

It is blood pressure during the systolic phase of the cardiac cycle. It is when the ventricles have contracted and forced the blood into the arteries.

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76
Q

What is the diastolic pressure?

A

Blood pressure during the diastolic phase of the heart (relaxation). When the ventricles are relaxed.

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77
Q

What is a sphygmomanometer?

A

A traditional device used to measure blood pressure.

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78
Q

What are the units for blood pressure?

A

MmHg (millimetres of mercury)

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79
Q

What is peripheral resistance?

A

Contact between blood and the walls of the blood vessels causes friction and this impedes the flow of blood.

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80
Q

When vessels constrict what happens regarding blood pressure? Why?

A

This makes the lumen narrower and increases resistance. In turn blood pressure increases, this is because there is the same volume of blood in a smaller space.

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81
Q

What is one sign of a high blood pressure?

A

Oedema

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82
Q

What is oedema?

A

Fluid building up in tissues and causing swelling. Oedema may also be associated with kidney or liver disease, or with restricted body movement.

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83
Q

How does tissue fluid build up and where does it get deposited?

A

AT the arterial end of a capillary, blood is under pressure. This forces fluid and small molecules normally found in plasma out through tiny gaps between the cells of the capillary wall into the intercellular space, forming tissue fluid. Blood cells and larger plasma proteins stay inside the capillary; their larger size prevents them passing through the gaps in the capillary wall. The tissue fluid drains into a network of lymph capillaries which returns the fluid to the blood via a lymph vessel which empties it into the vena cava. If blood pressure rises above normal, more fluid may be forced out of the capillaries. In such circumstances, fluid accumulates within the tissue causing oedema.

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84
Q

What is tissue fluid also known as?

A

Interstitial fluid

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85
Q

Which out of carbohydrates, proteins and lipids provide the most energy? (In order)

A

Lipids, Protein, Carbohydrates

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86
Q

What does carbohydrate mean?

A

Hydrated carbon

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87
Q

Which group are sugar and starch in?

A

Carbohydrates

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88
Q

What is the carbohydrate general formula?

A

Cx(H20)n

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89
Q

Sugars are either?

A
  • Monosaccharides
  • Disaccharides
  • Polysaccharides
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90
Q

What is a monosaccharide?

A

Single sugar units

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91
Q

What is the general formula of a monosaccharide?

A

(CH2O)n where n is the number of carbon atoms in the molecule

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92
Q

Monosaccharides have between … and … carbon atoms?

A

Three and seven

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93
Q

What is the most common number of carbon atoms in a monosaccharide?

A

6

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94
Q

Name three monosaccharides?

A
  • Glucose
  • Galactose
  • Fructose
95
Q

What are glucose, galactose and fructose also known as?

A

Hexose sugars

96
Q

Describe the structure of a hexose sugar?

A

Has a ring structure formed by 5 carbons and an oxygen atom; the sixth carbon projects above or below the ring.

97
Q

When we eat monosaccharides regarding digestion, do they take a while to be digested?

A

No monosaccharides are readily absorbed an require little or no change before being used in cellular respiration this is because of their small size.

98
Q

What do monosaccharides provide when consumed?

A

A rapid source of energy causing a sharp rise in blood sugar.

99
Q

How do we get glucose?

A

From starch and glycogen which are polymers made up of glucose.

100
Q

How do we get galactose?

A

Occurs in our diet from the disaccharide sugar lactose.

101
Q

How do we get fructose?

A

Is a sugar that occurs naturally in fruit, honey and some vegetables.

102
Q

What is a disaccharide?

A

Two monosaccharides joined together by a glycosidic bond in a condensation reaction which releases water as the two sugar molecules combine in the reaction.

103
Q

What is the bond that forms between two sugar units?

A

Glycosidic bond

104
Q

What four atoms make up all organisms?

A

Hydrogen, carbon, oxygen and nitrogen

105
Q

What is a condensation reaction?

A

The process of joining to small molecules together to form a more complex molecule. Water is released when the two molecules joint together.

106
Q

What is a hydrolysis reaction?

A

It is a reaction that splits a complex molecule into a smaller molecule by the addition of water.

107
Q

What is a 1-4 glycosidic bond?

A

When a bond forms between Carbon 1 on one molecule and Carbon 4 on the other.

108
Q

What is a polysaccharide?

A

Are polymers made up from simple sugar molecules joined by glycosidic bonds into long chains. Each sugar monomer is joined into the chain in a condensation reaction with a water molecule released during the reaction.

109
Q

Name three main disaccharides

A

Sucrose
Maltose
Lactose

110
Q

What is sucrose made up of?

A

Glucose and fructose

111
Q

What is maltose made up of?

A

Two glucose molecules

112
Q

What is lactose made up of?

A

Galactose and glucose

113
Q

How can a glycosidic bond between two sugar units in a disaccharide be split?

A

By hydrolysis which is the addition of water.

114
Q

When does the hydrolysis of disaccharides occur?

A

When carbohydrates are digested in the gut and when carbohydrate stores in a cell are broken down to release sugars.

115
Q

What happens when disaccharides and polysaccharides are eaten?

A

They have to be digested into monosaccharides before being absorbed, which takes some time, so the monosaccharides are released more slowly therefore eating complex carbohydrates does not cause the swings in the blood sugar levels like when eating monosaccharides.

116
Q

What are three main types of polysaccharides found in food?

A

Starch, cellulose and glycogen

117
Q

Why are starch and glycogen effective storage molecules?

A

They are compact because of their spiral shape that holds the atoms close together. They have a low solubility in water which mean they do not affect the concentration of water in the cytoplasm and so do not affect the movement of water into or out of the cell by osmosis.

118
Q

What is starch made up of?

A

A mixture of amylose and amylopectin

119
Q

Describe the properties of amylose?

A

Is composed of a straight chain of between 200 and 5000 glucose molecules with 1,4 glycosidic bonds between adjacent glucose molecules. The position of the bonds cause the chain to coil into a spiral shape.

120
Q

What is the structure of amylopectin?

A

Polymer of glucose but it has side branches. A 1,6 glycosidic link holds each side branch to the main chain.

121
Q

What’s good about glycogen?

A

It has numerous side branches which can be rapidly hydrolysed for energy, giving easy access to stored energy.

122
Q

Where is glycogen stored in humans?

A

The liver and muscles

123
Q

What are lipids?

A

It is the general term for fats and oils.

124
Q

What is the benefit of lipids?

A

Large amounts of energy can be consumed in a small mass of food.

125
Q

What are triglycerides?

A

A triglyceride is a lipid. It is made up from a molecule of glycerol joined to three fatty acid molecules.

126
Q

What is the bond that forms between each fatty acid and the glycerol?

A

Ester bond

127
Q

In a triglyceride how many ester bonds are there?

A

Three

128
Q

What is a saturated fat?

A

A fatty acid with no double bonds present in its hydrocarbon chain and the lipid chain contains the maximum amount of hydrogen atoms is called a saturated fatty acid.

129
Q

What is the shape of a saturated fat?

A

The hydrocarbon chain is long and straight.

130
Q

Can extra hydrogens be added to a saturated fat?

A

No more hydrogens can be added because it is saturated containing the maximum amount of hydrogen atoms with no double bonds.

131
Q

What are the major sources of saturated fats?

A

Animal fats from meat and dairy products are major sources of saturated fats.

132
Q

Why are saturated fats solid at room temperature?

A

Saturated hydrocarbon chains pack closely together. The strong intermolecular bonds between triglycerides made up of saturated fatty acids results in fats that are solid at room temperature.

133
Q

What are the different types of unsaturated fats?

A

Monounsaturated and polyunsaturated

134
Q

What is the difference between monounsaturated fats and polyunsaturated fats?

A

Monounsaturated fats have only one double bond between two of the carbon atoms in each fatty acid chain whereas polyunsaturated fats have a larger number of double bonds.

135
Q

Why are unsaturated fats oils at room temperature?

A

Unsaturated fats contain double bonds and double bonds causes a kink in the hydrocarbon chain. These kinks prevent the unsaturated hydrocarbon chains from packing closely together. Increasing the distance between the molecules weakens the intermolecular forces between unsaturated triglycerides resulting in oils that are liquid at room temperature.

136
Q

What is a monounsaturated fat?

A

A fatty acid with one double bond present in its hydrocarbon chain is a mono-unsaturated fatty acid.

137
Q

What is a polyunsaturated fat?

A

A fatty acid with more than one double bond present in its hydrocarbon chain is a polyunsaturated fatty acid.

138
Q

What is a good source of monounsaturated fats?

A

Olive oil

139
Q

What is a good source of polyunsaturated fats?

A

Most vegetable oils, nuts and fish

140
Q

How can you make an unsaturated fat solid at room temperature?

A

By adding hydrogen to the double bonds making them saturated.

141
Q

How is cholesterol made?

A

Is made in the liver from saturated fats and we also acquire it in our diet.

142
Q

What is an essential fatty acid?

A

A fatty acid that is essential for growth and which the body is unable to make.

143
Q

What is a basal metabolic rate?

A

The metabolic rate of a person who is completely at rest but not asleep. It is a measure of the energy required for activities that go on all the time.

144
Q

What people have higher BMR’s?

A
  • Males
  • Heavier people
  • Younger people
  • More active people
145
Q

If you have a balanced input you will be ?

A

A normal weight

146
Q

If you have an unbalanced energy intake to energy used, you will be?

A

Either overweight if your energy intake is higher or underweight if you energy used is higher

147
Q

What is obesity?

A

A person is obese if they are overweight to the extent that there are substantial health risks associated with this.

148
Q

Define Body Mass Index (BMI)?

A

A figure used to describe a person’s body mass relative to height.

149
Q

How do you calculate BMI?

A

BMI=body mass kg/ height m2

150
Q

What is a better measurement than BMI?

A

Waist-to-hip ratio

151
Q

What is the consequence of obesity?

A

Obesity increases the risk of coronary heart disease and stroke. The more excess fat you carry, especially around your middle, the greater the risk to your heart. Obesity can be greatly increase your risk of type II diabetes which in turn increases your chance of coronary heart diseases and stroke.

152
Q

What is type 1 diabetes?

A

Occurs when the body is unable to make insulin.

153
Q

What is type II diabetes?

A

The body either does not produce sufficient insulin or the body fails to respond to the insulin that is produced.

154
Q

What is insulin and why is diabetes bad?

A

Insulin is a hormone that helps reduce blood glucose levels. After the consumption of food, insulin is produced by the pancreas and released into the bloodstream where it absorbs the glucose and returns the blood glucose level to normal. If you have type II diabetes caused by frequent consumption of sugar-rich foods it means you have reduced the sensitivity of cells to insulin resulting high blood sugar levels.

155
Q

How is cholesterol transported around the body?

A

In order to be transported in the bloodstream, insoluble cholesterol is combined with proteins to form soluble lipoproteins.

156
Q

What are lipoproteins?

A

An association between proteins and lipid molecules such as cholesterol and triglycerides. Lipoproteins are found in blood plasma and in lymph where they play an important part in the transport of lipids.

157
Q

What are the two types of lipoproteins?

A

High-density lipoproteins and Low-density lipoproteins

158
Q

What fats make HDL’s?

A

Unsaturated fats

159
Q

What fats make LDL’s?

A

Saturated fats

160
Q

What do HDL’s do?

A

They transport cholesterol from the body tissues to the liver where it gets broken down. This lowers blood cholesterol levels and helps remove the fatty plaques of atherosclerosis.

161
Q

In HDL’s what percentage is higher protein or cholesterol?

A

HDLs have a higher percentage of protein and less cholesterol compared to LDLs, hence higher density.

162
Q

What are lipoproteins made up of?

A

Triglycerides from fats and cholesterol and protein

163
Q

What do LDLs do?

A

They circulate in the bloodstream and bind to receptor sites on cell membranes before being taken up by the cells where the cholesterol is involved in synthesis and maintenance of cell membranes.

164
Q

What is the problem with LDLs?

A

Excess LDLs overload these membrane receptors, resulting in high blood cholesterol levels. This LDL cholesterol may be deposited in the artery wall forming atheroma.

165
Q

To keep healthy, what is desirable regarding the amount of HDLs and LDLs?

A

LDLs are associated with the formation of atherosclerotic plaques whereas HDLs reduce blood cholesterol deposition. Therefore it is desirable to maintain a higher level of HDLs and a lower level of LDLs.

166
Q

What is healthier saturated or unsaturated fats?

A

Unsaturated fats are healthier as they make HDLs which are the good cholesterol.

167
Q

Why does smoking increase you risk of CHD? (4 points)

A
  • Carbon monoxide binds to haemoglobin which reduces the supply of oxygen to the cells. This results in an increased heart rate as the body reacts to provide enough oxygen for the cells.
  • Nicotine, stimulates the production of the hormone adrenaline which causes an increased heart rate and causes arteries and arterioles to constrict -> raising blood pressure.
  • Chemicals found in smoke damage lining in the arteries -> triggering atherosclerosis
  • Smoking has been linked with a reduction of HDL cholesterol level.
168
Q

Why can inactivity lead to CHD?

A

Moderate exercise helps prevent high blood pressure and can help lower it. Exercise not only maintains a healthy weight it also seems to raise HDL cholesterol levels without affecting the level of LDLs.

169
Q

Give an example of an inherited disease which can increase the chances of you suffering from CHD

A

In familial hypercholesterolaemia, mutations in the LDLR gene cause the LDL receptors, involved in the removal of LDL from the blood, not to form or to have a shape that makes them less efficient. This results in high blood LDL levels

170
Q

Which protein does Apolipoprotein A code for?

A

Major protein in HDL

171
Q

What is the function of Apolipoprotein A?

A

Helps in the removal of cholesterol to the liver for excretion.

172
Q

How could a mutation of Apolipoprotein A increase your risk of CHD?

A

Mutations in the APOA are associated with low levels of HDL and reduced removal of cholesterol from the blood. This causes an increased risk of CHD as there are higher levels of cholesterol in the blood which can build up as atheroma leading to atherosclerosis.

173
Q

Which protein does Apolipoprotein B code for?

A

Main protein in LDLs

174
Q

What is the function of Apolipoprotein B ?

A

The molecule that transfers cholesterol from the blood to the cells.

175
Q

How could a mutations in Apolipoprotein B increase your risk of CHD?

A

Mutations of the APOB gene results in higher levels of LDLs in the blood and a higher susceptibility to CVD.

176
Q

Which protein does Apolipoprotein E code for?

A

Major component of HDLs and VLDLs (Very low density-lipoproteins)

177
Q

What is the function of Apolipoprotein E?

A

Involved in the removal of excess cholesterol from the blood to the liver.

178
Q

How could a mutation of Apolipoprotein E increase your risk of CHD?

A

The APOE contains three main alleles, producing three forms of protein E2, E3 and E4. APOE4 slows the removal of cholesterol from the blood and therefore having the E4 allele may increase your risk of coronary heart diseases.

179
Q

Why is CHD multifactorial?

A

Because heredity, the physical environment, the social environment environment and lifestyle behavioural choices all contribute to the risk.

180
Q

How can the lack of antioxidants increase your chance of CHD?

A

Antioxidants bind to free radicals (atom that has an unpaired electron) to stop them from oxidising with cells and enzymes. Antioxidants stop free radicals to stop them reacting with cells.

181
Q

How can high levels of salt increase your risk of CHD?

A

With more salt more water enters your blood which means there is a greater volume of blood in the same space therefore increasing blood pressure. With high blood pressure there is a higher chance of damage to the blood vessels causing atherosclerosis. People are eating too much salt because of its high level in processed foods.

182
Q

How can stress increase your risk of CHD?

A

Adrenaline and cortisol released which causes the blood vessels to narrow which increase blood pressure and therefore increasing risk of damage to blood vessels causing atherosclerosis.

183
Q

How can alcohol increase your risk of CHD?

A

Liver is responsible for cleaning our blood by breaking down cholesterol and by removing toxins. If large quantities of alcohol are drank, liver can become damaged which leads to unclean blood. Unclean blood increases the chance of plaque deposition.

184
Q

What ways can the risk of cardiovascular disease be decreased?

A
  • Stop smoking
  • Maintaining a resting blood pressure below 140/85
  • Maintaining low blood cholesterol level
  • Maintaining a normal BMI/low waist-to-hip ratio
  • Taking regular physical activity
  • Moderate or no use of alcohol
  • Reduce stress
185
Q

Name some drugs that control blood pressure (6)

A
  • ACE inhibitors
  • Calcium channel blockers
  • Diuretics
  • Statins
  • Platelet inhibitors
  • Anticoagulants
186
Q

What is the effect of ACE inhibitors?

A

They are effective anti-hypertension drugs which reduce the synthesis of angiotensin II.

187
Q

How do ACE inhibitors work?

A

Angiotensin II causes vasoconstriction of blood vessels to help control blood pressure. ACE inhibitors prevent the hormone being produced, therefore reducing vasoconstriction and lowering pressure.

188
Q

Name three side effects of taking ACE inhibitors? (4)

A
  • Dry cough
  • Dizziness - caused by rapid lowering of blood pressure
  • Abnormal heart rhythm.
  • Reduction in kidney function
189
Q

What is the effect of calcium channel blockers?

A

Anti-hypertension drugs that reduce blood pressure by preventing construction.

190
Q

How do calcium channel blockers work?

A

Block the calcium channel in the muscle cells in the lining of arteries. The blood vessel does not constrict because of the lack of calcium.

191
Q

What are side effects of taking calcium channel blockers? (3)

A
  • Dizziness
  • Headaches
  • Swollen ankles
192
Q

What is the effect of diuretics?

A

They increase the volume of urine produced by the kidneys, therefore rid the body of excess fluids and salt.

193
Q

How do diuretics work?

A

Leads to a decrease in blood plasma volume and cardiac output -> lowers blood pressure.

194
Q

What are the side effects of taking diuretics?

A
  • Dizziness
  • Nausea
  • Muscle cramps
195
Q

What is the effect of taking statins?

A

They inhibit an enzyme involved in the production of LDL cholesterol by the liver.

196
Q

How do statins work?

A

LDLs (too much of them) cause receptors to be blocked once cells have been full up. This means they build up the arteries leading to atherosclerosis. Lack of production of the enzyme decreases chance of atherosclerosis as less LDLs are made.

197
Q

What are the side effects of taking statins? (3)

A
  • Tiredness and disturbed sleep
  • Feeling sick/vomiting/diarrhoea
  • Headaches
198
Q

What is the effect of platelet inhibitors?

A

Reduces the platelet aggregation and clotting

199
Q

How do platelet inhibitors work?

A

They reduce the stickiness of platelets and the likelihood of clot formation.

200
Q

What is the side effect of taking platelet inhibitors?

A

-Internal bleeding

201
Q

What is the effect of anticoagulants?

A

Reduces the platelet aggregation and clotting.

202
Q

How do anticoagulants work?

A

Interferes with the production of vitamin K and therefore affects the clotting synthesis as vitamin K is a co-factors needed for clotting to occur.

203
Q

What is the side effect of taking anticoagulants?

A

-Risk of internal bleeding

204
Q

What would be a good diet to reduce the risk of cardiovascular disease?

A
  • Energy balanced
  • Reduced saturated fats
  • More polyunsaturated fats
  • Reduced cholesterol
  • Reduced salts
  • More non-starch polysaccharides, such as pectins and guar gum.
  • Includes oily fish
  • More fruit and vegetables
205
Q

Why is it good to have reduced saturated fats in your diet and more polyunsaturated fats?

A

Saturated fats make LDLs which are the bad lipoproteins whereas polyunsaturated fats make HDLs which are the good cholesterol that are broken down easily.

206
Q

Why is it good that you having reduced cholesterol in your diet?

A

High levels of cholesterol build up as atheroma in your blood vessels causing atherosclerosis

207
Q

Why is good to have reduced salt in your diet?

A

High levels of salt in your diet mean that blood volume is high because water is attracted to the salt in your blood. This high volume causes a high blood pressure.

208
Q

Why is it good to have more non starch polysaccharides in your diet?

A

These polysaccharides, known as soluble fibre, have been found to lower blood cholesterol. They are only partially digested, forming a gel that traps the cholesterol and prevents its absorption.

209
Q

What re oily fish healthy to eat?

A

They contain omega-3 fatty acids which is a group of polyunsaturated fatty acids with their first double bond between the third and fourth carbon atoms. These are essential for cell functioning and have been linked to a reduction in heart disease and joint inflammation.

210
Q

Why is it important that you eat lots of fruit and vegetables?

A

Fruits and vegetables contain antioxidants and often non-starch polysaccharides.

211
Q

Regarding volume to surface area what do small organisms have? What does this mean for an organism?

A

A high surface area to volume ratio. This means substances and water can enter and leave by diffusion or osmosis.

212
Q

Regarding volume to surface area what do large organisms have?

A

They have a smaller surface area to volume ratio.

213
Q

What make water the perfect solvent?

A
  • Water is a polar molecule
  • Water is liquid at room temperature
  • Water easily dissolves molecules held together by ionic bonds
214
Q

Describe the structure of arteries.

A
  • Relatively thick wall
  • Smooth muscle
  • Elastic fibres
  • Lined smooth layer of endothelial cella
  • Narrow lumen
215
Q

What is the structure of capillaries?

A

Very thin wall only one cell thick.

216
Q

Describe the structure of veins.

A
  • Relatively thin wall
  • Very little smooth muscle or elastic fibres
  • Wide lumen
  • Valves
217
Q

Why do arteries have a thick wall?

A

To withstand high blood pressure

218
Q

Why do arteries have smooth muscle?

A

It alters the diameter of the lumen to vary blood flow

219
Q

Why do arteries have elastic fibres?

A

They allow walls to stretch when blood is pumped into the artery and then recoil, smoothening blood flow.

220
Q

What do the lined layer of epithelial cells in the arteries help to do?

A

They are a low friction surface to ease blood flow.

221
Q

Why are the capillaries walls only one cell thick?

A

To allow rapid diffusion between blood and tissues.

222
Q

Why are the veins walls relatively thin?

A

The blood in the veins is under low pressure

223
Q

Why is there very little smooth muscle or elastic fibres in the veins?

A

There is no pulse of blood so no stretching and recoiling.

224
Q

Why do the veins have a wide lumen?

A

Large volume acts as a blood reservoir

225
Q

Why are valves present in veins?

A

To prevent the back flow of blood

226
Q

Explain why the mammalian heart has two sides?

A

Two sides allow oxygenated and deoxygenated blood to stay separate, which allows as much oxygen as possible to be carried to the cells. Having two sides allows a different amount of muscle on each side, so that there can be a higher pressure on one side (pumping to the body) compared to the other (pumping blood to the lungs).

227
Q

What are the health effects of atheroma?

A
  • Increased blood pressure, which can damage the kidneys and retina and cause strokes
  • Aneurysms, where the increased pressure of blood caused by the blockage can lead to the bursting of an artery and internal bleeding.
  • Angina, chest pain often felt during exercise, caused by reduced flow to heart due to narrowing of coronary arteries
  • Heart attack, when a coronary artery becomes totally blocked, usually a clot, and a part of the heart is starved of oxygen and dies
  • Stroke, an interruption to the blood supply of the brain which can cause paralysis or even death.
228
Q

Which has more 1,6 glycosidic bonds, amylopectin or glycogen?

A

Glycogen as it is more branched

229
Q

What are the similarities of glycogen and starch?

A
  • Both have spirals
  • Both polymers of glucose
  • Both have glycosidic bonds
  • Both insoluble
  • Both contain 1,6 glycosidic bonds
230
Q

What are the differences between glycogen and starch?

A
  • More branches (glycogen)
  • Hydrolysed quicker (glycogen)
  • Glycogen is less compact
231
Q

What are the advantages of cohort studies?

A
  • You are able to control the study e.g tell people to monitor what they eat.
  • More reliable
232
Q

What are the disadvantages of cohort studies?

A

-You need a very large group

233
Q

What are the advantages of case control studies?

A

-You are choosing the people who have it (therefore more evidence as they all have it)

234
Q

What are the disadvantages of case control studies?

A
  • Less reliable as you are asking people about the past which often they can’t remember.
  • Not always true -> people may lie, e.g how much alcohol did you drink in this period

Biology AS Level (4 decks)

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