Term
| Explain why many animals have a heart and circulation (mass transport to overcome limitations of diffusion in meeting the requirements of organisms). (Activity 1.2) |
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Definition
| Small organisms can survive by oxygen and carbon dioxide etc. diffusing in and out of them. However, larger animals which have a low surface area to volume ratio will need a circulatory system to circulate these substances with in their body. |
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Term
| Explain the importance of water as a solvent in transport, including its dipole nature. (Activity 1.5) |
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Definition
| Water is a polar molecule. This is beneficial in many ways. Firstly, it means that water is a liquid at normal temperatures. Secondly, many chemicals dissolve easily in water making them easy to transport. Thirdly, the specific heat capacity is high, taking 42000 Joules to heat one cm3 of water 1oC. This maintains a constant body temperature. |
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Term
| Explain how the structures of blood vessels (capillaries, arteries and veins) relate to their functions. (Activity 1.6) |
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Definition
Arteries carry blood away from the heart. This blood is under high pressure so the walls must be thick, with lots of muscle and elastic fibre, and the lumen must be narrow.
Veins carry blood under low pressure to the heart. The Veins have a wide lumen and less muscle and elastic tissue than an artery.
Cappillaries only have one cell thick walls with a very small lumen, just wide enough for red blood cells to travel down. The capillaries are designed for the exchange of chemicals through the walls by diffusion. |
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Term
| Describe the Cardiac cycle (atrial systole, ventricular systole and diastole). (Activity 1.7) |
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Definition
| Firstly, blood is pumped out of the atrium and into the ventrical. During this step, there is high pressure in the atrium, thus the name Atrial Systole. Then the Ventricles contract pushing blood out into the body. At this step, there is high pressure in the ventricles thus the name Ventricular Systole. Finally, both chaimbers of the heart relax and blood is sucked into the chaimbers. Because the heart relaxes, this step is called Diastole. |
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Term
| Relate the structure and operation of the mammalian heart to its function, including the major blood vessels. (Activities 1.3 and 1.4) |
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Definition
| The right side of the heart pumps blood to the lungs whilst the left side of the heart pumps blood to the rest of the body. If the blood starts by coming into the right atrium via the vena cava, it is deoxygenated. It is then pumped into the right ventricle and then pumped out of the heart and into the lungs via the pulmonary artery where it is oxyginated. Then the blood flows back to the heart via the pulmanory vein, into the left atrium, where it is pumped into the left ventricle and pumped to the rest of the body via the aorta. The left ventricle has the thickest wall as it has to pump blood all the way through out the body... |
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Term
| Explain the course of events that leads to atherosclerosis (endothelial damage, inflammatory response, plaque formation, raised blood pressure). (Activity 1.8) |
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Definition
| Firstly, there is damage to the endothelium. This causes an inflamatory response. White blood cells and cholesterol move into the wall of the blood vessel. This deposit is called an atheroma. Calcium salts and fibrous tissue build up causing the atheroma to go hard and to form a plaque. The blood vessel is now much narrower, increasing the blood pressure. The blood pressure could then cause another atheroma. This is positive feedback in effect. |
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Term
| Describe the blood clotting process (thromboplastin release, conversion of prothrombin to thrombin and fibrinogen to fibrin) and its role in cardiovascular disease (CVD). (Activity 1.8) |
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Definition
| When blood comes into contact with collagen, thromboplastin is released from the damaged tissue and platelets. This converst Prothrombin into Thrombin. Thrombin then converts soluble fibrinogen into insoluble fibrin. If there is already an atheroma in the place where are clott forms, the artery may be thin enough for the clott to completely stop the blood flow, thus preventing oxygenated blood from providing cells with oxygen - possibly killing them. This is CVD. |
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Term
| Analyse and interpret quantitative data on illness and mortality rates to determine health risks (including distinguishing between correlation and causation and recognising conflicting evidence). (Activity 1.9) |
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Definition
Correlation - when an increase in one thing is accompanied by an increase in another (positive). (e.g. the length of a TV programme and the percentage of the class asleep)
Causation - a change in one variable is responsible for a change in the other. (e.g. its not the length of the TV programme but the fact that they did not get enough sleep which accounts for the percentage of children asleep). |
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Term
| Explain why people's perceptions of risks are often different from the actual risks (including underestimating and overestimating the risks due to diet and other lifestyle factors in the development of heart disease). (Activity 1.9) |
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Definition
| People tend to overestimate the risks if something is involuntary, not natural, unfamiliar, dreaded, unfair or very small. Sometimes if the risk is far off into the future - like a heart attack - one will underestimate the chance of it happening. For example few people bother about the fact that smoking NOW will affect their health in the FUTURE. |
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Term
| Evaluate design of studies used to determine health risk factors (including sample selection and sample size used to collect data that is both valid and reliable). (Activity 1.10) |
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Definition
Cohort studies - a group of people are followed over time to see who develops the disease.
Case-control studies - a group of people who have the disease are compared with a group of people who do not have the disease. (the groups's history is observed...)
A good study should have a clear aim, a representative sample and valid and reliable results. |
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Term
| Describe the factors that increase the risk of CVD (genetic, diet, age, gender, high blood pressure, smoking and inactivity). (Age and Gender Activity 1.11. Genetic Inheritance Activity 1.19. Blood Pressure Activities 1.12, 1.13 and 1.22. Diet Activities 1.17 and 1.20) |
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Definition
| The main factors which increase the risks of CVD are a high blood pressure - high pressure could cause a break in the epithelial cells, obesity - large amounts of cholesterol and high blood pressure, blood cholesterol and other dietary factors, smoking - harmful toxins in teh blood, and genetic inheritance - genes which make you more likely to get CVD (maybe more likely to be obese or higher cholesterol). |
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Term
| Distinguish between monosaccharides, disaccarides and polysaccharides (glycogen and starch - amylose and amylopectin) and relate their structures to their roles in providing and storing energy (alpha-glucose and cellulose are not required in this topic). (Activity 1.14) |
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Definition
sugars and starch are composed of many single sugar units put together. One of these units is called a monosaccharide. Two are called a disaccharide. Three or more become a polysaccharide.
Starch (found in plants) is made up of polysaccharides in two main molecules - amylose and amylopectin. Amylose is a straight chain between 200 and 5000 glucose molecules with 1,4 glycosidic links. this forms a spiral. Amylopectin is also made of a chain of glucose but it has side branches. A 1,6 glycosidic link holds each protrusion onto the main chain.
Glycogen found in animals, bacteria and fungi is also a polymer of glucose. It has many side branches meaning it can be easily hydrolised giving easy access to stored energy. In humans, Glycogen is stored in the liver and muscles.
These chains of glucose are good for storing energy as they are compact, insoluble so they do not affect the concentration of water in cells. |
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Term
| Describe how monosaccharides join to form disaccharides (sucrose, lactose and maltose) and polysaccharides (glycogen and amylose) through condensation reactions forming glycosidic bonds, and how these can be split through hydrolysis reactions. (Activities 1.14 and 1.15) |
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Definition
Sucrose is formed from a glucose and fructose sugar.
Maltose is formed from two glucose sugars.
Lactose is formed from a galactose and glucose sugar.
The bond in Maltose is a 1,4 glycosidic link. It is know by this because the bond is made at its first and fourth carbon atom. An oxygen atom joins them and a water molecule is released thus the name of the reaction - condensation reaction. If water is added however, the disaccharide will break into two molecules of glucose again. This is called a hydrolysis reaction. |
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Term
| Describe the synthesis of triglyceride by the formation of ester bonds during condensation reactions between glycerol and three fatty acids and recognise differences between saturated and unsaturated lipids. (Activity 1.16) |
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Definition
Three fatty acids and one glycerol molecule make up one triglyceride molecule. The molecules bond with an ester bond again a condensation reaction. The bond is between an oxygen and carbon atom (the carbon has a double bond between an oxygen).
A saturated lipid has a chain of hydrocarbons which is saturated with hydrogen atoms. An unsaturated lipid however will have one or more double bonds between any of the carbon atoms meaning there are less hydrogen atoms in the hydrocarbon chain. As a saturated lipid's chain is straight they pack together well making the bonds between the molecules hard to break and therefore increasing their melting point (they are solid at room temp.). However, unsaturated lipids do not pack so well together as they have a kink where the carbon double bond is, thus lowering their melting point (they are liquid at room temp.). |
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Term
| Analyse data on energy budgets and diet so as to be able to discuss the consequences of energy imbalance, including weight loss, weight gain, and development of obesity. (Activity 1.17) |
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Definition
If energy input is equal with energy output a normal weight will be maintained. If your enery input is less than your energy output, you will lose weight and vice versa. Obesity would be the outcome if much more energy is continually consumed than the amount that is used up.
body mass/kg
***BMI= ------------
(height/m)^2 |
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Term
| Analyse and interpret data on the possible significance for health of blood cholestorol levels and levels of high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs). (Activity 1.18) |
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Definition
| HDLs can be thought of as the good cholesterol as a higher amount of this is good, where as LDLs are the cholesterol which is bad for you. LDL is the major component of cholesterol risk for CVD. |
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Term
| Describe the evidence for a causal relationship between blood cholesterol levels (total cholesterol and LDL cholesterol) and CVD. (Activity 1.18) |
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Definition
| Lots of studies done etc... |
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Term
| Describe how to investigate the Vit. C content of food and drink. (Activity 1.21) |
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Definition
| Juices titraited into a DCPIP solution till colour changes. find amount of Vit. C needed to change colour of DCPIP then you can find the amount in each fruit juice... |
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Term
| Describe how the effect of caffeine on heart rate in Daphnia can be investigated practically, and discuss whether there are ethical issues in the ues of invertebrates. (Activity 1.23) |
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Definition
| Daphnia put under microscope in slide with cotton wool and cirtain conc. of caffeine solution, then heart beats counted... |
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Term
| Discuss how people use scientific knowledge about the effects of diet (including obesity indicators), exercise and smoking to reduce their risk of coronary heart disease. (Activity 1.17 and 1.25) |
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Definition
| If it is known that a bad diet and smoking increase the risk of CHD, then people can have a good diet and not smoke, thus decreasing their risk of CHD. If exercise is know to decrease the risk of CHD more people can do it to reduce their risk. |
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Term
| Describe the benefits and risks of treatments for CVD (antihypertensives, plant statins, anticoagulants and platelet inhibitory drugs). |
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Definition
ACE inhibitors (antihypertensives) lower the blood pressure. Side effects - dizziness, dry cough, abnormal heart rhythms and a reduction in the function of the kidney.
Calcium channel blockers (antihypertensives) block calcium channels in the muscles lining the arteries. blood pressure lowers because muscles can't contract. Side effects - headaches, dizziness, swollen ankles, abnormal heart rhythms, flushing red and constipation. (these may make symptoms worse...)
Diuretics increase the volume of urine produced by the kidneys thus lowering the blood pressure. Side effects - dizziness, nausea or muscle cramps.
Anticoagulants - stop clood clotting therefore blood clott cannot block artery but this could cause internal haemorrhage.
Platelet inhibitory same sort of thing... stops platelets... |
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