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Edexcel Snab Topic 1
Lifestyles, Health and risk
| Question | Answer |
|---|---|
| What process do Amoeba's and flatworms carry out? | Diffusion |
| Suggest how gas exchange occurs in an amoeba. | Gas exchange occurs Membrane is thin,oxygen enters cell ,carbon dioxide leaves cell.{O2 / oxygen / CO2 / carbon dioxide} are {small / non-polar} (molecules) ; concentration gradient ;large surface area (to volume. |
| What is Diffusion? | Movement of molecules or ions from a region of their high conc to a region of high conc by relatively slow random movement of molecules. |
| How is blood pumped in insects? | Blood circulates in large open spaces, single heart pumps blood out into cavities surrounding animal's organs. Substances can diffuse between blood & cells. Heart muscle relaxes, blood drawn from the cavity back into heart,small valved openings. |
| Suggest why the insect does not need blood vessels to transport its blood around the body. | As Heart with all it's openings provide a large surface area to volume ratio, diffusion is fast enough, body cells close to heart and they have a low met rate and movement of blood back into the heart is fast enough. |
| Why do animals need a closed circulatory system? | Larger and more active, carried in tubes; generates high blood pressure. Travels faster, Oxygen and Glucose delivered quickly. |
| What do valves do? | Ensures blood flows in one direction and prevents backflow. |
| How does single circulation work in a fish? | Heart pumps DO blood to gills; gas exchange happens. Oxygen diffuses from water around gills into the blood, CO2 from the blood into the surrounding area. Gills provide a large SA for gas exchange. O blood leaves gills and flows around rest of the body. |
| What is a double circulation? | RV of the heart pumps DO blood into lungs; where it receives oxygen. O blood returns to heart to be pumped a second time, to the rest of the body. |
| What is the disadvantage of single circulation? | Blood is delivered at lower pressure which limits met rate. |
| What is an advantage of double circulation? | Blood can pass slowly through lungs which maximises gas exchange, pumped at higher pressure around the body, enabling organisms to be active and maintain a constant body temp. |
| Why does the wall of the left ventricle have a thick muscle? | To generate high pressure and pump blood quickly around body, |
| What do coronary arteries? | Supply the heart muscle with oxygen and glucose. |
| What are the properties of water? | 1. Polar molecule;uneven distribution of charge, forms H bonding . 2. Solvent,many chemicals can dissolve in water. Polar molecules can easily dissolve in water unlike non-polar molecules. |
| What are the properties of water?[2] | 3. Large amount of energy needed to break H bonds, and raise temperature of water. Water warms and cools slowly, allows organisms to avoid rapid changes, in their internal body temp, maintain a steady body temp. |
| Why are arteries more likely to develop atherosclerosis? | Blood is under higher pressure, more chance of damage to the endothelium |
| How does the structure of an artery relate to it's function? | WIDE WALL-WITHSTAND BLOOD UNDER HIGH PRESSURE ELASTIC FIBRES-ALLOWING ARTERY TO STRETCH NARROW LUMEN-MAINTAIN HIGH PRESSURE RECOIL-MAINTAIN PRESSURE SMOOTH LINING-REDUCES FRICTION |
| What happens when the heart contracts? | Elastic wall of arteries stretches. |
| What happens when the heart relaxes? | Elastic wall of arteries recoils. |
| How is blood flow through the veins is helped by? | Contraction of skeletal muscles Low pressure in chest cavity when breathing, it helps draw blood into heart Veins have valves, prevent backflow. |
| What is atrial systole? | AV Valves pushed open by pressure of blood as atria fill up. Atria walls contract forcing blood into ventricles. |
| What is ventricular systole? | Ventricles contract from base upwards, Semilunar valves in aorta and Pulmonary artery open, blood is pushed out through arteries. AV valves close. |
| What is diastole? | Atria and ventricles relax and elastic recoil of heart wall lowers pressure in atria and ventricles. blood under high pressure in arteries causes SL to close. |
| What does the Aorta do? | Carries blood away from the heart and Carries oxygenated blood. |
| What does Pulmonary artery do? | Carries blood away from the heart. |
| What does Pulmonary vein do? | Carries oxygenated blood. |
| What is Athereosclerosis | -Cascade of events... -High BP/toxins,Cig smoke,damage Endothelium. -Inflammatory response;White blood cells onto artery wall & Cholestrol accumulates;Atheroma -Ca salts & fibres build up;loses elasticity.Plaque. -Plaque narrows lumen,rise in BP. |
| What is a blood clot? | Platelets stick to damaged artery wall. Thromoplastin released;release Prothrombin,converted to Thrombin; acts as enzyme catalyses conversion of soluble plama protein Fibrinogen to long insoluble strands,Fibrin.Form mesh,traps RBC,form blood clot. |
| What happens if atherosclerosis happens in Coronary arteries? | Lumen will get narrower, restricts the amount of Oxygen, reaching heart muscle cells. Decrease in Aerobic Respiration, Insufficient energy. |
| What is a risk? | The probability of something happening that you do not want to happen. |
| What is a correlation? | A Change in one of the variables is reflected by a change in the other variable. |
| How do you calculate a risk? | 1 in 68349515/25494 = 1 in 2681 per year |
| Who do people overestimate a risk? | - Not in control of the risk - Risk is unfamiliar - Risk is dreaded - Risk is dreaded - Consequences are sudden and severe. |
| Who do people underestimate a risk? | - Effect in the long term future - In control of the risk and it is familiar. |
| How do scientists determine risk factors? | Look for correlations. |
| What is a Cohort study? | A group of people who do not have the disease, followed over a long period of time. Eventually some will develop and some won;t develop disease. Compare exposure to risk factors. Expensive and takes a long time. |
| What are prospective studies? | Look what happens to people in the future. |
| What is a case control study? | Two groups of people used, one group has the disease(CASE) and the other doesn't have the disease (CONTROL). Retrospective studies as they look at what happened in the past. |
| Why is it important for the groups to contain same age and same sex? | As it allows potential risk factors to be investigated. |
| What are the features of good cohort or case-control studies? | -Clear aim & hypothesis -Sample of people that is representative of population -Valid and reliable results from diagnosis and measurements,questionnaires and sample size. |
| What are the Risk Factors for CVD? | 1. Age and Gender/ UK men are at higher risk then women as women have a oestrogen protection till their menopause. Also CVD increases as they get older, arteries become less elastic/more damaged and other risk factors building up in life. |
| What are the Risk Factors for CVD? [2] | -Genetic Factors -High Blood Pressure ( diet, exercise and smoking) -Lifestyle factors: Diet, exercise and smoking. |
| What are the Risk Factors for CVD? [3] | Smoking: Affects Circ System. Chemicals damage lining of arteries, Nicotine stimulates adrenaline;increases heart rate and constricts arteries results in high bp. Haemoglobin carried CO in smoke, less oxygen reaches body, increased heart rate. |
| What are the Risk Factors for CVD? [4] | Exercise helps to prevent high blood pressure. Exercise raises HDL cholesterol, it alos reduces chance of diabetes. |
| How is blood pressure is measured? | With a Sphygmomanometer. |
| Why does Blood pressure drop? | Friction between blood and the walls of blood vessels slows the flow of blood, 'peripheral resistance'. Arterioles and capillaries have a larger total surface area; slows the flow even move causing pressure to drop. |
| What causes high blood pressure? | High salt diet, Loss of elasticity, and hormones such as adrenaline. |
| What is Oedema? | When fluid builds up in the tissues and causes swelling. |
| How is tissue fluid formed? | - Capillaries -Blood enters capillary, high pressure from artery. -Forces plasma out,pores in capillary wall. Fluid passes into spaces between cells forming TF Blood pressure rises above normal and TF is forced out of capillaries, fluid collects; Oedem |
| What are Monosaccarides? | Single sugars, (CH20)n. Rapid source of energy because they are absorbed easily and require little change before they are used by cells for respiration, releasing energy. |
| What are the 3 types of Monosaccarides? | 1. GLUCOSE- Main Respiratory substrate, found in fruit, honey, vegetables. 2.FRUCTOSE- Found in fruit, honey, and vegetables. Sweet and attracts animals, helps seed dispersal. 3.GALACTOSE- Part of Disaccaride sugar lactose, found in milk |
| What is a Disaccharides? | Double sugars, made from 2 monosaccharides joined by condensation reaction. |
| What are the 3 types of Disaccharides? | 1.MALTOSE- Formed from Glucose and Glucose.Found in germinating seeds, when stored starch is broken down for food. 2.SUCROSE- Formed from glucose and fructose, sugar transported in plants. 3.LACTOSE- Formed from glucose and galactose, in milk |
| What are Polysaccharides? | Long polymer chains made from monosaccharides joined by Glycosidic bonds. E.g. starch and cellulose and glycogen. |
| What is Starch? | An energy store in plants, made up of Amylose; straight chain of glucose molecules coiled in spiral shape. No branching and joined by 14-4 GB. Spiral shape held by Hydrogen bonding.and Amylopectin; Polymer of Glucose, side branches helf by 1-4 & 1-6 GB. |
| What is Glycogen? | Polysaccaride storage molecules in bacteria,fungi & animals.Stored in muscles & liver. Polymer of glucose monomers. Numerous side branches,easily hydrolysed-individual glucose molecules,fast access to stored energy.Has 1-4 & 1-6 GB attaching to branches. |
| Compare Starch and Glycogen? | Both are polymers of glucose and energy storage molecules. Glycogen has more side branches then starch. Starch is made up of Amylose and Amylopectin. Glycogen does not contain Amylose and Amylopectin. |
| Why are starch and glycogen suitable energy storage molecules? | COMPACT-Large numbers of molecules can fit into small space. INSOLUBLE- X Osmotic effect on cells LARGE-Remain within cells and contain alot of energy EASILY HYDROLYSED-when required for energy. |
| What is a Condenstaion reaction? | Join Monosaccarides together to form Disaccarides and Polysaccarides. A Glycosidic bond is formed and water is produced. |
| What is a Hydrolysis reaction? | The reverse of Condensation, Water is added to GB, so bond splits and individual monosaccarides are produced. |
| Why are Lipids a good energy store? | They provide twice as much energy per gram. Insoluble in water and contain Carbon,Hydrogen and Oxygen. |
| What are Triglyceride? | Contains One Glycerol and 3 Fatty Acids. Forms an Ester bond. |
| How can triglycerides be hydrolysed? | By lipase enzymes, water is added in the reaction. |
| What are Saturated lipids? | There are no double bonds between Carbon atoms. Solid at room temp, Comes from animals, straight Hydrocarbon chain, allows them to pack closely. |
| What are Unsaturated lipids? | Have double bonds between carbon atoms.Liquid at room temp and comes from plants. There are kinks in the chain, stops hydrocarbon packing together closely. |
| What is cholestrol important for? | For Cell membranes, Sex and growth hormones and bile salts |
| Where is Cholestrol made in? | Made in the liver but found in Sat fats. Cholestrol is insoluble in water and X dissolve in blood plasma. Has to be joined with Proteins to form Lipoproteins which can travel in blood system. |
| What are the 2 main trnasport Lipoproteins? | LDL and HDL. |
| How are LDL's formed? | When Saturated fats join with cholesterol and protein. Carried in blood stream and bind to receptors on cell membranes and then taken into cells. Increase in LDLs, increase blood cholesterol and leads to atherosclerosis. |
| How are HDL's formed? | Unsaturated fats joined with cholesterol. Carries Cholesterol to the liver where it is broken down and this lowers blood cholesterol and helps remove plaques of atherosclerosis. |
| How could you have more HDL's? | Eating low fat diet and avoid saturated fats. |
| How do Statins work? | They lower the blood cholesterol level. They inhibit cholesterol synthesis. They give more LDL receptors on liver , so more LDL's are removed. |
| What are the risks taking Statins? | -muscle inflammation -liver damage -joint aches -constipation/diarrhoea -kidney damage |
| What is the BMR? | The energy needed for essential processes such as heartbeat,breathing. |
| How can you calculate BMI? | Body mass(kg)/ Height(2)[m] 30> - obseity |
| What happens if you are obese? | It increases the risk of Type 2 Diabetees; increases the risk of CVD , Stroke. Raises BP, Blood cholesterol level. |
| Why may people be obese? | Less exercise, eat high fat foods and energy intake greater then energy use. |
| Why is CVD a multifactorial disease? | Several factors increase risk of disease? |
| What do free radicals do? | Damage cells and may lead to CVD. Vitamins contain antioxidants to protect against this. |
| How can salt increase risk of CVD? | Causes kidneys to retain water, increases BP and risk of Atherosclerosis. |
| How can stress increase risk of CVD? | Release of adrenaline which makes arteries constrict, raises bp. Lead to poor diet and alcohol intake. |
| How does alcohol consumption increase risk of CVD? | Damages liver cells and reduce ability to remove glucose and lipids from blood. Increase in LDL's. Reduce alcohol intake to lower the risk of CVD. |
| How can you control blood pressure? | ACE inhibitors- inhibit synthesis of hormone Angiotensin II, reduces constriction blood vessels & lowers bp. - CCB; Stops muscle contraction,stops blood vessel contricting,lowers bp. -Diuretics: Drugs that increase urine. Decreases volume and lowers bp. |
| How can you control you;re diet | Reduce Sat fat, More polyunsaturated fat, Reduce cholesterol, Reduce salt, eat oily fish, eat more fruit and vegetables. |
| What do Anticoagulant and Platelet Inhibitory drugs do? | Prevent formation of blood clot in an artery.Make platelets less st |
| What does Aspirin do? | Reduce stickiness of platelets, stop forming clot. Risks are bleeding of stomach wall. |
| What does Warfarin do? | More effective than aspirin however high risk of Gastrointestinal bleeding. |
| How could you overall reduce the risk of CVD? | Reduce SAT FAT- reduces BC Increase Exercise - Reduces BP Stop smoking- Increases BP and increase risk of atheroma Reduce salt- High BP Reduce alcohol - Increase in LDL and increase in bp Reduce cholesterol - Atherosclerosis Reduce Energy intake - |
| What is a cardiac cycle? | The cardiac cycle is the sequence of events that occurs when the heart beats. |
| Why do animals have a mass transport system? | To overcome the limitations of diffusion.. |
| How can clotting help? | Minimise blood loss Help prevent the entry of pathogens Provide a framework for repair |
| How can Sterols and stanols help? | By competing with cholesterol during it's absorption in intestine |
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