6483458
Description
Flashcards by Hannah Le Poidevin, updated more than 1 year ago
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Created by Hannah Le Poidevin
about 8 years ago
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| Question | Answer |
| Osmosis | The movement of (only) water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration |
| Diffusion | Diffusion is where particles move from an area of high concentration to an area of low concentration. This includes all liquids and gases. |
| What are exchange surfaces like? | They are thin so substances only have a short distance to diffuse. They have a large surface are so lots of substance can diffuse at once. Excahnge surfaces in animals have lots of blood vessels to get stuff in and out of the blood quickly. Gas exchange surfaaces in animals are often ventilated too -air moves in and out. |
| Structure of leaves | Carbon dioxide diffuses into air spaces within the leaf then diffuses into cells. The underneath of a leaf is an exchange surfaces. Oxygen and water vapour all diffuse out of the stomata but the stomata can be closed if too much is eascaping. |
| Describe the thorax | -The thorax is separated from the bottom of the body by the diaphragm. -The lungs are like big pink sponges and are protected by the ribcage. -Air goes through the traches which splits into two tubes called bronchi. -Bronchi split into smaller tubes called bronchioles which get smaller and smaller and end in bags called alveoli where the gas exchange takes place. |
| What is the thorax? | The upper part of your 'body' |
| What is the abdomen? | The lower part of your body |
| What is ventilation? | Breathing in and out |
| Describe what happens when you breath in | The intercostal muscles and diaphragm contract. The thorax volume increases. This decreases the pressure, drawing air in. |
| Describe what happens when you breath out? | Intercostal muscles and diaphragm muscles relax. The intercostal volume decreases. The pressure increases pushing air out. |
| What are artificial ventilators? | They are used to help people artificially breath, for example if they're under an anaesthetic. |
| How did they work? | They used to be a giant case and when air was drawn out of the case, it would decrease pressure, forcing air into the lungs. When air was pumped in to the case it would increase pressure and air was forced out of the lungs. However, this interfered with blood flow to thr lower abdomen. |
| How do they work now? | Now it works by pumping air into the lungs. Air is pumped into the lungs and they fill up. When they stop pumping the lungs relax and push air out. This can occasionally result in a burst alveoli if the lungs can't cope with the artificial air flow. |
| What is the job of the lungs? | To provide oxygen to the blood and remove waste carbom dioxide. |
| How does it do this? | The lungs have lots of little sacs called alveoli where gas exchange takes place |
| How are alveoli specialised to maximise diffusion of oxygen amd CO2? | - Large surface area - Moist wall lining - Good blood supply - Thin walls |
| How does the inside of the intestine aid with digestion? | It has villi which are small little projections to increase the surface area so food is absorbed much more quickly into the blood. |
| How are villi specialised to help with digestion? | They only have a single layer of surface cells and have a very good blood supply to assist quick absorption. |
| What is active transport? | When a substance moves from an area of low concentration to an area of high concentration. This process requires energy to happen. |
| What is needed to allow active transport to happen? | Energy from respiration |
| How are root hairs specialised? | The surface cells of a root grow into hairs. This increases the surface area for abosorbing water and mineral ions. It is small so there is not such a long way for things to travel. |
| How do humans use active transport? | We sometimes use active transport in the gut to get glucose and amino acids from the gut (where there's a lower concentration) to the blood (where there's a higher concentration) |
| What tube transports food? Describe it | Phloem tube. Made of living cells with small holes in the ends to let stuff flow through. Transports food substances (mainly dissolved sugars) to growing regions amd storage organs. Transport goes in both directions. |
| What tube transports water? Describe it | Xylem tube. Made of dead cells joined end to end with no end cell walls. They carry water and minerals through from the roots to the leaves in the transpiration system. |
| What is the transpiration stream? | Leaves have stomata to allow gas exchange, however, because there's more water in the plant than in the air surrounding water eacapes through the stomata because of diffusion as well as through photosynthesis. This means there is a shortage of water in the leaves, so water is drawn from another part of the plant to the leaves via the xylem tube. Water is then taken from the roots to other parts of the plant etc. etc. to create a constant transpiration stream. |
| What does the circulatory system carry to and take away from cells? | Carries oxygen and glucose and takes away CO2 and urea. |
| Describe how the circulatory system works? | Deoxygenated blood is pumped from the heart to the lungs where it becomes oxygenated. The blood then goes back to the heart and is pumped around the body, giving out the oxygen. It then arrives back at the heart as deoxygenated blood again. |
| What is the heart made of? | It is a pumping organ with walls made of mostly muscle tissue. It has valves which stop the blood being pumped backwards. |
| What are the 9 parts of the heart? | RIGHT SIDE: 1) vena cava 2) right atrium 3) right ventricle 4) pulmonary artery LEFT SIDE: 5) pulmonary vein 6) left atrium 7) left ventricle 8) aorta BOTH: 9) valves |
| Label the parts of the heart | |
| What are arteries? | Arteries carry blood away from the heart. They have thick muscle walls compared to the small lumen in the middle. Because the blood comes from the heart at a high pressure, the walls of the arteries have to be thick and elastic. |
| What are capillaries? | Arteries branch off into smaller capillaries. These carry blood really close to the cells and have permeable surfaces to allow substances to diffuse in and and out. They carry food and oxygen close to the cells, and carry away waste products such as CO2. Their walls are only one cell thick to speed up the rate of diffusion. |
| What are veins? | Veins carry blood to the heart. The blood is at a low pressure, so they have thin walls and a bigger lumen to help with blood flow. They also have valves to keep the blood going the right way. |
| Describe red blood cells | Red blood cells carry oxygen round the body. They are donought shaped to give a larger surface area. They have no nucleus to give more space for the oxygen. They contain a red pigment called haemoglobin that combines with oxygen in the lungs to become oxyhaemoglobin, and in the body tissues splits to become oxygen and haemoglobin again to realease the oxygen into the cells. |
| Describe white blood cells | They have a nucleus. They can change shape to absorb unwelcome microorganisms. They can also produce antibodies to fight foreign microorganisms, and antitoxins to neutralise toxins produced by these microorganisms. |
| Describe platelets | Platelets are small fractions of cells with no nucleus. They float about in the blood waiting for an accident and then clot at the wound to stop blood getting out and microorganisms getting in. Lack of platelets can cause excessive bleeding and bruising. |
| What is found in plasma? | - Red and white blood cells - Glucose and amino acids - Carbon dioxide - Urea - Hormones - Antibodies and antitoxins |
| What is used if a patient loses a lot of blood? | When someone looses a lot of blood, for example in an accident, they're heart can still pump the blood around their body as long as it's topped up. An artificial blood (a blood substitute) is used such as a saline (salt solution) which is safe as long as there are no air bubbles and can keep people alive even after losing 2/3 of red blood cells. This gives enough time for the patient to produce enough red blood cells or have a blood transfusion. Ideally, the blood substitute would eliminate the need for a transfusion at all. These are being developed but have some side effects. |
| What are artificial hearts? | Artificial hearts are mechanical heaets that can be fitted if someones heart fails. They are usually used as a temporary fix but can be used as a permemant fix. |
| What are the advantages and disadvantages? | The main advantage is that they aren't rejected by the body's immune system because they're normally made from plastic or metal. However, sometimes parts can stop working or wear down and sometimes the electric motor stops working. The surgery can lead to bleeding or infection, and blood clots often occur, so to stop this the patient has to take blood thining tablets which can cause problems if the patient is hurt in an accident. |
| Artificial valves | If it's just the valves that stop working, artificial valves can be used instead. The surgery is a lot less drastic than for the whole heart. However blood clotting still occurs so blood thining tablets have to be taken. |
| What are stents? | Coronary herat disease is when fatty deposits block the arteries so blood can't flow through easily. This can cause heart attacks. A stent is a small tube that opens up the artery and allows blood to flow to the heart muscles. This reduces the risk of heart attacks. However, the arteries may close up over time as the stent irratates it and causes scsr tissue to grow. And also tablets have to be taken to stop blood clots. |
| What is homeostasis? | The maintanence of a constant internal environment (keeping stuff the same within your body) |
| What are the six things that need to be controlled? | - Temperature - Glucose levels - Ion/ salt levels - Water levels - CO2 - Urea |
| What is the thermoregulatory system and what does it do? | The thermoregulatory system is in your brain and it controls bodu temperature.. It has sensors thst detect thr temperature of your blood and recieves impulses from your skin regarding external temperature. |
| What does your body do when you're warm? | Hairs lie flat. Blood vessels dialate to maximise the amount of blood near the surface to give off heat. Sweat glands open up and sweat is given off which cools you down. |
| What does your body do when you're too cold? | Hairs stand up to create an insulating layer. Sweat glands close off. You shiver (muscles contract automatically) which needs respiration which makes energy to warm you up. Blood vessels contract to minimise blood flow nesr the surface. |
| What are the roles that the kidneys perform? | - Removal of urea - Adjustment of water content - Adjustment of ion content |
| Removal of urea | Proteins can't be stored in the body so any excess amino acids are converted into carbohydrates or fats and stored. Urea is a waste product of this reaction. Urea is posinous. It is released by the liver into the blood stream and then removed by the kidneys. It is then stored in the bladder until it's released in urine. |
| Adjustment of ion content | Ions such as sodium are taken into the body through food. If the ion content is wrong, it could upset the balance between water and ion molecules. This can damage cells because too much or too little water might be drawn into the cell through osmosis. This could damage cells or mean they don't work properly. Excess ions are removed by the kidneys. Some is lost through sweat but the kidney's controls the levels. |
| What are the 3 ways water is lost from the body? | Through urine, sweat (which can both be controlled) and through air breathed out (which can't be controlled). This means the controlled factors that affect water content is: - water taken in - water lost through sweat - water lost through urine |
| How is your urine different on a hot day compared to a cold day? | On a hot day urine is very yellow because it's dilute and a small volume. Lots of water is lost through sweat. Whereas on a cold day, urine is pale yellow as it's undilute and a big volume. No water is lost through sweat. |
| How do sports drinks help with homeostasis? | Sports drink contain lost of water, ions and sugar. Water and ions replace those lost through sweat, and sugar replaces that used by muscles during resperation. |
| How do the kidneys work? Ultrafiltration | A high pressure is built up which squeezes sugar, ions, water and urea into the Bowman's capsule. The membranes between the bloodstream and the Bowman's capsule stop big molecules such as proteins and blood cells being squeezed out. |
| Reabsorbtion | As the liquid flows along the nephron, useful substances are reabsorbed back into the blood stream: - All sugar is reabsorbed by active transport - Sufficent ions are reabsorbed by active transport - Sufficent water is reabsorbed |
| Release of wastes | Remaining substances including urea continue out of the nephron into the bladder as urine. |
| What happens if the kidneys don't work properly? | Waste substances build up in the body until the levels of water and ions can no longer be contolled. Eventually this can lead to death. When someones kidneys fail they can either have a transplant or dialysis. |
| What is dialysis? | Dialysis has to be done reguarly (3 times a week) to keep things at normal levels and remove waste substances. |
| How does dialysis work? | In a dialysis machine, the blood flows alongside a membrane like that of the Bowman's capsule. The dialysis fluid has the same concentraton of dissolved ions and glucose as healthy blood so they don't miss out. Only waste substances such as urea and excess ions and water diffuse across the barrier. |
| What are the negatives of dialysis? | - Many patients with kidney faliure have to have a session 3 times a week for 3-4 hours each time. Also it may cause blood clot or infection. |
| How do kidney transplants work? | At the moment the only cure to kidney faliure is a transplant. However, the doner kidney could be rejected by the body if it think it's foreign. To prevent this a doner with a close tisdue type is used Tissue type is based on antigens (proteins on the surface of a cell). Tablets are taken which suppress the immune system and stop it fighting the kidney. |
| How does glucose get into the body and what is it used for? | Glucose gets into the body through foods containing carbohydrates. It os removed from the cells by metabolism. Exercise removes much more glucose. |
| What organ controls the levels of glucose? | The pancreas controls the level of glucose, using the hormones insulin and glucagon. |
| What does the body do if the levels of glucose are too high? | The pancreas releases insulin into the blood stream which makes the liver turn the insulin into glycogen. |
| What does the body do if the levels of insulin are too low? | The pancreas secretes glucagon into the blood stream which makes the liver turn glycogen into glucose. |
| What is type 1 diabetes? | A condition where the pancreas produces little or no insulin which can result in high glucose levels which can kill them. |
| How can the problem be controlled? | - Limiting the intake of foods rich in simple carbohydrates - Regular exercise - Injecting with insulin which is done several times a day, often at mealtimes. This makes sure glucose is removed quickly and stops the build up of it. This stops glucose levels getting too high and is extremly effective. The level of glucose depends on their diet and exercise. |
| Where does insulin come from? | It used to be extracted from the pancreases of pigs and cows, but now human insulin is made by genetic engineering which doesn't cause problems like it used to coming from different animals. |
| Having a transplant | Diabetics can have a pancreas transplant. A succesful operation would mean not having to inkect themselves with insulin again, but if the body rejects it, it means taking immunosuppressive drugs which often have serious side effects. Modern research into artificial pancreases and stem cell research may mean the elimination of organ rejection in the future. |
| Biology B | woooooo |
| Why is the population increasing? | The population of the world is over 6 billion and increasing. This is because advances in medicine and farming mean less people are dying from disease or hunger. |
| How is the population increase affecting the environment? | We want and need more resources. There are more people demanding resources, more people are demanding a higher standard of living. So raw materials such as oil are used to make things like plastic. Energy is needed tl make these things and often to run them tol. However, many raw materials are bwing used quicker than they're being replace so we're running out. |
| How does waste affect water? | Sewage and toxic chemicals from factories are getting into oceans, rivers and lakes and harming those animals (including humans) that depend upon them. chemicals (e.g fertilisers) also get washed into water. |
| How is waste affexting land? | We use toxic chemicals (e.g pesticides/ herbicides) in farming. We also use waste lanfill sites and bury nuclear waste too. |
| How is waste affecting the air? | Smoke and gases are released into the atmosphere and pollute the air. |
| What are the 4 main ways we use up land? | -Farming - Building - Landfill sites - Mining |
| How can CO2 be sequestered? | - In oceans, lakes and ponds - In plants as carbon compounds - Peat bogs Stoeing it is really important as it means it's removed from the atmosphere. |
| What determines the temperature of the Earth? | A balance between the heat from the sun and the heat radiated back to Earth. Gases in the atmosphere act like an insulating air round the earth. They absorb the sun's heat and re-radiate it in all directions, including back to earth. This keeps the heat in at night, otherwise we'd get very cold. |
| What are greenhouse gases and why are they bad? | Greenhouse gases are these insulating gases. The mains ones we worry about are methane ans CO2. The earth is gradually heating up because of these gases and causing global warming. |
| Why are forests cut down? | - To provide timber for building - To make space for farming to grow food crops or crops for biofuels. - To produce paper |
| What are the four main problems deforestation leads to? | - More methane - More CO2 - Less biodiversity - Less CO2 taken in |
| How does deforestation lead to more methane in the atmosphere? | Cutting down trees makes space for crops such as rice to be grown. Rice is grown in moist, warm conditions ideal for decomposers which produce methane. It also means space for more cattle which fart methane. |
| How does deforestation lead to more CO2 on the atmosphere? | Carbon in wood is released when the tree is burnt to give clear land. Microorganisms feed on dead wood and release CO2 when they respire. |
| How does deforestation lead to less CO2 taken in? | The trees and other plants take in and then store CO2 when performong photosynthesis. |
| How does deforestation lead to less biodiversity? | Habitats are destroyed so certain species can't survive or lose plants they feed on. This means lost oppurtunities as there are probably loads of materials that could be used for new foods, clothing or new medicines we will never know about. |
| What is a peat bog? | A bog is an acidic and waterlogged area of land. Plants don't fully decay in bogs because there's not enough oxygen. The partly rotted plants gradually build up to form peat. So the carbon in the plants is stored in the pest instead of being released into the atmosphere. |
| Why is CO2 being released into the atmosphere from peat bogs? | Peat bogs are being destroyed and drained for farmland. The peat is also dried and used as fuel or in compost. When the bog is destroyed the peat decomposes to release the CO2 into the atmosphere. This is contributing to the greenhouse effect. |
| What are the consequences of global warming on water levels? | Sea levels have risen a little over the last 100 years as the ice melts. This causes flooding, esspecially in low level places such as the Netherlands, East Anglia and the Maldives. |
| How are weather patterns changing because of global warming? | It's thought that places will experince hotter, more extreme weather, such as hotter, longer droughts. Hurricanes form over water that is 27°c so there may be mlre hurricanes. However, the weather is hars to predict so no one is completely sure. |
| How are the consequences of global warming affecting animals and plants? | The distribution of many plant and animal species may change. As the weather gets hotter, species that thrive in those conditions may become more widely spread, whereas species that prefe colder climates may become less widely distributed. Biodiversity could be destroyed if those species are unable to survive and adapt. Also, migration patterns may change. For example, more birds may migrate further north as it becomes warmer. |
| How are the consequences of global warming affecting animals and plants? | The distribution of many plant and animal species may change. As the weather gets hotter, species that thrive in those conditions may become more widely spread, whereas species that prefe colder climates may become less widely distributed. Biodiversity could be destroyed if those species are unable to survive and adapt. Also, migration patterns may change. For example, more birds may migrate further north as it becomes warmer. |
| How are scientists collecting data on climate change? | - Satellites tomoniter snow and ice cover and to measure sea surface. - Recording tempurature and speed of ocean currents - Automatic weather stations are recording atmospheric temperature. |
| How are scientists collecting data on climate change? | - Satellites tomoniter snow and ice cover and to measure sea surface. - Recording tempurature and speed of ocean currents - Automatic weather stations are recording atmospheric temperature. |
| Why is this data only useful if covered over a long enough time scale and wide enough area? | Tests need to be repeated and time needs to be taken to make sure this is gradually happening e.g to make sure species numbers are falling gradually, not down one year and up the next. They also need to be sure it's happening every where, not just in one small area. |
| Why is this data only useful if covered over a long enough time scale and wide enough area? | Tests need to be repeated and time needs to be taken to make sure this is gradually happening e.g to make sure species numbers are falling gradually, not down one year and up the next. They also need to be sure it's happening every where, not just in one small area. |
| How can fuels be made using fermentation? | Fermentation is when bacteria or yeast break sugars down by anaerobic respiration. Fuels can be made by fermentation of natural products - often waste products. |
| How can fuels be made using fermentation? | Fermentation is when bacteria or yeast break sugars down by anaerobic respiration. Fuels can be made by fermentation of natural products - often waste products. |
| What is the word equation for the breakdown of glucose by fermentation? | Glucose --> Ethanol + energy + CO2 |
| What is the word equation for the breakdown of glucose by fermentation? | Glucose --> Ethanol + energy + CO2 |
| How is ethanol made by anaerobic fermentation of sugar? | The yeast make ethanol when they break down glucose by anaerobic respiration. Sugar cane juices can be used |
| How is ethanol made by anaerobic fermentation of sugar? | The yeast make ethanol when they break down glucose by anaerobic respiration. Sugar cane juices can be used |
| What can be used to make ethanol based biofuels? | - Sugar cane juices - glucose from maize starch by the action of carbohydrase |
| What happens to the ethanol before it's used as fuel? | It's distilled to separate it from the remaining glucose and yeast. |
| What is gasohol? | It is a mixture of ethanol and petrol used in some cars countries such as Brazil. |
| What gases is biogas made up from? | 30% carbon dioxide and 70% mathane. |
| What is used to make biogas? | Lots of different microorganisms that ferment animal and plant waste that contains carbohydrates such as human waste, waste from pigs and food waste. Sludge waste e.g from a sewer works or sugar factory can be used to produce biogas on a larger scale. By products are used to fertilise crops and gardens. |
| What is it made in? | A simple fermenter called a generator or digester. Generators need to be kept at a constant temperature to keep microorganisms respiring. There are two types of generator, a batch generator or a continuos generator. |
| Can bigoas be stored? | No, it can't be stored as a liquid (it needs too high a pressure) so it needs to be used straight away for heating, cooking, lighting, powering turbines or generating electricity. |
| How are biogas generators being used? | Large scale biogas generators are being set up in some countries. Also, in some countries small biogas generators are used to provide power for a village or a family to use for a cooking stove and heating and lighting. |
| How do biogas generators work? | They have an inlet for waste material, an outlet for digested material (by products) and a biogas outlet for thr biogas. |
| How do batch generators work? | They are manually loaded uo with the waste material, left to digest, then the digested material is manually cleared out. |
| How do continuous generators work? | They make biogas all the time. Waste is continuously fed in and biogas is produced at a continous rate. These are more suited to large-scale projects. |
| What four factors have to be debated when designing a generator? | - Cost - Convenience - Efficiency - Position |
| How does cost affect it? | Continous generators cost more than batch ones because the waste has to be mechanically pumped in and removed all the time. |
| How does convenience affect it? | Batch generators are less convenient because they have to be manually loaded, emptied and cleaned. |
| How does efficency affect it? | Gas is produced most quickly at 35°c so some generators need to be insulated or kept warm, e.g solar panels. There should be no leaks to stop gas leakage. |
| How does position affect it? | The waste will smell when delivered so they are best away from homes. It's also good if they're next to the waste source. |
| What are the environmental advantages of using biogas? | - The CO2 released is from plants that took it in recently, so it's carbon neutral. - Doesn't produce significant amounts of sulphur dioxide or nitric acid thst produce acid rain. - Methane is a greenhouse gas that is released from untreated waste. Burning it means it's NOT released into the atmosphere. |
| What are the economical advantages of using biogas? | The raw material is cheap (maybe even free) and readily available. |
| What are the social effects of using biogas? | - The digested material is better for crops than undigested material, so people can grow more crops. - In some communities, women spend hours looking for firewood. Biogas means they don't have to. - Biogas generators act as a waste disposal system getting rid of all the animal and human waste that would otherwise lie around and pollute water supplies. |
| How can the 'efficiency' of food production be improved? | - Redcuing the number of stages in the food chain - Restricting energy lost by farm animals - Developing new food sources |
| How can you reduce the number of stages in the food chain? | For a given area of land, a lot more food can be produced by growing crops than by animals. For beef cows, only 10% of what they eat can become useful food. But sometimes places are unsuitable for growing crops so animals are a better idea. |
| How can you restrict energy lost by farm animals? | In countries such as the UK, animals are intensively farmed. Thry are kept close together in small cages indoors so they don't lose much energy moving or keeping warm. So basically they grow faster on less food. This makes the animals cheaper |
| What is mycoprotein? | Protein grown from fungus. It is used to make a meat substitute for vergitarians. |
| How is mycoprotein grown? | A fungus called fusarium is the main source of mycoprotein. The fungus is grown in fermenters using glucose syrup that is obtained by digesting maize starch with enzymes for food. The fungus respires aerobically so oxygen is supplied, nitrogen (as ammonia) and other minerals. To stop other microorganisms growing, the ferementers are first sterilised using steam. The incoming nutrients are heat sterelised and air is filtered. The mycoprotein is harvested and purified. |
| What are the advantages of mycoproteins? | In some developing countries it's difficult to find protein as animals need space and grass. So mycoprotein can be an efficent way of providing enough protein. The microorganisms grow quickly amd don't need much space. And they can even feed on waste materials thst can't be fed to animals. |
| What are the disadvantages of intensive farming? | - Some people think it's unethical - Animals living so close together means disease like avian flu and foot and mouth disease can spread more easily. - To stop these spreading, animals are given antibiotics that then enter humans. This can produce immune bacteria for humans. - The animals need to be kept warm and this uses fossil fuels. - Lots of animals are fed on fish despite the fact fish stocks are low. |
| How can where food is grown cause problems? | Some food products have lots of 'food miles'. This means they were transported a long way by lorry/ train/ aeroplane/ boat etc. These vehicles all bun scsre fossil fuels and release carbon dioxide into the atmosphere. |
| What are the consequences of over fishing? | There's less fish for us to eat. The ocean's food chains are affected. Some species of fish are dying out. |
| How can we tackle this problem? | Keep the number of fish at a sustainable level by - Fishing quotas - there are limits on the number and size of fish that can be caught. This prevents species being overfished. Net sizes - limits on the mesh size. This means 'unwanted' fish such as shrimp can slip out and baby fish can also get out so they can continue breeding. |
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