1349052
Description
Flashcards by Chima Power, updated more than 1 year ago
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Created by Chima Power
about 10 years ago
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| Question | Answer |
| Diffusion | Such takes when particles in fluids can spread easily from one place to another and is completely random. Movement of any particles from a region of high concentration to a region of low concentration. Osmosis is only movement of water molecules. |
| Partially permeable membrane | Doesn't let all types of particles through as only let part through is partially permeable |
| Osmosis | Partially permeable membranes let water through, it is a certain type of diffusion where only water moves across a partially permeable membrane. |
| Osmosis in sugar solution | In a dilute solution of sugar high concentration of water, solvent, as low concentration of sugar, solute. Concentrated sugar solution has low concentration of water and high concentration of sugar. |
| Osmosis in cytoplasm in cell | Cytoplasm of cell made up of chemicals dissolved in water inside a partially permeable bag of cell membrane, cytoplasm contains a fairly concentrated solution of sugars and salts. Water moves from area of high concentration of water molecules, dilute solution, to an area of low concentration of water, concentrated solution, across the membrane of a cell. |
| Osmosis in animals | If water in cell used in chemical reaction cytoplasm becomes more concentrated. More water immediately moves in by osmosis. If cytoplasm too dilute water leaves so balances out. Can cause a problem, if solution outside is more dilute water will move into the cell such that cell will swell and burst. If solution outside too highly concentrated water will move out cell will shrivel up can no longer survive. Illustrates importance of maintaing constant internal conditions. |
| Osmosis in plants | Plants rely on osmosis to support leaves and stems, causes vacuole to swell and press cytoplasm against the plant cell wall. Pressure builds up until no more water can physically enter the cell making it rigid and hard. Plants need fluid surrounding cell to have a higher concentration of water than the cytoplasm of cell. If this happens water leaves the cell by osmosis, cells will not support the plant tissue. |
| Active transport | Substances need to move in and out of cells when dissolved in water can be done by diffusion along a concentration gradient. Sometimes substances needed by a cell must move against a concentration gradient, or across a partially permeable membrane special process called active transport. |
| Moving substances of active transport | Cells can absorb ions from very dilute solutions, enables cells to move substances like sugar and ions, from one place to another through the cell membranes. Requires energy as energy for transport system to carry molecule across then return to original position. Energy comes from cellular respiration. Therefore if a cell makes a lot of energy can carry out large amounts of active transport like root hair cells or cells lining gut so have lots of mitochondria |
| Importance of active transport | particularly important obtaining mineral ions that are in a dilute solution more than that within in the plant cells. Through active transport this is possible. Sugars like glucose always actively absorbed out of your gut and kidney tubules into your blood. Often done over a large concentration gradient. |
| What sport drinks contain | Colouring, flavouring and some sugar or sweeteners are added, along with a tiny amount of mineral ions and little carbon dioxide for fizz. |
| Biological processes occurring when you exercise. | Release energy by respiration to make your muscles contract and move your body, using up sugar. Also sweat to keep body temperature down which contains mineral ions and water. Can affect concentration of your fluids. If body fluids become concentrated water will leave your cells by osmosis, cells become dehydrated. If water and mineral ions lost not replaced cells don't work as efficiently as balance disturbed. To keep exercising these must be replaced, also applies to recovering properly after exercise. So sport drinks come in. |
| What's a sport drink | Mainly made of water contains sugar, glucose, contains more mineral ions than most normal soft drinks. Has colouring, flavouring added to make it pleasant to drink. Most drinks claim to aid hydration of tissues, replace lost energy, and replace lost electrolytes (mineral ions you lose when you sweat) |
| Evaluating sports drinks | Usually more expensive than soft drinks evidence claiming doing what they say have lots of water so dilute the body fluids . Allows water to move back into cells and rehydrate them by osmosis. Contain salt which raises ion levels, ions move into cells by diffusion. Raise blood sugar levels so sugar moves back into cells by diffusion and active transport. |
| Evaluating sport drinks negatives | Very expensive evidence shows that using for short term exercise not needed. Isotonic sport drinks not required for activities less than an hour. Simple tap water suffice to hydrate cell and orange squash replace sugar. use of dilute orange solution with little salt should replace mineral ions as effective as most commercial products. Evidence also shows milk drinks good for cell rehydration and replacing sugar and salts using exercise. Provides muscles with protein and extra vitamins |
| Proficiency of lungs | Bigger the organisms and more complex, their surface area to volume ratio decreases. So quick material exchange is hard. In many larger organisms special surfaces where gas and solute exchange takes place. Adapted to be as effective as possible found in plants and animals |
| Adaptations for exchanging material in | Having a large surface area Being thin, providing a short diffusion path having an efficient blood supply in animals, moves diffused substances and maintains a high concentration gradient, being ventilated in animals to make gaseous exchange more proficient higher concentration gradient |
| Musk turtles adaptation for exchange in materials | Have specially adapted tongue has lots of tiny buds that increase surface area, also has good blood supply used for gaseous exchange as well as eating. Buds on tongue absorb oxygen from water that passes over them. Turtle so effective at gaseous exchange it can stay underwater for months at a time. |
| Exchange of gases in the lung | Made of cluster of alveoli, tiny air sacs give lungs large surface area to volume ratio, important for the most effective diffusion of oxygen and carbon dioxide. Alveoli has good blood supply oxygen moving from air in lungs to blood while carbon dioxide moving from blood to lungs from blood. Resulting gas exchange on steepest concentration gradient possible makes exchange rapid and effective. Layer of cells between the air in lungs and blood in capillaries also very thin. Allows diffusion to take place over shortest distance possible. Spherical structure of alveoli give good surface are to volume ratio. Moist lining, surfactant, allows for stretch of cells and particles diffuse better over moist surface. |
| Ventilating the lungs | maintaining a steep concentration gradient of both oxygen in and carbon dioxide out known as ventilating the lungs or breathing. Takes place in specially adapted breathing system. |
| Thorax | Upper chest region of the body, in humans include ribcage, heart and lungs. |
| diaphragm | strong sheet of muscle separating thorax from digestive organs used to change volume of chest during ventilation of lungs |
| How ventilation of lungs work | Caused by movement of ribcage and diaphragm. Intercostal muscles contract pulling ribs upwards and outwards, diaphragm contracts flattening out, increased volume of chest means lower pressure as diaphragm contracts air in. Decreased volume means increased pressure. As you breath in oxygen rich air moves in ensure high concentration gradient, as breath out carbon dioxide rich air to ensure diffusion out of carbon dioxide from blood stream. |
| Exchange in gut | Nutrients from eaten food is broken down in the gut, the food molecules then converted into simple sugars like glucose, amino acids, fatty acids and glycerol. Products of digestion required for respiration, growth and repair. So successful exchange surface very important |
| Absorption in the small intestine | Food molecules go from small intestine to blood by combination of diffusion and active transport. food molecules small enough to freely pass through walls of small intestine to blood vessels by diffusion as move across concentration gradient high concentration of food in the gut and lower concentration in the blood |
| Villi | Lining of small intestine folded into thousands of tiny finger like projections called villi. Greatly increase the uptake of food by diffusion as shape allows for high surface area. As only a certain number of food molecules can diffuse over a certain area in the gut. Each individual villi is covered in microscopic micro villi. Further increasing surface are viable for diffusion |
| Small intestine blood supply | Like alveoli has great blood supply carries away nutrients as soon as diffused made up of capillaries ensures steep concentration gradient maintained makes diffusion as rapid and efficient as possible |
| Active transport in the small intestine | Longer since your last meal the less food molecules in your gut resulting in more in your blood than in your gut. Hence glucose and other dissolved food molecules are then moved from small intestine to blood by active transport. Digested food molecules must move against concentration gradient. Ensures no food is wasted and lost in excrement. |
| Exchange in plants | Plants heavily rely on diffusion to attain carbon dioxide from air for photosynthesis. Use osmosis to take water from soil and use active transport to obtain mineral ions from soil. Have adaptations that make exchanges as efficient as possible |
| Gas exchange in plants | Carbon dioxide required for photosynthesis, flattened shape of the leaves increases surface area for diffusion. Plus most plants have thin leaves which means distance carbon dioxide must diffuse from outside air to the photosynthesising cells kept as short as possible. Finally have many air spaces in their structure so that carbon dioxide come in contact with more cells giving a large surface area for diffusion |
| Problems with gas exchange in plants | Cells constantly lose water by evaporation because of properties that make it a great for gaseous exchange i.e. large surface area. If water vapour lost leaves and plants will die. However when dark don't require carbon dioxide because no light for photosynthesis, limiting factor. Plus carbon dioxide from respiration can be used for photosynthesis. But carbon dioxide required when factors affecting photosynthesis not limited. Leaves adapted to only allow carbon dioxide through when required covered in waxy cuticle which water and gasproof. |
| Stomata | All over leaf surface small openings called stomata, can be opened when leaves needs to allow air into the leaves. Carbon dioxide from atmosphere diffuses into air spaces then into cells along a concentration gradient. Oxygen produced by photosynthesis is removed from the leaf by diffusion into surrounding air. maintains high concentration from oxygen from the cells to air spaces of leaf. Stomata can be closed rest of time to limit water loss. Opening and closing of stomata controlled by guard cells. Water is also lost to air by diffusion when stomata are open. |
| Uptake of mineral ions and water in plants | Plants roots adapted to take up mineral ions from soil as efficiently as possible. Roots are thin with divided tubes to cover large surface area. root hair cells have tiny projections that push out between soil particles like villi. Water moves into root hair cells by osmosis across partially permeable membrane then only short distance across root to xylem. From where moved around plant. Plants roots adapted to take in mineral ions by active transport. have plenty mitochondria to supply energy as well as large surface area and short diffusion pathway. |
| Transpiration stream | As water evaporates from the surface of leaves water is called up to replace the evaporated water via the xylem, this constant movement of water molecules through the xylem from the roots to the leaves is known as the transpiration stream. |
| Effect of environment on transpiration | Anything increasing rate of photosynthesis increased the rate of transpiration so hot weather increases rate of transpiration. Hot dry windy conditions that increase rate of evaporation increase rate of transpiration |
| Controlling water loss in transpiration | Most plants have waxy cuticle which is waterproof preventing water loss, in very hot conditions the cuticle may be thick and shiny. Most stomata found on underside of plant so away from direct sun and heat and reduces time open. if plants lose water faster than can replace it wilts. It's a protection mechanism against water loss, leaves collapse and hang over, surface area available for water loss greatly reduced. Finally stomata will close stopping photosynthesis and risking overheating but prevents water loss and further overheating. Plants remain wilted until temperature drops sun goes in or rains |
| The circulatory system | This is a transport system which is vital to supply the needs of your body cells and remove the waste material produced. This is the function of your circulatory system, this is made of three parts: blood vessels, heart and blood. |
| Double circulation | In body have double circulation one that carries to your lungs and back allowing oxygen and carbon dioxide to be exchanged with air in the lungs. The other pumping blood around the rest of the body and back to the heart. Vital in warm blooded active animals like humans as it makes the circulatory system very efficient. Fully oxygenated blood from the lungs is pumped around the body at a high pressure. So that more areas of your body can receive fully oxygenated blood quickly. Arteries carries blood around the body and veins carry blood to the heart. |
| Heart as a pump | It's an organ that pumps blood around the body, made up of two simultaneous pumps (double circulation) about 70 times a minute. Walls of heart made entirely of muscle which is supplied with blood by coronary arteries. These muscle contractions are as a result of electrical impulses by the sinoatrial node which controls the heart rate. |
| Heart structure |
Two sides of the heart fill and empty at same time, giving a strong coordinated heart beat. Blood enters through top chamber atria. De-oxygenated blood through vena cava to right atrium. Blood from pulmonary vein is oxygenated from lungs. Atria contract, forcing blood into ventricles. Valves close to stop backward flow. Ventricles contract forcing blood out of heart right ventricle through pulmonary artery to lungs de-oxygenated. Left ventricle through aorta oxygenated around body.
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Arteries
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These carry blood away from the heart to the organs of the body, blood is usually bright red oxygenated blood. Stretch as blood is forced through them and afterwards go back to shape so have pulse maintaining high pressure. If cut will spurt blood due to high pressure. Have thick walls, small lumen and thick layer of muscle and elastic fibres. |
| Veins | Carry blood to the heart, usually low in oxygen de-oxygenated deep purply red colour. Don't have a pulse. Often have valves that prevent the back-flow of blood as it moves back to the heart. Have thin walls and large lumen. |
| Capillaries | These are huge network of tiny vessels linking arteries to veins. They have a very thin wall (a single cell thick), enabling substances like oxygen and glucose to diffuse easily out of blood and into cells. Also so that substances produced by cell can diffuse into capillaries like carbon dioxide. Moreover have narrow vessel to gain a large surface area to volume ratio to have great rate of diffusion. |
| Stents | Can be used when supply of oxygen to heart interrupted causing pain, heart attack and even death. As coronary arteries can become narrow as you age, get narrower as are result of fatty deposits forming on lining of vessels. Stents are metal mesh that are placed in the artery, then tiny balloon is inflated to open blood vessel and stent. As soon as this done blood flows freely, can be used without general anaesthesia. These can be used almost in any blood vessel in the body. Many now release drugs to prevent blood from clotting. |
| Bypass surgery | In this operation doctors replace narrow or blocked coronary arteries with bits of vein from other parts of the body. Is effective for badly blocked arteries where stents can't be used but surgery is expensive and general anaesthesia is involved. |
| Leaky valves | Valves keep blood flowing in one direction must withstand large amounts of pressure. Such may weaken and start to leak so heart becomes inefficient. Person will become breathless will eventually lead to death. Doctors can operate on heart and replace the faulty veins. Mechanical valves made of titanium and polymers, last long, but must take medicine rest of life that prevents blood from clotting. Biological valves are those based on animals like pigs or cattle, work extremely well, and patient doesn't need medication however only last 15 years. |
| Transport in the blood | Blood is a tissue consisting of fluid called plasma which carries red blood cells, white blood cells and platelets suspended in the plasma. Plasma also carries dissolved substances around the body. Average person has between 4 and 5 litres of blood. |
| Plasma | Yellow liquid, transports all blood cells, transports carbon dioxide, urea (a waste product formed in your liver as a result of breakdown of proteins in kidneys urea is removed from blood to form urine) carried to the kidneys in the plasma, all the small soluble products of digestion pass into blood from small intestine carried by the plasma around the body to other organs and individual cells. |
| Red blood cells | These attain oxygen from lungs, carry oxygen to tissues and cells where required. Blood cells have adaptations to make them very efficient: Have biconcave discs that means pushed in at both sides, giving them greater surface area to volume ratio for diffusion of oxygen to occur. The cells are packed full of red pigment called haemoglobin that can carry oxygen. In high concentration of oxygen haemoglobin reacts with oxygen to form bright red oxyhaemoglobin in other organs where concentration of oxygen is low oxyhaemoglobin splits up. Forming purply red haemoglobin and oxygen and oxygen diffuses out of cell. Such this a reversible reaction. Blood cells don't have a nucleus so that there is more space for to pack in molecules of haemoglobin. There are more red blood cells than any other kind of cell with 5 million in each cubic millimetre of your blood. |
| White blood cells | Much bigger than red blood cells and are fewer. Have a nucleus and form part of the bodies defence mechanism against harmful micro-organisms. Some white blood cells form antibodies against micro-organisms, others produce antitoxins, others consume invading bacteria and viruses. |
| Platelets | These are small fragments of cell without a nucleus, important in aiding blood clotting at site of a wound by helping producing a network of protein threads. Threads then capture lots of red blood cells and more platelets in order to form a jelly like clot, stop excessive blooding. Clot dries and hardens to form a scab. Scabs protects skin as it grows and stops bacteria getting into your body through the wound. |
| Artificial blood | Used as without blood would die, transfusions have different blood groups that must be matched, blood can only be stored for limited time and there is often a shortage of blood donors. Some people will not accept blood transfusions for religious reasons, artificial blood development would solve these problems. |
| Plasma or saline | Simplest way to replace blood in an emergency is with donated plasma or even saline (salt water). Plasma carries a little dissolved oxygen however saline doesn't carry oxygen or food. It just replaces the lost blood volume to keep the blood pressure constant. This can allow time for your blood to make more blood or for a matched blood transfusion to be sufficed. |
| Perfluorocarbons (PFC's) | Most sophisticated form of artificial blood are very non reactive substances that can carry dissolved gases around the body. Oxygen can readily diffuse in PFC's. After accidents or surgery capillaries may be squashed almost shut so red blood cells can't get through in this case PFC's can be used as they don't contain cells can carry oxygen into swollen tissues of a damaged body. Can be kept for a long time and don't carry diseases. However don't dissolve in water so getting them into blood is difficult, don't carry as much oxygen as red blood cells so large amounts are needed to supply the body. Also broken down quickly and can cause severe side effects. |
| Haemoglobin based products | Solution made that doesn't include any red blood cells, haemoglobin often taken from human or animal blood although can be synthetically or genetically engineered bacteria. Haemoglobin in solution carries more oxygen than red blood cells and does not need to kept in a fridge. Although is broken down very quickly in the body only lasting 20 to 30 hours. But does not clot or fight disease has also caused severe problems for patients in trials. So far has been unsuccessful in future may save many lives. |
| Artificial heart | Saves lives as many people die before can attain a heart transplant as must wait till donor heart is a match. Temporary hearts have been developed that can support your natural heart until it can be replaced. Since 2004 1000 people have been fitted with artificial hearts, these need a lot of machinery, most patients must stay in the hospital. IN 2010 first person left hospital with artificial heart in backpack always a risk of blood clotting which can be life threatening but new technology can allow for new livelihood until a heart is attained Advantages are don't have to wait for donor, no need to match tissue, no need for immunosuppresant drugs. Disadvantage is size and cumbersome, problems with blood clotting, limited mobility and expensive. |
| Phloem | Transports sugar around the body a product of photosynthesis from the leaves including the growing areas of the stem and the roots where sugars are required for making new plant cells. Food is also transported to the storage organs where needed to provide an energy store for the winter. Phloem is a living tissue. Greenfly and aphids which are plant pest can stick their sharp mouthparts into the phloem and consume sugary fluids if this happens at such a great rate plant can die. |
| Xylem | These move water and mineral ions around the plant from the soil and are comprised of dead living tissue. In woody plants like trees the xylem makes up most of the wood and the phloem is found in a ring just under the bark. Therefore young trees in particular are vulnerable to attack by animals as if the bark is consumed water supply through phloem is broken and plant will die. |
| Why plant transport is important | Very important to move food as a product of photosynthesis around the plant, all cells need sugar for respiration and growth. Movement of water and mineral ions is as important as mineral ions are required for production of proteins and other molecules in cells. Water is required for several reasons: For photosynthesis in order to make sugar reacting with carbon dioxide, in order to hold the plant upright as when cells have plentiful supply of water the vacuole presses the cytoplasm against the cell wall, this pressure gives support for young plants and for structure of the leaf for young plants this is the main method of support. |
| Controlling internal conditions | For body to properly work conditions in the body must stay constant. Through homoeostasis it is able to control internal conditions within a very narrow range. Many of the functions in your body aid to maintain internal environment as constant as possible. |
| Removing waste products | Cells are constantly producing waste products as products of chemical reactions that take place in the body. however the more extreme the conditions the greater amount of waste products produced. The two main waste products are carbon dioxide and urea which cause problems in the body of levels are allowed to increase, |
| Removing waste products: Carbon dioxide | Produced during respiration by every cell in the body vital to be removed as dissolved carbon dioxide produces an acidic solution which would affect the working enzymes in cells. The body is able to remove carbon dioxide by moving the carbon dioxide out of the cell into your blood then through your blood stream to your lungs and them almost all is removed from lungs as you breath out. The air you breath in contains 0.04% carbon dioxide while the air you breath out contains 4% carbon dioxide. |
| Removing waste products: Urea | Extra protein must be broken from worn out body tissue or extra consumed protein. Amino acids cannot be used as fuel for your body so the liver removes the amino groups and breaks it down into urea. The rest of the amino acid can then be used in respiration or to make other molecules. Urea passes from liver cells to blood and is poisonous so if levels build it can cause damage. However it's filtered out of your blood by your kidneys and passed out of the body as urine with excess water and salt. |
| Maintaining body balance | Must control water and ion levels enter the body when you eat or drink and water is lost by breathing sweating and urine while the ions are lost through sweat and urine. This balance is important so cells don't become damaged as if concentrations of bodily fluids change water will move in and out of cells via osmosis which could damage cells. Body temperature is also important if it gets too high or low it can be fatal, plus sugar levels must be controlled as the amount of sugar going into the body and being used is always changing so must be controlled. In these ways homoeostasis plays a key role in our bodies. |
| Functions of kidney | Excretion- Produce urea in liver when break down excess urea, poisonous, kidneys filter out the blood get rid of it as urine stored in bladder. Also vital in controlling water balance, if short of water kidneys conserve it and if too much kidney's get rid of excess. Also important in maintaining mineral ion balance, passed out in the urine. |
| How do kidneys work | Filters your blood then reabsorb everything the body need they have a rich blood supply. Glucose, amino acids, mineral ions, urea and water all move out of the blood into the kidney tubules by diffusion along the concentration gradient. The blood cells and large molecules like protein or too large to diffuse out. All the sugar is reabsorbed back into the blood through active transport. |
| Selective reabsorbption | Amount of water reabsorbed depends on what's needed in the body, selective absorption. Amount of water reabsorbed dependant on sensitive feedback mechanism. Urea lost in urine though some leaves kidney tubules and moves back into the blood by diffusion along the concentration gradient. |
| What urine contains | Waste urea with excess mineral ions and water quantities vary on what has been taken in. On hot day little urine intake so concentrated as has little water relatively dark yellow colour. Cool day drink a lot of liquid excess water dilute light yellow colour almost colourless. Water, glucose, urea and salts are colourless though urine colourless cause of urobilins, yellow pigment from breakdown of haemoglobin in liver. Excreted by kidneys. |
| Kidney failure | Can be damaged and destroyed by infection or genetic problems or accident untreated of both kidneys can result in death. Toxins like urea build up in the body and salt and water balance is upset |
| Dialysis | Machine that carries out the function of a kidney, dialysis machine, reliant on the process of dialysis to clean out blood where persons blood leaves the body and flows through partially permeable membrane. From which on the other side of these membranes are dialysis fluids, containing the same concentration of useful fluids as in the blood. Dialysis treatment restores the concentration of these dissolved substances to normal levels. Overtime other substances build up so dialysis must be carried out at regular intervals. Takes eight hours for dialysis to complete, have to remained attached to the machine for several hours several times a week. Must also manage their diets, must keep blood chemistry as stable as possible. |
| How dialysis works | Loss of useful substances is prevented careful control of dialysis fluid, containing the same concentration of fluids and mineral ions in the body, meaning there is no net movement of glucose and useful mineral ions out of the blood. Ensures glucose and mineral ions aren't lost. As dialysis fluid contains normal plasma levels of mineral ions any excess ions are removed from the blood, by diffusion along the concentration gradient. Dialysis fluid contains no urea, steep concentration gradient from blood to fluid, large proportion of urea leaves the body, there is no active transport. In 1964 home dialysis machines were made available for the first time though they are big and expensive. Over many years the balance of substances in the blood can become difficult to control. Keeps people with kidney failure alive, mirrors the action of the kidney in the body. |
| Kidney transplants | Diseased kidneys can be replaced in a kidney transplant using a healthy kidney from the donor. Healthy kidney joined to a blood vessel in groin of the recipient. Aim is for it function normally to clean and balance the blood. One kidney can balance your blood chemistry and and remove waste urea for a lifetime. |
| Kidney transplants: The rejection problem | Antigens of the donor will be different to the recipient, risk antibodies of the immune system of recipient will attack the antigens of the donor. Resulting in rejection and destruction of donated kidney. Ways of reducing risk of rejection: Match between antigens of donor and recipient can be matched as closely as possible, can use a donor with a tissue type very similar to the recipient. Recipient given immunosuppressant drugs to suppress their immune system for the rest of their lives, helps prevent rejection of kidney, drugs are constantly improving, so now the need for a really close kidney tissue match is reducing. Disadvantage drugs prevent patient dealing with infectious disease, must take care if become ill, though relatively low price to pay for new kidney. Transplanted organs only last average 9 years, yet some last longer, once organ fails must return to dialysis and wait for another suitable kidney to be found. |
| Dialysis vs transplants | Kidney transplants free from restriction that come from regular dialysis, you can also eat what you want, almost normal life. Disadvantages are risk of rejection, must take medicine daily in case kidney is rejected, must have regular check ups to identify if kidney has begun to reject the organ. Largest disadvantage is that you many ascertain the chance to have a kidney transplant. Dialysis more readily available than kidney transplant, enables to lead a relatively normal life. Disadvantages are you must eat a special diet, and take regular sessions on the machine for prolonged periods of time, long term dialysis can be more expensive than kidney transplant. |
| Finding kidney donor | Main source is from those who suddenly die, often road accidents or stroke or heart attack. In UK organs can be taken from people if they carry an organ donor card or are on the online donor register. Relative of someone who has recently died can be given consent. Never enough kidney's to go around, many don't register to become donor and as cars improve their fewer accidents. Thousands of people are constantly having dialysis, don't have opportunity for kidney transplant. 2008-9 2497 had kidney transplant, at the end of year still 7000 on dialysis waiting for a kidney. Scientists working on xenotransplantation producing genetically engineered pigs with organs that can be used for human transplant. Others hope stem cell research will produce way of growing new kidney on demand, so no one dies waiting for suitable organ to become available. |
| Controlling body temperature | Body temp must constantly be around 37 degrees celsius, optimum temperature for enzyme function, skin temperature can vary without detriment. Though core body temperature must be kept stable, with only a few degrees change enzymes don't properly function Things can affect internal body temperature: - Energy produced in muscles during exercise - Fever caused by disease - External temperature rising or falling |
| Basic temperature control | Change clothing, light fire, turn on air conditioner or heater. Control of core body temperature relies on thermoregulatory centre in the brain, containing receptor sensitive to temperature change, monitor temperature of blood flowing through brain. Extra info from receptors on skin send impulses to brain can determine change in 0.5 degrees celsius. If temperature increases too much lead to sweat glands release more sweat cooling the body down. Sweating makes you lose water and mineral ions, must restore this. Skin may become redder as blood flow around at a faster rate, cooling it down. Will look paller if become cooler less blood flows through skin, lose less energy. |
| Cooling the body down | If get too hot enzymes denature and can no longer catalyse reactions, when core temperature begins to rise impulses sent from the thermoregulatory centre to the body so energy is released: - Blood vessels supply your skin capillaries dilate, allowing more blood to flow through, skin flushes so lose more energy through radiation - Rate of sweating increases extra sweat cools the body down as it evaporates. In humid weather when the sweat doesn't evaporate much harder to cool down. |
| Reducing energy loss | If get too cold rate of enzyme controlled reactions becomes too slow to sustain life as cells begin to die. If core body temperature falls to low impulses sent from thermoregulatory centre to body to conserve and release more energy. - Blood vessels that supply your skin capillaries contract to reduce blood flow through the capillaries, reduces energy released by radiation through skin - Sweat production reduced, less sweat evaporates so less energy is released - May shiver, muscles contract and release rapidly, results in respiration and release of energy, raises body temp as raises stop shivering stops. |
| Treating kidney failure | Issues ( yeah i got them): - Some developing countries people will sell one of their kidneys, need money to pay for food, medicine or education for family. US shortage of organ donors, suggested people could be paid for to go on the organ donor register. Families become desperate with loved one has kidney failure may buy from illegal market. - Many families who lose a loved give consent for organ donation, knowing loss has given other people a chance of life is a comfort - Transplants and dialysis costly, in UK 3% of NHS budget spent on dealing with kidney failure problems. Average cost yearly of dialysis is 30800 pounds while cost of kidney transplant around 17000 pound and immunosuppressant drugs cost 5000 pounds yearly - 23000 people in UK who have had kidney transplant, improving quality of life, saves NHS 512 million pounds yearly compared to keeping patients on dialysis. |
| Donor cards | In UK people can sign up to become organ donor at same time attain driving licence many don't even though filling out register is short. Many not considering death or CBA. In other countries everyone on the donor list until opt out, provides more organs for transplantation. Suggesting method could be used in the UK |
| Too hot or too cold | If body temperature below 35 degrees celsius then suffering from hypothermia normal working of body affected. Very young and old are more at risk. first signs are extreme tiredness, not wanting to move, may not realise how cold you are, skin cold to touch, face goes greyish blue and puffy with blue lips. Become drowsy and speech becomes slurred. Eventually stop shivering and as enzymes don't work. 30000 die from hypothermia each year in UK, mainly during winter months, contributes to excess winter mortality. Excess heat is bad, heat stroke happens when body is too hot. Most common cause is very hot, humid weather, with exercise as exercise releases energy. So hot and humid sweat can't evaporate to cool you down if don't drink enough you can't sweat can't lose energy. Body temp keeps going up stop sweating and skin becomes flushed and red. Become confused seeing hallucinations eventually go into a coma and die! Very old and young at risk so are very active young people |
| Controlling blood glucose | Important have constant supply of glucose needed for respiration, system in body that controls this within narrow limits. |
| Insulin and control of blood glucose levels | Without control system blood glucose levels would enormously vary; very high after a meal and very low several hours later - so low cells wouldn't have enough glucose to respire. Situation prevented by pancreas; small pink organ found under the stomach - constantly monitors and controls glucose concentration using two hormones, one known as insulin. When blood glucose concentration rises insulin released allows glucose to move from blood to cells and converts glucose into an insoluble carbohydrate glycogen. Insulin controls the storage of glycogen in the liver glycogen converted back to glucose when required - your blood glucose stays stable within a narrow range of concentrations. |
| What causes diabetes | If pancreas doesn't make enough or any insulin cannot control glucose concentration - type 1 diabetes. Without diabetes glucose concentration get very high after exercise, eventually kidney excrete glucose through urine. Produce lots of urine and constantly thirsty. Without insulin glucose can't get into the cells of the body, so lack energy and feel tired, lethargic. Break down fat and protein to use as fuel so lose weight. This type usually starts in young children and teenagers. Before there was treatment people would eventually fall into a coma and die. |
| Treating diabetes | If have type 1 diabetes require replacement insulin before meals - a protein digested in the stomach. Usually as an injection to get into the blood. Injected insulin allows glucose to be taken into your body cells and converted into glycogen in the liver. Stops concentration of glucose in the blood from getting too high. As blood glucose levels fall the glycogen is converted into glucose - blood glucose levels kept as stable as possible. If you have type 1 diabetes must be careful about mount of carbohydrate eat, must have regular meals, must regularly exercise to keep heart and blood vessels healthy. Need careful planning to keep your blood sugar levels steady and cells supplied with glucose. Insulin injections treat diabetes successfully but don't cure it for people with type 1 diabetes will have to take these injections daily for the rest of their lives. |
| Glucagon and control of blood glucose levels | When blood glucose concentration falls below the ideal range glucagon is secreted. This makes your liver break down glycogen converting it back to glucose. - Storage glucose released into the blood By using two hormones and glycogen store in liver blood glucose concentration kept fairly constant. |
| Treating diabetes: Using insulin from other organisms | In early 1920s Charles Best and Frederick Banting made dogs diabetic by removing their pancreas. Gave them extracts of pancreas taken from other dogs containing insulin found could use extracts of animal pancreas to treat humans with diabetes, many dogs died but millions of people have been saved. For years insulin from cows and pigs were used to treat humans yet the insulin is not identical and supply depended on the amount of animals that were killed for meat, sometimes not enough insulin. Recently genetic engineering has been used to develop bacteria that can produce human insulin, genetically identical to human insulin and supply is constant. Now used by most people with type 1 diabetes, though there are some ethical concerns. |
| Curing type 1 diabetes | None are widely available: Doctors can successfully transplant a pancreas though this is difficult and risky. Operations only done on hundreds in UK each year in UK. 25000 people with diabetes in UK, not enough donors and must use immunosuppressants. Transplanting the pancreatic cells that make insulin from both dead and living donors has been attempted but with limited success. In 2005 scientists produced insulin secreting cells from embryonic stem cells and used them to cure diabetes in mice. In 2008 scientists using genetic engineering they use mouse pancreas cells that usually make enzymes to produce insulin. Other groups are using stem cells from diabetic patients. Hope eventually be able to genetically engineer human pancreatic cells so work properly, being able to return to patient without any rejection problems as they were initially theirs. Seems easiest solution would be to use stem cells from human embryos specially created for the process - for some not ethically unacceptable. |
| Treating type 2 diabetes | Often result of obesity or lack of exercise or both, pancreas still make insulin but less. Cells stop properly responding to insulin. Can be treated by: - Eating a balanced diet controlling carbohydrate intake - Losing weight - Doing regular exercise Drugs that: - Help insulin work better on the body cells - Help pancreas make more insulin - Reduce the amount of glucose you absorb from your gut. If none of these treatments work insulin infections will be used - this type often affects old increasingly affecting the young. |
| Effects of population expansion | Changes made have driven species to extinction some worry may be threatning our own survival. |
| Human population growth | In past 200 years human population has rapidly grown by 2010 almost 7 billion growing now. If happened to other species nature would restore balance: predators, lack of food, buildup of waste product or disease. Though this doesn't apply to humans have overcome these 'problems'. Standard of living has improved in UK vast amounts of electricity and fuel provide energy for homes and work. Use fossil fuels to produce electricity oil to produce electricity, oil based fuels to cars, planes, trains and boats and to make materials like plastic. |
| Effect on land and resources | More land used for building of houses, shops, industrial sites and roads. Some destroy habitats of living organisms. Use billions of acres of land for farming - natural animal and plant populations are destroyed. In quarrying dig up great areas of land for resources it holds like rocks and metal ores - reduces land use for other organisms. Population drains earth resources raw materials being used up many of which are non renewable like natural gas, once metal ores processed cannot be replaced. |
| Managing waste | Increasing amount of waste: human bodily waste, rubbish from packaging, uneaten food and disposable goods - dumping of waste reduce amount of land available to organisms apart from scavengers. Has been an increase in manufacturing and industrial activity as a result more industrial waste. Waste produces presents a problem - if not properly treated can lead to pollution. Water can be polluted by sewage, by fertilizers from farms and toxic chemicals from industry. Air we breath in may be polluted by smoke and poisonous gases like sulfur dioxide. land itself can be polluted by toxic chemicals from farming like pesticides and herbicides. Can also be contaminated by industrial waste like heavy metals, chemicals in turn can be washed from the land into waterways. If population continues to affect our ecology everyone will be affected |
| Polluting the land | People pollute the world in different way as population grow so does pollution - more bodily waste and sewage from homes. If not properly treated, soil becomes polluted with chemicals and gut parasites. In developing world large amounts of household and hazardous industrial waste. Household waste goes into landfill sites, take up a lot of room and destroy natural habitat. Toxic chemicals can spread from the waste into the soil. Toxic chemicals also a problem in industrial waste, can posion soil for miles around ex. Chernobyl nuclear accident (1986) soil contaminated for thousands of miles away from original accident. 30yrs later some sheep in Chernobyl cannot be sold due to high radioactivity. Land can be polluted due to side effect of farming - weeds compete with crops for light, water and mineral ions. Animal and fungal pests attack crops and eat them. Farmers increasingly use chemicals to protect their crops. Herbicides (weedkillers) kill weeds but leave crops unharmed, pesticides kill insects that might otherwise attack crops. |
| The problem with pesticides and herbicides | They are poisonous and when sprayed on plants can get into the soil from there they can be washed out into streams and rivers. Can also become part of the food chain as toxins get into the organisms that feed on plants or live in the soil. Leads to dangerous levels of poisions building in top predators |
| Polluting the water | Growing pop means growing need for food, add fertilizers to soil to ensure it's fertile. Minerals in fertilizers contain nitrates easily washed from the soil into local streams, ponds and rivers. Untreated sewage that runs into waterways and pumped into sea also contains high concentrations of nitrates. Nitrates and other minearals cause plants to grow rapidly, die to competition for light others die naturally. Large increase in microorganisms feeding on these dead plants, increase in decomposer reduces oxygen levels dissolved in water not enough to support fish and other animals - die and decomposed by more microorganisms - use even more oxygen. Eventually oxygen levels become so low that all aquatic animals die and pond or stream becomes 'dead' - called eutrophication. |
| Polluting water: Toxic chemicals | Like pesticides or herbicides or poisonous chemicals from landfill sites can also be washed into waterways. Same effect on aquatic life food webs as those on land. Largest carnivorous fish die or fail to breed due to build up of toxic chemicals in their bodies. In countries (many) including UK there are restrictions on use of chemicals in farms. Same applies to treatment of sewage and to landfill sites, to help avoid these problems arising. |
| Measuring pollution levels in water | Oxygen and pH levels can be measured using instruments, water can be analysed to show the level of polluting chemicals like pesticides or industrial waste. Bioindicators - species which can only be found in clean or polluted water - used to monitor pollution levels in our waterways. |
| Air pollution | When air polluted everyone affected - major source burining of fossil fuels. |
| Formation of acid rain | When fossil fuels are burned, carbon dioxide released into the atmosphere - waste product. Also often contain sulfur impurities, react with oxygen when burn to form sulfur dioxide. Ex. At high temperature in car engines nitrogen oxides are released into the atmosphere. These can cause serious breathing problems is concentrations get too high. Sulfur dioxide and nitrogen oxides also dissolve in rainwater and react with oxygen in the air to form dilute sulfuric acid and nitric acids. Produces acid rain measured with a pH of 2 - more than vinegar |
| Effects of acid rain | Directly damages the environment - if falls onto trees may kill the leaves and if falls into soil the roots. Whole ecosystem can be destroyed. Can also have an indirect effect on the environment - as falls into lakes, rivers and streams water becomes slightly acidic. If concentrations of acids become too high animals and plants can die. Difficult to control as formed from factory pollution. Comes from cars and vehicles used everyday. Sulfur dioxide and nitrogen oxides carried high in the air by wind - neighbouring countries have fullest effect. Their clean air benefits others. |
| Solutions to acid rain | UK + other countries working to reduce pollution from factories, vehicles and power stations. Introduced measures to reduce amount of sulfur dioxide and nitrogen oxides in the air. Low sulfur oil and diesel now used in vehicles. More and more cars fitted with catalytic convertors - once hot remove nitrogen oxides before released into the air. Strict rules concerning the levels of sulfur dioxide and nitrogen oxides exhaust fumes in new cars. In UK introduced cleaner lower sulfur fuels like gas in power stations and started generating electricity from nuclear power. Also put systems in power station chimneys to clean the flue gases before released into the atmosphere. Result levels of sulfur dioxide and acid rain in the air has reduced over the last 40 yrs. Many European countries have done the same, though many countries still have no controls in place. |
| Global dimming | Form of air pollution - increase in number of tiny solid particles in the air, sulfur products from burning part of problem so is smoke from any part of burning. Particles reflect sunlight so less light hits the surface of the Earth - causes a dimming effect. Global dimming can result in cooling of temperatures at earth's surface. In Europe by controlling sulfur emissions and smoke effect being reversed while in other countries continues to get worse as population increases. |
| Deforestation and peat destruction | As world pop grows need more land, food and fuel. One solution to this has been cutting down large areas of forests. Lost of forests may have long term effects on environment and ecology of the Earth. |
| Effects of deforestation | When forests used for farming tress are felled and are burned known as slash and burn clearence. Wood isn't used its burned. Land used is only fertile for short durations of time after which forest is destroyed and no trees are placed in replacement. Deforestation increases the amount of carbon dioxide as trees are burned so carbon dioxide is released through combustion. Dead vegetation left behind decays attacked by decomposing microorganisms releasing carbon dioxide. Also leads to loss of carbon dioxide 'sink' as plants take in carbon dioxide from the air through photosynthesis and lock it up in plant material like wood. |
| Loss of diversity | Tropical rainforest contain the most diversity of living organisms than any other land environment. If lose forests lose biodiversity as many species of animals and plants die out. Many of which have not been identified or studied - could destroy sources of new medicines or food for the future. Deforestation taking place at an enormous rate. In Brazil area of quarter of UK lost each year. When forests cleared often replaced by a monoculture (single species) like oil palms - process greatly reduces biodiversity. |
| Cows, rice and methane | Much of deforested land used to produce food for growing population - one of the food is rice - as rice grows in swampy conditions, paddy fields, methane is released - another gas that affects global warming - ows to it. Another food and source of methane are cattle. Cows produce methane through their digestive breakdown and release it into the atmosphere at regular intervals. Recently number of cattle raised to produce cheap meat - burgers - has grown enormously. So levels of methane are rising - many of these cattle are raised on farms created by deforestation. |
| Peat bog destruction | Peat bogs another resource widely destroyed - peat bogs form over thousands of years - usually in marshy areas. Made of plant material that cannot decay completely because the conditions are very acidic with a lack of oxygen. Peat acts as a massive carbon store. Peat can be burned as a fuel also widely used by gardeners as helps improve qualities of the soil. When peat burned or used in gardens, carbon dioxide released into the atmosphere and carbon store is lost. Peat formed very slowly so being destroyed faster that it is being created. In UK gov trying to persuade gardeners to use alternative 'peat free' composts to reduce carbon dioxide emissions. Compost can be made from bark, from garden waste, from coconut husks and other sources - problem persuading gardeners to use them. |
| Global warming | The climate of the Earth is getting warmer. |
| Changing conditions | For millions was natural balance carbon dioxide released by living things into the atmosphere from respiration matched by the amount removed. Carbon dioxide removed by plants for photosynthesis and huge amounts dissolved in the oceans, lakes and rivers. Say carbon dioxide is sequestered in plants and water, or carbon dioxide and water act as a carbon dioxide sink. As result carbon dioxide levels in air stayed constant for a long time. Though now through human activity carbon dioxide levels increasing and number of plants available are decreasing. So natural sinks can't cope - levels of carbon dioxide in the atmosphere are building and level of methane are rising too. |
| Energy from the sun reaches the Earth and much is radiated back to space, though greenhouse gases like carbon dioxide absorb some of it's energy so it can't escape. As result Earth and the atmosphere is kept warm - ideal for life. As carbon dioxide and methane act like a greenhouse around the Earth - known as greenhouse gases. Way in which they keep the surface of the Earth warm is the greenhouse effect - vital for life. | |
| Global warming | As level of carbon dioxide and methane greenhouse effect is increasing. More greenhouse gases in the atmospehere to trap the energy of the Sun and temperature of the Earth's surface is going up very small only about 0.55 degrees celsuis from 1970 to present day. Not much but an increase in only a few degrees can cause: - Changes in Earth climate: see an increase in severe and unpredictable weather conditions. Some think high winds and severe flooding early result of this - Rise in sea levels: If earth warms up lead to ice caps of north and south poles and glaciers melting, owing to rising sea levels. Evidence already happening will mean more flooding for low lying shores and parts of countries even whole countries. - Reduced biodiversity: Many organisms unable to survive, becoming extinct - loss of polar bears - Changes in migration patterns: Migration patterns of birds, insects and mammals may change - Changes in distribution: Some animals may extend range as conditions become more favorable other range will shrink. As temp rise less carbon dioxide can be held in water. |
| Biofuels | Renewable form of fuel - production of biofuels has become increasingly important in all countries. Their made from natural products by fermentation using yeast or bacteria. Two main types of biofuels - ethanol based fuels and biogas. |
| Ethanol based fuels | Some deforested land used for biofuel crops which grow rapidly. Sugarcane grows 4 to 5 meters in a year and maize (sweetcorn) is also fast. Sugar rich products are fermented anaerobically with yeast. Producing ethanol and carbon dioxide. Can extract the ethanol by distillation and use it in cars as fuel. Car engines need special modification to run pure ethanol as fuel, though this isn't major, though many cars can run a mixture of oil and ethanol without these modifications. |
| Advantages of ethanol as fuel | Efficient and doesn't produce toxic gases when you burn it - much less polluting. You can mix ethanol with conventional petrol to make a gasohol which greatly reduces pollution emissions. This is a carbon neutral process as there is no overall increase in carbon dioxide in the atmosphere when you burn it - the plants take in carbon dioxide through photosynthesis when it's burned it's returned to the atmospehere. |
| Disadvantages of ethanol as a fuel | Takes a lot of plant material to produce ethanol - use of ethanol limited to countries with adequate space and climate to grow plant. Attempting to find ways of producing economically viable quantities from plants that grow fast and well in Europe - tried pine trees - looking at fast growing grasses. |
| The latest biofuels | Main problem finding enough ethanol, if Europeans added 5% ethanol to fuel need 7.5 billion litres of ethanol yearly - lots of plants. Main method of ethanol production use edible parts of plants which many people could use to eat. Aim is to make it work ethically and financially in the future - must find way to use waste cellulose rich biomass rather than edible parts of plants. Latest biofuels use bacteria, enzymes, steam or chemicals to breakdown the cellulose in biomass - use straw and woodchips as raw materials. End product are sugars which can be respired by yeast to make ethanol |
| Biogas | Becoming more and more important produced naturally in sewers and and rubbish dumps - increasingly used as a fuel around the world. |
| What is biogas? | This is a flammable mixture of gases - formed when bacteria breaks down plant material or animal waste products in anaerobic conditions. Biogas is mainly methane but composition of mixture varies. Depends on what's put in generator and which bacteria are present. |
| Biogas generators | When bacteria decompose waste material in anaerobic conditions they produce methane - flammable gas can use as fuel for cooking or heating. Can also use to produce electricity or as car fuel. Bacteria involved in biogas production best a 30 degrees celsuis - work best in hot countries. Though this is an exothermic reaction so if put energy in initially and is well insulated can work anywhere. Slurry can also be used as fertiliser. |
| Scaling up biogas generators | Now operate on small scale, supplying energy needs of a family or farm at most a village. 7 million biogas generators in China produce as much as 22 million tonnes of coal - waste vegetable, animal dung and human faeces - mainly raw material. Excellent for fertilizer but low quality biogas. size and design depends on local conditions - some underground for better insulation others above as cheaper and easier to install. Many countries now look at biogas generators and experimenting on them on large scale. Waste material produced from sugar factories, sewage farms and rubbish tips can be used to produce biogas. In UK relatively slow only starting to use be used. Herds of cattle containing several thousand cows produce large amounts of slurry. Can be used to produce biogas in turn produces electricity already done in US and Saudi Arabia could be done in UK. Important fuel in future can get rid of waste - provide clean renewable source of energy. |
| Food chains in food production | In developed countries much diet consist of protein - cows, goats used to produce meat eat plants - by time reaches us much of the plant's energy has been used. Some cases even feed animals to animals - ground up fish often part of chicken feed. More stages the less efficient, limited amount of earths surface that can be used for food - most efficient food is growing plants and eating them as these have the least stages. Biomass produced by plants would be used to feed people producing human biomass would have less hunger |
| Artificially managed food production | Farmers applies ideas of lost energy through movement and excretion to make food production more efficient - cheaper. want maximum amount of biomass without feeding more. Accomplished by: - Limiting animal movement (enclosed spaces) , don't use muscles for movement so have more biomass available from food for growth. - Controlling surrounding temperature so animals will not have to use too much energy to keep warm or cooling down, leaving more biomass available for growth. Happens in massive poultry rearing sheds where much of the chicken we eat comes from. |
| Efficient farming | Birds kept in sheds can be ready to eat within weeks - always have plenty of food with little room to move - risk of disease spreading so close together so must constantly be monitored which is costly but can be sold for meat very quickly. Animals reared in this way can appear more as factory products - factory farming. Method used due to increased demand for cheap meat - only way farmers can meet demand. Other hand animals live restricted unnatural lives. Birds reared outside grow more slowly but have better quality of life. Takes more space, time and weather can b e problem but don't have to pay for heating or lighting. More aware of how our cheap meat is produced - more intensive systems being developed with greater awareness of animal welfare issues. |
| Food miles | Another aspect of efficiency is how far the food travels. Greater distance more fuel more carbon dioxide emissions - people more aware and many buy food grown relatively locally. |
| Sustainable food production | As human pop grows must be more aware of sustainable food production - producing foods in ways we can continue to for years. Involves maintaining health of soil so plant crops grow well overtime. Involves taking care of fish stocks in the ocean so they don't run out. |
| Managing the oceans | In past 60 years commercial fishing fleets of large shipping companies have been built - capable of taking large quantities of fish at a time - uncontrolled overfishing, stocks of edible fish being depleted. Important to maintain fish stock at level where breeding continues successfully. Serious restrictions on fishing are being put in place. Can controlling the size of holes in the nets so only big fish are caught can also be bans on fishing in the breeding season and strict quotas imposed on fisherman - sustainable fishing. |
| Mycoprotein production | New food based on fungi produced known as mycoprotein - means protein from fungus. Grows and reproduces quickly on a relatively cheap sugar syrup in large specialised containers called fermenters. Fusarium, the fungus used to grow this, needs aerobic conditions to do so. In optimum conditions it can double its mass every two hours. Sustainable food source as uses cheap food and reproduces quickly |
| Fermenter | Designed to react to changes keeping conditions as stable as possible - attain maximum yield: Air supply to provide energy for respiration for the fungi Stirrer to keep microorgaims suspended, ensure temperature constant without and oxygen throughly mixed Many have paddles act as stirrers, but for mycoprotein fermenters gases bubble through and mix the contents together Water cooled jacket used to remove excess energy released by respiration - rise in temperature used to heat water which is replaced by cold water Measuring instruments constantly monitoring conditions like pH and temperature so neccessary changes can be made |
| Mycoprotein processing | fungal biomass harvested and purified - dried and processed to make mycoprotein - pale yellow solid with a faint taste of mushrooms, though on its own it has very little flavour. Given flavour and texture to make it similar to normal food. High protein low fat alternative protein content similar to that of prime beef. Used by vegetarians and those who want to reduce their weight. When first made people believed that world food shortage was occurring didn't happen but this cheap and efficient protein surfaced. High in protein, fibre, low in fat and calories and sustainable - widely used in developed countries |
| Food and water - a vicious cycle? | Grow pop need more water and food through can impact environment. Need water as much as food so do animals. Way of supplying water is a dam - creates a reservoir source of drinking water and for irrigating crops. Environmental issues: Destroy ecosystem in particular below the dam where rivers may be completely lost can cause huge areas to dry out. Floodplains with fertile soil disappear can no longer be used for farming Environments destroyed as resevoirs forms so animals, plants and human lose homes Act as breeding ground for mosquitoes who can spread disease Can add methane to the environment as eutrophication can occur. |
| How can we be sure of greenhouse effect | Build up of greenhouse gases is evidenced believe global warming at least partially due to human activities. Throughout history evidence of extreme patterns similar to those occurring today - before deforestation and all. Weather not same as climate which is weather in area over long periods of time. Validity, reproducibility and repeatability of data must be ensured scientists take daily readings - temperature of Earth overtime, cores of ice thousands of years old, rings of tree trunks and type of pollen in peat bogs. Much evidence published by well respected journals but some controversy 2009 didn't publish data that showed global temperature was falling slightly - must govs now convinced must change ways to limit damage global warming could do |
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