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88 Cards in this Set
- Front
- Back
Osmosis
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Diffusion of water from a dilute to a more concentrated solution
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What can pass through a partially permeable membrane?
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Water molecules
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Most soft drinks contain
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Water, sugar and ions
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Why do sports drinks contain sugar?
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To replace the sugar used up during exercise
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Why do sports drinks contain ions and water?
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To replace those that are lost from sweat during exercise
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What happens if during exercise we do not replace the lost sugars, water and ions?
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Our cells will not work as efficiently
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Active transport
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When substances are absorbed against the concentration gradient which requires energy from respiration
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How does having a large surface area make exchanging materials more effective?
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More cells are exposed so that they can absorb more substances
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How does being thin make exchanging materials more effective?
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This makes the distance path shorter and so will take less time
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What traits in animals help make exchanging materials more effective? (2)
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Having an efficient blood supply
Being ventilated |
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The size and complexity (number of cells) increases
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The difficulty of exchanging materials
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The surface are of the lungs is increased by
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Alveoli
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The surface area of the small intestine is increased by
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Villi
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Villi absorbs the products of digestion by
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Active transport
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How does the breathing system work?
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The oxygen from the air taken in from the lungs uses red blood cells to diffuse into the bloodstream
Carbon dioxide made from respiration diffuses out of the bloodstream back into the air |
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Ventilation
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The movement of air into and out of the lungs
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What happens during inhalation?
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Oxygen moves into the lungs
The intercostal muscles move the ribcage up and out so that the diaphragm contracts This increases the volume in the thorax - lowering the pressure inside in comparison to outside the body, making air rush in |
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What happens during exhalation?
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Carbon dioxide moves out of the lungs
The intercostal muscles move the ribcage down and in so that the diaphragm relaxes This decreases the volume in the thorax - increasing the pressure inside in comparison to outside the body, making it rush out |
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How does carbon dioxide enter the leaves of a plant?
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Through diffusion
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What is the advantage of root hairs?
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Larger surface area for absorbing more water and mineral ions
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How is the surface area of leaves increased?
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Flattened shape and air spaces
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Why do plants have stomata?
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To obtain carbon dioxide from the atmosphere and remove oxygen produced in photosynthesis
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Where is water vapour lost in plants?
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In the stomata of the leaves
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In what conditions is water evaporated most in plants?
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Hot - because the water will gain enough kinetic energy to evaporate
Dry - as there is more water on the plant than in the air (diffusion) Windy - since it would simply be carried off |
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What do plants do to prevent wilting?
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The stomata closes when more water is being lost than what is being gained to replace it
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What controls the size of the stomata?
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Guard cells
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Describe the function and structure of the heart
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The heart is an organ which pumps blood around the body
It is made up of left and right atria and ventricles The wall of the heart is made of muscle tissue |
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Arteries
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Transport blood away from the heart
Have thick walls containing elastic fibresin order to carry the blood under high pressure |
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Veins
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Transport blood to the heart
Have thinner walls with valves because it carries blood under low pressure so it needs to avoid backflow |
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Coronary arteries
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Deliver blood to the heart
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What is the effect of cholesterol on blood vessels? What is done if this happens?
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Forms plaques narrowing the tube and so restricting the blood flow - which if occur in the coronary arteries can cause heart attacks
Stents are used to keep them open |
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Capillaries
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Carry blood to cells for transporting substances via blood
Has thin walls (only one cell thick) for easier diffusion |
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How does the heart pump blood?
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Blood enters the atria which then contracts, forcing the blood down into the ventricles
The ventricles then contract forcing the blood out of the heart |
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Double circulation system
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The heart supplies blood using 2 main pathways - one for the lungs and the other for the rest of the body
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The pulmonary artery and vein supply what with blood?
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The lungs
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The aorta and vena cava supply what with blood?
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The rest of the body
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What side are the pulmonary vein and aorta and what do they carry?
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Left side
They carry oxygenated blood |
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What side are the pulmonary vein and vena cava and what do they carry?
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Right side
They carry deoxygenated blood |
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What is blood and what is it consisted of?
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Blood is a tissue which contains white blood cells, red blood cells, plasma and platelets
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What does blood plasma transport? (3)
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Carbon dioxide from the organs to the lungs
Soluble materials from the small intestine to the organs Urea from the liver to the kidneys |
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Haemoglobin
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A red pigment which is in red blood cells
In the lungs it combines with oxygen to form oxyhaemoglobin; in other organs the oxyhaemoglobin splits back into haemoglobin and oxygen |
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Red blood cells
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Transport oxygen from the lungs to the organs
They have no nucleus so that there is more space for oxygen |
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White blood cells
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Part of the body's defence mechanism against microorganisms
They have a nucleus |
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Platelets
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Fragments of cells which helps the blood to clot at the site of a wound
Has no nucleus |
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Xylem tissue
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Transports water and mineral ions from the roots to the stem and leaves
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Transpiration stream
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The movement of water from the roots through the xylem and out of the leaves
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Phloem tissue
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Transports sugar from the leaves to the rest of the plant (for growth and storage)
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What waste products need to be removed from the body? (2)
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Carbon dioxide - which is produced in respiration and removed via the lungs
Urea - produced in the liver by the breakdown of excess amino acids and removed by the kidneys as urine which is stored in the bladder until urination |
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If we drink too much or too little water
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The water and ion content is wrong meaning that too much water may move into or out of the cells by osmosis, damaging the cells
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How do the kidneys produce urine?
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It filters the blood and then absorbs all the sugar and only the ions and water that it needs
All of the urea and excess water and ions is released as urine |
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What is a dialysis machine used for and what does it do?
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People with kidney failure
It has the correct concentrations (the same as blood) of dissolved substances so the blood goes back to normal levels through partially permeable membranes Blood flows in and waste substances such as urea and water leave, just like a normal kidney would |
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A diseased kidney can be replaced with a healthy one from a
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Donor
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What are the advantages and disadvantages of dialysis?
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There is no risk of rejection and is easier to get than getting a replacement kidney
You have to go through the process very frequently |
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What are the advantages and disadvantages of a kidney transplant?
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If successful the patient can lead a normal life
The kidney may be rejected by the person's immune system or get infected |
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Why may the body "attack" the donor organ?
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Our body will not be able to recognise its antigens and so antibodies may "attack" it
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Antigens
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Proteins on the surface of cells
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How can we help prevent a transplanted kidney being rejected? (2)
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The chosen kidney will have similar "tissue-type" to their one before
The patient is given drugs which suppress the immune system |
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Body temperature is monitored and controlled by the
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Thermoregulatory centre in the brain which has receptors sensitive to the temperature of the blood flowing through the brain
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Temperature receptors in the skin send
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Impulses to the thermoregulatory centre in the brain also providing information about the body's temperature
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What happens if our core body temperature is too high? (2)
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The sweat glands release more sweat which cools down the body as it evaporates
The blood vessels dilate supplying the skin capillaries with more blood closer to the surface of the skin so more heat is lost |
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What happens if our core body temperature is too low? (2)
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Muscles contract rapidly causing them to shiver which needs respiration. More energy is released in order to heat up the body
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The blood glucose concentration in our body is controlled by the
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Pancreas
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What does the pancreas do?
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Produces the hormones insulin and glucagon
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What does the hormone insulin do?
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Allows glucose to move from the blood into our cells
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What happens if blood glucose levels fall?
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Glucagon causes glycogen to be converted into glucose which can be released into the blood
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Liver stores excess glucose as an insoluble molecule called
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Glycogen
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The body secretes insulin when
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The body's blood glucose concentration is too high
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Type 1 diabetes
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A disease which means that a person cannot produce enough insulin
As a result, that person is at danger of their blood glucose concentration becoming too high |
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How may type 1 diabetes be controlled? (3)
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With careful attention to diet, exercise and by injecting insulin
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Unless waste is properly handled
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More pollution will be caused
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Why is more waste being produced?
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Rapid growth in the human population
Increase of the standard of living |
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Waste may pollute (3)
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Water - by sewage, fertiliser and toxic chemicals
Air - by gases such as sulphur dioxide which leads to acid rain (destroying habitats) Land - by pesticides and herbicides which can be washed away into waterways |
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Why is there less land available?
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We are using it to build, quarry, farm and dump our waste on
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What are the reasons for deforestation? (3)
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Timber
To provide land for agriculture - crops from which biofuels, based on ethanol, can be made We can use some of the products for medicine |
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What are the disadvantages of deforestation?
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Burning the wood releases carbon dioxide into the atmosphere
Reduces the biodiversity as it destroys habitats Rice fields and cattle which can be moved onto the new land release methane meaning that more methane is being released into the atmosphere |
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Peat bogs store
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carbon dioxide which means that by damaging them you release that stored carbon dioxide into the atmosphere
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Peat bog
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Marshy ground which contains partially dead material which can be burned or used to make soil better
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Why is "peat free" compost of increasing importance?
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Doesn't release carbon dioxide
Does not use up the peat required for dragonflies and birds to survive Develops quicker than peat compost |
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What contributes to global warming?
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An increase of carbon dioxide and methane
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What are the effects of global warming? (5)
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Changes climates
Sea levels rise Reduces biodiversity Changes migration patterns Changes the distribution of species |
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How can oceans and lakes remove carbon dioxide from the atmosphere?
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Sequestration
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Biofuels
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Natural products containing carbohydrates anaerobically ferment creating biogas which is mainly methane
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As you go up the stages in the food chain
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The biomass of the organisms decrease
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How can we make food production more efficient? (3)
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Reducing the number of stages in food chains
Restricting energy loss from food by movement Restricting energy less from heat by controlling the temperature of their surroundings |
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Why are fish stocks declining? (2)
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Fish are being taken at a faster rate than they breed
Fisherman have to keep up their living despite the threat of extinction |
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What helps conserve the fish stocks?
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Quotas
Net size |
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What fungus produces mycoprotein?
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Fusarium
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Mycoprotein - what is it and how is it produced?
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A protein-rich food suitable for vegetarians which is grown in glucose syrup in aerobic conditions which is then harvested and purified
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