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86 Cards in this Set
- Front
- Back
What are the two ways in which dissolved substances move? |
Diffusion and Active transport |
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What is osmosis? |
The diffusion of water from a dilute to a more concentrated solution through a partially permeable membrane that allows the passage of water molecules. |
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What do most soft drinks contain? |
Water, sugar and ions |
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Why do sports drinks contain sugars, water and ions? |
To replace sugar, water and ions during energy release in activity and sweating. |
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What happens when water and ions are not replaced? |
Balance of ion/water is disturbed and cells work inefficiently |
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What is active transport? |
The process of substances being absorbed against a concentration gradient, and requires energy from respiration |
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How is the effectiveness of an exchange surface area increased? (4) |
Large surface area Being thin for a short diffusion path Having an efficient blood supply Being ventilated |
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How is the surface of lungs increased in humans? |
By the alveoli |
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How is the surface area of the small intestine increased in humans? |
By the villi |
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What is the function of the villi? |
Provides a large surface area with an extensive network of capillaries to absorb the products of digestion by diffusion and active transport. |
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Where are the lungs located in the body? |
In the thorax, protected by the ribcage
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What is the lower part of the body called?
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The abdomen |
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What separates the abdomen and the lungs? |
The diaphragm |
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What does breathing do? (2) |
Allows oxygen to diffuse into the bloodstream Allows CO2 to diffuse from the bloodstream into the air |
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What is ventilation? |
The movement of air into and out of the lungs |
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Explain inhaling (4) (Exhaling is just the opposite) |
Intercostal muscles contract Ribcage moves out and up Diaphragm contracts |
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What are the exchange processes in plants? (2) |
Carbon Dioxide enters leaves by diffusion Most of the water and mineral ions are absorbed by roots |
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How is the surface area of plants increased? (2) |
Roots have root hairs to increase surface area Leaves have flattened shape and internal air spaces for increased surface area |
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What is the function of stomata? (2) |
Obtain Carbon dioxide Remove oxygen produced in photosynthesis |
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How do plants prevent wilting? |
Stomata can close |
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In what conditions is evaporation more rapid? (3) |
Hot Dry Windy |
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What is the function of the guard cells? |
They surround the stomata control the size of the stomata |
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What is the function of the circulatory system? |
Transports substances around the body |
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What is the function of the heart? |
Pumps blood around the body |
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What are the names of the four main chambers of the heart? |
Left Atria Right Atria Left Ventricle Right Ventricle |
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Explain processes in the heart in detail (3) |
Blood enters atria Atria contracts and forces blood into the ventricles Ventricles contract and force blood out of the heart |
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What is the function of valves? |
Valves help blood flow in the right direction |
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Give the function of veins and arteries (1 each) |
Blood flows to from the heart to organs through the arteries Blood returns to heart through the veins |
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Give the features of an artery (2) |
Thick Walls Elastic Fibres |
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Give the features of a vein (2) |
Thinner Walls Valves to prevent back-flow of blood |
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What are stents? |
A small mesh tube used to keep arteries from becoming too narrow, especially coronary arteries to prevent heart disease |
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What are capillaries? |
Thin-walled blood vessels in the organs |
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What is the function of a capillary? |
Transporting substances to and from the blood to surrounding cells through the walls of the capillary |
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What is blood? |
A fluid tissue consisting of plasma and other substances |
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What substances are in plasma? (3) |
Red blood cells White blood cells Platelets |
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What does blood plasma transport? (3) |
CO2 from organs to lungs Soluble products of digestion from small intestine to other organs Urea from liver to kidneys |
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What are red blood cells used for? |
Transport oxygen from the lungs to the organs |
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Give 2 features of a red blood cell |
Have no nucleus Packed with a red pigment called haemoglobin |
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What does haemoglobin do in the lungs? |
Combines with oxygen to form oxyhaemoglobin |
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What does oxyhaemoglobin do in organs other than the lungs? |
It splits up into haemoglobin and oxygen |
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What is the role of white blood cells? |
They are part of the body's defence against microorganisms |
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What are platelets? |
Small fragments of cells that help clot blood at wounds |
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Do white blood cells and platelets have a nucleus? |
Platelets don't White blood cells do |
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Name the two plant tissue used for transport |
Xylem and Phloem |
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What and where does the xylem transport substances to? |
Transports water and mineral ions From roots to stem and leaves |
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What and where does the phloem transport substances to? |
Transports dissolved sugars
From leaves to rest of plant (growing regions and storage organs) |
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List waste products that need to be removed from the body (2) |
Carbon dioxide Urea |
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How is carbon dioxide produced in our body? |
By respiration via the lungs when we breathe out |
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How is urea produced in our body? |
When amino acids are broken down in the liver and removed by kidneys in urine |
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Give the steps of how the kidney produces urine (5) |
Filter the blood Reabsorb sugar Reabsorb dissolved ions needed by body Reabsorb as much water as needed Release urea, excess ions and water as urine |
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What are the two ways in which a person with kidney failure is treated? |
Using a kidney dialysis machine Kidney transplant |
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What does dialysis do to the blood? |
Restores concentration of dissolved substances in the blood to normal levels, at regular intervals |
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Explain the steps of dialysis (4) (NOT DIALYSIS MACHINE) |
Blood leaves body enters dialysis machine Blood is filtered by machine Blood enters bubble trap where bubbles are removed Clean blood re-enters body |
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Explain the steps of a dialysis MACHINE (4) |
Blood is passed through a partially permeable tube surrounded by dialysis fluid Dialysis fluid keeps moving so urea level is left low Urea from blood diffuses into dialysis fluid Sugar and ion concentration are kept the same |
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What does dialysis fluid consist of? (3) |
Low urea Ideal sugar concentration (same in blood and dialysis fluid) Ideal ion concentration(same in blood and dialysis fluid) |
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What are the problems with dialysis? (2) |
Unable to/difficult to work, do activities etc. due to transport difficulties You must regularly use the dialysis machine which may interrupt daily routines |
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What is a kidney transplant? |
When a diseased kidney is replaced by a healthy one from a donor |
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What is the problem with a kidney transplant? |
The kidney can be rejected by the body's immune system unless precautions are taken |
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What are antigens? |
Proteins on the surface of cells |
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Why does the immune system reject kidneys sometimes? |
The antibodies may attack the antigens on the donor's organ as they do not recognise them as part of the recipient's body |
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How is kidney rejection prevented? |
Donating a kidney with a similar kidney type Using drugs to supress the immune system |
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Why does the body sweat? |
To cool the body |
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What is body temperature monitored and controlled by? |
The thermoregulatory centre in the brain that has receptors sensitive to blood temperature |
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If the core temperature is too high then... (2) |
Blood vessels supplying skin capillaries become larger so more blood flows through capillaries and more heat is lost Sweat glands release more sweat which evaporates and cools the body |
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If the core temperature is too low then... (2) |
Blood vessels supplying skin capillaries constrict so less blood flows through capillaries and less heat is lost Muscles shiver, using respiration to warm the body |
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What is the blood glucose concentration monitored and controlled by? |
Pancreas |
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How does the pancreas descrease blood glucose? |
Produces insulin which allows glucose to move from blood to cells |
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How does the pancreas increase blood glucose? |
Glucagon is produced, which causes glycogen to be converted into glucose and be released in the blood |
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What is type 1 diabetes? |
A disease where a person's blood glucose concentration is too high because the pancreas does not produce enough insulin |
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How is type 1 diabetes controlled? |
Attention to diet, exercise and injecting insulin |
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What are the issues with rapid population growth? (2) |
More waste More pollution |
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What are the three types of pollution? |
Land, water and air |
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How is water polluted? (3) |
With sewage, fertiliser or toxic chemicals |
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How is air polluted? (2) |
With smoke and gases such as SO2 |
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How is land polluted? (2) |
With toxic chemicals (eg. pesticides and herbicides) |
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How do humans reduce the amount of land available for animals and plants? (4) |
Building Quarrying Farming Dumping Waste |
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What are the negative effects of deforestation? |
Increased release of CO2 into atmosphere because of burning and activities of microorganisms Reduced rate of CO2 being locked up as wood Reduction in biodiversity |
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Why do people cut down trees? |
For land for crops for biofuels such as ethanol Space for cattle fields (has led to more methane from cow flatulence) |
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What are the effects of destroying peat bogs |
Releases Carbon Dioxide into the atmosphere |
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What is global warming caused by? |
Levels of carbon dioxide and methane in the atmosphere rising |
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What are the potential effects of global warming (5) |
Climate change Rise in sea level Reduced biodiversity Changes in migration patterns in birds etc. Changes in distribution of species |
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Where in the world can Carbon Dioxide be hidden away? (apart from trees and fossil fuels) |
In oceans, lakes and ponds |
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How is biogas such as methane made? |
By anaerobic fermentation of plant products or waste containing carbohydrates |
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How can the efficiency of food production be increased? (2) |
By reducing the number of stages in food chains Restricting energy loss from livestock by limiting their movement and heat regulation so more |
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How is fishing controlled so it doesn't get out of hand? (2) |
Net size limit Fishing quotas |
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How is the fungus 'Fusarium' useful? |
Produces mycoprotein, a protein rich food for vegetarians Produces biomass due to aerobic conditions when grown on glucose syrup |