Biology Flashcards

What 6 things must the body control?
THe body temperature, water content, ion content, blood sugar level, carbon dioxide levels, urea levels.
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Where is the thermoregulatory centre?
in the brain.
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What happens when the body is too hot?
Hairs lie flat, sweat is produced by sweat glands and evapourates from the skin which removes heat. The blood vessels supplying the skin dilate so blood flows close to the surface. heat is then easily transferred to the environment from the blood.
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what happens to the body when you're too cold?
Hairs stand up to trap an insulating layer of air. No sweat is produced. Blood vessels supplying the skin capillaries constrict to close off the skin's blood supply. You shiver as it needs respiration which releases some energy to warm the body.
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What are the kidneys three main functions?
removal of urea, adjustment of ions in the blood, adjustment of water content of the blood.
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Proteins cant be stored by the body so what happens to them?
Any excess amino acids are converted into fats and carbohydrates which can be stored. This process occurs in the liver, urea is produced as a waste product.
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Why is it important to keep the ion and water content in the body constant?
Because it can affect osmosis , meaning too much or too little water can be drawn into the cells. This can damage the cells.
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Where are some ions lost?
In sweat.
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What are the three ways water is lost from the body?
Through urine, in sweat and in the air we breathe out.
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What is the water balance between?
Liquids consumed, amount sweated out, amount excreted by the kidneys in the urine.
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What do sports drinks contain and why?
Water, sugar and ions to replace what is lost in sweat and the glucose replaced the that is used up by muscles during exercise.
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What do sports drinks manufacturers claim their drinks do?
Improve endurance and rehydrate you faster than plain water.
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What are nephrons?
The filtration units in the kidneys.
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Describe ultrafiltration?
1) a high pressure is built up so water, urea, ions and sugar are squeezed out of the blood into the bowman's capsule. 2) membranes between blood vessels and the bowman's capsule act like filters so big molecules aka proteins, stay in the blood.
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Describe the process of reabsorption.
As liquid flows along the nephron useful substances are reabsorbed into the blood. ALL sugar is reabsorbed, whch involves active transport against the concentration gradient. Sufficient ions are reabsorbed. excess ions aren't. Water is reabsorbed.
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What happens to the waste substances after ultrafiltration?
They continue out of the nephron, into the ureter and down to the bladder as urine.
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Why does dialysis have to be done regularly?
To prevent dissolved substances from building up.
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In a dialysis machine where does blood flow?
Alongside a selectively partially permeable barrier, surrounded by dialysis fluid. Its permeable to ions and waste substances but not big molecules.
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What is the concentration of dialysis fluid?
It contains the same concentration of dissolved ions and glucose as healthy blood, therefore useful dissolved ions and glucose wont be lost during dialysis.
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What substances can diffuse through a dialysis barrier?
Waste substances such as urea, and excess ions.
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How many times a week on average is dialysis performed?
3 times a week for 3-4 hours.
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What part of the body will reject a donated organ?
A patient's immune system- the foreign antigens on the donor kidney are attcked by the patient's antibodies.
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What precautions are taken when receiveing an organ transplant?
A close tissue match is chosen. Tissue type is based on antigens, which are proteins on the surface of most cells. The patient is treated with immunosuppressants, so their immune system won't attack the transplanted kidney.
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What do insulin and glucagon control?
Blood glucose level.
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Where are changes in blood glucose monitored and controlled?
In the pancreas, using the hormones insulin and glucagon.
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What happens when blood glucose level is too high?
Insulin is secreted by the pancreas, and glucose is removed by the liver. Insulin makes the liver turn glucose into glycogen (which can be stored).
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What happens when blood glucose is too low?
Glucagon secreted by the pancreas. Glucose is added by the liver. Glucagon makes liver turn glycogen into glucose.
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What is type 1 diabetes?
When the pancreas produces too little or no insulin.
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How can diabetes be controlled?
Avoiding foods rich in carbohydrates, exercising after eating, or injecting insulin at mealtimes so the liver removes glucose as soon as it enters the blood.
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How is insulin made for people with diabetes?
Genetic engineering.
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What are the 4 main ways humans reduce the amount of land and resources available to other animals and plants?
Building, Farming, Dumping Waste, Quarrying for metal ores.
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Where is C02 sequestered?
Oceans, lakes, ponds, green plants, peat bogs.
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What do gasses in the atmosphere act as?
An insulating layer.
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What causes global warming?
Greenhouse gasses such as C02 and methane mean less heat is re-radiated out to space.
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What are some of the reasons for deforestation?
Provide timber, more land for farming (cattle, or more rice fields, more crops for biofuel, more paper.
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What are the main things deforestation leads to?
More methane due to rice as decomposers from the waterlogged conditions produce methane. Also from cattle. More c02 in atmosphere, as burning trees releases C02, also microorganisms feed on dead wood. Less C02 absorbed. Less biodiversity.
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Why does destroying peat bogs add more C02 to the atmosphere?
Peat bogs are acidic and waterlogged. Plants don't fully decay when they die as theres not enough oxygen, the partly rotted plants form peat. Peat starts to decompose when bogs are drained so the C02 stored is released.
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Consequences of global warming?
Sea levels rising as water expands and ice caps melt, more extreme weather, change in species distribution, extinction, reduced biodiversity, changes in migration patterns.
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How are fuels made?
By fermentation of natural or waste products. When bacteria or yeast break sugars down by anaerobic respiration.
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How is ethanol made?
By anaerobic fermentation of sugar, usually from sugar cane juices or from maize starch by the action of carbohydrase (enzyme). Ethanol is then distilled to seperate it from the yeast & remaining glucose.
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What is a mixture of petrol and ethanol called?
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How is biogas made?
BY anaerobic fermentation of waste materials, usually 70% methane and 30% C02. It is the fermentation of plant and animal waste which contains carbohydrates.
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Where is biogas made?
In a digester or a generator. Two types are batch generators and continuous generators.
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Why cant biogas be stored as a liquid?
Because it needs too high a pressure so has to be used right away.
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What are by-products of biogas used for?
Fertilise crops and gardens.
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What is the main difference between batch and continuous generators?
Batch generators have to be manually loaded with waste and must be cleaned after every session. Continuous generators have waste continuously fed in and are suited to large-scale biogas projects.
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What factors need to be considered when biogas generators are being designed?
Cost, convenience, efficiency, position.
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Benefits of biogas?
More carbon neutral, less sulfur dioxide or nitrogen oxides which cause acid rain, its cheap, can be used as fertiliser, act as a waste disposal system.
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How is efficiency of food production improved?
Reducing numbers in food chain, restricting energy lost via heat and movement, developing new foods such as mycoprotein.
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What is the main source o mycoprotein?
A fungus called fusarium, grown in fermenters using glucose syrup obtained by digesting maize starch with enzymes.
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How is mycoprotein produced?
Through aerobic respiration, so oxygen is supplied with nitrogen (as ammonia). To prevent other microorganisms growing the fermenter is sterilised using stead. Incoming nutrient are heat sterilised and the air supply is filtered.
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Downsides of intensive farming?
Disease spreads quickly, such as foot and mouth and avian flu. Antibiotics are used to creates resistance for humans in medicine. Fossil fuels are required to create the ideal conditions. Fish stocks are low and fish is used to feed the animals.
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What is being done to tackle overfishing?
Fishing quotas (limits on number and sixe of fish that can be caught in certain areas), net size (limits to mesh size of fish nets to reduce 'unwanted' and discarded fish. It also means younger fish will slip through the net, allowing them to breed)
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Other cards in this set

Card 2


Where is the thermoregulatory centre?


in the brain.

Card 3


What happens when the body is too hot?


Preview of the front of card 3

Card 4


what happens to the body when you're too cold?


Preview of the front of card 4

Card 5


What are the kidneys three main functions?


Preview of the front of card 5
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