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Questão	Responda
What is blood ?	Blood is a tissue and consists of a fluid called plasma in which red blood cells, white blood cells, and platelets are suspended.
What does blood plasma transport ?	Blood plasma transports: ■ carbon dioxide from the organs to the lungs ■ soluble products of digestion from the small intestine to other organs ■ urea from the liver to the kidneys
Describe how red blood cells transport oxygen ?	Red blood cells transport oxygen from the lungs to the organs. Red blood cells have no nucleus. They are packed with a red pigment called haemoglobin. In the lungs haemoglobin combines with oxygen to form oxyhaemoglobin. In other organs oxyhaemoglobin splits up into haemoglobin and oxygen.
What are white blood cells ?	White blood cells have a nucleus. They form part of the body’s defence system against microorganisms
What are platelets ?	Platelets are small fragments of cells. They have no nucleus. Platelets help blood to clot at the site of a wound.
What does xylem tissue transport ?	xylem tissue transports water and mineral ions from the roots to the stem and leaves
What does phloem tissue transport ?	phloem tissue carries dissolved sugars from the leaves to the rest of the plant, including the growing regions and the storage organs.
What is transpiration ?	the movement of water from the roots through the xylem and out of the leaves is called the transpiration stream
Describe how carbon dioxide and urea are formed and how they are removed from the body	■ carbon dioxide, produced by respiration and removed via the lungs when we breathe out ■ urea, produced in the liver by the breakdown of amino acids and removed by the kidneys in the urine, which is temporarily stored in the bladder.
Describe what happens if the water or ion content of the body is wrong ?	If the water or ion content of the body is wrong, too much water may move into or out of the cells and damage them. Water and ions enter the body when we eat and drink
Describe how a healthy kidney produces urine ?	A healthy kidney produces urine by: ■ first filtering the blood ■ reabsorbing all the sugar ■ reabsorbing the dissolved ions needed by the body ■ reabsorbing as much water as the body needs ■ releasing urea, excess ions and water as urine.
State 2 ways in which people who suffer from kidney failure may be treated ?	People who suffer from kidney failure may be treated either by using a kidney dialysis machine or by having a healthy kidney transplanted.
How does dialysis help someone with kidney problems ?	Treatment by dialysis restores the concentrations of dissolved substances in the blood to normal levels and has to be carried out at regular intervals.
describe in detail how dialysis works ?	In a dialysis machine a person’s blood flows between partially permeable membranes. The dialysis fluid contains the same concentration of useful substances as the blood. This ensures that glucose and useful mineral ions are not lost. Urea passes out from the blood into the dialysis fluid.
What is a kidney transplant and state one challenge with this ?	In kidney transplants a diseased kidney is replaced with a healthy one from a donor. However, the donor kidney may be rejected by the immune system unless precautions are taken.
Describe in detail how transplanted kidneys may be rejected ?	Antigens are proteins on the surface of cells. The recipient’s antibodies may attack the antigens on the donor organ as they do not recognise them as part of the recipient’s body.
How can donor kidney rejection be prevented ?	To prevent rejection of the transplanted kidney: ■ a donor kidney with a ‘tissue-type’ similar to that of the recipient is used ■ the recipient is treated with drugs that suppress the immune system.
State one way that the body cools down and one challenge presented by this ?	Sweating helps to cool the body. More water is lost when it is hot, and more water has to be taken as drink or in food to balance this loss.
Where and how is body temperature monitored ?	Body temperature is monitored and controlled by the thermoregulatory centre in the brain. This centre has receptors sensitive to the temperature of the blood flowing through the brain Also temperature receptors in the skin send impulses to the thermoregulatory centre, giving information about skin temperature.
State 2 things that happen if core body temperature gets too high ?	If the core body temperature is too high: ■ blood vessels supplying the skin capillaries dilate so that more blood flows through the capillaries and more heat is lost ■ sweat glands release more sweat which cools the body as it evaporates
State 2 things that happen if core body temperature gets too low ?	If the core body temperature is too low: ■ blood vessels supplying the skin capillaries constrict to reduce the flow of blood through the capillaries ■ muscles may ‘shiver’ – their contraction needs respiration, which releases some energy to warm the body.
By what and how are glucose levels monitored ?	The blood glucose concentration of the body is monitored and controlled by the pancreas. The pancreas produces the hormone insulin, which allows the glucose to move from the blood into the cells.
describe the role of glucagon in glucose concentration regulation ?	A second hormone, glucagon, is produced in the pancreas when blood glucose levels fall. This causes glycogen to be converted into glucose and be released into the blood.
What is type one diabetes ?	Type 1 diabetes is a disease in which a person’s blood glucose concentration may rise to a high level because the pancreas does not produce enough of the hormone insulin.
State how type 1 diabetes can be controlled ?	Type 1 diabetes may be controlled by careful attention to diet, exercise, and by injecting insulin.
State how waste pollutes water air and land	Waste may pollute: ■ water, with sewage, fertiliser or toxic chemicals ■ air, with smoke and gases such as sulfur dioxide, which contributes to acid rain ■ land, with toxic chemicals such as pesticides and herbicides, which may be washed from the land into waterways.
State how humans reduce the amount of land available for other animals and plants ?	Humans reduce the amount of land available for other animals and plants by building, quarrying, farming and dumping waste.
Large-scale deforestation in tropical areas, for timber and to provide land for agriculture, has:	■ increased the release of carbon dioxide into the atmosphere (because of burning and the activities of microorganisms) ■ reduced the rate at which carbon dioxide is removed from the atmosphere and ‘locked up’ for many years as wood.
Deforestation leads to .........	• decreased biodiversity • loss of habitats • increased carbon dioxide (concentration) • global warming
State 2 reasons that deforestation has occurred ?	• (to provide land) for farming / agriculture • (to provide land) for quarrying • (to provide land / wood) for building • to provide fuel • to produce paper
how does the destruction of peat bogs affect carbon dioxide levels in the atmosphere ?	The destruction of peat bogs and other areas of peat releases carbon dioxide into the atmosphere.
An increase in the Earth’s temperature of only a few degrees Celsius could lead to what ?	■ may cause big changes in the Earth’s climate ■ may cause a rise in sea level ■ may reduce biodiversity ■ may cause changes in migration patterns, eg in birds ■ may result in changes in the distribution of species.
How is carbon dioxide removed from the atmosphere ?	Carbon dioxide can be sequestered in oceans, lakes and ponds and this is an important factor in removing carbon dioxide from the atmosphere
How can biofuels be made ?	Biofuels can be made from natural products by fermentation. Biogas, mainly methane, can be produced by anaerobic fermentation of a wide range of plant products or waste material containing carbohydrates.
How can the efficiency of food production be increased ? 1	At each stage in a food chain, less material and less energy are contained in the biomass of the organisms. This means that the efficiency of food production can be improved by reducing the number of stages in food chains.
How can the efficiency of food production be increased ? 2	The efficiency of food production can also be improved by restricting energy loss from food animals by limiting their movement and by controlling the temperature of their surroundings.
Why is it important to maintain fish stocks and how can this be achieved ?	Fish stocks in the oceans are declining. It is important to maintain fish stocks at a level where breeding continues or certain species may disappear altogether in some areas. Net size and fishing quotas play an important role in conservation of fish stocks.
What is mycoprotein and how is it produced ?	The fungus Fusarium is useful for producing mycoprotein, a protein-rich food suitable for vegetarians. The fungus is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified.
Describe and explain how an increase in the humidity in the air around a plant will affect the rate of water loss from the plant.	(rate of water loss / transpiration) decreases / slows (because) less water can evaporate or it is more difficult for water to evaporate (due to) a lower (humidity) gradient / air is saturated
Describe how a plant avoids wilting when there is not much water available.	guard cells (will) close the stomata (to) prevent / reduce water loss / evaporation
Describe how the body responds when the blood glucose concentration begins to decrease.	pancreas detects (low) blood glucose produces glucagon (so) glycogen is converted to glucose
Give one advantage and one disadvantage of using the modern ventilator rather than the iron lung ventilator	advantage any one from:  more freedom of movement for patient  more portable  does not affect blood flow in lower body disadvantage any one from:  (tube in trachea) uncomfortable  more difficult to eat/talk
Describe how ions are obtained and transported through plants ?	Ions: 1. taken up by diffusion or active transport 2. from an area of high to low concentration (diffusion) or an area of low to high concentration (active transport) 3. travels in the xylem to the leaves or from the roots / soil
Describe how water is obtained and transported through plants ?	Water: 1. taken up by osmosis from an area of low to high concentration travels in the xylem to the leaves 2. transpiration stream : • movement replaces water as it evaporates from leaves in the xylem
Describe how sugar is obtained and transported through plants ?	Sugar: made during photosynthesis travels in the phloem to other parts of the plant or to storage organs or travels up and down

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	Criado por gfhgfhg gfhgfhg quase 8 anos atrás