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Biology > B7 > Flashcards

B7 Flashcards

1
Q

What do red blood cells do?

A

They transport oxygen from the lungs to the rest of the body. They don’t have a nucleus so they can be packed full with haemoglobin – a substance that binds with oxygen. They have a biconcave shape to give them a large surface area for exchanging oxygen.

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2
Q

What is plasma?

A

The liquid that carries nutrients (e.g. glucose and amino acids), antibodies, hormones and waste (e.g. carbon dioxide and urea).

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3
Q

What do white blood cells do?

A

They help to fight infection by protecting your body against attack from microorganisms.

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4
Q

What are platelets?

A

Small fragments of cells that help blood to clot at the site of a wound.

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5
Q

Humans have a double circulatory system, what does each circuit do?

A

The first pumps deoxygenated blood to the lungs to take in oxygen. The blood then returns to the heart. The second one pumps oxygenated blood around the body. The blood gives up its oxygen at the body cells and the deoxygenated blood returns to the heart to be pumped out to the lungs again.

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6
Q

What does the right atrium of the heart do and where does the blood go after that?

A

It’s receives deoxygenated blood from the body (through the vena cava). The deoxygenated blood then moves through the right ventricle, which pumps it to the lungs via the pulmonary artery.

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7
Q

What does the left atrium do and where does the blood go after that?

A

Receives oxygenated blood from the lungs (through the pulmonary vein). The oxygenated blood then moves through the left ventricle, which pumps it out round the whole body (via the aorta).

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8
Q

What do the valves in the heart and veins do?

A

Prevent the back flow of blood.

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9
Q

What do the two coronary arteries do?

A

Supply the heart muscle cells with blood.

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10
Q

Why is the left ventricle wall thicker than the right ventricle wall?

A

The left ventricle has to pump blood all the way around the body, the right only pumps to the lungs.

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11
Q

Why do the atria have thin walls?

A

They only pump blood to the ventricles.

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12
Q

What is blood made up of?

A

Cells, platelets and plasma

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13
Q

What are chemicals exchanged between?

A

Cells and capillaries

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14
Q

Arteries branch into capillaries, what are capillaries?

A

Really tiny blood vessels. They have permeable walls, so substances can diffuse in and out. Networks of capillaries in tissue are called capillary beds.

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15
Q

What exchanges between the cells and capillaries?

A

As blood passes through capillary beds small molecules (e.g. water, glucose and oxygen) are forced out of the capillaries to form the tissue fluid, which surrounds the cells. These substances can then diffuse out of the tissue fluid into the cells. Waste chemicals (e.g. carbon dioxide and urea) diffuse out of the cells into the tissue fluid, then into the capillaries.

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16
Q

What does tissue fluid do?

A

It allows cells to get the substances they need and to get rid of waste without a capillary supplying every single cell.

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17
Q

What is the job of a skeleton?

A

To support the body and allow it to move – as well as protect vital organs.

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18
Q

What do joints do?

A

Allow the bones to move.

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19
Q

The bones at a joint are held together by ligaments. Describe a ligament

A

They have high tensile strength but they are also slightly elastic – this means that they help to stabilise joints but still allow movement.

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20
Q

The ends of bones are covered with a smooth layer of cartilage, what is the purpose of this?

A

To reduce friction between bones. Also cartilage can be slightly compressed so it acts as a shock absorber, like a cushion between bones.

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21
Q

What do the membranes at some joints do?

A

They release oily synovial fluid to lubricate the joints, allowing them to move more easily by reducing friction.

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22
Q

What are bones attached to?

A

Tendons (which also attach muscles to other muscles).

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23
Q

How do muscles move bones at a joint?

A

By contracting (becoming shorter).

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24
Q

Tendons can’t stretch much, why is this?

A

So when a muscle contracts a tendon pulls on the bone, transmitting the force from the muscle to the bone.

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25
Q

Why do muscles usually come in antagonistic pairs?

A

Muscles can only pull on bones to move the joint – they can’t push.

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26
Q

What information is needed to develop the right exercise regime?

A

Essential background information such as: health problems, current medication, previous fitness treatments, other lifestyle factors (e.g. smoking or drinking), family medical history and current physical activity.

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27
Q

What is the recovery period?

A

The time it takes for your blood pressure and heart rate to return to their resting levels after you stop exercising. The fitter you are, the shorter your recovery period.

28
Q

Why isn’t BMI always the most accurate indicator of fitness?

A

Because muscle is more dense (heavier per unit of volume) than fat, meaning your BMI might be outside the ‘normal’ range if you have lots of muscle.

29
Q

What is a sprain?

A

Damage to a ligament, usually by being stretched too much.

30
Q

What is a dislocation?

A

When a bone comes out of its socket.

31
Q

When does a torn tendon occur?

A

When a muscle contracts in one direction, but is being pulled in the opposite direction.

32
Q

If a sprain is not too severe, it can be treated using the RICE method. What is the RICE method?

A

Rest – to avoid any further damage.
Ice – to help reduce swelling, it works by reducing the temperature and blood flow to the injured area.
Compression – a firm bandage is placed around the injured part to help reduce swelling and prevent further damage from excessive movement of the injured joint.
Elevation – raising an injured limb as high as possible to help reduce swelling by making it easier for blood to flow back to the heart.

33
Q

How do physiotherapists treat skeletal muscular injuries?

A

They may give treatment to reduce pain and swelling (e.g. RICE, Cortisone injections) and therapies (e.g. laser treatment) to speed up healing. They will also advise on the best exercises to do to rehabilitate after an injury.

34
Q

How is body temperature kept constant?

A

Temperature receptors in the skin detect the external temperature and receptors in the hypothalamus detect the temperature of the blood. The nervous system helps to control body temperature using negative feedback.

35
Q

What happens to your body when you get too hot?

A

Vasodilation. This means that more blood gets to the surface of the skin. Warm blood then loses more of its heat to the surroundings. Your sweat glands also produce sweat - when the water in the sweat evaporates heat is used, which cools the body.

36
Q

What responses are produced by effectors to counteract a decrease in body temperature?

A

Vasoconstriction. This means that less blood gets to the surface of the skin, which stops the blood losing as much heat to the surroundings. You shiver – your muscles contract rapidly. This increases the rate of respiration and warms the tissue surrounding the muscles.

37
Q

What is type one diabetes?

A

This is where the pancreas stops producing insulin. This means that the blood sugar levels can rise to a dangerous level. It is controlled by injecting insulin into the blood, usually at meal times. The injection has to have the right amount of insulin to make sure the body doesn’t remove too much sugar.

38
Q

What is type two diabetes?

A

Sometimes called late-onset diabetes. Having a poor diet or being obese increases the risk of developing type two diabetes. This occurs when the body no longer responds its own insulin, or doesn’t make enough insulin. It can be controlled by exercising and eating a carefully controlled diet. For example by eating foods that are high in fibre and complex carbohydrates which are digestive more slowly than simple sugars.

39
Q

What features of microorganisms make them ideal for industrial use?

A
  • They reproduce rapidly under under the right conditions, so products can be made quickly.
  • They have plasmids – these can be genetically modified so you can make the microorganism to produce the product you need.
  • Their biochemistry is quite simple.
  • They can make complex molecules that are difficult to produce artificially.
  • There aren’t any ethical concerns with using microorganisms.
40
Q

How are microorganisms used to make antibiotics?

A

Some types of bacteria and fungal I can be used to produce medicines on a large scale. E.g. penicillin is an antibiotic made by growing penicillium mould in a fermenter.

41
Q

What are fermenters?

A

Containers where large amounts of microorganisms are grown. The conditions inside fermenters are kept at the optimum for growth to get the biggest possible amount of desirable products.

42
Q

How is food made from fungi?

A

A type of single celled protein made by fungi is used to make meat substitutes for vegetarian meals, e.g. Quorn.

43
Q

How are enzymes used to make cheese?

A

Traditionally cheese is made using a mix of enzymes called rennet from the lining of a calfs stomach. Now chymosin (the important enzyme in rennet) can be produced by genetically modified microorganisms in large quantities – it’s used as a vegetarian substitute for rennet.

44
Q

How are enzymes used for washing powder?

A

Enzymes produced by bacteria can be used to make biological washing powder is because they help to break down stains. For example, amylase enzymes can remove carbohydrate stains and lipases can get rid of fat stains.

45
Q

How can microorganisms be used to make biofuels?

A

Used can produce ethanol, a waste product of anaerobic respiration. Microorganisms can also be used to make biogas. It’s made by the fermentation of plant and animal waste containing carbohydrates.

46
Q

What is genetic modification?

A

Where a gene from one organism is transferred to another.

47
Q

What happens once the gene is transferred?

A

The organism with the transfer gene will then produce a protein using instructions in that gene. The proteins can be made even though the gene came from another organism because all organisms use the same genetic code.

48
Q

What are the stages of genetic modification?

A
  • Firstly the gene is isolated – its position on the source DNA is identified.
  • The useful gene is then replicated to create lots of copies. Each gene is joined to a vector – a carrier for the gene which makes it easier to insert into a new cell. Plasmids and viruses are often used as vectors. - Vectors containing the useful gene are transferred into new cells, e.g. bacterial cells.
  • Not all of the new cells will be modified, e.g. the vector might not have been transferred properly.
  • The last stage is to identify the individuals that have been successfully modified.
49
Q

How is genetic modification useful for making medicines?

A

Genetically modified bacteria have been used to make medicines cheaply, quickly and in large quantities, for example insulin. The gene for human insulin production can be transferred into bacteria. This means that the insulin made by the bacteria is exactly the same as human insulin, so there’s less chance of patients having an allergic reaction to it.

50
Q

How is genetic modification useful for making crops herbicide-resistant?

A

Some plants have natural resistance to things like herbicides. Therefore we can cut out the gene that’s responsible and stick it into any useful plant we like, e.g. potato plants.

51
Q

What are the disadvantages of herbicide resistant crops?

A

They can be more expensive than normal crops. Also some people are worried that the gene might be transferred into wild plants (e.g. weeds), making them hard to kill. Also they could encourage the use of weed killers which could reduce biodiversity, and it’s possible that the weed killers could pollute water systems or get into food chains.

52
Q

How can you test for a genetic disorder that is caused by a faulty gene?

A

Take a DNA sample – DNA isolated from white blood cells.
Make a gene probe – this is a strand of bases that’s complimentary to the faulty gene you’re looking for.
Use the gene probe – the gene probe is mixed with the DNA if the
gene is present the probe will stick to it – their bases will lock together perfectly.

53
Q

What is a fluorescent chemical marker?

A

A marker that is stuck on the end of the sequence of bases so you can locate the gene probe once it’s stuck to a gene. The marker will glow when you shine UV light on it.

54
Q

How can nanotechnology be used improve packaging properties?

A

Food can be made to last longer using nanoparticles that kill harmful microorganisms. Also some smart packaging uses the nano particles to change the packaging’s properties depending on the conditions. E.g. a milk carton could be made to change colour when the milk goes off.

55
Q

How can a biomedical engineering be used to improve human health?

A
  • The heart has a group of cells which determine how fast it beats, if they stop working the heartbeat becomes a regular. The cells can be replaced with a pacemaker. This produces an electric current to control the heartbeat.
  • Also faulty heart valve is can be replaced – either with animal or mechanical valves.
56
Q

What is a perfect closed loop system?

A

All when all the output from processes all stores within the system or recycled – are used as inputs to other processes all stores in the system. There are no outputs and there are no inputs.

57
Q

How are ecosystems a type of closed loop system?

A
  • Oxygen and carbon dioxide are waste products and reactants of photosynthesis and respiration.
  • Dead organic plant matter is used by microorganisms this food.
  • Mineral nutrients (e.g. Nitrogen) are produced by microorganisms and absorbed by plants.
  • Reproductive structures are eaten by other organisms.
58
Q

No ecosystem is it perfect closed loop system because some output always lost. Give some examples of this

A
  • Some dead organic matter and nutrients can be carried out of an ecosystem by air and water.
  • Some organisms migrate from one ecosystem to another.
59
Q

What is a stable ecosystem? Give an example

A

An ecosystem that has balanced input and output’s. For example in a rainforest a lot of water is lost as it flows out through rivers, but this output is balanced by the gain of water from the high level of rainfall.

60
Q

How is vegetation beneficial to ecosystems?

A
  • It reduces soil erosion, for example roots help to bind the soil together.
  • it prevents extremes of temperatures.
  • It promotes cloud formation.
61
Q

What is eutrophication?

A

Nitrates from fertilised fields are washed into rivers and lakes by rain. These cause algae to grow at the surface of the water which prevents light from reaching the plants below, meaning these organisms die because they can’t photosynthesise. This leads to low levels of oxygen because the oxygen being used up by bacteria that decompose and dead material is not replaced. This leads to animals that need oxygen from the water suffocating.

62
Q

What leads to eutrophication?

A

When farmers use fertilisers to plants extra nutrients. This unbalances ecosystems because the input of nutrients is much higher than normal.

63
Q

How can human activities damage ecosystems?

A
  • Farmers using fertilisers can lead to eutrophication.
  • Overfishing and unsustainable timber harvesting removes a food source and habitats and organisms.
  • Humans often clear natural areas of vegetation which can reduce the biodiversity of an ecosystem. They can also increase soil erosion which causes desertification.
  • Human activities create non-recyclable waste e.g. metals like Mercury, that can’t be used again within a system.
64
Q

Why do using fossil fuels mean that human systems aren’t closed loops?

A
  • Using fossil fuels produces waste emissions that aren’t used again.
  • Fossil fuels take millions of years to form from the decay of dead organisms, but only seconds to use.
  • When fossil fuels are used it inputs energy into the system from outside the system.
65
Q

Why do humans rely on ecosystems?

A

Ecosystems provide us with clean air, water and food. Ecosystems also provide humans with fertile soil that is full of mineral nutrients – this is needed to produce crops. Most crop production also needs pollination. This is carried out by organisms (e.g. bees) and things like wind.

66
Q

How can sunlight be used as a sustainable source of energy for sustainable agriculture?

A

Sunlight could be used to power equipment used in sustainable agriculture, for example heating and lighting systems in greenhouses and irrigation systems.

67
Q

How may conserving natural ecosystems conflict with community needs?

A

For example population growth means that more people have to be fed. This raises the issue of whether to increase food production, e.g. by fishing more and removing organisms faster than they can be replaced. Or to produce more crops, at the risk of damaging an ecosystem by increasing desertification.

Biology (5 decks)

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