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AQA GCSE Biology (Old GCSE) > Biology B3 > Flashcards

Biology B3 Flashcards

1
Q

What is the name for the diffusion of water from a dilute to a more concentrated solution through a partially permeable membrane?

A

Osmosis.

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2
Q

What is the definition of turgid?

A

When a cell is firm, swollen and full of water.

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3
Q

What is the definition of flaccid?

A

When a cell is limp, wilted and lacking water.

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4
Q

What has happened to a plasmolysed cell?

A

When a flaccid cell’s membrane begins to shrink away from the cell wall.

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5
Q

What is lysis?

A

When a turgid cell becomes so swollen that it bursts.

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6
Q

What happens to flaccid cells when they are in a solution that is too salty?

A

They become crenated (crinkled).

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7
Q

What is active transport?

A

Moving solutes from a low concentration to a high concentration (against the concentration gradient). This requires energy.

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8
Q

What are villi?

A

A structure in an organism’s digestive system with a high surface area.

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9
Q

How are villi adapted to increase the exchange of substances?

A

They have a high surface area, they have a one cell thick membrane, they are covered in microvilli, they have a dense capillary network inside of them and they have a solid lacteal at the centre to absorb fats.

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10
Q

How does gas exchange happen in an alveolus?

A

The inside of the alveolus is high in oxygen, whilst the blood is high in carbon dioxide. This means that the two gases can move in and out of the alveolus on a concentration gradient.

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11
Q

How does air enter the lungs?

A

The air pressure in the lungs is lowered, meaning that air is forced in.

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12
Q

Where does gas exchange happen in plants?

A

In the root hair cells and in the spongy mesophyll in the leaves.

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13
Q

Which of the two exchange surfaces in plants has a high surface area?

A

The root hairs.

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14
Q

Which of the two exchange surfaces in plants has guard cells and operates through a concentration gradient?

A

The spongy mesophyll and stomata.

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15
Q

What four factors affect the rate of transpiration in a plant?

A

Light intensity, temperature, wind speed and humidity.

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16
Q

Which is the only artery in the body that carries deoxygenated blood?

A

The pulmonary artery.

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17
Q

What is the name of the circulatory system that includes the heart and the lungs?

A

The cardiovascular system.

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18
Q

Why do arteries have a thicker elastic wall than veins?

A

Because the blood is under higher pressure.

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19
Q

Why do veins have valves but arteries don’t?

A

Because in veins, the blood is at a much lower pressure so is more likely to low backwards.

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20
Q

What is a stent?

A

A mesh that is used to widen the lumen (diameter) of an artery to remove blockages.

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21
Q

What are capillaries?

A

Tiny blood vessels that are only cell thick, meaning that oxygen and glucose can easily diffuse through them.

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22
Q

What is the name of the tiny fragments of cells in the blood that form scabs?

A

Platelets.

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23
Q

What is the name of the body’s transport medium?

A

Plasma.

24
Q

What is haemoglobin?

A

The chemical in red blood cells that binds with oxygen to form oxyhemoglobin.

25
Q

What are the three internal conditions that the body needs to keep constant?

A

Hydration, glucose and temperature.

26
Q

What are three waste products in the body?

A

Salts, urea and carbon dioxide.

27
Q

What is the name for the regulation of the body’s internal conditions?

A

Homeostasis.

28
Q

What is xylem?

A

The structure in plants that carries water through the process of transpiration.

29
Q

What is phloem?

A

The structure in plants that carries sugars and minerals through the process of translocation.

30
Q

In the nephron in the kidneys, how are waste products removed from the blood?

A

The blood is under such high pressure that they are just squeezed out of the blood.

31
Q

What is squeezed out of the blood in the nephron?

A

Glucose, water, mineral ions and urea.

32
Q

What chemicals that are squeezed out of the blood in the nephron are later reabsorbed into the blood?

A

Most of the glucose, some water and some ions.

33
Q

Why do our blood vessels dilate when we are hot?

A

When they dilate, they move closer to the surface of the skin, meaning more heat can radiate out of the blood.

34
Q

Why do we sweat when we are hot?

A

Sweating puts moisture onto out skin. Some of this moisture takes heat energy out of the skin and evaporates, making the skin feel cold.

35
Q

Why do our hairs stand on end when we are cold?

A

They trap a layer of air against the skin, making it more difficult for heat to radiate out of the skin.

36
Q

What are the two methods of treating kidney failure?

A

Blood dialysis and kidney transplants.

37
Q

Why do some transplanted kidneys get rejected by the body?

A

The body’s immune system recognises the kidney as a foreign body and attack it.

38
Q

How can organ rejection be reduced?

A

Take an organ from a close relative.

39
Q

What is insulin?

A

A hormone that lowers blood sugar levels by increasing the permeability of the liver and storing excess glucose as glycogen.

40
Q

What is glucagon?

A

A hormone that raises blood sugar levels by breaking down stored glycogen into glucose.

41
Q

What has happened to someone with type 1 diabetes?

A

Their pancreas does not work properly and cannot produce insulin. They are insulin dependent.

42
Q

How can type 1 diabetes be treated?

A

There is currently no cure for type 1 diabetes so the only way to treat it is by injecting insulin when the body’s blood sugar is too high.

43
Q

Why is the human population increasing?

A

Because the birth rate is exceeding the death rate.

44
Q

Why does the Earth have a limited carrying capacity?

A

It has finite resources that will one day run out.

45
Q

What are the main pollutants contributing to climate change?

A

Carbon Dioxide, Sulphur Dioxide, Nitrous Oxide.

46
Q

What are the impacts of acid rain?

A

It dissolves limestone buildings and poisons lakes.

47
Q

What are some of the issues of deforestation?

A

It destroys habitats, reduces the amount of oxygen producing trees and increases the risk of floods.

48
Q

What are the three types of biofuels?

A

Biodiesel made from rapeseed, ethanol made from fermented sugar cane and biogas produced by anaerobic fermentation.

49
Q

What is beneficial about biofuels?

A

They are carbon neutral, so they only produce as much CO2 as they took in when they were growing.

50
Q

How is mycoprotein produced?

A

It is grown in a fermenter from fungi.

51
Q

What is mycoprotein used for?

A

It is used to make vegetarian food such as quorn that contain lots of useful nutrients.

52
Q

What conditions need to be controlled in a mycoprotein fermenter?

A

Temperature, pH and glucose, vitamin and mineral levels.

53
Q

Why are battery animals sometimes better than free range animals?

A

Battery animals do not move around so do not use up as much energy. When they are eaten, more food is transferred up the food chain.

54
Q

Why is battery farming considered unethical?

A

It is cruel to keep the animals locked up unable to move for their whole life.

55
Q

How is energy transferred through a food chain?

A

The producer (plants) takes in energy from the sun. It is then eaten by the primary consumer, which is then eaten by the secondary consumer, which is then eaten by the tertiary consumer etc.

56
Q

How have fish stocks been allowed to recover in recent years?

A

Increasing sizes of the holes in nets prevents unwanted fish being caught and government fishing quotas restrict the amount of fish that people can catch.

AQA GCSE Biology (Old GCSE) (3 decks)

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