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GCSE Science AQA > Biology - Homeostasis and Response > Flashcards

Biology - Homeostasis and Response Flashcards

1
Q

What is homeostasis?

A

Regulating the conditions inside the body.

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2
Q

Give three conditions controlled by homeostasis

A

Blood water levels, blood glucose levels, and body temperature

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3
Q

What is negative feedback?

A

Doing something to return a condition back to its normal levels.

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4
Q

True or false? Muscles and glands are examples of receptors.

A

False. They are effectors.

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5
Q

What is the central nervous system (CNS) made up of?

A

The brain and spinal cord.

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6
Q

Which type of neurone carries impulses from the central nervous system (CNS) to effectors?

A

Motor neurone

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7
Q

Why is the nervous system important in humans?

A

The nervous system enables humans to react quickly to their surroundings and control their behaviour.

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8
Q

A rabbit is eating some grass. It sees a fox and hops away from it. What is the stimulus? Where are the receptors that detect the stimulus?

A

The stimulus is the fox (the threat of predation). The receptors are in the rabbit’s eyes.

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9
Q

Which type of neurone carries impulses from the receptors to the central nervous system (CNS)?

A

Sensory neurones

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10
Q

What does the central nervous system (CNS) do?

A

It decides what to do with the signal sent from the receptors. It sends instructions to the effectors.

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11
Q

True or false? Reaction time is the time it takes to detect a stimulus.

A

False. Reaction time is the time it takes to respond to the stimulus.

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12
Q

What is a synapse?

A

The junction between two neurones.

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13
Q

How are nerve signals transferred across a synapse?

A

Chemicals diffuse across the synapse and set off a new signal in the next neurone.

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14
Q

Reflexes do not involve conscious parts of the brain. Why is this advantageous?

A

It means that reflexes can be rapid and automatic, reducing the chance of injury.

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15
Q

A gardener gets stung by a nettle. She immediately moves her hand away in a reflex action. What is the effector?

A

The muscles in her hand.

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16
Q

What are the main components of a reflex arc?

A

Stimulus -> receptor -> sensory neurone -> central nervous system (CNS) via relay neurones -> motor neurone -> effector -> response

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17
Q

What does the cerebellum do?

A

Controls muscles

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18
Q

Give two things that the medulla controls.

A

It controls unconscious activities such as breathing and heart rate.

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19
Q

Alzheimer’s disease causes severe memory loss and difficulty communicating. Suggest a part of the brain that Alzheimer’s disease affects.

A

The cerebral cortex (this part of the brain is responsible for memory and language).

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20
Q

Why is it so difficult to study and treat the brain?

A

The brain is really complex and delicate.

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21
Q

Suggest how neuroscientists discovered which region of the brain controls memory?

A

By looking at the brains of patients with memory loss and what parts were damaged.

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22
Q

What risks are involved with removing a brain tumour from a patient?

A

Brain surgery could cause physical damage to the brain or problems with how it functions.

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23
Q

What is hyperopia?

A

Long-sightedness

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24
Q

What is myopia?

A

Short-sightedness

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25
Q

As well as glasses, give three modern ways of treating vision problems.

A

Contact lenses, laser eye surgery and replacement lens surgery.

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26
Q

In the eye, what does the lens do?

A

Focuses light onto the retina.

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27
Q

In the eye, what does the retina do?

A

The retina contains cells that are sensitive to brightness and colour.

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28
Q

In the eye, what does the optic nerve do?

A

Sends information from the retina to the brain.

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29
Q

How does the eye focus on near objects?

A

The ciliary muscles contract, suspensory ligaments relax, and the lens gets fat. This bends light more.

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30
Q

How does the eye focus on far objects?

A

The ciliary muscles relax, suspensory ligaments tighten, and the lens gets thin. This bends light less.

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31
Q

A doctor shines a light into the eyes of an unconscious man to check whether or not his brain is still functioning. Suggest how the doctor can tell this.

A

If the brain is functioning, the person’s pupil should become smaller as the brain controls the size of the pupil.

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32
Q

What is the thermoregulatory centre?

A

A part of the brain that monitors the blood temperature.

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33
Q

How does the body increase its temperature if it is too cold?

A

Muscles shiver, blood vessels contract near skin, hairs stand up on end.

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34
Q

How does the body decrease its temperature if it is too hot?

A

Sweat, blood vessels dilate (open up) near skin, hairs lie flat

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35
Q

Which hormone is released by the pancreas?

A

Insulin

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36
Q

Which gland releases ADH?

A

Pituitary gland

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37
Q

Which gland releases adrenaline?

A

Adrenal gland

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38
Q

Is the thyroid a gland?

A

Yes

39
Q

Which acts faster, nervous response or hormonal response?

A

Nervous response

40
Q

Which acts for longer, nervous response or hormonal response?

A

Hormonal response

41
Q

Which gland monitors and controls blood glucose concentration?

A

Pancreas

42
Q

True or false? In Type 2 diabetes, a person becomes resistant to their own insulin.

A

True

43
Q

Give two treatments for controlling Type 2 diabetes.

A

Eating a carbohydrate-controlled diet and getting regular exercise.

44
Q

What is Type 1 diabetes?

A

Type 1 diabetes is when the pancreas does not produce enough insulin.

45
Q

After eating a carbohydrate meal the blood glucose level goes up and then goes back down. Why?

A

Carbohydrate is digested to form glucose. The glucose enters the blood and raises the blood glucose levels. Then insulin is released turning glucose into glycogen, reducing the blood glucose levels again.

46
Q

How does the body increase blood glucose levels if they are too low?

A

The pancreas releases glucagon which converts glycogen back into glucose.

47
Q

Give three examples of substances that are removed from the body in urine.

A

E.g. excess water, ions and urea.

48
Q

What happens in the kidneys during filtration?

A

Substances are filtered out of the blood as it passes through the kidneys.

49
Q

Name two molecules that are absorbed back into the blood during selective reabsorption.

A

E.g. glucose and water.

50
Q

Suggest two reasons why you might lose more water from the body during exercise.
Why might you lose more water from the body during exercise?

A

You will sweat more and breathe more heavily so will lose more water from your skin and lungs.

51
Q

What would happen to the cells in the body if the ion content of the blood was incorrect?

A

Water would enter or leave cells by osmosis and may be damaged or not work as normal.

52
Q

Explain how the liver and kidneys respond to eating foods high in protein.

A

High protein foods may produce too many amino acids. The liver converts these into fats and carbohydrates. Urea is produced as a waste product of this and is filtered out the blood in the kidneys.

53
Q

True or false? A dialysis machine works by active transport.

A

False. It works by diffusion and osmosis.

54
Q

What is a possible risk to a patient having a kidney transplant?

A

The donor kidney can be rejected by the patient’s immune system. Reduce the risk by giving drugs to prevent rejection.

55
Q

Suggest what would happen to the composition of the blood if the kidneys fail.

A

Waste chemicals such as urea would build up. Water and ion content will also vary uncontrollably.

56
Q

How does a kidney dialysis machine work?

A

Urea and excess ions and water diffuse from the blood into the dialysis fluid across a partially permeable membrane.

57
Q

Mr Correct drinks too much water. How does Mr Correct’s body respond to having too much water in his blood?

A

The pituitary gland in his brain detects the water level is too high. It releases less ADH so less water is reabsorbed in his kidneys and more water leaves his body in his urine.

58
Q

Name the hormone that stimulates sperm production.

A

Testosterone.

59
Q

What term is used to describe the release of an egg from an ovary?

A

Ovulation

60
Q

Describe how hormones control the growth and release of an egg.

A

FSH causes an egg to mature. LH then causes the egg to be released at day 14.

61
Q

Describe how the lining of the uterus changes over the stages of the menstrual cycle.

A

Uterus lining breaks down.
Lining builds up again.
Lining is maintained.
If no embryo implants in the uterus wall by day 28 it breaks down again.

62
Q

What does Oestrogen do?

A

Repairs and thickens the uterus lining.
Inhibits FSH.
Stimulates release of LH.

63
Q

What does Progesterone do?

A

Maintains the uterus lining.

Inhibits LH.

64
Q

What does LH do?

A

Stimulates the release of the egg.

65
Q

What does FSH do?

A

Causes an egg to mature in the ovary.

Stimulates release of Oestrogen.

66
Q

How long is the menstrual cycle?

A

28 days.

67
Q

At what day does the egg get released?

A

Day 14.

68
Q

Give one example of a non-hormonal method of contraception.

A

E.g. condom, female condom, diaphragm, spermicide, sterilisation or abstinence.

69
Q

Which hormone does the contraceptive injection contain?

A

Progesterone

70
Q

Which hormones do contraceptive pills contain?

A

Progesterone and oestrogen

71
Q

Give two ethical reasons why somebody might disagree with the use of IVF.

A
  1. Unethical to destroy unused embryos.

2. Could be used to select preferred characteristics in your child.

72
Q

Mrs Correct is having IVF treatment. At which point in the process is she given FSH and LH? Why is she given these hormones?

A

FSH and LH are given to Mrs Correct before egg collection. They are given to stimulate several eggs to mature so that more than one egg can be collected.

73
Q

Give one advantage and one disadvantage of IVF.

A

Advantage: e.g. an infertile couple is able to have a child.
Disadvantage: e.g. IVF can lead to multiple births. IVF has a low success rate. IVF can also be stressful.

74
Q

Name the gland that produces adrenaline.

A

Adrenal glands.

75
Q

What is the ‘basal metabolic rate’?

A

The rate at which chemical reactions happen in the body when the body is at rest.

76
Q

What does the thyroid release?

A

Thyroxine

77
Q

What does thyroxine do?

A

Regulates the body’s basal metabolic rate (energy used by the body at rest).

78
Q

Sophie is frightened of a spider. She finds a big spider in her bath and her heart starts to race. Explain Sophie’s response.

A

Sophie’s brain sends nervous impulses to her adrenal glands which release adrenaline. This increases her heart rate so more oxygen and glucose get to her brain and muscles.

79
Q

What is phototropism?

A

The growth of a plant in response to light.

80
Q

Name the hormone that controls growth at the tips of shoots and roots of plants.

A

Auxin.

81
Q

Gravity causes auxins to collect on the lower side of the root. Explain how this causes the root to grow downwards.

A

The auxins cause the lower side of the roots to grow slower, so the root bends downwards.

82
Q

Light causes auxins to collect on the shaded side of the shoot. Explain how this causes the shoot to grow towards the light.

A

The auxins cause the shaded side of the shoot to grow faster, so the root bends towards the light.

83
Q

When investigating how a plant grows under different light conditions, what other factors might you have to keep constant?

A

Temperature, amount of water, soil, plant species and starting size.

84
Q

Which plant hormone is used to grow cells in tissue cultures?

A

Auxin

85
Q

What does it mean if a seed is said to be ‘dormant’?

A

The seed won’t germinate until it has been through certain conditions.

86
Q

A gardener adds gibberellin to her plants. Give two things that gibberellin stimulates in a plant.

A

Gibberellins stimulate seed germination, stem growth and flowering.

87
Q

Explain how a farmer could use a plant hormone to kill weeds in her crop fields without killing her crops.

A

Auxins could be used which only affect the weeds. They disrupt the weeds growth causing them to die.

88
Q

Explain how plant hormones can be used to improve the growth of plants from cuttings.

A

A rooting powder that contains auxins can be added to the cut end of the cuttings so that they produce roots rapidly and start growing as new plants.

89
Q

How can you use chemicals to speed up the growth and and ripening of chillies?

A

Ethene gas speeds up the ripening, and gibberellin makes them grow larger.

90
Q

Which organ releases Oestrogen?

A

Ovaries

91
Q

Which organ releases Progesterone?

A

Ovaries

92
Q

Which organ releases LH?

A

Pituitary gland

93
Q

Which organ releases FSH?

A

Pituitary gland

94
Q

That is correct. True or False?

A

True

GCSE Science AQA (7 decks)

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