Biology Paper 2 GCSE Flashcards Preview

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Flashcards in Biology Paper 2 GCSE Deck (165)
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1

What is Homeostasis?

The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to external and internal changes

2

What does Homeostasis do?

maintains optimal conditions for enzyme action and all cell functions

3

Homeostasis contains control of what 3 things?

Blood glucose concentration
body temperature
water levels

4

All control systems include what?

- Cells called receptors
- coordination centers
- effectors

5

What do receptors do?

detect stimuli (changes in the environment)

6

What is an example of a coordination centre and what do they do?

brain, spinal cord, pancreas
They receive and process information from receptors

7

What do effectors do?

muscles or glands, which bring about responses which restore optimum levels

8

What do nervous systems do?

enables humans to react to their surrondings and to coordinate their behaviour

9

How does the nervous system work?

information from receptors passes along cells (neurones) as electrical impulses to the central nervous system. The CNS is the brain and spinal cord. The CNS coordinates the response of effectors which may be muscles contracting or glands secreting hormones

10

What is a synapse?

a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.

11

What does sensory neurones do?

carry signals from receptors to the spinal cord and brain.

12

What does a relay neurone do?

carry messages from one part of the CNS to another.

13

What do motor neurones do?

carry signals from the CNS to effectors.

14

What is the endocrine system?

composed of glands which secrete chemicals hormones directly into the bloodstream. The blood carries the hormone to a target organ where it produces an effect

15

What is the pituitary gland?

a 'master gland' which secretes several hormones into the blood in response to body conditions. These hormones in turn act on other glands to stimulate other hormones to be released to bring about effects.

16

How is blood glucose concentration monitored and controlled?

Pancreas

17

If the blood glucose concentration is too high what does the pancreas do?

pancreas produces the hormone insulin that causes glucose to move from the blood into the cells and glucose is converted to glycogen in liver

18

In liver and muscle cells excess glucose is converted to what?

glycogen for storage

19

What is Type 1 diabetes?

disorder in which the pancreas fails to produce sufficient insulin. It is characterised by uncontrolled high blood glucose levels and is normally treated with insulin injections

20

What is Type 2 diabetes?

the body cells no longer respond to insulin produced by the pancreas. A carbohydrate controlled diet and an exercise regime are common treatments. Obesity is a risk factor for Type 2 diabetes

21

If the blood glucose concentration is too low what does the pancreas do?

the pancreas releases glucagon. The glycogen is broken down to glucose and amino acids/fats are broken down

22

What is the post-synaptic neurone?

neurone after the synpase

23

What is the neurotransmitter?

a type of chemical released by the neurone

24

How do nerve impulses travel from one neurone to the next?

1. A chemical called a neuronetransmitter is released from the presynaptic neurone.
2. The neuronetransmitter diffuse across the synpase.
3.The neurotransmitter bind to the receptors on the post-synaptic neurone causing a new impulse to be sent along the post-synaptic neurone
4. the neurotransmitters diffuse back across the synapse and are absorbed by the pre-synaptic neurone to be used again

25

What is reaction time?

time between the presentation of a stimulus and the imtiation of the muscular response to that stimuli

26

How is glucose controlled using negative feedback control?

Blood glucose is controlled by the liver. When the blood glucose level is too high insulin is released and glucose is taken in by cells. Then if the blood glucose gets too low glycogen is released and is broken down into glucose. Insulin allows glucose to move from your blood into your cells where its used for respiration. Excess glucose is converted into glycogen and stored in the liver and muscle cells. Glycogen is insoluble and can be converted back into glucose

27

How is glucose controlled using negative feedback control?

Blood glucose is controlled by the liver. When the blood glucose level is too high insulin is released and glucose is taken in by cells. Then if the blood glucose gets too low glycogen is released and is broken down into glucose. Insulin allows glucose to move from your blood into your cells where its used for respiration. Excess glucose is converted into glycogen and stored in the liver and muscle cells. Glycogen is insoluble and can be converted back into glucose

28

What is Oestrogen?

Main female reproductive hormone produced in the ovaries. It causes the lining of the uterus to get thicker. It prevents FSH and LH.

29

What is ovulation?

At puberty eggs begin to mature and one is released every 28 days

30

What is Testosterone?

Main male reproductive hormone produced by the testes and it stimulates sperm production