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BIOLOGY > The Nervous System and Mitosis - TOPIC 2 > Flashcards

The Nervous System and Mitosis - TOPIC 2 Flashcards

1
Q

what is mitosis

A

when a cell reproduces itself by splitting in two to form two genetically identical offspring

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2
Q

what is the product at the end of mitosis

A

two new genetically identical diploid daughter cells

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3
Q

what are the 5 stages of mitosis

A

interphase
prophase
metaphase
anaphase
telophase

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4
Q

what happens in interphase

A

the cell grows and increases the amount of sub cellular structures it has and also duplicates its DNA

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5
Q

what happens in prophase

A

chromosomes condense and the membrane around the nucleus breaks down and the chromosomes lie free in the cytoplasm

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6
Q

what happens in metaphase

A

chromosomes line up in the middle of the cell

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7
Q

what happens in anaphase

A

spindle fibres pull the chromosomes apart and the 2 arms of the chromosomes are pulled to opposite end of the cell

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8
Q

what happens in telophase

A

membranes re-form around each of the sets of chromosomes and they become the nuclei of the two new cells

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9
Q

what is cytokinesis

A

before telophase ends, cytoplasm and cell membrane divide to form 2 separate cells

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10
Q

what are the uses of mitosis

A

it is used by multicellular organisms to grow and replace cells which have been damaged AND by some organisms to reproduce by asexual reproduction

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11
Q

number of cells =

A

2^number of divisions by mitosis

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12
Q

how do animals grow

A

By cell division when animals are young but when they are old, cell division is only used to replace old or damaged cells and cell differentiation is lost early

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13
Q

how do plants grow

A

by cell elongation, but unlike animals, they continue to differentiate

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14
Q

where does cell division take place in plants

A

in the tips of roots and shoots (meristems)

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15
Q

what is a tumour

A

a mass of abnormal cells

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16
Q

what is cancer

A

the result of changes in cells that leads to uncontrolled cell division

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17
Q

what are stem cells

A

undifferentiated cells

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18
Q

what can stem cells do

A

divide to produce lots more undifferentiated cells which can then develop in to different types of cells

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19
Q

where are stem cells found

A

in early human embryos or in bone marrow

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20
Q

what are embryonic stem cells used for

A

growth and development of organisms and replace damaged cells

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21
Q

what are stem cells used for in adults

A

they are used to replace damaged cells

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22
Q

how are stem cells used in medicine

A

they are used to cure diseases such as sickle cell anaemia

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23
Q

what are the potential risks of using stem cells in medical treatments

A

tumour development
disease transmission
rejection
ethical issues

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24
Q

what are meristems used for in plants

A

they produce unspecialised cells which can form any cell type in the plant so they go on to form specialised tissues like xylem and phloem

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25
Q

what is a stimuli

A

changes in the environment

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26
Q

what does the CNS consists of

A

the brain and spinal cord only

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27
Q

what are effectors

A

muscles or glands which respond to nervous impulses and bring about a response to a stimulus

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28
Q

how do muscles respond to nervous impulses

A

by contracting

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29
Q

how do glands respond to nervous impulses

A

by secreting hormones

30
Q

what are the different neurones involved in the transfer of information to and from the CNS

A

sensory neurones
relay neurones
motor neurones

31
Q

what are sensory neurones

A

neurones that carry information as electrical impulses from sensory receptors to the CNS

32
Q

what are relay neurones

A

neurones that carry electrical impulses from sensory neurones to motor neurones

33
Q

what are motor neurones

A

neurones that carry electrical impulses from the CNS to the effectors

34
Q

what is reaction time

A

the time it takes you to respond to a stimulus

35
Q

transmission of information to and from the CNS summarised flow diagram

A
  1. stimulus
  2. receptors
  3. sensory neurone
  4. relay neurone / CNS
  5. motor neurone
  6. effector
  7. response
36
Q

what is the structure of a neurone

A

a cell body with a nucleus and the cell body has extensions that connect to other neurones

37
Q

what do dendrons and dendrites do

A

carry nerve impulses TOWARDS the cell body

38
Q

what do axons do

A

carry nerve impulses AWAY from the cell body

39
Q

what is a myelin sheath and what does it do

A

it is a fatty layer that acts as an electrical insulator and speeds up the electrical impulse

40
Q

what is a synapse

A

the gap between two neurones

41
Q

what is the function of neurotransmitters

A

the nerve signal is transferred by neurotransmitters which diffuse across the gap and then set off a new electrical signal in the next neurone

42
Q

why do neurones deliver information really quickly

A

because the signal is transmitted by electrical impulses

43
Q

describe the main stages in a reflex arc

A
  1. when a stimulus is detected, impulses are sent along a sensory neurone to a relay neurone
  2. When the impulses reach a synapse between the sensory neurone and relay neurone, they trigger neurotransmitters to be released. These cause impulses to be sent along the relay neurone
  3. When the impulses reach a synapse between the relay neurone and a motor neurone, the same things happens, Neurotransmitters are released and cause impulses to be sent along the motor neurone
  4. The impulses then travel along the motor neurone to the effector
  5. If the effector is a muscle, it will respond to the impulse by contracting and if a gland it will secrete a hormone
44
Q

what are the main regions of the brain

A

cerebrum
cerebellum
medulla oblongata

45
Q

what is the function of the cerebrum

A

it controls movement, intelligence, memory, language and vision

46
Q

what is the function of the cerebellum

A

it is responsible for muscle coordination and balance

47
Q

what is the function of the medulla oblongata

A

it controls unconscious activities such as breathing and heart rate

48
Q

what are the different ways to see the brain

A

CT scanners
PET scanners

49
Q

what do CT scanners do

A

they use X-rays to produce an image of the brain, but you can only see the main structures and not the functions

50
Q

what do PET scanners do

A

produce images which show which parts of the brain are active and can be used to investigate the structure and function of the brain

51
Q

why is it hard to repair damage to the nervous system

A

neurones in the CNS don’t readily repair themselves AND parts of the nervous system are not easy to access AND it may lead to more damage

52
Q

what is the structure of the eye

A

cornea
lens
pupil
iris
retina
cones

53
Q

what does the cornea do

A

it refracts light into the eye

54
Q

what does the lens do

A

it refracts light and focuses it onto the retina

55
Q

what does the pupil do

A

it is the hole in the eye through which light enters

56
Q

what does the iris do

A

controls the diameter of the pupil

57
Q

what does the retina do

A

contains two types of receptor cells

58
Q

what do ciliary muscles and suspensory ligaments do

A

control the shape of the lens

59
Q

what does the optic nerve do

A

transmits electrical impulses from the eye to the brain

60
Q

how do you look at near objects

A
  1. the ciliary muscles contract, which slackens the suspensory ligaments
  2. the lens becomes a more rounded shape
  3. this increases the amount by which it refracts light
61
Q

how do you look at distant objects

A
  1. the ciliary muscles relax, which allows the suspensory ligaments to pull tight
  2. this pulls the lens into a less rounded shape
  3. so it refracts light by a smaller amount
62
Q

what is long - sightedness

A

being unable to focus on near objects because the lens is the wrong shape OR doesn’t refract the light enough OR the eyeball is too short

63
Q

how to cure long sightedness

A

you can use glasses or contact lenses with a convex lens so the lens refracts the light rays so they focus on the retina

64
Q

what is short sightedness

A

being unable to focus on distant objects because the lens is the wrong shape and refracts light too much OR the eyeball is too long

65
Q

how to cure short sightedness

A

you can use glasses or contact lenses with a concave lens so that the light rays focus on the retina

66
Q

what is colour blindness

A

when you can’t tell the difference between certain colours

67
Q

what causes colour blindness

A

when the cones in the retina is not working properly

68
Q

what is the cure for colour blindness

A

there is no cure because cone cells can’t be replaced

69
Q

what is a cataract

A

a cloudy patch on the lens, which stops light from being able to enter the eye normally

70
Q

what happens to your vision if you have a cataract

A

you will have blurred vision and have difficulty seeing in bright light and may experience colours looking less vivid

71
Q

how to cure a cataract

A

surgically, by replacing the faulty lens with an artificial lens

BIOLOGY (9 decks)

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