Unit 2 - Cells And Control Flashcards

1
Q

Mitosis occurs in

A

Body cells only

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2
Q

Examples of when mitosis is needed

A

Growth

Repair

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3
Q

Mitosis is a type of

A

Cell division

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4
Q

5 stages of mitosis

A
IMPAT
Interphase
Prophase
Metaphase
Anaphase
Telophase
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5
Q

What happens during interphase

A

DNA copies (chromosome is visible)

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6
Q

What happens in prophase

A

Each chromosome consists of two chromatids

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7
Q

What happens during metaphase

A

Nuclear membrane breaks down

Chromosomes line up along middle of cell

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8
Q

What happens during anaphase

A

Chromatids become chromosomes as they separate and one from each pair is pulled to each pole of the cell

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9
Q

What happens during telophase

A

Spindle fibres disappear and new nuclear membrane forms around each group of chromosomes

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10
Q

What is it called when the cell splits into 2

A

Cytokinesis

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11
Q

Why does cancer occur

A

Uncontrolled mitosis causes tumour

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12
Q

How does cell division occur in animals

A

Mitosis causes identical cells
These differentiate
Then can become specialised eg nerve cells

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13
Q

How does cell division occur in plants

A

Mitosis causes new cells
Cells have vacuoles to take in water by osmosis and can elongate
These can then differentiate into specialised cells
They grow and differentiate throughout life

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14
Q

What is a percentile chart

A

Show typical trend of growth of an organism

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15
Q

When is a percentile chart used

A

To monitor growth eg of baby

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16
Q

3 types of stem cell

A

Embryonic
Adult
Meristems

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17
Q

Embryonic cells is

A
From an embryo
Early stage (8cells)
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18
Q

What can embryonic cell be used for

A

Replace/repair brain cell
Retina cell
Drug testing

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19
Q

Positive of using embryonic cell

A

Easy to get
Can produce (specialise) into any other cell
Replace faulty cell with good one

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20
Q

Negatives of using embryonic cells

A

Ethical (alive)

May not stop dividing so cause cancer

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21
Q

What is an adult stem cell

A

From differentiated tissue, such as skin or bone

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22
Q

What are adult stem cells used for?

A

Leukaemia treatment

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23
Q

Positives of using adult stem cells

A

No ethical issue
No rejection to body
Replace faulty cell with good one

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24
Q

Negatives of using adult stem cells

A

Produce few types of cell

May not stop dividing so cause cancer

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25
Q

What are meristem stem cells

A

Found in plant cells (roots tips and shoots)

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26
Q

What can meristem stem cells be used for

A

To produce any kind of plant cell

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27
Q

What is the cerebellum

A

Part of the brain that coordinates and controls precise smooth movement

28
Q

What is the cerebral hemisphere

A

Part of the brain the controls voluntary movement and is responsible for learning and memory

29
Q

What is the medulla oblongata

A

Part of the brain that regulates heart beat and breathing rate

30
Q

2 methods of accessing brain tissue under the skull

A

CT (computerised tomography) scan

PET (positron emission tomography) scan

31
Q

Why is it difficult to repair brain

A

Radiotherapy could damage healthy tissue

Skull protects the brain

32
Q

Why is it difficult to get the the spinal cord

A

Spine protects it

33
Q

What are sensory receptors

A

Dendrites of a sensory neurone

34
Q

What does a sensory neurone do

A

Carries impulses to CNS

35
Q

What do motor neurones do

A

Carry impulses from CNS to effector organs

36
Q

Where are relay neurones

A

Only in the CNS

37
Q

What is a synapse

A

Where 2 neurones meet

38
Q

How does impulse cross the synapse

A

Causes chemical neurotransmitter to be released

This diffuses across the synapse and fits into receptors, causing new electrical impulse to be released in next neurone

39
Q

What does an axon do

A

Carries impulses away from the cell body

40
Q

What does a dendrite do

A

Receives impulses from receptor cells and other neurones

41
Q

What is myelin sheath

A

Fatty layer of insulation around a neurone

42
Q

What is a reflex arc

A

Involves only 3 neurones, with impulses passing to and from spinal cord

43
Q

Why is a reflex arc needed

A

For fast responses eg blinking

44
Q

What is a reflex arc a faster response

A

Brain doesn’t have to process it so less synapses have to be crossed

45
Q

What is an eye

A

Sensory receptor that detects the stimulus of light

46
Q

What does a cornea do

A

Refracts the light in to the eye

47
Q

What is the iris

A

Muscle that controls how much light comes in

48
Q

What is the iris muscle controlling

A

The diameter of the pupil

49
Q

What does a lens do

A

Refracts light to focus on the retina

50
Q

What is the retina

A

A layer of tissue at the back of the eye containing receptor cells for light and colour

51
Q

Nerves convert image into electrical impulses, what sends the signal to the brain?

A

Optic nerve

52
Q

What are ciliary muscles

A

They change the shape of the lens, depending on distance of object

53
Q

What are suspensory ligaments

A

Connect lens to ciliary muscles

54
Q

What does the optic nerve do

A

Carry impulse from retina to brain

55
Q

What happens to ciliary muscles, suspensory ligaments and the shape of the lens when an object is near

A

Ciliary muscles - contracted
Suspensory ligaments - slack
Shape of lens - fat and rounded

56
Q

What happens to ciliary muscles, suspensory ligaments and the shape of the lens when an object is far

A

Ciliary muscles- relaxed
Suspensory ligaments - tight
Shape of lens - thin and flattened

57
Q

What is myopia

A

Short sightedness

58
Q

How can myopia be treated

A

Concave lens

59
Q

What is hyperopia

A

Long sightedness

60
Q

How can hyperopia be corrected

A

Convex lens

61
Q

3 types of vision correction

A

Contact lenses
Laser surgery
Lens replacement

62
Q

What is cataracts

A

When the lens becomes cloudy

63
Q

How can cataracts be treated

A

Replacing lens with clear, artificial lens

64
Q

Why does colour blindness occur

A

When one type of cone is missing or not functioning properly

65
Q

What do cones do

A

Determine colour of the image depending on how much they are stimulated