Unit 2 - Cells And Control Flashcards Preview

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Flashcards in Unit 2 - Cells And Control Deck (65):
1

Mitosis occurs in

Body cells only

2

Examples of when mitosis is needed

Growth
Repair

3

Mitosis is a type of

Cell division

4

5 stages of mitosis

IMPAT
Interphase
Prophase
Metaphase
Anaphase
Telophase

5

What happens during interphase

DNA copies (chromosome is visible)

6

What happens in prophase

Each chromosome consists of two chromatids

7

What happens during metaphase

Nuclear membrane breaks down
Chromosomes line up along middle of cell

8

What happens during anaphase

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

9

What happens during telophase

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

10

What is it called when the cell splits into 2

Cytokinesis

11

Why does cancer occur

Uncontrolled mitosis causes tumour

12

How does cell division occur in animals

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

13

How does cell division occur in plants

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

14

What is a percentile chart

Show typical trend of growth of an organism

15

When is a percentile chart used

To monitor growth eg of baby

16

3 types of stem cell

Embryonic
Adult
Meristems

17

Embryonic cells is

From an embryo
Early stage (8cells)

18

What can embryonic cell be used for

Replace/repair brain cell
Retina cell
Drug testing

19

Positive of using embryonic cell

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

20

Negatives of using embryonic cells

Ethical (alive)
May not stop dividing so cause cancer

21

What is an adult stem cell

From differentiated tissue, such as skin or bone

22

What are adult stem cells used for?

Leukaemia treatment

23

Positives of using adult stem cells

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

24

Negatives of using adult stem cells

Produce few types of cell
May not stop dividing so cause cancer

25

What are meristem stem cells

Found in plant cells (roots tips and shoots)

26

What can meristem stem cells be used for

To produce any kind of plant cell

27

What is the cerebellum

Part of the brain that coordinates and controls precise smooth movement

28

What is the cerebral hemisphere

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

29

What is the medulla oblongata

Part of the brain that regulates heart beat and breathing rate

30

2 methods of accessing brain tissue under the skull

CT (computerised tomography) scan
PET (positron emission tomography) scan

31

Why is it difficult to repair brain

Radiotherapy could damage healthy tissue
Skull protects the brain

32

Why is it difficult to get the the spinal cord

Spine protects it

33

What are sensory receptors

Dendrites of a sensory neurone

34

What does a sensory neurone do

Carries impulses to CNS

35

What do motor neurones do

Carry impulses from CNS to effector organs

36

Where are relay neurones

Only in the CNS

37

What is a synapse

Where 2 neurones meet

38

How does impulse cross the synapse

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

What does an axon do

Carries impulses away from the cell body

40

What does a dendrite do

Receives impulses from receptor cells and other neurones

41

What is myelin sheath

Fatty layer of insulation around a neurone

42

What is a reflex arc

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

43

Why is a reflex arc needed

For fast responses eg blinking

44

What is a reflex arc a faster response

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

45

What is an eye

Sensory receptor that detects the stimulus of light

46

What does a cornea do

Refracts the light in to the eye

47

What is the iris

Muscle that controls how much light comes in

48

What is the iris muscle controlling

The diameter of the pupil

49

What does a lens do

Refracts light to focus on the retina

50

What is the retina

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

51

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

Optic nerve

52

What are ciliary muscles

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

53

What are suspensory ligaments

Connect lens to ciliary muscles

54

What does the optic nerve do

Carry impulse from retina to brain

55

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

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

56

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

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

57

What is myopia

Short sightedness

58

How can myopia be treated

Concave lens

59

What is hyperopia

Long sightedness

60

How can hyperopia be corrected

Convex lens

61

3 types of vision correction

Contact lenses
Laser surgery
Lens replacement

62

What is cataracts

When the lens becomes cloudy

63

How can cataracts be treated

Replacing lens with clear, artificial lens

64

Why does colour blindness occur

When one type of cone is missing or not functioning properly

65

What do cones do

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