cells and control Flashcards

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1
Q

what do chromosomes contain

A

genetic information

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2
Q

where is genetic information stored

A

the nucleus of a cell

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3
Q

how is genetic information stored

A

chromosomes

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4
Q

what are chromosomes

A

coiled up lengths of DNA molecules

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5
Q

what is a diploid cell

A

2 copies of each chromosome (normal body cells)

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6
Q

where does each copy of the chromosomes come from

A

1 mother
1 father

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7
Q

what does mitosis make

A

two identical cells - nucleus contains same number of chromosomes as the original cells

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8
Q

what is mitosis for

A

growth and repair

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9
Q

what happens in mitosis

A

multicellular organisms divide to produce new cells in the cell cycle.

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10
Q

how do multi cellular organisms use mitosis

A

to grow and to replace cells which may have been damaged

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11
Q

what is asexual reproduction

A

uses mitosis to reproduce

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12
Q

what is the first stage of cell cycle

A

interphase

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13
Q

what happens during interphase

A

before it divided, the cell has to grow and increase the amount of sub cellular structures such as mitochondria and ribosomes.

it then duplicates the dna, copied and forms X-shaped chromosomes.

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14
Q

what happens after interphase

A

mitosis and cytokinesis

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15
Q

what are the four stages of mitosis in order

A

prophase
metaphase
anaphase
telophase
(PMAT)

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16
Q

what is prophase

A

the chromosomes condense, getting shorter and fatter.
the membrane around the nucleus breaks down and the chromosomes lie free in the cytoplasm

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17
Q

what is metaphase

A

the chromosomes line up at the centre of the cell

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18
Q

what is anaphase

A

cell fibres pull the chromosomes apart.
the two arms of each chromosome go to opposite ends of the cell

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19
Q

what is telophase

A

membranes form around each of the sets of chromosomes.
these become the nuclei of the two new cells - nucleus has divided

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20
Q

what is cytokinesis

A

the cytoplasm and cell membrane divided to form separate cells

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21
Q

when does cytokinesis happen

A

happens before telophase ends

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22
Q

what is produced by mitosis

A

2 new daughter cells

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23
Q

characteristics of the daughter cells

A
  • same sets of chromosomes in its nucleus
  • genetically identical diploid cells
  • genetically identical to the parent cell
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24
Q

what is growth

A

increase in size or mass

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25
Q

what is cell differentiation

A

the process by which a cell changes to become specialised for its job

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26
Q

what do specialised cells allow

A

multicellular organisms to work more efficiently

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27
Q

what is cell elongation

A

where a plant cell expands, making the cell bigger and so making the plant grow

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28
Q

what is cancer

A

uncontrolled cell division which results in a mass of abnormal cells called a tumor which invades and destroys surrounding tissues

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29
Q

what are percentile charts used for

A

to monitor growth over time, so overall pattern in development can be seen and any problems highlighted

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30
Q

what 3 measurements are taken for percentile charts

A

length
mass
head circumference

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31
Q

what does the chart show

A

number of percentiles
e.g. the 50th percentile shows the mass that 50% of babies will have reach at a certain age

32
Q

what can stem cells do

A

can differentiate into different types of cells

33
Q

what are undifferentiated cells called

A

stem cells

34
Q

how do stem cells differentiate

A

divide by mitosis to become new cells

35
Q

where are stems cells found in humans

A

early human embryos
bone marrow

36
Q

what group is a stem cell

A

embryonic

37
Q

where are stem cells contained in plants

A

meristems (plant tissue)

38
Q

how can stem cells be used

A

in medicine, to cure some diseases

39
Q

example of stem cells in medicine

A

stickle cell anaemia

40
Q

3 potential risk for scientists

A
  1. tumor development - stem cells divide very quickly and scientists are unable to control the rate of cell division
  2. disease transmission - viruses are inside cells, if the donor has a virus it could effect the recipient
  3. rejection - body may recognise them as foreign and trigger a immune response to get rid of them
41
Q

what is the ethical issue in using stem cells

A

shouldn’t be used as each one is a ‘potential human life’

42
Q

what is made up of the central nervous system (CNS)

A

the brain
the spinal cord
neurones

43
Q

what is the spinal cord

A

a long column of neurones that run from the base of the brain down the spine, at several places, neurones branch off down and connect to other parts of the body

44
Q

what does the spinal cord do

A

relays information between the brain and the rest of the body

45
Q

what is the cerebrum

A

largest part of the brain, divided into two halves called the cerebral hemispheres

right - controls muscles on the left side of the body
left - controls muscles on the right side of the body

different parts of the cerebrum are responsible for different things
- movement
- intelligence
- memory
- language
- vision

46
Q

what is the cerebellum

A

responsible for muscle coordination and balance

47
Q

what is the medulla oblongata

A

controls unconscious activities like breathing and your heart rate

48
Q

what do scanners do

A

investigate brain function

49
Q

what does a CT scan do

A

uses X-Rays to produce an image of the brain

50
Q

what does the CT scan show

A

it shows the main structure of the brain, however does not show the functions

51
Q

what does a PET scan do

A

uses radioactive chemicals to shows which parts of the brain are active when the person is inside the scanner
they are detailed

52
Q

what does the PET scanner show

A

both the structure and function of the brain in real time, can study disorders (Alzheimer’s)

53
Q

3 problems when treating the CNS

A
  1. hard to repair damage - don’t repair themselves
  2. not easy to access - not possible to remove surgically certain places
  3. problems can lead to permanent damage - surgery could damage further
54
Q

order and explanation of the response of the CNS

A
  1. nervous system is made up of neurones
  2. sensory detectors sense a change in your environment
  3. stimulus is detected by receptors, info is then converted to a nervous electrical impulse and sent along sensory neurones to the CNS
  4. the CNS coordinates the response, impulses travel through the CNS along relay neurones
  5. the CNS sends info to an effector along a motor neurone, the effector responds accordingly
  6. the time it takes you to respond to a stimulus is called your reaction time
55
Q

what do neurones do

A

transmits information rapidly as electrical impulses

56
Q

neurones facts

A
  • cell body with nucleus (plus cytoplasm and sub cellular structures)
  • very long (speeds up the impulse)
  • has extensions to connect other neurones
57
Q

what do dendrites and dendrons do

A

carry nerve impulses towards the cell body

58
Q

what do axons do

A

carry nerve impulses away from the cell body

59
Q

what are axons surrounded by

A

myelin sheath

60
Q

sensory neurones facts

A
  • one long dendron carries nerve impulses from receptor cells to the cell body, located in the middle of the neurone
  • one short axon carries nerve impulses from the cell body to the CNS
61
Q

motor neurone factors

A
  • many short dendrites carry nerve impulses from the CNS to the cell body
  • one long axon carries nerve impulses from the cell body to effector cells
62
Q

relay neurone factors

A
  • many short dendrites carry nerve impulses from sensory neurones to the cell body
  • an axon carries nerve impulses from the cell body to motor neurones
63
Q

what is the connect between two neurones is called a

A

synapse

64
Q

how is the nerve signal transferred

A

by chemicals called neurotransmitters, which diffuse across the gap

65
Q

step by step how do reflexes prevent an injury

A
  1. reflexes are automatic, rapid responses to stimuli - reduce chance of being injured
  2. the passage of info in a reflex (from receptor to effector) is called a reflex arc
  3. the neurones in a reflex arc go through the spinal cord or unconscious part of the brain
  4. when a stimulus is detected by receptors, impulses are set along a sensory neurone to relay neurones in the CNS
  5. when the impulses reach a synapse between the relay neurone and motor neurone, the same thing happens - neurotransmitters are released and cause impulses to be sent along a motor neurone
  6. When the impulses reach a synapse between the relay neurone and a motor neurone, the same thing happens. Neurotransmitters are released and cause impulses to be sent along the motor neurone.
  7. The impulses then travel along the motor neurone to the effector (in this example it’s a muscle, but it could be a gland).
  8. The muscle then contracts and moves your hand away
  9. as you don’t have to spend time thinking about the response, it’s quicker than normal responses
66
Q

what does the cornea do

A

refracts and bends light into the eye

67
Q

what does the iris do

A

controls how much light enters the pupil

also refracts light, focusing into the retina

68
Q

what does the retina do

A

light sensitive part which is covered in receptor cells called rods and cones (detect light)

69
Q

what are rods

A

more sensitive in dim lights but can’t sense colour

70
Q

what are cones

A

cones are sensitive to colours but not so good in dim light

71
Q

what does the optic nerve do

A

carries these impulses from the receptor to the brain

72
Q

what is longsightedness

A

unable to focus on near objects

occurs when lens is wrong shape and doesn’t bend light enough or the eyeball is to short

73
Q

what is shortsightedness

A

people cannot focus distant objects

occurs when lens is wrong shape and bends light too much or the eyeball is too long

74
Q

how to fix longsightness

A

convex lens

75
Q

how to fix shortsightness

A

concave lens

76
Q

what is colourblind

A

can’t tell the difference between certain colours

77
Q

what is a cataract

A

cloudy patch on the lens, stops lights entering normally