cells and control Flashcards

1
Q

mitosis

A

a type of asexual cell division which results in the production of two genetically identical daughter cells

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2
Q

what are the 3 parts of the cell cycle

A

interphase
mitosis
cytokinesis

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3
Q

interphase

A

when not dividing, the DNA is spread out in long strings
before division the cell has to grow and make more subcellular structures
DNA is then duplicated to form X-shaped chromosomes

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4
Q

what are the 4 stages of mitosis

A
PMAT
prophase
metaphase
anaphase
telophase
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5
Q

prophase

A

chromosomes condense

nuclear membrane starts to break down

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6
Q

metaphase

A

chromosomes line up in the centre of the cell

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7
Q

anaphase

A

spindle fibres pull chromosomes apart

two arms of each chromosome go to opposite ends of the cell

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8
Q

telophase

A

new nuclear membranes form around each set of chromosomes to become the two separate nuclei

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9
Q

cytokinesis

A

the cytoplasm and cell membrane divide to form two separate cells

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10
Q

number of cells after x number of divisions formula

A

number of cells = 2^x (where x is the number of divisions)

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11
Q

growth

A

an increase in size or mas

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12
Q

animals and plants grow and develop due to what 3

A

cell differentiation
cell division
cell elongation (in plants only)

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13
Q

what is cell division and growth like in animals (5)

A
  • all growth happens by cell division
  • tend to reach full size when young and then stay that size
  • cells divide quickly when young
  • as an adult, division is mainly for REPAIR
  • cell differentiation is lost at a very young age
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14
Q

what is cell division and growth like in plants (3)

A
  • growth in height is mainly due to cell elongation
  • cell division occurs mainly in the tips of the roots and shoots (meristem areas)
  • plants continue to grow and differentiate throughout their whole lives
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15
Q

cancer

A

case of uncontrollable cell division

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16
Q

what can cause cancer

A

is there is a change in one of the genes that controls cell division then a cell may begin to divide uncontrollably
this results in an abnormal mass of cells known as a tumour - if the tumour invades and destroys surrounding tissue it is a cancer

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17
Q

what is the use of percentile charts

A

growth charts can be used to assess a child’s growth to identify an overall pattern and see any potential problems

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18
Q

when would doctors be likely to investigate further based on a percentile chart

A

if the baby is above the top or below the bottom percentile line
if they change two or more percentile lines
if there is an inconsistent pattern

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19
Q

stem cells

A

undifferentiated cells

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20
Q

where are human stem cells found

A

PLURIPOTENT stem cells are found in early human embryos
adults have stem cells found in certain places such as the bone marrow that are MULTIPOTET are used to replace damaged cells

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21
Q

where are plant stem cells found

A

MERISTEMS produce unspecialised cells that act like embryonic stem cells, they remain PLURIPOTENT

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22
Q

how can stem cells be used in medicine

A
  • treat diseases (eg sickle cell anaemia can be cured with a bone marrow transplant)
  • embryonic stem cells can be stimulated to differentiate into specialised cells
  • these cells can be used to replace those damaged by disease or injury
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23
Q

risks of using stem cells in medicine (4)

A
rejection (if grown from someone else, may be recognised as foreign and trigger an immune response - taking suppressant drugs makes them more susceptible to disease)
tumour development (if scientists can't control the rate of division of transplanted cells)
disease transmission - if donor cells are infected the virus could be passed on
research into using embryonic stem cells raises ethical issues because of potential human life
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24
Q

what is the path from stimulus to response

A

stimulus -> receptor -> sensory neurone ->CNS ->motor neurone ->effector ->response

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25
how is information in the nervous system sent
as an electrical impulse via neurons
26
neuron structure
cell body with nucleus dendrons and dendrites axons myelin sheath
27
dendrons and dendrites
carry the impulses to the cell body
28
axons
carry impulses away from the cell body
29
myelin sheath
insulates some axons and acts as an electrical insulator, speeding up the impulse
30
are dendrites and axons long or short in each type of neuron
sensory long dendron short axon motor short dendron short axon relay short dendron long axon
31
synapse
the connection between 2 neurons
32
describe what happens at a synapse
neurotransmitters carrying the signal diffuse across the synaptic left to trigger an electrical impulse in the next neuron
33
reflex
automatic, rapid responses to stimuli
34
reflex arc
the passage of information in reflex form from receptor to effector
35
what are the 6 stages of a reflex
1) a stimulus is detected by receptors 2) impulse is sent along sensory neuron to a relay neuron in the CNS 3) synapses carry impulse across to the next neuron 4) impulses are passed from relay neuron to motor neuron 5) impulse travels from the motor neuron to the effector such as a muscle 6) a muscle contracts and you move away from the source of danger
36
example of reflexes in the eyes
light receptors in the eye detect very bright light and sends a message along the reflex ac that tells circular muscles in the iris to contract making the pupil smaller, allowing less light in so that very bright light doesn't damage the eyes
37
5 parts of the eye
``` cornea lens iris retina optic nerve ```
38
cornea
refracts light into the eye
39
lens
refracts light, focusing it onto the retina
40
iris
controls how much light enters the eye
41
retina
light sensitive part covered in receptor cells (rod and cone)
42
rod cells
more sensitive in dim light | can't sense colour
43
cone cells
less sensitive in dim light | sensitive to colour
44
optic nerve
carries electrical impulses from the receptors to the brain
45
colour blindness(definition, most common version, cure?)
can't tell the difference between certain colours most common form is red-green colour blindness caused by red and green cone cells not working properly currently no cure as cone cells can't be replaced
46
cataract (what is it, effects, cure?)
cloudy patch on the lens, stopping light from being able to enter the eye properly blurred vision, less vivid colours, difficulty looking at bright light can be treated by replacing the faulty lens with an artificial one
47
how does the eye focus
the lens is elastic, so the eye can focus light onto the retina by changing the shape of the retina
48
how does the eye focus when looking at close objects
ciliary muscle contracts suspensory ligaments slacken lens becomes more rounded light is refracted more
49
how does the eye focus when looking at faraway objects
ciliary muscle relaxes suspensory ligaments pull tight lens becomes less rounded light is refracted less
50
long sightedness
can't focus on nearby objects | light is focused behind the retina
51
what causes long sightedness
- wrong shape lens doesn't bend light enough | - eyeball is too short
52
how to fix long sightedness
convex lens ()
53
short sightedness
can't focus on faraway objects | light is focused in front of the retina
54
what causes short sightedness
- wrong shape lens bends light too much | - eyeball is too long
55
how to fix short sightedness
concave lens )(
56
spinal cord
a long column of neurons that runs from the base of the brain down the spine at several places, neurons branch off and connect with other parts of the body relays information between brain and the rest of the body
57
cerebelllum
responsible for motor coordination
58
medulla oblongata
controls unconscious activities such as breathing and heart rate
59
cerebrum
largest part of the brain two halves called cerebral hemispheres which control the opposite side of the body different parts of the cerebrum are responsible for different tasks; memory, intelligence, vision, language etc.
60
CT scanning
uses x-rays to produce an image of the brain shows map but no function if a structure is damaged or there is loss of function that can be identified
61
PET scanning
use of radioactive chemicals to show which parts of the brain are most active very detailed shows structure and function shows if some areas of the brain are usually inactive or active (useful for studying disorders affecting brain's activity)
62
why are there issues with treating problems in the CNS (3)
- no way to repair neurons or nervous tissue - if a problem develops it is inaccessible - treatment for problems in the CNS can lead to permanent damage