HOMEOSTASIS CGP Flashcards

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1
Q

-what is homeostasis
-what does homeostasis controlx3
-homeostasis maintans optimum conditions for cell functions and…….

A

regulation of internal conditions of cell/organism to maintain optimum conditions for function - in response to internal/ external changes.
-blood glucose concentration
-body temp
-water levels

enzyme action

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2
Q

all automatic control systems contains 3 things- what do each do

what 2 types of Responses can automatic control systems involve

A
  • receptors, detect stimuli (changes in
    environment)
  • coordination centres (brain, spinal cord, pancreas) receive + process info from receptors
  • effectors, muscles / glands, produce responses to restore optimum levels.

-nervous, chemical

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3
Q

describe reflex arc from stimulus to effector - 6 steps
reflex arc similar to what happens when CNS coordinates a response but in reflex arc, its automatic/rapid so X involve consious part of brain, there’s an extra neurone instead.

A

-receptors detect stimulus
-electrical impulses pass along sensory to relay to motor neurones
-at synapse btwn neurones, chemicals cross the gap by diffusion and continue the electrical signal.
-the relay neurone is in spinal chord(CNS) so there are synapses there to carry the impulse to motor
-impulse travels from motor neurone to effector
-mucsle contracts/ gland secrete hormones

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4
Q

If level of something becomes too high/low body uses negative feedback- describe this for a high level
- the effector will keep producing response if stimulated by co-ord centre. What happens then

A

-receptor detects stimulus- level too high
-coordination centre processes info and organises response
-effector produces response which counteracts change . level decreases

-levels change too much the other way . receptors detect this, negative feedback happen again

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5
Q

4 parts of the nervous system- describe what they are/ do

A

-sensory neurones- carry electrical impulses from receptor cells to CNS
-cns- brain+spinal chord
-motor neurones-carry electrical impulses from CNS to effectors
-effectors-muscles/ glands -respond to impulses

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6
Q

what responses do glands/ muscles have
7 parts of how the CNS coordinates a response- from stimulus to response

A
  • secreting hormones. contracting
    1-stimulus, 2-receptor, 3-sensory neurone, 4-cns, 5-motor neurone, 6-effector, 7-response
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7
Q

what is synapse
what happens at a synapse

A

-connection btwn 2 neurones
-when electrical impulse reaches end of neurone, stimulates release of chemical.
-chemicals diffuse across synapse to activate electrical impulse in next neurone

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8
Q

why are reflex actions important- what are they

A

-automatic, rapid responses - don’t involve consious part of the brain- reduce chance of injury

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9
Q

RP reaction time- 5 steps

A

-sit with arm resting on edge of table
zero end should be level with persons thumb and forefinger
-let go- no warning
-measure reaction time by number on ruler when caught
-repeat few times, calculate mean distance ruler fell
*conversion table shows reaction time in Seconds using mean distance
-person drink caffeinated drink + after 10 mins repeat

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10
Q

4 control variables for RP reaction time

what else u should make sure x1

*- how else can u do this experiment
*- pros of testing like this instead

A

-same person catching
-same hand to catch
-always drop from same height
-person tested X had caffeine before experiment

-person X have more caffeine after- has side effects

-computer tests- eg click mouse as soon as they see a stimulus

-more precise- remove human error
-more accurate- time in milliseconds
-person can’t predict when to respond by reading body language

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11
Q

what is brain made of + control
3 parts of the brain + where they are

A

billions of interconnected neurones- controls complex behaviour
-cerebral cortex- front (outer wrinkly bit)
-mudulla- front of line going down from brain
-cerebellum- back- fuzzy ball in sack under wrinkly bit

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12
Q

what does cerebellum, cerebral cortex + medulla each do

A

-cerebral cortex-responsible for consciousness,intelligence, memory, language
-medulla-controls unconscious activities eg breathing
cerebellum- responsible for muscle contraction

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13
Q

3 methods used to study brain+ explain

A

-studying patients with brain damage-
certain part of brain damaged, effects on patient tell us what that part has to do with

-electrically stimulating different brain parts
put tiny electrodes in brain tissue and zap w/ electricity. See what this causes- gives idea on what that part does.

-MRI scans- produce detailed pic of brain structure- find which parts active when doing certain things eg recalling memory

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14
Q

difficulties investigating brain function/treating brain damage+ disease. x2

Pro of knowing how brain works from investigating

A

-brain complex + delicate-
difficult to investigate + treat brain
-risk of physically damaging brain + causing more problems

-allows development of treatment for disorders of the nervous system

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15
Q

what is the eye
name all 9 parts of eye
salty cats in palaces love rainbows cos sun out

A

a sense organ
Sclera
Cornea
Iris
pupil
Lens
Retina
Ciliary muscles
Suspensory ligaments
Optic nerve

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16
Q

describe what these do:
Sclera
Cornea
Iris
pupil
Lens

A

sclera- tough supporting wall/tissue
cornea-transparent layer @ front of eye- refracts light into eye
iris-has muscles to control diameter of pupil- how much light enters eye
pupil- hole in middle of eye
lens-focuses light on retina

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17
Q

describe what these do:
Retina
Ciliary muscles
Suspensory ligaments
Optic nerve

A

retina-contains receptor cells sensitive to light+colour
Cilliary muscles-controls shape of lens
suspensory ligaments- controls shape of lens
optic nerve-carries impulses from receptors to brain

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18
Q

-what happens when bright light shone in eye
x3 points
-harm of bright light=

A

-light receptors detect light and send impulse to brain
-brain sends impulses to muscles in iris .reflex triggered- pupil made smaller
-circular muscles in iris contract + radial muscles relax. -reduces amount of light that can enter

-damage retina

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19
Q

3 alternatives to glasses

A

contact lenses
laser eye surgery
replacement lens surgery

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20
Q

what happens to eye in dim light x3
-why

A

radial muscles contract
circular muscles relax
pupil becomes wider

-light receptors in retina sense low light
sends electrical impulse to brain
brain sends impulses to muscles in iris

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21
Q

what is accommodation in eye
To focus on a near object: x3

A

changing shape of the lens to focus on near or distant objects
-ciliary muscles contract
-suspensory ligaments loosen
-lens becomes thicker (curved) + refracts light more (strongly)

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22
Q

To focus on a distant object: x3

A

*ciliary muscles relax
*suspensory ligaments pulled tight
* the lens pulled thin + only slightly refracts light rays

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23
Q

what is Hyperopia-
- why does it happen
-what happens
-what lenses correct it- -what do they do

A

-longsighted x focus close
-lens wrong shape/ doesn’t refract light enough OR eyeball too short
- near object image brought into focus behind retina
-convex lens (curves out)
-refract light rays to focus on retina

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24
Q

what is myopia
- why does it happen
-what happens
-what lenses correct it- what do they do

A

-short sighted-x focus far
-lens refracts light too much OR eyeball too long
-images of distant objects brought into focus infront of retina
-concave lenses (curve inwards)
-refract light rays to focus on retina

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25
Q

3 alternatives to glasses- briefly describe
-pros of contact lenses and different types
-disadvantage of each surgery

A

-contact lenses- thin lenses on eye surface
lightweight,almost invisible, convenient
hard lenses OR soft lenses- more comfy, higher risk of infection

-laser eye surgery-
change cornea shape w/ laser- change power of refraction
-laser eye-risk of complications eg infection

-replacement lens surgery-replace lens with plastic one- more effective in long sightedness
-replacement lens-more risky than laser eye-could damage retina-
(+infection)

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26
Q

what does the thermoregulatory centre do-
where is it
what does it contain
where does it recieve impulses from

A

monitors + controls body temp -
-in brain
-contains receptors sensitive to temp of blood flowing through brain
and
-gets impulses from receptors in skin that give info on skin temp

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27
Q

describe how body temp controlled via negative feedback if too high 3 points
And then if too low. 3 points

A

-temp receptors detect temp is too high/low
-thermoregulatory centre recieves info and + triggers effectors
-blood vessels dilate, sweat produced to counteract change
-OR blood vessels constrict , sweating stops, skeletal muscles shiver

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28
Q

*what are antagonistic effectors

A

effectors that do opposite things at same time to keep precise temp levels. This allows more sensitive response

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29
Q

3 mechanisms that lower body temp
explain 2 of them

A

hairs flatten, sweat, vasodilation
-sweat gland produce sweat- evaporates from skin + transfers energy to environment
-blood vessels dilate - more blood flows close to skin surface, more energy transferred to environment

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30
Q

4 mechanisms that increase body temp
-explain them

A

-hairs stand up
-sweating stops
-vasoconstriction
-skeletal muscles contract(shiver)

-hairs stand up- trap insulating layer of air
-sweating stops- reduce energy lost
-blood vessels constrict + close off skins blood supply
-shivering needs respiration which transfers some energy to warm body

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31
Q

-what are hormones +
how do they get to target organs
-differences of hormones to nerves x2

A

chemicals secreted by endocrine glands directly into blood stream. carried by blood to target organ(to produce an effect)
-effects slower, effects last longer, act in more general way (nerves act on precise area)

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32
Q

what gland is ‘master gland’ -what does it do
-why is it ‘master gland’ x2

A

pituitary gland-
secretes hormones to regulate body conditions-
-these hormones act on other glands
-directs other glands to release hormones that bring a change

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33
Q

-6 parts of endocrine system u need to know
-what do they produce and the purpose of these.

A

*pituitary gland-hormones-that act on other glands
* pancreas-insulin-regulate blood glucose levels
* thyroid-thyroxine-regulates metabolism rate, heart rate, temp
* adrenal gland-adrenaline -prepares fight/flight response
* ovary-oestrogen-involved in menstrual cycle
* testes-testosterone-controls puberty/ sperm production in males

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34
Q

-organ that controls blood glucose concentration
-what happens when blood glucose levels too high x3

A

pancreas
produces
-insulin secreted by pancreas
-insulin causes glucose to be taken in by cells out of blood
-In liver + muscle cells,excess glucose converted + stored as glycogen
(so blood glucose reduced)

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35
Q

what happens when blood glucose conc. too low x3
.
.
.

what do glucagon and insulin form

eating what type of food increases glucose levels

A

-glucagon secreted by pancreas
-glucagon triggers liver cells to convert glycogen into glucose
-liver releases glucose into blood.
(blood glucose level increases)

-negative feedback cycle bcse they have opposing effects

-carbs (type of sugar)

36
Q

-what is type 1 diabetes- common treatment
-what is type 2 diabetes
- what is a risk factor
-common treatments

A

-pancreas X produce enough insulin
-insulin injections
(helps to limit carb intake+ excercise)
-body cells X respond to insulin pancreas produces
-obesity
-carb-controlled diet
-regular exercise- removes excess glucose in blood

37
Q

insulin injection-
things u know about it
how does it help

A

-very effective
-several injections
-mainly meal time-
-makes sure glucose removed quickly once food digested
-stops level getting too high

38
Q

how do kidneys carry out their function x2

A

-filter waste products out of blood
-blood reabsorb useful substances to produce urine (selective reabsorption) eg water, glucose, ions
(basically all glucose is reabsorbed. barely any in urine)

39
Q

-how is urea made starting with protein digestion x5
-what happens to urea made in liver x3

A

-digesting proteins=excess
amino acids- can’t be stored
-in liver, deamination happens
-amino acids broken down+stored
- ammonia is by-product of deamination
- Ammonia = toxic
quickly converted to urea-

-urea sent to kidneys in blood
-filtered out
-excreted in urine

40
Q

-what happens to ions you take in from food. 1 eg
-what happens if water/ion content in body wrong
x2
-where are ions+ urea lost from x2
-where is water lost from x3
-how do we balance amount of water in body x2
how do we balance amount of ions in body x1

A

absorbed into blood- eg sodium
-too much/ too little water enters cells by osmosis
-cells dont work properly/ damaged

-skin in sweat -kidneys urine
-exhalation, sweat, kidneys in urine

-consume water, remove water in urine
-Kidneys- reabsorb ions / remove them

41
Q

-water level/ urine concentration controlled by hormone…
-this is released into….. from ……
- The hormone is released when….
- What does this hormone do
–this process is controlled by x2

A

-ADH hormone-
-released into bloodstream from pituitary gland
-when blood is too concentrated
-causes kidney tubules to become more permeable so more water reabsorbed into blood from kidney tubules
(increases blood water content and urine concentration
- brain(receptors monitor water content in blood)
-negative feedback

42
Q

what happens when blood water content too high x3

A

-receptor in brain detect level too high
-Coordination centre in brain receives info + coordinates response
-pituitary gland release less ADH- Kidney tubules less permeable, less water reabsorbed into kidney tubules

43
Q

what happens if kidneys X work right x2
2 ways to keep kidney failure person alive

A

-waste substances build up in blood
-X control ion+ water levels in body - eventual death

dialysis, kidney transplant

44
Q

-Describe how dialysis works-4
-why are useful substances not lost from blood
-how often
-down sides x3
- positive

A

-blood flows btwn partially permeable membrane- not permeable to large molecules (like membrane in kidney) (eg protien)
-and dialysis fluid- same conc. of ions+ glucose as healthy blood
-waste substances diffuse across
-useful substances X lost from blood- no concentration gradient- fluid +persons blood have same levels of useful substances

-3 times a week for 3/4 hrs

-risk blood clots/ infections
-unpleasant experience
-costly for NHS
—- allows valuable time till donor organ found

45
Q

-who are kidney transplants taken from x2
-risks x2
- why is transplant better than dialysis x2
-con

A

-ppl who died suddenly + r on donor register/have donor card (their relatives must agree too)
-ppl still alive
(kidneys ideally matched by blood type)

-small risk to donor
-kidney rejected by immune system- treated w/ to drugs prevent this- can still happen

-cheaper in long run
-X spend hours on dialysis
-long waiting list for kidneys

46
Q

female reproductive hormone+what it does
male reproductive hormone+ what it does

reproductive hormones cause……… ……. …… to develop

A

oestrogen- causes physical changes+involved in menstrual cycle
testosterone-stimulates sperm production

-secondary sex characteristics

47
Q

4 stages in menstrual cycles

A

1- menstruation starts-uterus lining breaks down for 4 days
2- day 4-14 uterus lining builds up to layer of blood vessels- ready to receive fertilised egg
3-Ovulation-egg develops and released from ovary on day 14
4- wall maintained for 14 days. if fertilised egg doesn’t land on uterus wall, cycle starts again

48
Q

4 hormones involved in menstruation in order and what they do( not hormones they stimulate)

what happens when progesterone level falls

A

-FSH-causes maturation of egg
-Oestrogen-causes uterus lining to grow
-LH stimulates release of egg (day 14)
-Progesterone- maintains uterus lining during second half of cycle (after egg released)

level falls-lining breaks down(cycle restarts)

49
Q

2 menstrual hormones
produced in pituitary gland
2 menstrual hormones produced in ovaries

-what hormone does FSH stimulate ovaries to produce
-what does oestrogen stimulate + inhibit
-what hormone does LH inhibit
-what does progesterone inhibit

A

FSH
LH

progesterone
oestrogen

FSH stimulates-oestrogen

Oestrogen- stimulates LH, Inhibits FSH

LH -X inhibit or simulate any hormone

Progesterone- inhibits release of LH + FSH

50
Q

6 methods of contraception-

A

oral contraceptives
injections/implants/skin patches
barrier methods
intrauterine devices
spermicidal agents
abstaining
surgery

51
Q

what hormones are in oral contraceptive pill.

how do both these hormones reduce fertility
How do they do this individually

A

progesterone + oestrogen

-both inhibit FSH so no eggs mature

progesterone- stimulates thick mucus-preventing sperm reaching egg

oestrogen- if taken everyday to keep level high-inhibits FSH production. Eventually egg X develop + FSH X produced

52
Q

1pro + 2cons of combined oral contraceptive pill (progesterone + oestrogen)

A

-over 99% effective

-side effects- headaches, nausea
-X protect against STD’s

53
Q

what pill is better than the combined oral contraceptive pill—
why—

A

Progesterone only pill- same effectiveness, less side effects

54
Q

what is the contraceptive patch.
how long does it last

A

-small patch w/ oestrogen + progesterone stuck to skin. Lasts 1 week

55
Q

describe contraceptive implant
how long does it last

A

implant inserted under arm skin. continually releases progesterone .
last for 3 yrs

56
Q

describe contraceptive injection

how long does it last

A

-injection w/ progesterone
-lasts for 2-3 months

57
Q

what is an Intrauterine device-
what does it do-
what are the two types-

A
  • T shaped device put in uterus
    kills sperm + stop fertilised egg being implanted

-Plastic IUD release progesterone
-Copper IUD stop sperm surviving in uterus

58
Q

what do all barrier methods do

3 methods of barrier contraception

A

stop sperm getting to egg

-Condoms-Male/Female
-Diaphragm (used w/ spermicide)
-Spermicide- used alone

59
Q

-what do condoms do
-a pro of condoms

-what is a diaphragm

what is spermicide-
con of spermicide-

A

-prevent sperm entering vagina
-only contraception that protect against STD’s

-plastic cup put over cervix as a barrier. used with spermicide

spermicide-substance that kill/disable sperm
-not very effective when used alone

60
Q

-describe Sterilisation to stop having a child
-important thing to remember with this method

A

cut/tie fallopian tubes or sperm duct
permanent procedure- very small chance tubes can rejoin

61
Q

3 ways other than barrier + hormonal methods

what is ‘natural method’
pro
con

A

sterilisation, abstinence, natural methods

find out when in cycle woman is most fertile + avoid sex
-popular w/ ppl who think barrier+hormonal methods r unnatural
-not very effective

62
Q

what is in the ‘fertility drug’ given to women
-why is it given
-how does it help-
-pro of ‘fertility drug’
-cons x2

A

FSH, LH

woman has low FSH - eggs X mature– no eggs released (by LH) + can’t get pregnant
-stimulates ovulation

-woman can become pregnant in normal way- effective
-X always work- may have to do it many times- expensive
-too many eggs stimulated- unexpected multiple pregnancy

63
Q

why is IVF used-
4 steps to IVF-

A

if ‘fertility drug’ or medication X work

*give mum FSH + LH to stimulate maturation
of several eggs.
* eggs collected + fertilised by fathers sperm in lab OR sperm injected into egg (if man has low sperm count)
* fertilised eggs develop into embryos in incubator
* When embryos are tiny balls of cells, 1 or 2 inserted in mothers uterus/womb

64
Q

pro of IVF
3 cons and describe these

A

can give infertile couple child

-emotionally + physically stressful (vomit, abdominal pain, dehydration)
-low success rate-upsetting if multiple failures
-lead to multiple births-risky for mum+ babies (<risk miscarriage, stillbirth)

65
Q

what has helped IVF success rate

what tools have been developed, how do they help

how does time lapse imaging help

A

advanced microscopy techniques help Improve IVF techniques + so success rates

micro-tools- used on egg and sperm + remove cells from embryo for genetic testing

monitor embryo growth to identify ones likely to cause successful pregnancy

66
Q

why r ppl against IVF
x2

A

-results in many unused embryos- destroyed
Unethical as each embryo is a potential life

-ethical issues on genetic testing before implanting. Could lead to selection of preferred characteristics

67
Q

when is adrenaline released
where are adrenal glands

What does adrenaline do x3

A

-times of stress/ fear
-above kidneys

-increases heart rate
-boosts supply of O2 + glucose to brain cells + muscles
-preparing body for fight/flight

68
Q

how is adrenaline released x3

body controls levels of hormones in blood using….

A

-brain detects fear/ stress
-sends nervous impulses to adrenal glands
-glands respond + secrete adrenaline

negative feedback

69
Q

where is the thyroid gland
what does thyroxine do x2

A

in the neck

-regulates basal metabolic rate- speed that chemical reactions occur when body is resting

-stimulates protein synthesis for growth + development

70
Q

thyroxine is released in response to which hormone.
where is this hormone released from-
what is thyroxine made of-

A

TSH (thyroid stimulating hormone)
-pituitary gland
-iodine+amino acids

71
Q

describe how negative feedback is used to control level of thyroxine in blood x3

A

when level higher than normal-
-secretion of TSH from pituitary gland is inhibited
Less thyroxine released from thyroid
level of thyroxine in blood falls

72
Q

what is auxin,
how does it produce desired results-
what does it control

A

plant hormone-
-promotes growth near tips of shoots+ inhibits growth in roots
-controls growth in response to light-(phototropism) and gravity ( gravitropism)

73
Q

where is auxin produced, where does it move to, why

A

-produced in tips. moves backwards for cell elongation process (occurs behind tips)

74
Q

what happens if tip of shoot removed

-what happens when shoot tip exposed to light 3 points

A

no auxin available so shoot can stop growing

-more auxin accumulates on shaded side
-cells elongate/grow faster on shaded side
-so shoot bends towards light

75
Q

what happens when shoot is growing sideways- 3 points

A

-gravity produces unequal auxin distribution in tip- more on lower side
-lower side grows faster
-shoot grows upwards

76
Q

what happens when root is growing sideways- 3 points

A

-gravity produces more auxin on lower side
-extra auxin inhibits growth so cells on top elongate faster
-cell bends downwards

77
Q

RP effect of light on growth
x7

A

-10 seeds in 3 labelled petri dishes
-line each w/ moist cotton wool
-let seeds germinate in warm place
-make sure same amount have germinated in each dish, if not, remove some so equal number
-measure height of each seedling and work out mean for each dish
-place in different conditions
-work out new mean for each dish

78
Q

RP effect of light on growth
-what is independent variable
what are the 5 control variables- explain how to control them

A

light

no.of seeds-use same no.
type of seeds-seeds from same packet
temp-keep petri dishes in stable temp
water-add same amount of water to dampen cotton wool. water them w/ same amount each day
light intensity- distance btwn seed and bulb the same

79
Q

what are three different conditions for RP effect of light on growth

what are the effects on growth x3

A

full sunlight
in box with partial light
darkness

-full light + partial light grow similar height
-partial light bent to light
-darkness- grow longest- bcse they grow rapidly to reach light
-darkness- leavs small/yellow-X photosynthesise

80
Q

Rp effect of gravity on plant growth
3 steps

A

-place seedlings on damp cotton wool in petri dish with roots pointing in different directions
-store vertically in dark
-all roots will grow down

81
Q

uses of auxins x3
explain them

A

-weed killers
Weedkillers developed using auxins -disrupt growth of broad leaved plants (weeds) -kill them
-rooting powders-contain auxins. Added to cuttings, roots produced quickly and grow as new clone plants
-promoting growth in tissue culture-auxins added to growth medium -plant cells divide into roots +shoots

82
Q

what are giberellins, what do they do x3

what is ethene
what does it dox2

A

plant growth hormone

stimulates seed germination, stem growth, flowering

-gas produced by aging plant parts
-effects growth by controlling cell division
-stimulates enzymes that cause ripening

83
Q

Gibberellins can be used to: x3

describe each

A
  • end seed dormancy
  • promote flowering
  • increase fruit size.

some Seeds X germinate till been through certain conditions - dormancy. Giberellins alter dormancy- make seeds germinate at different time- all seeds in batch germinate together

some plants need certain conditions to flower. Treated w/ gibberellin- flower w/out change in environment + grow bigger flowers

-seedless fruit grow smaller than seeded.Gibberellins increase growth to match seeded type

84
Q

use of ethene.
what do some fruits do as they ripen?

A

used in food industry to control fruit ripening during storage+transport.
-produce more ethene

85
Q

a pro of using ethene to ripen fruit

A

fruit picked when unripe, less fragile, gas added on way to store

86
Q

what is the cns
what is a coordination centre

A

CNS- brain + spinal chord (where reflexes + actions are coordinated)
Coordination centre- An organ that processes info from receptors and organises response from effectors