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Homeostasis Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is homeostasis

A

the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes

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2
Q

what does homeostasis help maintain

A

optimal conditions for enzyme action and all cell functions

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3
Q

what does homeostasis control in the human body

A

blood glucose concentration
body temperature
water levels

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4
Q

what can the automatic control systems be

A

nervous or chemical responses

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5
Q

what do all control systems have

A

receptors
coordination centres
effectors

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6
Q

what are receptors

A

cells that detect stimuli (changes in the environment)

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7
Q

what do coordination centres do

A

process the information received from the receptors e.g brain, spinal cord and pancreas

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8
Q

what do effectors do

A

bring about responses to bring the conditions in the body back to optimum levels , eg muscles or glands

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9
Q

what does the nervous system allow us to do

A

react to our surroundings and coordinate actions in response to stimuli

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10
Q

how does the nervous system work (4 steps)

A
  1. receptor cells convert a stimulus into an electrical impulse
  2. this electrical impulse travels along cells called sensory neurons to the central nervous system (CNS)
  3. here the information is processed and the appropriate response is coordinated resulting in a electrical impulse being sent along motor neurones to effectors
  4. the effectors carry out the response (muscles contracting or glands secreting hormones)
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11
Q

what are reflexes

A

automatic responses which take place before you have time to think

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12
Q

why are reflexes important

A

prevent the individual from getting hurt

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13
Q

where does the information travel for a reflex

A

down a pathway called a reflex arc

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14
Q

how does the reflex arc help reflexes

A

allows vital responses to take place quickly

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15
Q

why is the reflex arc an unusual response to stimuli

A

the impulse does not pass through the conscious areas of your brain

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16
Q

how does a reflex happen (5 steps)

A
  1. a stimulus is detected by receptors
  2. impulses are sent along a sensory neuron
  3. in the cns the impulse passes to a relay neuron
  4. impulses are sent along a motor neuron
  5. the impulse reaches an effector resulting in the appropriate response
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17
Q

examples of reflex arcs

A

pupils getting smaller to avoid damage from bright lights
moving your hand from a hot surface to prevent damage

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18
Q

what are synapses

A

the gaps between two neurons

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19
Q

how does a response work with synapses (3 )

A

1.when the impulse reaches the end of the first neuron a chemical is released into the synapse
2. the chemical diffuses across the synapse
3. when the chemical reaches the second neuron, it triggers the impulse to begin again in the next neuron

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20
Q

what is reaction time

A

how long it takes you to respond to a stimulus.

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21
Q

how can reaction time be measured

A

ruler drop test

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22
Q

what is the brain made up of

A

many connected neurons

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23
Q

what does the brain control

A

complex behaviour

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24
Q

what is the brain a part of

A

the central nervous system along with the spinal cord

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25
Q

what are the the components of the brain

A

cerebral cortex
cerebellum
medulla

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26
Q

what does the cerebral cortex do

A

controls consciousness, intelligence, memory and language
it is the outer part of the brain

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27
Q

what is the cerebellum

A

controls fine movements of the muscles; rounded structure towards the bottom/back of brain

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28
Q

what is the medulla

A

controls unconscious actions such as breathing and heart rate ;’ found in the brain stem in front of the cerebellum

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29
Q

why is investigating brain function and treating brain damage and disease difficult

A

it is complex and delicate
it is easily damaged
drugs given to treat diseases can’t always reach the brain because of its surrounding membranes
it is not fully understood which part of the brain does what

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30
Q

how can neuroscientist twists map out regions of the brain (3 methods)

A

studying patients with brain damage
electrically stimulating different parts of the brain
using mri scanning

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31
Q

how does studying patients with brain damage help map out regions of the brain

A

observing the changes in an individua following damage on a certain area of the brain can provide information on the role this area has

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32
Q

how does electrically stimulating different parts of the brain be done and help map out regions of the brain

A

pushing an electrode into the brain
the stimulation may result in a mental or physical change in the individual providing information on the role this area of the brain has

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33
Q

how does using mri scanning techniques help map out the regions of the brain

A

a magnetic resonance imaging scanner can be used to create an image of the brain
this can be used to show which part of the brain is affected by a tumour, or which part is active during a specific task

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34
Q

what is the eye

A

a sense organ containing receptors sensitive to light intensity and colour

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35
Q

how are eye structures adapted

A

allow the eye to change its shape to focus on near or distant objects (accommodation) and to dim light

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36
Q

what is the retina

A

layer of light sensitive cells found at the back of the eye

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37
Q

what happens in the retina

A

when light hits it, the cells are stimulated ,
impulses are sent to the brain which interprets the information to create an image

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38
Q

what is the optic nerve

A

a nerve that leaves the eye and leads to the brain

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39
Q

what does the optic nerve do

A

carries the impulses from the retina to the brain to create an image

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40
Q

what is the sclera

A

white outer layer which supports the structures inside the eye

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41
Q

what is important about the sclera

A

it is strong to prevent some damage to the eye

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42
Q

what is the cornea

A

the see through layer at the front of the eye

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43
Q

what does the cornea do

A

it allows light through and the curved surface bends and focuses light onto the retina

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44
Q

what is the iris

A

muscles that surround the pupil

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45
Q

how do irises alter the size of the pupil

A

contract or relax

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46
Q

what happens to the iris in bright light

A

the circular muscles contract and radial muscles relax to make the pupil smaller - avoiding damage to the retina

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47
Q

what happens to the iris in dim light

A

the circular muscles relax and the radial muscles contract to make the pupil larger - so more light can enter to create a better image

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48
Q

what do ciliary muscles and suspensory ligaments do

A

hold the lens in place and control its shape

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49
Q

how do the eyes focus on a near object

A

the ciliary muscles contract
the suspensory ligaments loosen
the lens is then thicker and more curved - this refracts the light more

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50
Q

how do the eyes focus on a distant object

A

the ciliary muscles relax
the suspensory ligaments tighten
the lens then becomes thinner - light is refracted less

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51
Q

when do eye defects occur

A

when light cannot focus on the retina

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52
Q

what is myopia

A

short sightedness

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53
Q

why does myopia occur

A

the lens is too curved so distant objects appear blurry

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54
Q

what is hyperopia

A

long sightedness

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55
Q

when does hyperopia occur

A

when the lens is too flat so it cannot refract light enough

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56
Q

how are myopia/hyperopia treated (4)

A

spectacle lenses
contact lenses
laser eye surgery
replacement lens

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57
Q

how are spectacle lenses used to treat eye defects

A

concave lenses to spread out the light to treat myopia
convex lenses bring the rays together to treat hyperopia

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58
Q

how do contact lenses treat eye defects

A

work in same way as glasses
allow activities such as sport or the carried out
hard or soft contact lenses last for different lengths of time

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59
Q

how does laser eye surgery treat eye defects

A

lasers used to either reduce thickness of the cornea so it refracts light less or change its curvature to refract light more strongly

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60
Q

how does a replacement lens treat eye defects

A

hyperopia treated by replacing lens with an artificial one made of clear plastic

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61
Q

what are the risks of replacement lens

A

damage to retina
cataracts developing

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62
Q

what does the thermoregulatory centre do

A

monitors and controls body temperature

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63
Q

where is the thermoregulatory centre found

A

the brain

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64
Q

what does the thermoregulatory centre contain

A

receptors that monitor the temperature of the blood
receptors in the skin that send impulses to the thermoregulatory centre

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65
Q

what happens if human body temp is too high

A

sweat
vasodilation

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66
Q

how does sweat cool you down

A

evaporates from skin surface resulting in increased energy transfer away from the body

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67
Q

how does vasodilation cool you down

A

more blood flows closer to the surface of the skin resulting in increased energy transfer from the body

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68
Q

what happens if body temperature decrease too much

A

sweating stops
skeletal muscles contract rapidly (shivering)
hairs stand on end
vasoconstriction

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69
Q

how does shivering warm you up

A

generates heat from respiration

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70
Q

how does hairs standing on end warm you up

A

creates an insulating layer which traps warm air

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71
Q

how does vasoconstriction warm you up

A

blood does not flow so close to the surface resulting in less heat lost

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72
Q

what does the endocrine system do

A

sends hormones around the body and produces a response when they reach a target tissue

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73
Q

what is the endocrine system made up of

A

glands which secrete hormones directly into the bloodstream

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74
Q

what is the pituitary gland

A

master gland

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75
Q

what does the pituitary gland do

A

secretes hormones into the blood to either have an effect on the body or act on other glands to stimulate them to produce different hormones

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76
Q

what does the pancreas do

A

secretes insulin
controls blood glucose levels

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77
Q

what does the thyroid do

A

secretes thyroxine
controls metabolic rate, heart rate and temperature

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78
Q

what does the adrenal gland do

A

secretes adrenaline
involved in the fight or flight response

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79
Q

what does the ovary do

A

secretes oestrogen

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80
Q

what is oestrogen involved in

A

the menstrual cycle and the development of female secondary characteristics

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81
Q

what do the testes do

A

secrete testosterone

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82
Q

what does testosterone do

A

is involved in the production of sperm and the development of male secondary sexual characteristics

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83
Q

how are hormones transported

A

in the blood to a target organ or tissue where it has an effect

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84
Q

what is the speed of the hormonal system compared to nervous system

A

much slower but acts for longer

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85
Q

why does glucose concentration in blood need to be kept in a limit

A

glucose is needed by cells for respiration

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86
Q

what controls the concentration of glucose in blood

A

pancreas

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87
Q

what can increase glucose levels in the blood

A

eating foods that contain carbohydrates

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88
Q

what happens when glucose levels are too high

A

pancreas produces the hormone insulin

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89
Q

how does insulin act in the body

A

binds to cell in target organs (muscle and liver)

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90
Q

what does insulin cause to happen

A

glucose moves from the blood into the muscle cells for respiration
excess glucose converted into glycogen which is stored in the liver
blood glucose concentration is reduced

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91
Q

what results in less glucose in the blood and why

A

rigorous activity eg exercise uses glucose for respiration

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92
Q

when is glucagon produced

A

if glucose levels decrease

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93
Q

which organ produced glucagon

A

pancreas

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94
Q

how does glucagon work

A

binds to liver cells causing glycogen to be broken down into glucose
glucose is released into the blood increasing blood glucose concentration

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95
Q

how is blood glucose concentration kept constant

A

insulin and glucagon

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96
Q

how do insulin and glucagon work together

A

in a negative feedback loop

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97
Q

how does a negative feedback loop work

A

when blood glucose levels change a hormone is secreted to oppose the change
the action of this hormone cannot occur continually because when the blood arrives at a certain glucose concentration the other hormone is produced, resulting in the opposite effect

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98
Q

what is diabetes

A

inability to control blood glucose level

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99
Q

what is type one diabetes

A

the pancreas cannot produce enough insulin

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100
Q

what happened to blood glucose levels in type 1 diabetes

A

blood glucose levels can rise to a fatal amount

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101
Q

how is glucose excreted in type1 diabetes

A

glucose is extracted with urine and lots of urine is produced leaving the individual thirsty

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102
Q

how is type 1 diabetes treated

A

insulin injections at meal times
limit intake of simple carbohydrates
pancreas and pancreatic cell transplants
engineering pancreatic cells from mice to make insulin

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103
Q

how do insulin injections help improve type 1 diabetes

A

results in glucose being taken up into the bloodstream

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104
Q

what is type 2 diabetes

A

the body cells no longer respond to insulin

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105
Q

what happens to blood glucose levels in type 2 diabetes

A

can rise to a fatal amoutn

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106
Q

what is a risk factor of type 2 diabetes

A

obesity

107
Q

what are the treatments of type 2 diabetes

A

reducing number of simple carbs in diet
losing weight
increasing exercise

108
Q

what can different drugs do to help type 2 diabetes

A

make insulin more effective on cells
help pancreas make more insulin
reduce amount of glucose absorbed from the gut

109
Q

what is osmosis

A

the process by which water molecules move from a place of high concentration to a place of low concentration

110
Q

what happens if water concentration in the blood increases

A

cells in the body take up water

111
Q

why do body cells take up water when water concentration in the blood increases

A

concentration of water in bloodstream is higher than conc of water in cells so water moves into the cells by osmosis

112
Q

what happens when cells take up water

A

cells expand and may burst

113
Q

what happens if the concentration of water in the bloodstream decreases

A

cells in the body lose water

114
Q

why do cells in the body lose water when water conc in the blood decreases

A

conc of water in bloodstream is lower than conc of water in cells so water moves out of cells by osmosis

115
Q

what happens as cells lose water

A

shrink

116
Q

what happens if cells lose or gain too much water

A

do not function properly

117
Q

why are the kidneys important

A

they maintain the balance of water and other substances in the body

118
Q

how is urine made as blood moves through the body

A

filtering out waste products
selectively re absorbing useful substances such as glucose, ions and water

119
Q

what are waste products processed at the kidney

A

water
ions
urea

120
Q

how is water lost from the body

A

leaves at the lungs from exhalation
leaves skin in sweat
depending on conc of water in blood can be lost as urine

121
Q

how are ions taken into the body

A

via food

122
Q

what happens if the ion concentration is incorrect

A

too little or too much water may enter body cells because water potential of the blood is altered

123
Q

where are ions lost

A

sweat

124
Q

what happens to ions in the kidneys

A

certain amounts are reabsorbed into the blood after it has been filtered to ensure blood conc is maintained

125
Q

what happens to amino acids in the liver

A

delaminated to form ammonia

126
Q

how is urea made

A

ammonia is toxic so is converted to urea

127
Q

how is urea lost in the body

A

lost in sweat
filtered out of blood in the kidneys

128
Q

what is anti diuretic hormones

A

a hormone involved in the control of the loss of water as urine

129
Q

where is adh released to

A

the pancreas by the pituitary gland.

130
Q

when is adh released

A

when a receptor in the brain detects that the blood is too concentrated

131
Q

where does adh travel

A

in the bloodstream to the kidney tubules

132
Q

what does an increased amount of adh reaching tubules do

A

increases their permeability to water
so more moves out of tubule and back into bloodstream

133
Q

what is the result of increased ADH

A

smaller volume of more concentrated (yellow) urine
blood becoming less concentrated
because more water

134
Q

what is ADH production an example of

A

negative feedback loop

135
Q

how is ADH release a negative feedback loop

A

if the concentration of the blood increases/decreases, more/less ADH is secreted to reverse this change

136
Q

what is kidney failure

A

when your kidneys stop working

137
Q

what does kidney failure result in

A

waste products build up which can be harmful to the body and eventually result in death

138
Q

what are the two ways to treat kidney failure

A

dialysis
kidney transplants

139
Q

what is dialysis

A

the function of the kidneys being carried out using an artificial membrane

140
Q

where does the blood move during dialysis

A

between partially permeable membranes surrounded by dialysis fluid

141
Q

what is lost from the blood during dialysis

A

useful ions and glucose NOT
but urea , excess ions and water diffuse out of membrane

142
Q

how many times is dialysis done in a week

A

3 times

143
Q

how long does dialysis take

A

3-4 hours

144
Q

what are the problems of dialysis

A

possibility of blood clots forming
amount of time it takes
strict diet
unpleasant experience
build up of waste products between sessions leaves patient ill

145
Q

what do kidney transplants do

A

provide the individual with a healthy kidney

146
Q

who are kidney transplants from

A

people who have died suddenly or people who are still alive

147
Q

what is a positive of kidney transplants

A

the person has less regular hospital visits that dialysis
cheaper than overall cost of dialysis

148
Q

disadvantages of kidney transplant

A

could be rejected- antigens on donor organ foreign to immune system
immunosuppressant drugs leave person vulnerable to other diseases
transplanted kidneys do not last forever

149
Q

when are reproductive hormones released

A

during puberty

150
Q

what does reproductive hormones being released cause

A

secondary sexual characteristics to develop in men and women
eggs mature in women

151
Q

what is the main male reproductive hormone

A

testosterone

152
Q

where is testosterone produced

A

by the testes

153
Q

what does testosterone do

A

stimulates sperm production

154
Q

what is the main female reproductive hormones

A

oestrogen

155
Q

where is oestrogen produced

A

the ovary

156
Q

what does oestrogen do

A

produces physical changes
involved in the menstrual cycle

157
Q

what is the menstrual cycle

A

the process the body undergoes each month to prepare for a potential pregnancy

158
Q

what happens in the first 5/6 days of menstrual cycle

A

lining of the uterus breaks down and the woman has her period

159
Q

what happens between day 6-14 of menstrual cycle

A

the layer of lining in uterus builds up again

160
Q

what happens on the 14th day of the menstrual cycle

A

ovulation
an egg is released from the ovary and moves to the uterus via the fallopian tube

161
Q

what happens between ovulation and day 28 of menstrual cycle

A

if a fertilised egg has not been embedded in the lining by 28 days it breaks down and the cycle continues

162
Q

which four hormones control the menstrual cycle

A

follicle stimulating hormone (FSH)
oestrogen
luteinising hormone (LH)
progesterone

163
Q

what does FSH do in menstrual cycle

A

causes the maturation of an egg in the ovary in a follicle

164
Q

where is FSH produced

A

pituitary gland

165
Q

what does FSH stimulate in the menstrual cycle

A

the ovaries to produce oestrogen

166
Q

what does oestrogen cause

A

lining of the uterus to grow again

167
Q

where is oestrogen produced

A

the ovaries

168
Q

when is oestrogen secreted

A

as a result of FSH

169
Q

what does oestrogen stimulate in menstrual cycle

A

the production of LH and inhibits the secretion of more FSH

170
Q

where is LH produced

A

pituitary gland

171
Q

why is lh produced

A

as a result of oestrogen

172
Q

what does the release of LH result in

A

ovulation

173
Q

where is progesterone produced

A

the ovaries and secreted from egg follicle

174
Q

what does progesterone do in menstrual cycle

A

maintains the lining of the uterus and supports a pregnancy is the egg is fertilised

175
Q

what does progesterone inhibit

A

the release of FSH and LH

176
Q

what are examples of hormonal methods of contraception

A

the contraceptive pill
the contraceptive patch
the contraceptive implant
the contraceptive injection
IUD

177
Q

what are examples of non hormonal methods of contraception

A

spermicides
condoms
diaphragms
copper intrauterine device
male and female sterilisation
abstaining from intercourse

178
Q

what is the rule of the contraceptive pill

A

must be taken regularly or the bodies own hormones will be released , leading to an egg maturing

179
Q

what does the mixed pill contain

A

oestrogen and progesterone

180
Q

what does the oestrogen levels being high from the mixed pill result in

A

inhibits FSH so no eggs mature

181
Q

what does the mixed pill do to uterus lining

A

lining stops developing

182
Q

what does the mixed pill do to mucus in the cervix

A

becomes thick so sperm cannot move through

183
Q

what are side effects of the mixed pill

A

changes in mood
mood swings
depression
breast pain
breast enlargement
increased blood pressure

184
Q

what is the difference between the progesterone only pill and the mixed pill

A

this has less side effects in comparison to the mixed pill

185
Q

what does the contraceptive pill contain

A

oestrogen and progesterone

186
Q

how is the contraceptive patch applied

A

small and stuck on skin

187
Q

how long does the contraceptive patch last

A

one week

188
Q

what does the contraceptive implant do

A

releases a continuous amount of progesterone

189
Q

what does the implants release of progesterone result in

A

prevents the ovaries from releasing the egg
thicken the mucus in cervix
stops fertilised eggs embedding in the uterus

190
Q

how long does the contraceptive implant last

A

2 to 3 months

191
Q

what does the IUD do

A

releases progesterone

192
Q

what is the effect of the iUD

A

same as the implant

193
Q

how ius the IUD used

A

T shaped, inserted into the uterus

194
Q

what do non hormonal methods of contraception do

A

stop sperm fertilising the egg

195
Q

what do spermicides do

A

kill or disable sperm

196
Q

how effective are spermicides

A

70-80%

197
Q

what is a chemical method of n hormonal contraception

A

spermicide

198
Q

what are n hormonal barrier methods

A

condoms and diaphragms

199
Q

how are condoms worn

A

over the penis or inside the vagina

200
Q

what do condomsalso do

A

prevent the individual contracting sexually transmitted diseases

201
Q

what is a problem with condoms

A

it can tear and therefore let sperm through

202
Q

what is a diaphragm

A

a plastic cup

203
Q

where is a diaphragm used

A

positioned over the cervix

204
Q

what is a diaphragm used with

A

a spermicide

205
Q

what does the copper intrauterine device do

A

kills sperm in the uterus by stopping any fertilised embryos from implanting in the uterus lining

206
Q

what are the methods of male and female sterilisation

A

cutting and tying the fallopian tubes or sperm duct

207
Q

what does abstaining from intercourse ensure

A

an egg is not fertilised

208
Q

what are fertility drugs used for

A

increasing the chance of pregnancy

209
Q

what are the main hormones used in fertility drugs

A

FSH and LH to stimulate maturation and release of the egg

210
Q

what hormones does the mother receive in IVF

A

FSH and Lh to encourage maturation of eggs

211
Q

what happens to the eggs in IVF

A

extracted from the mother and fertilised in the lab using sperm

212
Q

what happens to the fertilised eggs in IVF

A

develop into embryos and one or two inserted in the uterus

213
Q

what are the benefits of IVF

A

provides a way for an infertile couple to have a child

214
Q

what are the cons of IVF

A

physically stressful due to hormones - can feel sick
emotionally stressful as may not work - 26% success rate
can lead to multiple births unexpectedly - risk to mother and babies
can be expensive if needs to be repeated

215
Q

what is negative feedback

A

when the body responds to an increase or decrease in a factor by returning it to its original level

216
Q

what does thyroxine do

A

regulates metabolic rate

217
Q

what is thyroxine important in

A

growth and development

218
Q

what is thyroxine released by

A

the thyroid gland

219
Q

what stimulates the release of thyroxine

A

the thyroid stimulating hormone

220
Q

how are levels of thyroxine controlled

A

negative feedback

221
Q

what happens when thyroxine levels increase

A

detected by receptors in the brain
inhibits release of TSH
inhibits release of thyroxine so levels fall

222
Q

when is adrenaline produced

A

times of stress to stimulate fight or flight response

223
Q

where is adrenaline released from

A

adrenal glands

224
Q

what is the release of adrenaline stimulated by

A

fear or stress , detected in the brain

225
Q

effects of adrenaline

A

increased heart rate and breathing rate
glycogen converted to glucose
pupils dilate
blood flow to muscles increased
blood flow to digestive system decreased

226
Q

why does heart rate and breathing rate increase from adrenaline

A

to deliver more oxygen and glucose to the brain and muscles for respiration

227
Q

why is glycogen in liver converted to glucose when adrenaline is released

A

for respiration

228
Q

why do pupils dilate from adrenaline

A

to let in more light

229
Q

what do plants need hormones for

A

to coordinate and control growth and tropisms

230
Q

examples of tropisms

A

phototropism
gravitropism

231
Q

what is phototropism

A

the response to light

232
Q

what is gravitropism

A

response to gravity

233
Q

why do hormones move in plants

A

move to where they are needed to produce the appropriate response

234
Q

what tropism do most plants show

A

positive phototropism because they grow towards the light source

235
Q

what is the process of positive phototropism

A

plant exposed to light on one side
auxin moves to shaded side of shoot
auxin stimulated cells to grow more here
so shoot bends towards the light
so plant receives more light - photosynthesis occurs faster

236
Q

what tropism do most shoots show

A

negative gravitropism as they grow away from gravity

237
Q

positive gravitropism process if a root is horizontal

A

auxin moves to lower side
cells of root grow on side with less auxin, so it stimulates cells to grow on the upper side
this makes the root bend and grow downwards

238
Q

why is positive gravitropism in roots beneficial

A

more likely to be increased levels on water and nutrients
provides stability for plant

239
Q

what happens when the auxin distribution is equal on both sides

A

it grows straight in that direction

240
Q

what are two other plant hormones called

A

gibberellins
ethene

241
Q

what are gibberellins important for

A

stimulating seed germination

242
Q

what is ethene involved in

A

cell division and ripening of fruits

243
Q

what do humans use plant hormomes for

A

to alter plant growth

244
Q

where do humans use plant hormones

A

agriculture and horticulture

245
Q

what are the benefits of humans using plant hormomes

A

increase yield
obtain desirable features
lower costs

246
Q

what is auxin used as

A

weed killers
rooting powders
promote growth in tissue culture

247
Q

what are many weeds

A

broad leaved

248
Q

how have weed killers with auxin been synthesised

A

to only affect broad leaved plants

249
Q

how does auxin kill weeds

A

increased auxin causes the cells to grow too rapidly

250
Q

how does auxin work as a rooting powder

A

rooting powder applied to a cutting of a plant and it is placed in the ground
roots grow and new plants grow quickly

251
Q

how does auxin promote growth in tissue culture

A

cells from plant are placed in a growth medium
auxin added
cells begin to form roots and shoots

252
Q

where is ethene used and why

A

food industry as it controls ripening

253
Q

what is ethene involved in in the food industry

A

controlling cell division and stimulates enzymes that result in fruit ripening

254
Q

what are the benefits of using ethene in food

A

reduces wastage
as more fruit is suitable to be sold and doesn’t ripen too early

255
Q

when is fruit picked

A

when it is not ripe

256
Q

what happens when fruit is transported and why

A

it is firm so it gets less damaged and bruised

257
Q

what happens to fruit when it is needed to be sold

A

it is exposed to ethene and warmer temperatures

258
Q

what are gibberellins used for

A

ending seed dormancy
promoting flowering
increasing fruit size

259
Q

how do gibberellins end seed dormancy

A

in the brewing industry
the germination rate of barley seeds os increased to make malt

260
Q

how do gibberellins promote flowering

A

allows flowering in any conditions and with bigger flowers

261
Q

what conditions are normally needed for flowering

A

longer days and low temperatures

262
Q

what do the seeds in fruit produce

A

gibberellins to increase size

263
Q

why is seedless fruit generally smaller

A

no seeds that produce gibberellins

264
Q

how can seedless fruit sometimes be big

A

can be sprayed with gibberellins to increase their size

Biology (22 decks)

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