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Mr Webber Biology > Plant And Animal Responsss ( 5.1.5) > Flashcards

Plant And Animal Responsss ( 5.1.5) Flashcards

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1
Q

Central nervous system

A

Consists of your brain and your spinal cord and relay neurones

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2
Q

Peripheral nervous system

A

Consists of all neurones which connect CNS to rest of body
These are: sensory neurones, which carry nerve impulses from receptors to CNS; motor neurones carry impulses from CNS to effectors

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3
Q

Prepherial Nervous system is functionally organised into 2 systems

A

Somatic nervous system: under conscious control, when you voluntarily decide to do something
Automatic nervous system: system works constantly under subconscious control ( e. Heart beat)

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4
Q

How is autonomic nervous system split

A

Sympathetic motor system - fight or flight

Parasympathetic- relaxation

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5
Q

How are messages passed along in the somatic nervous system

A

Message from brain or spinal chord passes along a single neurone to effector organs releasing acetylcholine

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6
Q

Features of the Autonomic nervous system

A

Involuntary action
Lightly myelinated axon
Neurotransmitters: acetylcholine (parasympathetic), noradrenaline ( sympathetic)
Stimulatory or inhibitory depending on neurotransmitter + receptors on effector organs
Sympathetic : involved in flight or fight response
Parasympathetic : involved in relaxation response
Effect smooth muscle heart and digestion

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7
Q

How does SAN control heart rate

A

SAN initiates contractions
Rate of these contractions is controlled by: hormones acting directly on SAN ( adrenaline), messages from the autonomic nervous system

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8
Q

Where are the hormones that act directly on SAN secreted from

A

2 centres in the medulla oblongata, each is linked by a motor neurone to the sino atrial node
Vagus nerve- parasympathetic
Accelerator nerve- sympathetic

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9
Q

hormones in plants

A

coordinate plant response to environmental stimuli

move around by active transport, diffusion, or mass flow in phloem and xylem vessels

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9
Q

hormones in plants

A

coordinate plant response to environmental stimuli

move around by active transport, diffusion, or mass flow in phloem and xylem vessels

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10
Q

what effects can plant hormones have

A

have different effects on different tissues
amplify each others effects
cancel out each other effects

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11
Q

role of auxin hormone

A

control cell elongation, prevent leaf fall, maintain apical dominance, involved in tropisms, stimulate the release of ethene, involved in fruit ripening

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12
Q

role of gibberellin

A

cause stem elongation, trigger the mobilisation of food stores in seed at germination, stimulate polled tube growth in fertilisation

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13
Q

role of ethene

A

causes fruit ripening, promotes abscission in deciduous trees

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14
Q

ABA (abscisic acid)

A

maintains dormancy of seeds and buds, stimulates cold protective responses, e.g, antifreeze production, stimulates stomatal closing

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15
Q

how plant hormones effect seed germination

A
  • when the seed absorbs water the embryo is activated and begins to produce gibberellins, - they in turn stimulate the production of enzymes that break down the food stores found in the seed
  • embryo uses these food stores to produce ATP for building materials so it can grow and break through the seed coat
  • gibberellins switch on genes which code for amylases and proteases - digestive enzymes required for germination
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16
Q

where is the food store in dicot seeds

A
  • the food store is in the cotyledons in dicot seeds and the endosperm in monocot seeds
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17
Q

reasons for and hormonal involvement in abscission

A

falling light levels lead to a falling concentration of auxin
the leaves respond to this change by producing the gaseous plant hormone ethene
at the base of the stalk lies the abscission zone which has cells sensitive to ethene
ethene seems to initiate gene switching in these cells resulting in the production of new enzymes that digest and weaken the abscission zone

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18
Q

Hormone effect on stomata closure

A

opening and closing of the stomata due to abiotic stresses is largely under control of the hormone ABA
the leaf cells appear to release ABA under abiotic stress
ABA is transported to the leaves where it binds to receptors on the plasma membrane of the stomatal guard cells changing the ionic concentration of the guard cells reducing the water potential and therefore turgidity causing stomata to close

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19
Q

The effect of unilateral light

A

When plants are partially shaded the shoots grow towards the light then grow straight towards it
This response appears to be the result of the way auxin moves down the shaded side + elongates the cell

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20
Q

Geotropism

A

Plants are responsive to gravity, in normal situations growing acts downwards
Shoots are usually negatively geotropic and roots are positively geotropic

21
Q

Abcission in plants

A
  • Falling light levels cause a decrease in auxin concentration, the plants respond to this by producing the gaseous plant hormone ethene.
  • Abscission zone at the base of the lead stalk is sensitive to ethene, which seems to initiate the switching on and off of some genes resulting in the production of enzymes, these enzymes weaken the abscission zone
  • vascular bundles that carry materials to the leaf are sealed off and fatty acids are deposited on the stem side of the separation layer forming a protective scar
  • in order to prevent pathogens entering
22
Q

Chemical defences to herbivory - tannins

A

group of chemical compounds called phenols produced by plants
very bitter taste which puts animals off eating the leaves
toxic to insects, inactive digestive enzymes
tea and red wine are both rich in tannins

23
Q

Chemical defences to herbivory - alkaloids

A
  • large group of very bitter tasting nitrogenous compounds found in many plants
  • many of them act as drugs affecting the metabolism of animals, and sometimes poisoning them
  • e.g caffeine which is toxic to insects and fungi, also prevents seed germination of other plants
24
Q

Chemical defences to herbivory - terpenoids

A

group of compounds produced by plants usually for essential oils but often act as toxins to insects and fungi that might attack the plant
pyrethrin acts as an insect neurotoxin interfering with the nervous system

25
Q

Chemical defences to herbivory - terpenoids

A

group of compounds produced by plants usually for essential oils but often act as toxins to insects and fungi that might attack the plant
pyrethrin acts as an insect neurotoxin interfering with the nervous system

26
Q

Chemical defences to herbivory - pheromones

A

chemical made by the plant which effects the social behaviour of other members in the same species
example - if a ample tree is attacked by insects it will release pheromones which is absorbed by leaves on other branches. these leaves will then make chemicals such as callose to help defend

27
Q

Chemical defences to herbivory - volatile organic compounds

A

similar to pheromones but act between themselves and other organisms.
e.g cabbages producing chemical signal to tract parasitic wasps when attacked by caterpillars

28
Q

folding in response to touch

A
  • Mimosa pudica

- sharp movement is aimed to frighten off large herbivores

29
Q

folding in response to touch

A
  • Mimosa pudica

- sharp movement is aimed to frighten off large herbivores

30
Q

phototropism

A

result of the movement of auxin across the shoot/ root if it is exposed to light that is stronger on one side than another
- auxin moves down the shaded side and is stored in the tip of the shoot, is a hormonal message

31
Q

geotropisms

A

in normal conditions plants receive a unilateral gravitational stimulus
shoots are usually negatively geotropic and roots are positively geotropic

32
Q

Role of auxins in apical dominance

A

Presence of auxins lowers growth in the lateral shoots
Auxins are synthesised in the meristem cells in the tip
Auxin diffuse away from the tip
Auxin binds to receptor sites
Lowering PH
Low PH of cell walls keeps them flexible and plasticky allowing the cells to expand as they absorb water
Large central vacuole is formed, auxins are destroyed by enzymes as the cell matures, PH rises and cell walls become rigid

33
Q

How gibberellins cause stem elongation

A

They effect the length of the internodes ( the region between leaves on a stem)
Discovered because they are produced by a fungus from the genus gibberella that effect rice. Infected seeds grew very tall and thin

34
Q

Difference between synergies and antagonism

A

Synergies - working together - 2 things that aid each other’s function
Antagonism - substances having opposed effects

35
Q

Effects sympathetic nervous response has

A 
Fight or flight 
Increase airway diameter 
Increase breathing rate 
Increase HR
increase blood flow to skeletal muscle 
Reduce peristalsis
36
Q

Effects parasympathetic nervous response has

A 
Relaxation response 
Restrict airways 
Reduce breathing rate
Reduce HR
increase blood flow to gut ( smooth muscle)
Increases peristalsis
37
Q

Calcium effect in muscle contraction

A

Ca2+ binds to troponin, causing it to change shape, dislodging/ moving the tropomyosin aside making actin binding sites available
With reduced ca2+ less myosin cross bridges are formed and actin filaments are pulled past the myosin with less force

38
Q

Some specialised cells in the retina of the eye respond to the ………….. and ………… of light

A

Intensity and wavelength

39
Q

Cells are able to convert energy from stimulus to a

A

Nerve impulse

40
Q

Process of managing an ecosystem to maintain biodiversity

A

Conservation

41
Q

Term that describes plants that loss their leaves seasonally

A

Deciduous

42
Q

Conversion of nitrogen gas to ammonium compounds in the soil

A

Nitrogen fixation

43
Q

Suggest two reasons a plant would need to respond to its environment

A

Response to abiotic stress / herbivory

44
Q

Substance that stimulates stomata closure

A

Abscisic acid

45
Q

How does the medulla oblongata control HR during exercise

A

The medulla oblongata receives signals from the chemoreceptors located in the carotid and aortic bodies that detect carbon dioxide in the blood .
During exercise the increase in carbon dioxide triggers the medulla oblongata to send signals down the sympathetic nerve to the sinoatrial node to increase heart beat

46
Q

Reasons why both plants and animals need to be able to respond to changes in their environment

A

Avoid abiotic stress
Avoid being eaten
To access resources

47
Q

3 differences in the way plant and mammalian hormones operate

A

Secreted from glands vs plant tissue
Transported in blood vs xylem
Mammalian hormones act more rapidly

48
Q

Why steroid hormones can diffuse through the membrane

A

They can diffuse through the phospholipid bilayer as they are fat soluble and hydrophobic

49
Q

Structural difference between motor and sensory neurone

A

Cell body at the start, impulse constantly moving away in a motor neurone whereas in the sensory neurone has cell body in the middle
Motor has no dendron

Mr Webber Biology (17 decks)

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