5.1.5- Animal and Plant Responses Flashcards

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1
Q

where is the cerebrum in the brain?

A

the folded top part of the brain

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2
Q

what is the function of the cerebrum

A

Controls voluntary actions
Eg-learning, memory, personality and consciousness

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3
Q

where is the hypothalamus in the brain?

A

next to the piturity gland

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4
Q

What is the function of the hypothalamus?

A

Regulatory centre for osmoregulation and temperature balance

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5
Q

where is the cerebellum?

A

the swirly part at the bottom of the brain.

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6
Q

what is the function of the cerebellum?

A

Controls unconscious functions, such as balance, posture and non-voluntary movement.

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7
Q

Where is the medulla oblongata in the brain?

A

the stem at the bottom

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8
Q

What is the function of the medulla oblongata?

A

Used in autonomic control, eg- heart rate and breathing rate

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9
Q

Where is the puiturity gland?

A

next to the hypothalamus, bottom front

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10
Q

What is the function of the puiturity gland?

A

Stores and releases hormones that regulate many body functions.

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11
Q

What is the knee jerk reflex?

A

-spinal reflex
-doctors use to it to see how the nervous system is working.
-patella tapped so patella tendon stretches (stimulus)
-this initiates the reflex arc
-contraction of extensor muscle above thigh
-absense of reflex= cereballar disease

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12
Q

What is the blinking reflex?

A

-involuntary blinking
-it protects the eye from damage

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13
Q

What are the 3 types of muscle?

A

-skeletal muscle
-cardiac muscle
-smooth muscle

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14
Q

What is skeletal muscle?

A

-also known as voluntary/striated muscle
-regularly arranged so contracts in one direction
-long cylindrical multinucleate fibres.
-contracts quickly, fatigues quickly
-contraction controlled by the somatic nervous system
-short length of contraction

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15
Q

What is the function of the skeletal muscle?

A

To move the bones of the skeleton about the joints

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16
Q

What is the cardiac muscle?

A

-surrounds the heart
-single cylindrical branched cells, separated by intercalated discs
-each cell has own nucleus
-striated
-contracts quickly, does not fatigue
-contraction is controlled by the autonomic nervous system and the myogenic control
-intermediate length of contraction

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17
Q

What is the function of cardiac muscle?

A

Causes the heart to contract and relax, so it can pump blood around the body.

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18
Q

What is smooth muscle?

A

-spindle shaped, unstriated, single nucleus
-contracts slowly, fatigues slowly
-can remain contracted for a long time
-contraction is controlled by the autonomic nervous system

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19
Q

What is the function of the smooth muscle?

A

-peristalsis in the gut walk
-pupil dilation and constriction in the eye
-vasodilation and vasoconstriction in the arterioles.

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20
Q

What is a neuromuscular junction?

A

A specialised synapse which occurs at the end of a motor neurone, where it meets a muscle fibre

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21
Q

What is the order of action at a neuromuscular junction?

A

*in the pre-synaptic neurone, everything is the same as as a synapse.
-when neurotransmitter diffuses across membrane, it causes depolarisation, which travels along the muscle, and down the tubule
-this causes the sacroreticulum’s membrane to also depolarise, which releases calcium ions
-these calcium ions move into the myofibril, which begins the contraction of the muscle

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22
Q

What is the A band of a myofibril?

A

Where actin and myosin remain

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23
Q

What is the H zone of a myofibril?

A

Where only myosin occurs

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24
Q

What is the I band of a myofibril?

A

Where only actin occurs

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25
Q

What is the M line of a myofibril?

A

A protein which anchors the myosin filaments

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26
Q

What is the Z line of a myofibril?

A

A protein that anchors the actin filaments

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27
Q

In a myofibril, what are the widths of actin and myosin like?

A

Actin= thinner line
Myosin= thicker line

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28
Q

what are the two proteins present in a myofibril called?

A

actin and myosin

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29
Q

what do actin and myosin give a muscle?

A

give striated muscles their distinct banding

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30
Q

explain the structure of actin?

A

-each actin filament is made up of two actin molecules
-made up of globular beads
-the two actin molecules are coiled around each other (like strings of beads)
-tropomyosin and troponin

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31
Q

explain the structure of mysoin?

A

-each filament is made up of 200 myosin molecules
-each molecule has 2 protruding heads and a long tail
-the heads contain ATPase
-resting myosin heads are bound to ADP and Pi

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32
Q

what are the 8 stages of the sliding filament of muscle contraction?

A

-when an AP arrives at NMJ, SPR releases calcium ions
-calcium ions bind to troponin
-troponin changes shape
-troponin pulls tropomyosin away from actin binding sites
-myosin head binds to the actin binding site forming a cross-bridge
-myosin head bends 45 degrees, pulling actin filament (releasing bound ADP and Pi)
-ATP is used to break cross-bridge, when it binds to the myosin head, causing it to detach from the actin
-myosin head straightens so becomes free to form a new cross-bridge further along the actin. The hydrolysis of ATP that recocks the head, so it ready to bind again at original position
THIS REPEATS

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33
Q

when muscles contract, what regions gets shorter?

A

-sarcomere
-H zone
-I band

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34
Q

during muscle contraction, what happens to the Z lines?

A

they move closer to one another

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35
Q

during muscle contraction, what region stays the same?

A

A band

36
Q

what are the 4 roles of ATP in muscle contraction?

A

-breaks the cross bridge, allowing the myosin head to reset
-actively transports calcium ions back into the sarcoplasmic reticulum when contraction stops
-relax= reacts with creatine to make creatine phosphate, which is used to maintain ATP supply in contracting
-protein synthesis (to make actin and myosin)

37
Q

how does creatine phosphate maintain the supply of ATP during muscle contraction?

A

-acts as a reserve supply of phosphate, which is available immediately to combine with ADP reforming ATP.
-it is used for short bursts of vigorous exercise.
-during relaxation, it is replenished.

38
Q

what are the survival importances of reflexes?

A

-fast, prevents harm
-doesn’t need to be learnt
-involuntary so free for more complex processes
-everyday actions

39
Q

what is the difference between the autonomic and the somatic nervous system?

A

A= non-conscious, from CNS to motor/smooth muscle, non-myelinated neurones, at least 2 neurones
S=conscious, from CNS to skeletal muscle, myelinated neurones, one neurone connects effector

40
Q

compare the sympathetic and parasympathetic nervous systems?

A

S=active during stress, increased HR, pupil dilation and increased VR, neurones secrete noradrenaline
P= active during sleep/relaxation, decreased heart rate, pupil constriction, body can go through digestion, neurones secrete acetylcholine.

41
Q

why do plants respond to the environment?

A

-to avoid abiotic stress
-to avoid being eaten by herbivores

42
Q

what is a tropism?

A

a directional growth response in which the direction of the response is determined by the direction of the external stimulus.
-eg- phototropism (directional growth towards light), geotropism (directional growth away from gravity)

43
Q

what is the plant response of nasties?

A

a mastic response is a non-directional growth response
eg- thigmonasty (plants respond to touch by suddenly dropping their leaves)

44
Q

what are plant hormones called and why?

A

phytohormones as they influence growth processes (cell division, cell elongation, cell differentiation)

45
Q

what effects do the same hormone in plants have ?

A

-different effects in different tissues
-different effects on the same tissue

46
Q

what effects do different hormones in plants have?

A

-opposite effects in the same tissue (ANTAGONISM)
-the same effects on the same tissue (SYNERGISM)

47
Q

what is the stem?

A

The main support of the plant

48
Q

what is the apical bud in a plant?

A

The growing point of the stem containing meristem tissue consisting of cells that can divide indefinitely

49
Q

what is the node in the plant?

A

The part of the stem of a plant from which a leaf, branch or aerial root grows

50
Q

what is the internode of a plant?

A

The area of the stem between two adjacent nodes

51
Q

what is the flower and flower stalk in a plant?

A

flower-reproductive structure, develops into a fruit
flower stalk-structure that supports the flower

52
Q

what is a leaf?

A

broad flat organ adapted for photosynthesis?

53
Q

what is the lateral bud and lateral shoot?

A

bud-A growing point along the stem
shoot-brunch that grows from a lateral bud

54
Q

what is a taproot and lateral root?

A

tap-The main route, providing water, support and minerals
lateral-A root that grows from the main root

55
Q

what is the root apex?

A

The growing point of the root containing meristem tissue consisting of cells that can divide indefinitely

56
Q

what is the petiole?

A

a leaf stalk, it attaches the leaf to the plant.

57
Q

what are the 4 hormones released by plants?

A

-auxin
-giberrelin
-ethene
-abscisic acid

58
Q

what are the effects of auxin?

A

-control cell elongation
-maintain apical dominance
-involved in tropisms
-stimulate the release of ethene
-inhibit leaf/fruit drop

59
Q

what are the effects of giberrelin?

A

-promote seed germination
-promote stem elongation
-stimulate pollen tube growth in fertilisation

60
Q

what are the effects of ethene?

A

-promotes fruit ripening
-promotes leaf drop and fruit drop (abscission)

61
Q

what are the effects of abscisic acid?

A

-maintains dormancy of seeds and buds
-stimulates cold protective responses
-causes stomata to close

62
Q

what is the definition of a hormone in terms of plant hormones?

A

a chemical messenger that has a long lasting response and travel to the target cells to produce this response

63
Q

what are the steps in auxins causing cell elongation?

A

-auxins produced by meristem cells in the tip
-auxins promote active transport of H+ ions into the plant cell wall
-this lowers the pH, so the low pH is optimum for enzymes, to keep the cell wall flexible
-elastins add enzymes which break bonds within the cell wall
-cell wall is weakened leading to cell elongation and stem growth

64
Q

what is used to investigate geotropism in plants?

A

the use of a rotating drum known as a clinostat

65
Q

what occurs at a clinostat?

A

the shoot will grow horizontally because the direction of gravity is constantly changing

66
Q

what do gibberellins affect?

A

they affect the length of the internodes, which are the regions between the leaves on a stem

67
Q

what type of plants produce little to no giberrelins?

A

plants that have short stems

68
Q

what does having limited giberrelins reduce?

A

reduces waste and makes the plants less vulnerable to damage by weather and harvesting

69
Q

what experiment was conducted for gibberellins?

A

experiment with dwarf and tall pea plants

70
Q

what do dwarf peas carry?

A

two copies of a mutant allele of a gene involved in GA synthesis?
-lele

71
Q

what do tall peas carry?

A

they carry at least one normal allele of the same gene
-LeLe or Lele

72
Q

what is the explanation behind applying GA to the stems of dwarf peas which leads to them growing taller?

A

GA causes growth but dwarf peas cannot make this so it has to be added

73
Q

what is the explanation behind the idea that GA concentration is higher in tall pea plants compared to dwarf pea plants, which otherwise are genetically identical?

A

-Le allele codes for an enzyme needed to synthesise GA
-le is mutant so lele dwarf peas can’t synthesise GA

74
Q

what can you do to make up for deficiencies in pea plant GA synthesis pathways?

A

two types of dwarf pea plants can be grafted together
-if you graft a second type of dwarf pea into a lele dwarf the graft will grow into a tall pea plant

75
Q

describe the practical used for gibberellin and seed germination?

A

-barley seeds (two dead and four alive)
-cut two of the unboiled/alive
-put on starch agar plate containing gibberellin
-repeat with no gibberellin
-incubate both for a day at 25 degrees
-flood each plate with dilute iodine solution after incubation

76
Q

why are the barley seeds incubated at 25 degrees?

A

temperature affects enzyme activity, 25 degrees is optimum temperature for germination

77
Q

what are 3 control variables for the gibberellin experiment?

A

-age of seeds
-incubation time
-Ga concentration in agar

78
Q

how does Ga affect seed germination?

A

-when water is soaked up, Ga is made in the seed embryo and diffuses into endosperm
-this switches on genes in a layer of cells called aleurone which makes amylase
-amylase hydrolyses starch to produce maltose when is then digested to a-glucose, which is used for respiration
-this provides energy as ATP for seedling growth

79
Q

how does abscisic acid cause stomatal closure?

A

-when the levels of water fall, ABA is produced in leaf and root cells
-the ABA bind to receptors on the stomata guard cells, causing potassium ions to leave the guard cell
-water follows by osmosis, causing reduced turgor and the guard cells close the stomata

80
Q

what is phototropism?

A

plants are sensitive to a lack of light, resulting from a light-sensitive pigment called phytochrome

81
Q

what does ethene promote in a plant and how?

A

promotes leaf drop by stimulating production of cellulase

82
Q

what does cellulase do in a plant?

A

digests cellulose in the walls of cells in the abscission zone causing petiole to snap, so the leaf falls

83
Q

what are 3 chemical defences of plants?

A

-tannins- bitter taste, toxic to insects
-alkaloids-bitter tasting nitrogenous compounds that are poisonous
-terpenoids- acts as toxins to insects and fungi

84
Q

what is a pheromone in plants?

A

a chemical made by an organism which affects the social behaviour of other members of the same species

85
Q

what is the volatile organic compounds in plants?

A

chemicals that affects behaviour in other species