5.5 - Plant and Animal responses Flashcards

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1
Q

What is the Nervous system?

A

A highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body.

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2
Q

What is the somatic nervous system?

A

A component of the peripheral nervous system associated with the voluntary control of the body movements via the use of skeletal muscles (voluntary movements)

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3
Q

What is the sympathetic system?

A

One of the two divisions of the autonomic nervous system that helps in fight-to-fight response when someone is stressed.

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4
Q

What is the central nervous system?

A

The central nervous system consists of the brain and spinal cord. It combines information from the entire body and coordinates activity across the whole organism.

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5
Q

What is a spinal chord?

A

A column of nerves that connects your brain with the rest of your body, allowing you to control your movements.

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6
Q

What is the sensory system?

A

Sensory system- A sensory system is a part of the nervous system responsible for processing sensory information. For example: vision, hearing, somatic sensation (touch), taste and olfaction (smell)

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7
Q

What is the motor system?

A

The part of the peripheral nervous system that is involved with movement

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8
Q

What is the peripheral nervous system?

A

Consists of the nerves that branch out from the brain and spinal cord. These nerves form the communication network between the CNS and the body parts.

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9
Q

What is the autonomic nervous system?

A

A component of the peripheral nervous system that regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal.

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10
Q

What is the parasympathetic system?

A

Controls bodily functions when a person is at rest. Some of its activities include stimulating digestion, activating metabolism, and helping the body relax.

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11
Q

What is the brain?

A

A complex organ that controls thought, memory, emotion, touch, motor skills, vision, breathing, temperature, hunger and every process that regulates our body. Together, the brain and spinal cord that extends from it make up the central nervous system, or CNS.

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12
Q

What are the effects of the cytokinin hormones?

A
  • Promotes cell division
  • Delays leaf senescence
  • To overcome apical dominance
  • Promotes cell expansion
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13
Q

What are the effects of the hormone abscisic acid?

A
  • Inhibits seed germination and growth

- Causes stomata closure when the plant is stressed by low water availability

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14
Q

What are the effects of auxin hormones? (Produced in the tip)

A
  • Promotes cell elongation
  • Inhibits growth of side-shoots
  • Inhibits leaf abscission (leaves falling)
  • Responsible for apical dominance
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15
Q

What are the effect of gibberellin hormones?

A
  • Promotes seed germination

- Promotes the growth of stems

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16
Q

What is the effect of ethene hormones?

A

-Promotes fruit ripening

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17
Q

What are the 2 divisions of the nervous system?

A

Central, peripheral

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18
Q

What are the 2 organs of the central nervous system?

A

Brain, spinal cord

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19
Q

What organ connects the central and peripheral nervous systems?

A

Spinal cord

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20
Q

What type of neurones is the brain mostly composed from?

A

Relay

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21
Q

What are the 2 divisions of the peripheral nervous system?

A

Sensory, motor

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22
Q

What are the 2 divisions of the motor nervous system?

A

Somatic, autonomic

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23
Q

What is the function of the somatic nervous system?

A

Conduct action potentials to effectors that are under voluntary / conscious control.

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24
Q

What are 2 structural features of the somatic nervous system?

A

Mostly myelinated neurones, single neurone connects CNS to effector

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25
Q

What effectors are controlled by the somatic nervous system?

A

Skeletal muscles

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26
Q

What is the function of the autonomic nervous system?

A

Conduct action potentials to effectors that are not under voluntary / conscious control.

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27
Q

What are 3 structural features of the autonomic nervous system?

A

Mostly non-myelinated neurones, at least 2 neurones connects CNS to effector, connections between neurones called ganglia

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28
Q

What 3 effectors are controlled by the autonomic nervous system?

A

Smooth muscle, glands, cardiac muscle

29
Q

What are the 2 divisions of the autonomic nervous system?

A

Sympathetic, parasympathetic

30
Q

What is the function of the parasympathetic nervous system?

A

To conserve energy

31
Q

What are 3 structural features of the sympathetic nervous system?

A

Ganglia close to CNS, 1:1 nerve:effector ratio, acetylcholine as neurotransmitter

32
Q

When do plant hormones start on the hormones mindmap?

A

49mins and 44 seconds in

33
Q

What are the different parts of the nervous system?

A

[-THE NERVOUS SYSTEM]
[-CNS] [-PERIPHERAL]
[-Brain] [-Spinal chord] [-Motor] [-Sensory]
[-Autonomic] [-Somatic]
[-Parasympathetic] [-Sympathetic]

34
Q

What is the function of the sensory nervous

A

Carries impulses and information to the CNS (Carries sensory information to the brain)

35
Q

What is the function of the somatic nervous system?

A

It connects to muscles and is part of the motor nervous system

36
Q

What are the effects of the sympathetic nervous system?

A
  • Prepares for activity
  • Uses the neurotransmitter: Noradrenaline
  • Stress
  • Increases heart rate
  • Increases ventilation of the lungs
  • Decreases digestion
  • Dilates pupils
  • An example of a sympathetic nerve is the accelerans nerve that increases the heart rate, this works by modulating the activity of the SAN
37
Q

What are the effects of the parasympathetic nervous system?

A
  • Prepares for rest and digest
  • Uses the neurotransmitter: Acetylcholine
  • Relaxation
  • Decreases heart rate
  • Decreases ventilation of the lungs
  • Increases digestion
  • Constricts pupils
  • An example of a parasympathetic nerve is the vagus nerve that decreases the heart rate, this works by modulating the activity of the SAN
38
Q

What is the function of each part in the brain?

A
  • Cerebrum = Responsible for conscious/higher thought
  • Cerebellum = Coordinates balance and fine control of movement & “muscle memory”
  • The hypothalamus & pituitary complex = Organises homeostasis
  • Medulla oblongata = Responsible for controlling autonomic responses (Involuntary responses, such as: The cardiovascular centre)
  • Corpus callosum = Joins the two hemispheres
39
Q

What are some of the causes for the medulla oblongata to be triggered to speed up the cardiovascular centre?

A
  • Stretch receptors detect muscle movements, and the medulla oblongata signals that the heart rate should be increased to increase oxygen movement to the muscles
  • Low blood PH
  • High blood pressure detected in the carotid sinus - A region of arteries with pressure receptors that can detect the blood pressure
40
Q

How does the hypothalamus and pituitary gland work together to bring about the fight or flight response?

A

The hypothalamus releases the CRH hormone
The pituitary is then triggered to release the ACTH
This goes through the blood and to the adrenal cortex
Cortisol etc is released for fight or flight response

The hypothalamus releases the TRH hormone
The pituitary is then triggered to release the TSH
This goes through the blood and to the thyroid gland
The hormone thyroxine is released which speeds up
the metabolism

41
Q

How is adrenaline released in the fight or flight response?

A
  • The hypothalamus activates the sympathetic nervous system

- The signal is sent to the adrenal medulla which then triggers the release of adrenaline

42
Q

What happens when an AP is sent across a neuro muscular junction?

A

-The signal will be sent through a myelinated motor neurone axon to the neuromuscular junction
-Voltage gated calcium channels open causing Ca2+ ions to flood in
-Vesicles fuse to the membrane and release the neurotransmitter via exocytosis
-Acetylcholine is released
-The acetylcholine binds to receptors on the sarcolemma membrane (The cell surface membrane of the muscle cell)
-Sodium ions move into the sarcolemma membrane
-A wave of depolarisation/AP is sent into the sarcolemma membrane and it spreads along the
muscle fibre and down the T-tubules
-The AP is carried into the muscle fibre

43
Q

What is the structure of the muscle fibre?

A

-Sarcolemma cell surface membrane on the outside
-T-tubules running transversely through the muscle
fibre
-Terminal cisternae of sarcoplasmic reticulum, a system of membranes within the cell that are connected to the T-tubules
-Multiple nuclei as it is made up of multiple fused individual muscle cells
-Many mitochondria to provide ATP for muscle contraction

44
Q

How does the AP travel in the muscle fibre once it has arrived from the neuromuscular junction?

A
  • The AP travels across the sarcolemma membrane and then down the entrance of the T-tubule
  • When the AP enters it will encounter the Terminal cisternae of sarcoplasmic reticulum which is connected to the T-tubule
  • Calcium is then released from the sarcoplasmic reticulum into the muscle fibre via voltage-gated ion channels to bind to troponin
  • This causes contraction
45
Q

What are the features of striated/skeletal muscle?

A
  • Voluntary control
  • Bundle of striated muscle cells with myofibrils within the sarcoplasm of each muscle cell
  • Appears striped under microscope because of the sarcomeres
46
Q

What happens within the sarcomeres?

A

Protein filaments slide past each other to shorten and lengthen

47
Q

What is a sarcomere?

A

The distance between the two dark “Z” lines on the myofibrils

48
Q

What is the structure of the sarcomere?

A

-Z lines on outside “Z”->|————|———–|

49
Q

What is the process of the sarcomere contracting?

A
  • The myosin heads interlock with the actin, forming cross bridges
  • After the binding the myosin heads change shape and then pull the actin filaments towards the centre of the sarcomere (this is called the power stroke)
  • The myosin heads then unbind using ATP to detach form the actin and they return to their original position
  • This entire process repeats causing the sarcomere to contract fully
  • Calcium is then released into the muscle fibre to bind to troponin
  • This causes tropomyosin to move out of the way, in turn starting the cross bridge cycle
  • This causes contraction
  • When the muscle relaxes, the myosin heads are prevented from binding to the actin. The actin and the myosin can now be separated by the action of an antagonistic muscle
50
Q

How is the structure of the sarcomere changed when it is contracted?

A
  • I band decreases
  • H band disappears
  • A band stays the same size
51
Q

What is the sarcomere?

A

-The functional unit of the muscle fibre

52
Q

What is the process of the cross bridge cycle?

A

-Calcium is released from the sarcoplasmic reticulum
-The calcium binds to the troponin
-This causes a conformational change to happen in the
troponin so that the actin binding sites become
exposed
-The myosin head now binds to the actin causing
tension in the muscle
-The power stroke begins, the myosin head changes
shape and ADP & Pi are released from the head
-This causes the entire myosin filament to be pulled
along the actin
-ATP binds to the myosin head, it is broken down into ADP + Pi to release the myosin head
-The ADP + Pi remains bound to the myosin head so
then the cycle can start again

53
Q

What is the role of the tropomyosin in a relaxed sarcomere?

A

-Tropomyosin blocks the binding sites of the actin filament to prevent the myosin heads binding to the
actin
-This means contraction is impossible

54
Q

How is rigor mortis caused in the sarcomere?

A
  • When a person dies, ATP is not produced
  • This means that the myosin head isn’t able to detach from the actin
  • This causes fibres to stay interlocked meaning the muscles are stiff
  • This is called rigor mortis
55
Q

How does the muscle stop contracting?

A
  • The muscle stops receiving signals from the nerves saying it needs to contract
  • The calcium is actively removed from the muscle and it is pumped back into the sarcoplasmic reticulum
  • This causes the tropomyosin to return to its original shape
56
Q

What are the three types of muscle?

A

Smooth, cardiac and striated muscle

57
Q

What are plant hormones?

A
  • Plant hormones are chemical messengers that are made in the tissues of plants
  • Often work by binding to receptors
  • Travel in the xylem/phloem and move via diffusion
58
Q

How do plants respond to stimuli?

A
  • Directional responses = Tropisms (Growing towards)
  • Phototropism - Response to light
  • Gravitropism - Response to gravity
  • Thigmotropism - Response to touch
  • Non- directional responses = Nastic responses
  • Thigmonasty - Response to pressure/danger
  • Chemical responses = Releasing chemicals in response to danger
  • Tannins
  • Alkaloids
  • Pheremones
59
Q

What are the commercial uses of each plant hormone?

A

-Auxins = Herbicides and to make seedless fruits
-Gibberellins = Fruit production, brewing, plant
breeding
-Cytokinins = For making tissue cultures
-Ethene = Controlling fruit ripening
-Abscisic acid = Killing plants

60
Q

What are meristem cells?

A

Totipotent stem cells that can differentiate into any plant cell type

61
Q

What is apical dominance?

A

When the apical meristem is dominant it means the plant grows upwards

62
Q

How does apical dominance occur?

A
  • Auxin produced at the tip diffuses down the plant
  • Auxin causes high abscisic in the side branch and low cytokinins
  • This stops lateral growth
63
Q

What would happen if the tip of the plant got cut off?

A

Auxin would not diffuse down the plant so lateral growth would not be inhibited

64
Q

What were the different outcomes from the plant experiment on tropisms? (by Darwin and Boysen-Jensen)

A

1) Control - Grows towards the light
2) Tip cut off - Doesn’t grow towards the light
3) Put an opaque cover over the tip - Doesn’t grow towards the light
4) Put an transparent cover over the tip - Grows towards the light
5) Opaque block covering the base - Grows towards the light
6) Agar jelly put in between tip and stem - Grows towards the light (Auxin can diffuse through the agar jelly from the tip to the stem)
7) Mica put in between tip and stem (Auxin cannot diffuse through the mica from the tip to the stem)

65
Q

What were the conclusions made from these experiments?

A
  • The tip was important for tropisms as it is where the light is absorbed and the auxin is produced
  • The signal was a chemical messenger
  • The signal is able to diffuse through agar jelly meaning that it must be a hormone (auxin)
66
Q

How does the the phototropism cause the plant to grow towards the light?

A

-The light is absorbed in the plant
-The auxin moves away from the light onto the other
side of the plant
-The auxin then causes hydrogen ions to be pumped
to the cell wall so it becomes acidic
-This causes the enzyme in the cell wall to work better in the low PH, the expansins loosen the cell wall causing it to elongate

67
Q

How do differing concentrations of auxin cause different effects on roots and shoots?

A

Low concentration of auxin = Stimulates roots

High concentration of auxin = Stimulates the shoots and inhibits the roots

68
Q

How do geotropisms cause root growth?

A
  • The auxins are heavy so they move to the bottom side of the cell
  • A high concentration in the bottom side of the cell inhibits growth in the root cell
  • This causes the top half of the root to grow, curved downwards