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Biology Mistakes > 5.1.5 Plants and animal responses > Flashcards

5.1.5 Plants and animal responses Flashcards

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1
Q

What are the similarities in the action of plant and animal hormones in cell signalling?

A
  • Hormones bind to RECEPTORS
  • Cause a cascade of enzyme reactions
  • May involve in the switching on/off of genes
  • Can have an affect on more than 1 TARGET TISSUE
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2
Q

Why are plants able to form more natural reproductive clones than animals?

A
  • Most plant cells are able to retain to differentiate to different cells (TOTIPOTENT)
  • Plants have meristems
  • Animal cells cant differentiate into all cell types (multipotent)
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3
Q

Mechanism of Photo tropism

A
  • Apical Cells (The apex/Tip of the shoot) produce auxins
  • Auxins diffuse down the shoot (through the parenchyma)
  • Auxins diffuse to the shaded side
  • Causes elongation of the cells of the shaded side
  • Bends the plant towards the light source
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4
Q

Mechanism of neuronal communication (steps)

A
  • Stimulus is picked up by the (named receptor)
  • Causes depolarisation of the sensory neurone
  • Action potentials are sent through the sensory neurone to the CNS (Brain or Spinal Cord)
  • Relay neurone relays the response down the motor neurone via action potentials
  • Synapses are present throughout the entire process (can explain how they work)
  • Motor neurone connects to a neuromuscular junction (receptor: muscle)
  • Causes depolarisation of muscle fibres
  • Causes muscle contraction
  • Actin and myosin slide over each other
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5
Q

3 ways farmers can maximise the efficiency of the transfer of energy up the food chains to primary consumers

A
  • Reduce their metabolic rate by reducing their movement
  • Keep them in optimum temperatures (stress free)
  • High protein caloric foods
  • Slaughter when mature
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6
Q

Physical Plant responses to Herbivory

A
  • Thorns
  • Inedible tissue
  • Stings
  • Barbs
  • Hairy Leaves
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7
Q

Chemical Plant responses to Herbivory

A
  • Tannins ( Bitter and Toxic to insects)
  • Alkaloids ( Bitter nitrogenous compounds)
  • Pheromones ( Warn other plants when under attack, elicits a response in other plants to defend themselves)
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8
Q

Mimosa pudica plant deffences

A
  • Contains a toxic alkaloid
  • Stem sharp Prickles
  • Quick folding leaves (K+ ion channels water follows causing rigidity)
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9
Q

Why are some plant pheromones not pheromones?

A
  • Volatile Organic Compounds (VOC)

- Similar to pheromones

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10
Q

What tropisms are present in plants?

A
  • Phototropism
  • Geotropism
  • Hydrotropism
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11
Q

Plant responses to abiotic stress

A
  • Leaf loss
  • Stomatal control
  • Freezing Prevention
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12
Q

Role of hormones in Leaf loss (deciduous) (steps)

A
  1. Lengthening of day triggers a number of changes in the plant
  2. Falling light levels mean lower amounts of auxins
  3. The lower concentrations of auxins lead to ethene being produced
  4. Abcsiion zone on the leaf stalk is sensitive to ethene
  5. Ethene causes gene switching which results in digestive enzymes being produced weakening the abscission zone
  6. Vascular bundles going to the leaf are sealed off
  7. More abiotic stress causes the leaf to fall
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13
Q

Role of hormones in Stomatal control (steps)

A
  • Produce ABA which causes stomatal closure
  • ABA binds to the plasma membrane of guard cells
  • This causes a decrease in water pressure closing the stomata
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14
Q

Role of hormones in seed germination (steps)

A
  • Water absorption by the seed promotes the production of gibberellins
  • This stimulates the production of enzymes that break down food stores
  • The plant uses this for growth
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15
Q

Role of Gibberellins

A
  • Stem elongation
  • Stimulates the breakdown of food stores (germination)
  • Pollen tube fertilisation
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16
Q

Role of Auxins

A
  • Cell elongation
  • Prevent leaf fall
  • Maintain Apical dominance
  • Root growth
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17
Q

Role of ethene

A
  • Leaf abscission in deciduous trees

- Fruit ripening

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18
Q

Role of ABA

A
  • Maintain Dormancy of seeds

- Stimulates stomatal closure

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19
Q

What effects do HIGH concentrations of auxins have?

A
  • Suppress lateral growth
  • Allows for apical dominance
  • Further down the stem there is less auxins so lateral growth occurs more
20
Q

What effects do Low concentrations of auxins have?

A
  • Promote root growth
  • High concentrations inhibit it
  • Allows more lateral growth
21
Q

Experimental evidence for the role of auxins

A
  • Shoot of the tip removes

- No growth and elongation of the plant

22
Q

Experimental evidence for gibberellins

A
  • Mutant seeds which don’t produce gibberellins don’t germinate
  • When Gibberellin biosynthesis inhibitors are applied the seeds don’t germinate
  • Stem elongation which produce elongation in plants
23
Q

Commercial use of plant hormones

A
  • Ripening Ethene
  • Weedkillers Auxins
  • Hormonal rooting powder (contains auxins which promote root growth)
24
Q

What does the CNS consist of?

A
  • Brain and spinal cord
25
Q

What does the peripheral nervous system consist of?

A
  • Neurones connected to the spinal cord

- Sensory, motor

26
Q

What are the 2 functional organisations of the nervous system?

A
  • Somatic nervous system

- Autonomic nervous system

27
Q

Somatic Nervous system

A
  • Under conscious control
28
Q

Autonomic nervous system

A
  • involuntary responses i.e. heartbeat, digestion, arteriole dilation/constriction
29
Q

Structure and function of the human brain

A
  • Cerebrum (Control voluntary actions, learning, thought etc)
  • Medulla oblongata (Autonomic control of heartbeat breathing)
  • Hypothalamus ( regulatory centre for water and temperature balance (produces hormones))
  • Cerebellum (Controls unconscious function balance, posture etc) (small bottom of the brain)
  • Pituitary gland ( stores and releases hormones also produces some hormones (anterior))
30
Q

What is the survival value of reflex reaction?

A
  • Present at birth
  • Very fast
  • Brain isn’t overloaded
  • minimises damage to the body
31
Q

Knee - Jerk reflex

A
  • Spinal reflex
  1. Stretching of the patellar tendon acts as a stimulus (action potentials generated)
  2. Sensory neurones carry action potentials to the relay neurone in the spinal cord
  3. Relay neurone sends action potential to motor neurones which go to effectors in the leg
  4. Relaxation of Hamstring flexor and Contraction of Quadriceps
  • Used to maintain posture and balance
32
Q

Blinking reflex

A
  • Cranial reflex
  1. Stimulus i.e light, sound, or touch generates action potentials
  2. (C5) Sensory neurone carries the impulse to a relay neurone in the lower brainstem
  3. Impulses are then sent through (C7) motor neurones to close the eyelids
  4. Consensual response so both eyelids close
  • Protect he eyes
33
Q

Flight or Flight system (mechanism)

A
  1. Hypothalamus communicates with the sympathetic nervous system and the adrenal-cortical system
  2. Adrenal medulla secretes adrenaline and noradrenaline into the bloodstream
  3. Heart rate increases, Pupils dialate, Blood glucose increases, Smooth muscles in airways relax
  4. This is to allow for more oxygenated blood, Better vision, Increase in respiration, More air into the lungs
34
Q

How does adrenaline work on the liver cells?

A
  1. Adrenaline (primary messanger) binds to a receptor
  2. This activates Adenylyl cyclase
  3. This converts ATP into cAMP (secondary messenger)
  4. cAMP activates other enzymes through a cascade effect which turn glycogen into glucose
35
Q

Glycogenolysis

A
  • Break down of glycogen into glucose
36
Q

Gluconeogenesis

A
  • Production of sugars from fat, pyruvates and lactae etc
37
Q

Glycogenesis

A
  • Conversion of glucose into glycogen
38
Q

How is heart rate controlled (nerves include)

A
  • Medulla oblongata is responsible for the control of the heart rate
  • Heart rate is DECREASED by the parasympathetic pathway through the vagus nerve connecting to the SAN
  • Heart rate is INCREASED through the sympathetic nervous system through the ACCELERATOR NERVE (SAN)
39
Q

What two receptors can change the heart rate?

A
  • Baroreceptors (detect blood pressure (low - increased heat rate))
  • Chemoreceptors (detect CO2 concentration in the blood)
40
Q

How can hormones such as adrenaline and noradrenaline affect the heart rate?

A
  • Affect the pacemaker reagion in the heart directly
  • Increases frequency of impulses produced by the SAN
  • This increases the heart rate
41
Q

Structure of Skeletal muscles

A
  • Straiated
  • Multinucleted
  • Voluntary
  • Cylindrical
42
Q

Structure of cardiac muscles

A
  • Striated
  • Uninucleated
  • Involuntary contraction (myogenic)
  • Branched shape
43
Q

Structure of smooth muscles

A
  • No strations
  • Uninucleated
  • Involuntary
  • Spindle shape
44
Q

What is the mechanism of muscular contrition?

A
  1. Wave of depolarisation in the sarcolemma spreads through t - tubules which is connected to the sarcoplasmic reticulum
  2. This causes Calcium ion channels to open
  3. Calcium ions flood into the sarcoplasm
  4. Calcium ions bind to troponin changing its shape
  5. MYOSIN HEAD BIND TO THE ACTIN FILAMENT FORMING A MYOSIN-ACTIN CROSS BRIDGE
  6. Myosin head flexes shortening the h-zone ATP molecule fixes to the myosin head causing it to detach
  7. ATPase hydrolysis ATP back to ADP returning the myosin head back to its original position
  8. This cycle is then repeated
45
Q

What is habituation and examples of habituation?

A
  • Repeated stimulation makes the organism accustomed to the stimulus (repolarisation cant occur fast enough)
  • Slug withdrawing tentacles
46
Q

Name a difference between a sensory neurone and motor neurone

A
  • Motor neurones Soma is in the CNS or brain
  • Sensory is in the middle of the cell
  • Sensory has no dendrites
47
Q

Give 2 reasons why animals and plants need to respond to changes in the environment

A
  • Accsess to resources

- Avoid predation

Biology Mistakes (6 decks)

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