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8A Flashcards

1
Q

Light sensitive cells located in

A

Retina

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2
Q

Photoreceptor in light-sensitive cells

A

Membrane bound organelles in the outer segment

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3
Q

Pigment forming photoreceptor in mammal eye

A

Rhodopsin

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4
Q

Describe effect of light intensity on light sensitive cells (graph with light intensities)

A

More flash intensity— more -ve mv
More intense flash—longer to return from -ve
More intense light—cell hyperpolarised faster

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5
Q

How does increasing hyperpolarisation of light sensitive cells result in impulses that can be interpreted by the brain (4 points)

A

1-Greater hyperpolarisation—less neurotransmitter released by rod cell
2-Greater #of action potentials generated in sensory neuron/bipolar cell
3-increased frequency of action potentials is interpreted as more intense light
4-by visual cortex/occipital lobe

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6
Q

Describe effect of multiple sclerosis on speed of conduction of nerve impulse

A

1-No significant difference in conduction speed from spinal cord to biceps
2-conduction speedfrom brain to biceps slower for people with multiple sclerosis
3-use of data manipulation

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7
Q

In multiple sclerosis, the immune system destroys the myelin sheath
Ecplain effect of ms on conduction of an impulse

A

1-conduction speed faster in myelinated neurons
2-bc in myelinated action potentials jump bw gals of m sheath / saltatory conduction
3- myelin removed, action potentials have to move along the whole axon slowing speed of conduction

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8
Q

Using the graph compare response of adp1 and tom1 mutants with response to C elegans

A

1-more worms with adp-1 mutants swim backward following tapping than wt
2-fewer tom1 mutants swim backward following tapping than wt
3-use data to support point 1-2
4-idea that adp1 mutation slows habituation

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9
Q

Describe the role of ion transport in maintaining resting potential of a neuron

A

1-active transport by Na/K pump
2- Na out of axon K into axon
3-passive diffusion of K out of axon
4-inside of membrane -ve compared to outside
5-membrane voltage stays at the same value

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10
Q

How does ttx inhibit nerve impulse

A

1-binds/inhibits voltage dependant Na channels
2-blocking rapid diffusion of Na into axon
3-reducing depolarization of axon
4-below the should for action potential to be triggered

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11
Q

Why does maintaining a resting potential require ATP?

A

1-ATP used by Na/K pump
2- to move Na and K ions across the membrane
3-to establish concentration gradients from Na and K ions

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12
Q

How is -70mv resting potential maintained

A

1-Na/K pump
2- Na channels closed
3-membrane relatively permeable to K
4-At rest high K in axon and high Na outside axon

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13
Q

How does change in pressure receptors cause action potential

A

1-pressurr deforms cell membranes in Pacinian corpuscle (pressure receptors)
2-influx of sodium ions into axon
3-depolarisation of axon moving though the axon in an action potential

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14
Q

Explain why amount of pressure doesn’t change the membrane potential after a medium or high pressure

A

1-theshold has been reached
2-results in action potential
3-action potentials are an all or nothing response since they either occur fully or not at all

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15
Q

Why does myelinated axon conduct impulses faster than unmyelinated?

A

1-myelin sheath is an insulator
2-therefore action potential only occurs at nodes of Ranvier
3-therefor nerve impulse “jumps” from one node to the next: saltatory conduction

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16
Q

Show how damage to myelin sheath can lead to muscle weakness

A

1-myelin sheath destroyed–transmission of nerve impulse impaired
2-fewer impulses reach muscle
3-fewer muscle fibers stimulated to contract—muscle weakness

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17
Q

Is it valid to say there is a relationship bw quantity of myelin in brain of person and whether or not they had demetia

A

1-all types of demetia lower level of myelin vs control
2-no relationship between amount of myelin in brain and type of demetia
3-no overlap of any SD of demetia vs control suggesting validity

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18
Q

Habituation crabs experiment comment on results

A

1- male and female crabs respond differently to the predator
2-female crabs showed greater habituation than male crabs
3-after 10 exposures there seems to be variability in the data

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19
Q

What statistical test to be used to compare increase of predator vs percentage of crabs running home

A

Correlation coefficient

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20
Q

Effect of light absorbtion on rod cells and bipolar cells

A

Rod cell: hyperpolarized
Bipolar neuron: depolarised

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21
Q

Describe effect of light intensity on mean potential differences of bipolar neurons

A

1-light intensity increases–mean potential difference increases
2-mean potential difference stays the same after 12

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22
Q

Two reasons why people might object to the use of mammalian retinas in investigation

A

-Removing retina from mammals can cause blindness/harm
-using anaesthetic causes harm to mammals
-not ethical

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23
Q

Response of muscles in eye to increasing light intensity

A

Circular contract, radial relax

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24
Q

Describe changes in whale heart beat when diving

A

1-heart rate increases when diving
2-the longer the whale is diving the lower the heart rate
3-dif bw maximum heart rate at surface and min heart rate in dive increases as dive duration increases

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25
Describe the role of rhodopsin in rod cells
1-rhodopsin is the photoreceptor 2-when light is absorbed, cis retinal becomes trans retinal 3-causes sodium channels to close 4-membrane becomes hyperpolarized
26
Explain why membrane potential changes bw -70 and +40 mb on the graph
1-Stimulus initiates change in voltage 2-Na channels open, Na moves in, less negative 3-if above threshold potential depolarization initiated
27
The protein coded for by the tom1 gene is involved in neurotransmitter release from a sensory neuron. Suggest how this gene could produce the results observed for the Tom 1 gene (5points)
1-sensible function of tom1 protein--reduced activity of Ca2+ channels 2-mutation results in less neurotransmitter being released 3-from sensory neuron 4-fewer action potentials stimulated in post synaptic membrane 5-of motor neurons
28
Suggest how adp1 gene mutation affects the transmission of nerve impulses at synapses
1-Ca channels remain responsive 2-idea of neurotransmitter remaining in synapse longer 3-resultijg in prolonged depolarization of post synaptic membrane
29
Suggest how a change in activity of na channels can result in an increase in electrical activity in the brain of a person with epilepsy
1-more Na channels open 2-allows membrane to depolarise 3-more easy to reach threshold/generate action potential 4-in large number of neurons
30
Explain how ca2+ is involved in synaptic transmission
1-impulse reaches pre-synaptic membrane 2-Ca2+ channels open and Ca2+ diffuses in 3-causing vesicles to fuse with the membrane 4-release of neurotransmitter into synaptic cleft
31
Suggest two reasons why impulses only travel in one direction across a synapse
1-neurotransmitters only found in presynaptic knob 2-idea that receptors only found in post-synaptiv membrane
32
Effect of acetylcholine in excitatory and inhibitory synapses of post synaptic cells
1-Acetylcholine depolarise post synaptic cell at an excitatory synapse but hyperpolarized post synaptic cell at inhibitory synapse 2-acetylcholine faster effect at excitatory synapse 3-Acetylcholine shows a greater change in membrane potential in excitatory synapse
33
Describe how an action potential is produced and resting potential restored in an axon
1-voltage gated Na channels open 2-Na diffuses into axon 3-axon depolarised 4-voltage gated Na channels close 5-voktage gated K channels open 6-K diffuse out of axon--REPOLARISING 7-K diffuses back into axon through non gated K channels restoring resting potential (or Na K pump restores resting potential)
34
Where in rod cell is opsin gene transcribed
Nucleus
35
What happens to rod cell membrane when light bleaches the light sensitive pigment
Na channels close, rod cell membrane hyperpolarized
36
Describe the role of ATP in response of rod cells to light (3marks)
1-atp provides anergy 2-synthrsis of rhodopsin 3-rejoining retinal to opsin 4-converting trans retinal to vis retinal 5- used by Na pump to actively pump na ions
37
How to improve experiment with cuttlefish
Repeat experiment Higher sound intensity above 165 Smaller intervals for both
38
Using table and your own knowledge show how cuttlefish become habituated to sound (4)
1- use sound frequency bw 100-200 2- use sound intensity 140-165 3-use a group of cuttlefish 4- testing cuttlefish with sound at regular intervals 5-idea of observing strength of flight response 6-reduced response shows that habituation has occured
39
Using info in graph compare speed of conduction in myelinated and unmyelinated neurons (2)
1-as diameter increases, speed increases for both 2-above 1μm myelinated neurons have faster speed of conduction than unmyelinated 3- diameter has greater effect on speed of conduction of myelinated neuron 4- linear relationship in myelinated but nonlinear in unmyelinated
40
Explain why speed of conduction in myelinated neuron with diameter of 1.5 μm is higher than unmyelinated neuron with the same diameter (3)
1-idea that myelin sheath insulates axon 2- breaks in myelin nodes of Ranvier 3- action potentials pnlynpccur at nodes 4- nerve impulse jumps from node to node/ saltatory conduction 5- in unmyelinated fibers action potential has to generated all along axon
41
Why is habituation of prairie dogs to humans on trails important
1- don't waste energy running from humans 2- more energy to run from predators 3-warning signal not ignored if predator
42
Discuss issues relating to using rat brains in study (2)
1- rats are living organisms -- harming wrong 2-need to carry out research not on humans 3- brain of rat similar to humans 4- rats can't consent
43
State two factors determining how quickly animal become habituated
1- time between each stimulus 2- duration of each stimulus 3- strength of stimulus
44
Note
Dendrites feel impulse Impulse moves away from dendrites
45
Explain role of acetylcholine in transmission of nerve impulse (2)
1- to transmit nerve impulse across synapse 2- bc action potential cannot cross gap 3- detail: vesicles, receptors on post synaptic cell, exocytosis 4- initiated action potential in post synaptic cell
46
Some pesticides are inhibitors of acetylcholinesterase Suggest how these pesticides could affect nervous system of insect and person spraying (2)
1- acetylcholinesterase needed to release acetylcholine from receptors/ conc remains high in synaptic cleft 2- idea of continuous action potentials 3- presynaptic cell will run out of acetylcholine
47
Suggest how plants can be genetically modified to resist insect damage
1- gene resisting insect 2- coding for tough cell wall or toxin 3- idea that gene isolated from plant 4- gene gun introducing gene to plant cell 5- idea of testing plants for gene
48
Describe how light is detected in animals (6)
1- rhodopsin in rod cells 2- rhodopsin absorbs light 3- cis retinal--trans retinal 4- rhodopsin splits into retinal and opsin 5- cells become less permeable to sodium 6- resulting in hyperpolarization 7- stimulus large enough--action potential 8- nerve impulse along optic nerve to brain
49
Looking at table explain how distribution of these ions is maintained
1- pump/active transport 2- Na move out/ K into cell 3- membrane permeable to K 4- impermeable to Na 5- membrane not permeable to organic anions
50
Suggest how metaflumizone makes ants immobile (3)
1- metaflumizone closes or blocks Na ion channels 2- no influx of sodium ions 3- no depolarization/action potential 4- no stimulation/contraction of muscles
51
Describe valid lab investigation to find min concentration of metaflumizone to make ants immobile (4)
1- range of 5 concentration 2- standardisation of ants (species) 3- method to assess mobility (observing immobility) 4-large sample size 5- named variable stated (time/solution volume) 6- repeat with a narrower range of concentrations
52
Some ants are resistant to metaflumizone suggest how this happens (3)
1- mutation in DNA 2- different protein produced 3- enzyme breaks down metaflumizone 4- metaflumizone no longer blocks channel
53
Explain the role of the synaptic bulb on the stimulation of the effector cell (3)
1- action potential causes influx of Ca2+ 2- vesicles fuse with pre-synaptic membrane 3- neurotransmitter released and attached to receptors on effector cell
54
Using table suggest how aging affects vision in low light
1- pupil size smaller in older people 2- radial fibers in iris contract less in older people
55
Explain advantage to rat of having increased rod cells when length of day is short
1- rat will have more hours of darkness 2- rod cells work well on low light levels 3- rats need to see to find food and avoid predators
56
Using table describe the effect of temp on refractory period (2)
1- idea that an increase in tekp reduces duration 2- data manipulation 3- reference to overlapping SD 4- idea that as temp increases range decreases
57
Use info in table to suggest how carbamazepine can be used to treat shaking caused by over active neurons in the brain in epilepsy patients
1- binds to blocks Na channels 2- no na diffuses in 3- no depolarization 4- no action potential in motor neurons 5- reduced muscle contraction
58
Describe how GALC gene is transcribed
1- DNA unwinds 2- mononucleotides line up against their complimentary bases 3- on the template stand 4- phosphodiester bonds form form bw adjacent mononucleotides 5- reference to RNA polymerase or DNA helicase 6- mRNA formed
59
How is a nerve impulse affected by Krabbe disease causing loss of myelin sheath (2)
Slows speed of impulse Idea that impulse cannot jump from node to node
60
Pyrethrin binds to insect neuron protein channels delaying their closure. Why does it not affect animal neurons
1- protein channels different 2- pyrethrin cannot bind 3- idea of dilution on mammals
61
Why does people who absorb insecticides have pupils with small diameter
1- circular muscles contract 2- radial muscles relax
62
Compare the effect of insecticides on the survival of each species of sand fly
1- increased conc kills more flies 2-organichloride kills more species b at lower conc 3- pyrethrin kills more species a at lower conc 4- 100% killed at lower conc of pyrethrin than organichloride
63
During action potential the distribution of Na and K changes. Explain how proteins in cell membrane enable conc of these ions to return to resting potential
1- proteins act as channels Repolarization 2- Na channels close 3- Na cannot enter neuron Resetting after hyperpolarization 4- k channels close 5- na k pump imports 2k for 3na
64
Describe how arrival of nerve impulse causes release of neurotransmitter
1- Ca enters presynaptic knob 2- vesicles containing neurotransmitter 3- fuse with pre-synaptic membrane releasing neurotransmitter into synaptic cleft

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