What happens if the threshold potentialo4m pni( c7:t1gah0ys is not reached ?

  At what membrane pote-a.xv 61 wqpmnntial do voltage-gated sodium channels open?

  The diagram shows a neu65qgs 70eg rg-hz wm:lron.
Which arrow indicates a dendrite?

  How do neonicotinoid pesticides :dnpx5,vc cxn j+w 4d/work?

  The diagram shows an action potential.fyg kl5)t/jjw/k1 nu lf 7.)bf

What is happening at point X?

  Which is the correct definition of saltw ex.2 wv,x-dq9e++p4lrz +sz.mzyh fatory conduction?

Neuronal cells have special membrane properti wgzmqwrc ) eo7+30ah9es that allow their axons to propagate ar egc+3 q9moz70)wwhaction potential from one cell to another. The diagram below shows a portion of an axonal plasma membrane.


1.(1)State the role of a sodium-potassium pump in axon.
(2)Describe the action of the sodium-potassium pump.
2.Distinguish between simple diffusion, facilitated diffusion and active transport.
3.Compare and contrast sodium-potassium pumps and potassium channels.

  What causes the exocytosis of neurotranh;m k;9zkog 5dsmitters at the presynaptic membrane?
I. Depolarisation of the postsynaptic membrane
II. Depolarisation of the presynaptic membrane
III. The diffusion of calcium ions

  What are the main factors that maintain a neuron’s resting -f/,mz h2ich* hof,u smdu58bpotential?

  What is not a function of the myelin sheath?

Explain how the resting potential is dc; nf . x,ii.bg9fm4dmaintained in a neuron.

The diagram represents a synaptic cleft bet5xuto1l o7bn*ween two neurons in an insect's nervous system. ot1u*5xobl 7n



Gardeners use pesticides that contain neonicotinoids to kill pests. Label with the letter X where neonicotinoids would bind.
1.(1)Explain how neonicotinoids work on insects.
(2)Suggest what the effect would be on synaptic transmission in cholinergic synapses if gardeners used (3)pesticides that were broken down by acetylcholinesterase.
2.Explain why neonicotinoid containing pesticides are less toxic to mammals than insects

1.Draw and label the structure of a typical neuronaj4tm lj r0(fjfrk( xb) -41c6k0yzqd .
2.Explain why myelination is essential for the rapid transmission of impulses.
3,Explain the importance of positive ions in the generation and propagation of an action potential.

Neonicotinoids are synthetic compounds )zz n*t7mjgd ax o+/l3that are widely used as pesticides. However, there are concerns about their effect on honey bees and other pollinating insects. The table below shows the results from a study where honey bees (Apis mellifera *oaz7/3ldz gnxt +) mjcarnica) were treated with non-lethal doses of two neonicotinoids, Imidacloprid and Clothianidin, and the effect it had on their homing instinct (ability to fly back to their hive).

1.Describe the mode of action of pesticides containing neonicotinoids on cholinergic synapses in insects.
2.Using the data, outline the effect of the neonicotinoids on honey bees.
3.Calculate the percentage increase between the control and those treated with 0.6 μM of Imidacloprid which did not arrive back at their hive.
4.State what the dependent variable is in this study.
5.(1)Based on the data, predict the effect that exposing honey bees to neonicotinoids will have on the fitness of the honey bee colony.
(2)Explain your answer to part (i).
6.The researchers concluded that neonicotinoids should not be used as pesticides due to their unintended effects on honey bees. Evaluate whether this data supports their conclusion.

  The graph below shows membrane voltage over time7: xk-lks amv7 during an action potential. Which letter represents the segment of the action potential when voltage-gated sodk7maxl:- 7skv ium channels are open and voltage-gated potassium channels are closed?

  Which two features are more abundant per unit length in a non-myelinated ne;6xp:ay( 39z wkli *r; edkznp e2d+tiuron than in a myelinatedl* dezipy:pk2+;na i9dr 36wz(k e t;x neuron?

  Which of the following is a/are correct de)+lc,wibo4xoxvnb emc - ;b;xu,z 77bscription(s) of the relative speed impulsexoox vclib,,c7)xmw b;;nb +u7e 4b-zs are conducted at?
I. As the diameter of axons increases, the speed at which impulses are conducted increases.
II. There is a negative correlation between animal size and the speed at which impulses are conducted.
III. Saltatory conduction in myelinated neurons is slower than the speed at which impulses are conducted in non-myelinated neurons.

  The diagram shows a 88 ionj4mc 9eaprocess that occurs in the membranes of neurons during a stage of thn89mj o4c8 eiae action potential. What process does the diagram depict?

  The image shows neurons that are foun+wrp o m,d nbhjt98r9(d in dog brains. What does letter X indicateohwbr (89d pnj +rm9,t?

  The diagram shows two neurons of equal dowfeq9l7bw xog p7el 4, 2m4+length and diameter. Which neuron will transfer an electrical impulsoe,xdw o7qfwlgepm4bl 4 9+72e faster?

  Which triggers the release of 8e. sjicr4vg7 neurotransmitters from the presynaptic membrane?

  Which mode of transport do neurothot .ko 96fs(aransmitters use to travel across a synapse?

  Which statement explains why a nerve impulse is electriuf ppru9 1.o e557ehmscal?

1.Explain why a resting potential is (3f 6gx;vv+vy x-kqzpnegative.
2.Explain how the structure of a neuron is adapted to its function.
3.Describe the events that occur to propagate an action potential within a neuron and between two neurons.