What happens if the threshold potpz 9 i.: ymz8rz5o(tadential is not reached ?

  At what membrane potential4l,r0 b1 uupy i,nom+z do voltage-gated sodium channels open?

  The diagram shows a neu+gf6a3; ; w*gaajkrzho )pcnb0/zai:ron.
Which arrow indicates a dendrite?

  How do neonicotinoid pesticidef lh *e5).fbi-5czlzr s work?

  The diagram shows an awptq7t/g5 y7hua*)06j. 9 jesqeu weection potential.

What is happening at point X?

  Which is the correct definitiovssjc8y,w7;c h 26ev,xa ls; jn of saltatory conduction?

Neuronal cells have special membrane properties thkye eyc)9) 1jlh-ge m 3h3io7fat allow their axons to propagate action potentialgm79jh) eo )kehi-f31y ycl3e 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 neurotransmittefk7.x*zl 34//vnm e9:g oeftj:cz .dkt9hmwr rs 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 thuwqu gr5 0j5(.ahpr8cc *wnf;co.l z/at maintain a neuron’s resting potential?

  What is not a function of the myelin sheath?

Explain how the resting h;. h:lnoy+*/djyosdpotential is maintained in a neuron.

The diagram represents a synaptic cleft be uo1qm d.7s3hmtween two neurons in an insect's nervousqm.dhu 1o7 3sm system.



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 neuron.a0pjdk :yt vf8 b+ af1rt;(za)
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 that are widely used as pesticides. Howega 4uc2gdasv8 2a8/llpg :5ruver, 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 carnica) were treated with non-lethal doses of two neonicotinoids, Imidacloprid and Clothianidsa85 lv g2:gr dlucg8a2ap/ u4in, 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 vq oftayk2c) ig+b866thb9om 6oltage over time during an action potential. Which letter represents the segment of the action potential when voltage-gated sodium channels are open and voltage-gatetcoq ig66b9 6k8amto2 hy b+)fd potassium channels are closed?

  Which two features are more abundant per unit length in a e ,)(8e-klbo5 qhybvo non-myelinated neuron thaelh) -bby qo8,e k5vo(n in a myelinated neuron?

  Which of the following is a/are correct description(s) of the relative speed 2i3xi)0eswhmtb+mnl o9, q 7oimpulses are conducted mbo)+ hw,2oil3is9tmx 7qne0 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 process that occurs in the membranes of neurons om5 ;biafreh/r e,2yq+6b l.j during a stage of the actiy.ro5 j,bmbl;r2h+iea 6 f/qeon potential. What process does the diagram depict?

  The image shows neurons that are found in dog brains. What d3uc88e2dnkm(8b atxl oe+to +oes letter X indicate 88(o bldnkxtmeato38+c+eu2?

  The diagram shows two neurons of equdgtf 4l uf(39k068dbpp* u akual length and diameter. Which neuron will transfer an electrical i04ulp 63df9kdfab8 ug p(*uktmpulse faster?

  Which triggers the relez/ sevc*k6:)gzo9z 2kx12n/j e yvv7eg/qdl tase of neurotransmitters from the presynaptic membrane?

  Which mode of transpo 4 pq i2gkbumh:2cil62rt do neurotransmitters use to travel across a synapse?

  Which statement explains why a nerve impulse is x1 kkqh*sogk+ c8tl(t1x7/iu electrical?

1.Explain why a resting potential is ne2( c6 / nrjag(dzn-fjxgative.
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.