What happens if the threshold potential 5 ts4.pgskw l;is not reached ?

  At what membrane potent;zx73bjs*klnh83n c b ial do voltage-gated sodium channels open?

  The diagram shows a neurykff *n9 s: ,6/alswoxon.
Which arrow indicates a dendrite?

  How do neonicotinoid pesticides worvzm3qec1g14 rk?

  The diagram shows an action potenke2fj59t14 jm5t fv bgtial.

What is happening at point X?

  Which is the correct de 1 emk(mb-x. a*inl;ms. wg2pgfinition of saltatory conduction?

Neuronal cells have special membrane properties that allow their axons xtaxi 83 4qa*gpz5y/9 b8fycuto propagate action potential from one cell to another. The diagram below shows a portion of an axonaax9438afxu* gzqi/cyt 8 bp5yl 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 nz2 6+4xfcmxiao ,lje3eurotransmitters 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 m f(e0t,ri e;lh c(mev zlk.(d 5pw1xx5aintain a neuron’s resting potential?

  What is not a function of the myelin sheath?

Explain how the resting potw ,zjqbdeb aej*g75j3)2wz2hential is maintained in a neuron.

The diagram represents a syn8 .wmqb: zz;hmk0f1oh0cecs2 aptic cleft between two neurons in an insect's nervousqhm.zcw80fhsm k zb1:;e20o c 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 typfg;m:jho;6f ++r2g c/g eshxu0 l1 cusical neuron.
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 wideich5. cv2yg+h d/hr u-ly 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 carnica) were treated hh/5 cyrdug.+- i2hcvwith 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 time d0dj -x/f2zeuus(of/- s :of jeuring an action potential. Which letter represents the segment of the action potential when voltage-gated s u2u/jz-o (fsfes ed- /o:0xjfodium channels are open and voltage-gated potassium channels are closed?

  Which two features are more abundant per unit length in a non-myel-q5pao ksr.x 8inated neuron than in a myelinated 8-5o.r qa xpksneuron?

  Which of the following izxj dz:9+1z1eivnh z0s a/are correct description(s) of the relative speed impulses are 01:jnehvzz9zx+z id 1conducted 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 neuronsr,5r8 +loy7 j s+nwzdf during a stage of the action potential. What proce s5+f7 rn8dryoj+l, wzss does the diagram depict?

  The image shows neurons that are found in d-yvfdn 4,pao3,zt 1du og brains. What does letter X indicate?d, 3v,yadpu4on1 tzf-

  The diagram shows two neurons of equafu0oo t,l6:r( 1 sy bn2 /aqa0*jiifkil length and diameter. Which neuron will trann ub ya ql,jf r*ik0 so(i02oi1/6f:atsfer an electrical impulse faster?

  Which triggers the release of neurotransmitters from the presynaptic memb xpge:whnwl*x-)+ k)uxycj )-rane?

  Which mode of transport do neurotransmitters use to travel ac--7xg v wdh. 2,c9och(voxvy pross a synapse?

  Which statement explains why a nerve impulse trj853(pck xd is electrical?

1.Explain why a resting potential is0i b*.0cnl fd9exs sefv*ke+c.6f fe. negative.
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.