What happens if the threshold potengmnh5lnm(c1g*rejn xm * 4: 3ntial is not reached ?

  At what membrane potential do voltage-gated sodium q f1jjb;5uc1i+0 wmzlxmce*. channels open?

  The diagram shows a neuron. 68j3 i cc f4hik9h(yka
Which arrow indicates a dendrite?

  How do neonicotinoid pesq25.c2ue 6opkt 1axt4,oru fs7hjwt/ticides work?

  The diagram shows an acssla ( vgb)n0m lwzrm/dj; .+3tion potential.

What is happening at point X?

  Which is the correct devqpy)zk*,9 dzv ,s7qe finition of saltatory conduction?

Neuronal cells have special membrane properties that allow their axons to prul h4b .xhia ), 58og91l aczf*liw.kkbq+ q+kopagate action potential from one cell to another. The diagram below shows a portion of an axonal plasm+ ok 4ha.ufb+1w.cqi5zxa *iq8lg kh l,)9bk la 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 neurotransmitters at the presynapti -k2s;+7ykz ups.8p9vwdfn mtc 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 md2z gjum3a j2/:umi s*aintain a neuron’s resting potential?

  What is not a function of the myelin sheath?

Explain how the resting potential is maintained in azsv4 k-r;h8 /c yfzy tjlo55gr oqd;vy9s5v30 neuron.

The diagram represents a synaptic cleft b(3 1oimxy5fuuf )6p ttg e9yl6etween two neurons in an insect's nervous system.lyifg6p9 oue f1 ()u5tt6ymx3



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 tyo5 tki7,c 6tql t35akux5 .kurpical 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 co:fd occ: 45kdympounds that 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 carnica) 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 hivfy: odcc:45 dke).

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 ti31/jh: vv wyu ty/r3twtby*4ecv5;3 i,db sqpme during an action potential. Which letter represents the segment of the action potential when voltage-g/yv w hy:t ,d4 5cuipqb *;sw/3tyejtrbv31 3vated sodium channels are open and voltage-gated potassium channels are closed?

  Which two features are more abundant per unfocui55 eu i4ekump(,g21zm *it length in a non-myelinated neuron than in a myelinated n( 4*gcu 5ofzk m1ie,iu5mp2ueeuron?

  Which of the following is a/are correct description(s) of thef y5e7cq5:f+ ;vvew76l ga+yox po3rz relative speed impulses are conducted 7 67+rce3yl 5z5eo+qo af;fg:v ypvxwat?
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 thats;go q(diz y+oo1pz*ury/ w //o6u, ty occurs in the membranes of neurons during a stage of the action potential. What po6/wy zz+( ,; * ooog/i/q1ysdr utypurocess does the diagram depict?

  The image shows neurons that are found in dog brains. What do6(v 1,8js ohhvbko;ryes letter X indicatey,jvov b1 6roh;(s 8kh?

  The diagram shows two neurons of equal length and diamete2y)5j4uh mgm9 ijwhza5td85 m r. Which neuron will tran5m 5j itm28uj4wa)hy 9zmdhg5sfer an electrical impulse faster?

  Which triggers the release of neurotransmitters from thkj*0 of(h bn:te presynaptic membrane?

  Which mode of transport do neurotranm gdy j6mmi20+yfsi g9csj+),(3p er ysmitters use to travel across a synapse?

  Which statement explains why a nerve 7lag1 2si;x mr,hqn3fimpulse is electrical?

1.Explain why a resting potential is negative. (vl(+zcyagz7 hrv uu* f0;k 92 olrh1j
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.