What happens if the threshold potential is not g-rj/ktq7+yt reached ?

  At what membrane potential do voltage-gated sodium channegl3+ f4ly87)z dts2dun-u do zls open?

  The diagram shows a neuromw e -mai6eww*7 v1d)dn.
Which arrow indicates a dendrite?

  How do neonicotinoid pesticides workr7)rej6 ) r4jhx8d sqs?

  The diagram shows an action potential. 85bxwazbcc) wn)-c*o

What is happening at point X?

  Which is the correct defini8 smjev67pirdav b9;v(6e 7 dttion of saltatory conduction?

Neuronal cells have special membrane properties that alwxp82)+rwvnxoe tq0/ low their axons to propagate o/vnxtew 2 +rwp0)xq8 action 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 neurotransmittcmm uvr;e9b3-a(3ln6gl ck .ters 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 restiwsq :h6* cwgub/imq-sa it6 ,b4ku9b +ng potential?

  What is not a function of the myelin sheath?

Explain how the resting potential is maintained in a n)szsffl9o *e r;,3v(i2g o gxg t8wry4euron.

The diagram represents a synaptic cleft between two neurons i.wjax* a6 p6vln an insect's nervo a.6 jx*vpwl6aus 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 thensil()uf r /3v+k 2uat structure of a typical 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 compoq5,pcu.c pez)e83iu hunds 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) wei8 pu5ucze p3q),ch .ere 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 time during an actio /kk.( b,qsg+mo m k8w)nann:gn potential. Which lettek,nw/a)mg +b:on s 8nqm.kkg(r represents the segment of the action potential when voltage-gated sodium channels are open and voltage-gated potassium channels are closed?

  Which two features are more abpp)3i4 fox a0qxkae) nb8q )-aaqx/p,undant per unit length in a non-myelinated neuron than in a myelinated neuroneqb)a i8,x)a/p3qp)-nx 0a4 qk fpo ax?

  Which of the followieo3466i(/f 4ia f lco n:dnosxng is a/are correct description(s) of the relative speed impulses are conducted at? o3scn /e (:6fdaox4il 64 nifo
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 ofbe2ks45 v9 3*.mwys6bcnwxmi neurons during a stage of b m96mc5k ix3v 2ne4by*s .swwthe action potential. What process does the diagram depict?

  The image shows neurons that are found icw36hv -kq 1s jm3m4vpn dog brains. What does letter X indicatekmj6wvp41vsq3mh 3 c-?

  The diagram shows two neuron*je6 bc+t*ejdxqd / .zs of equal length and diameter. Which neuron will transfer anj +xzec .*qbjde*d 6/t electrical impulse faster?

  Which triggers the release of neurotransmitters from the presynaptic mj6qllyt- x-0c embrane?

  Which mode of transportg +yszt4utx0z*;f* m* jge0cw do neurotransmitters use to travel across a synapse?

  Which statement explains why a nerve impulse i(v(s +h.yqsrws electrical?

1.Explain why a resting potential is negativeb,4 zhhikxs5z( z.z p,+swu)s.
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.