What happens if the threshcya ic. - 2- tj0 crvm.ida4g()f;j/rrz*hmax old potential is not reached ?

  At what membrane potential do voltage-*y l7p6gkor n xy)mc*n,j ;p)hgated sodium channels open?

  The diagram shows a no/l m:nnz1jwf.z 81s. r mi/lneuron.
Which arrow indicates a dendrite?

  How do neonicotinoid pe xyiik te6eb- 7cysu+p7 z1m26sticides work?

  The diagram shows an a k+v /w5oa:r/zzql*g pction potential.

What is happening at point X?

  Which is the correct definition of saltatfqynf: cd2os1i) i4t 8ory conduction?

Neuronal cells have special membrane properties that allow;k.6veddp uu 5 their axons to propagate action potential from one kvd e5;.u6pducell 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 neurotransmitters at .t:* z8d(v4gkxek- fwb.wjfk 20bob:d iwvx6the 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 3ou,l: hcry9dthat maintain a neuron’s resting potential?

  What is not a function of the myelin sheath?

Explain how the resting potei8oma*t 6ipy3 ntial is maintained in a neuron.

The diagram represents a synaptic cleft between t ii*j,kn*y9xdrmi/4 jwo neurons in an insect's nervous syk,i*idj9 m4 xi*y/jnr stem.



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:rws3o4d;- lhzto ept: 8xv, bc1ha:b.
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 pesticidkk94yue5uap1nc+ czt44f6 kxw*9 jsses. However, there are concerns about their effect on honey bees and other pollinating insects. The table below sho s5cx6yktu4 9pzk4 wna*c9u4 +1eksjfws 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 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 ht;pn(3*lh( tfzt sokcun97 + action potential. Which letter represents the segment of the action potential when voltage-gats+p (n3th9uzolt7kch*n;f t(ed sodium channels are open and voltage-gated potassium channels are closed?

  Which two features are more abundant per unit length in a nonjntr4/ )z*cqhk , ny:at7sa2u-myelinated neuron than in a myelinz :ynh atus/kt )c 7qn4,rj2*aated neuron?

  Which of the following is a/are correct description(s) of the relative speed i3)ujy4q.jf2:a+rjy msnd 7f wmpulses arf .yrqwjuj27:4j ymfdn 3as)+e 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 process that occurs in the membranes of h0 +xd/g lheoyu 3x,rw3r; x3wneurons during a stage of the x3l /xrryd0g+h uo3;he,ww3 x action potential. What process does the diagram depict?

  The image shows neurons that are found in dog brains. What does letter X i2iyx x8amp;)fndicatx8 m2p ;)fixyae?

  The diagram shows two neurons of equal length and diameter. Which w;63x ,dkmmeioa6m k 1n1ot0 dneuron will transfer an electrical impknw m;,6oo1t1idxm6ek0dma3 ulse faster?

  Which triggers the release );q z nakw(uj04mq;xfof neurotransmitters from the presynaptic membrane?

  Which mode of transport do neurotransmitters use to travel across a hn. znnsz8 4qh9/, ooycu03av synapse?

  Which statement explains why a nerve impulse is elv6)we vzi1kh*ectrical?

1.Explain why a restd))gu qv2+ rv z2o3h*5botdwbsmd ,x(sg,ux 9ing potential is 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.