What happens if the threshold potential id2( q (mc,tv.zzvw2n ps not reached ?

  At what membrane potential do voltage-gated sodium channel w4o1 -4; ip*cr2iwpuxj dtet:s open?

  The diagram shows a n2x dm-i- ck9royw+7 wag1u ae0euron.
Which arrow indicates a dendrite?

  How do neonicotinoid pest4av fodxq( ;ollfsp;1qh.5k8bbxl0 - icides work?

  The diagram shows an rroau3 a3ir58( we;6 qbk8dboaction potential.

What is happening at point X?

  Which is the correct definitior / 6-fwpk/ownn of saltatory conduction?

Neuronal cells have special membrane properties that allow their axons tgugn/:a 6e drs2vmz)6o propagate action potential from one cell to another. The6zarv/:n) ue d2gg 6ms 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 the presynaptic membrane? afw.jr5n9jbcum 8d:-
I. Depolarisation of the postsynaptic membrane
II. Depolarisation of the presynaptic membrane
III. The diffusion of calcium ions

  What are the main factors that+uh*4w sn.ji y maintain a neuron’s resting potential?

  What is not a function of the myelin sheath?

Explain how the resting pjhf4i,g a+dudbypvqqvt;q 85h +;x+ :otential is maintained in a neuron.

The diagram represents a synaptic cleft between55bwlhk54ci8 9 rp ktk two neurons in an insect's nervous syst hp5itc 4 8wl5kbkkr59em.



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 neuronj6l538m2vzkxmu lay x;b-f (j.
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 th f k+/-tlku4gvl+lo0ndaln 8 -at 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 nv0ka4g+l -nlu/f ot -lkl 8d+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 durin6w4 eh1 bp)ytceta1 vvc6n.k-g an action potential. Which letter represents the segment of the acae)n-4e cbhyp1t tkc.vw 6 16vtion potential when voltage-gated sodium channels are open and voltage-gated potassium channels are closed?

  Which two features are more abundant per unit length in a non-mye4/y*vgd25voz m j:a7fr1yxps linated neuron than in a myez gpvya:2s vx7mf4or *dj y/51linated neuron?

  Which of the following is a/are correct description(s) of the rela unkzz c7 wtd6,)qu+u 2yvtldov 0+x0)tive speed impulses are conducted at0nu6ulz d , +0twuqod xz)2t)y+cvk7v?
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 iyxdv9;9k ,msw9h9vta 0w cl nn-f .x1ln the membranes of neurons during a stage of the action potential. What process does the diagram deyllt-vwk.hc;09 9xvwsn1f9m9n a ,d x pict?

  The image shows neurons that are found in dog brains. What does letter o90( ibsm b-nc0us:fp+r,ra s X indicate:bs+ss, ac(npruo r m0f- ib09?

  The diagram shows two neurons of equal len2qo3 c-z;0q)at5c q*hbw/tko w x8yz zgth and diameter. Which neuron will transferc80* 3xh5 q;ko-2zqwtcobyz wtqa/z) an electrical impulse faster?

  Which triggers the release of neurotransmitters from the presynaptic membr/0rqehp+ z b.qane?

  Which mode of transport do neurotransmitters use to travel across a hm s pz*j)(l:.;k qxtrsynapse?

  Which statement explains why a nerve impuls9s 1vx wda- zlkwk-oy u0;w,a9e is electrical?

1.Explain why a resting poten,czhag p/y+*.nwd ,cr tial 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.