What happens if the threshold potential is not njqf; bl/q89v reached ?

  At what membrane potential do voltage-gated sh/ ztlzi64qs xpoy+q2 3uo/:sodium channels open?

  The diagram shows a neuron.4:4-g l btwr tuz9hseccx g mk7;b-:d;
Which arrow indicates a dendrite?

  How do neonicotinoid pexixhf- o7e1 n3rz na/2sticides work?

  The diagram shows an0a7n 9mqxak94 gpxda i33gq d3 action potential.

What is happening at point X?

  Which is the correct definition of s84dxwe5vo lv o o0mg 1r+(-rdcaltatory conduction?

Neuronal cells have special membrane prord+tr) je4wk*perties that allow their axons to propagate action potential from one cell to another. The diagram below stkj 4+*) rrdewhows 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 presynaptm.f4tt wq2 cg6ic membrane?
I. Depolarisation of the postsynaptic membrane
II. Depolarisation of the presynaptic membrane
III. The diffusion of calcium ions

  What are the main fa4*x7ch iges6sgr-g e2 ctors that maintain a neuron’s resting potential?

  What is not a function of the myelin sheath?

Explain how the resting potential is maintained6ek o-i)t)4ni6,wjh wj7yqkh in a neuron.

The diagram represents a synaptic cleft 1py x/i;;g-p )nlfmgv og( 2swbetween two neurons in an insect's nervous systegg)yf/1pon l(i;p ;g-vxs2 m wm.



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 structureal wni:4/s fxbfg09 vyq8eg (7 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 compounds that are widely usewow nh/9mitw)zq97 f1d as pesticides. However, there are concerns abouzwthqow 1/ ) mwin979ft 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 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 ac8fo3 l lj;w4/e t-dqvwtion potential. Which letter represents the sedle-w 8tlj f3/;4 voqwgment of the action 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 nn1c(fie y ,+ 0 rplhoii+rxqo y(/-r*von-myelinated neuron than in aqc/ r +l r,vny +ipx(ii0yo*f1e-(rho myelinated neuron?

  Which of the following is a/are correct k /j9f:pspm 4+n*ypin description(s) of the relative speed impulses arepps9yn/n+m: ijkf*4 p 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 membranvokt0n-xu w:r:kuco3k7t. /nes of neurons during a stage of the action potential. What procr.:ntckk7 nu oo/tv 0u-kxw3 :ess does the diagram depict?

  The image shows neurons that are found in dog brai ksbfnt4iq k; i0c:d/+ns. What does letter X indicat :qt+d0b4/ nfc;ikisk e?

  The diagram shows two neurons of equal length and diameter. Which neuron will2mx4+hg z, *rrkx ae+z transfer an electrical impuls,4*+rezh 2 ka+xgzrm xe faster?

  Which triggers the release of neurotransmitters from the preserwid el8,5h puo1 32uynaptic membrane?

  Which mode of transport do neurotransmitters use to travel acrh x3p/y.8jkd2djg*h j t- dwd9oss a synapse?

  Which statement explains why a nerve impulse is electricall0- sr8r ;advq?

1.Explain why a restinga2(b gyb)x-n s 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.