What happens if the threshold poten rfde8p1wq5 i/tial is not reached ?

  At what membrane potentiakjnpfa+-ji9ed) r7 o:l do voltage-gated sodium channels open?

  The diagram shows a 4o/ zz6yh5 aftneuron.
Which arrow indicates a dendrite?

  How do neonicotinoid pesticides+3tf*x- gawbte 9*v gu work?

  The diagram shows an action potentialgxbn xj-u/ *f jy.-8ff.

What is happening at point X?

  Which is the correct definition of saltatory copi6s t1m2 ldfzv/5 d(vtjf/t 2nduction?

Neuronal cells have special membrane pro6xr p6v227xfx 8gjzau perties that allow their axons to propagate action potential from one cell tv f za78xxjp622grux 6o 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 the presynaptic membwq(hwd a*ol 4o ),yw ycfuq0 ,4ddf2(wy t5f6mrane?
I. Depolarisation of the postsynaptic membrane
II. Depolarisation of the presynaptic membrane
III. The diffusion of calcium ions

  What are the main factors )g *h pvttc*ihk-v4k.that maintain a neuron’s resting potential?

  What is not a function of the myelin sheath?

Explain how the resting potential km(,lftoh-1jicno/-p,bxj qd5 5 sk:is maintained in a neuron.

The diagram represents a synaptic cleft between two neurons in an i 178hllbz6ok9qj v z8xnsect's nervous s kjlx l9hz8b1v7z 6qo8ystem.



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 typigx6xi:pm/7 s ecal 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 compouzq7th /2ff ll(4o4ydn nds 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 nqf4dt2 f/l4hl7 yzo( 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 f2 abf08 8g ifpco(q*wkjl+h/ pc25c uvoltage over time during an action potential. Which letter represents the segment of the action potentialo5 p2wfg(*8+8p fj 0ah 2lq fbcci/uck when voltage-gated sodium channels are open and voltage-gated potassium channels are closed?

  Which two features are more abundant per unit lemb*x*, e3 yeyhv0+o7aaa y,cmngth in a non-myelinated neuron than in a myelinated neur,a0+mevyb7*cmahy y* 3eoa x ,on?

  Which of the followin9/i grl .q;jfvhse*; pg is a/are correct description(s) of the relative speed impl /.eqv ;f*p;9jgis hrulses are 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 neurons duri( daztl. hx:5yng a stage of the action pote(:lhx dz .ya5tntial. What process does the diagram depict?

  The image shows neurons that are prond-+kl0 .ffound in dog brains. What does letter X indicat0 -+kl dopr.fne?

  The diagram shows two neurons of equal length and diameter. Which neuron ;1nx-mpi (8ppe urg k5will transfeiexuk-1;g58ppp(m n r r an electrical impulse faster?

  Which triggers the releasiiko4lt 5 cicc 8ez;b:m9j -d+e of neurotransmitters from the presynaptic membrane?

  Which mode of transport do neurotransmitters use to s1u qnsyx73 7-p86 k zikudfw+travel across a synapse?

  Which statement explains why a nerve impulse is electf1u39a.xkpod552v ha ts1 c7h g6qed frical?

1.Explain why a resting potential is negatp ohm 9k0ri:*zive.
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.