What happens if the threshold potential is not reached ?zlj1f/y 4w*x8q 3l az2ckt.nf

  At what membrane potential do voltage-gated sodium channe4- *n d7. zmodvlh9o/d9nnp/u3dwh +v .beqak ls open?

  The diagram shows a neurok vw+3.qhhwm/ ,1 rmgfn.
Which arrow indicates a dendrite?

  How do neonicotinoid pest5zbk 10 vh gs(h diu2(ikd5cb;icides work?

  The diagram shows an actio/ vrg-k4w4b+whp75g gfn dh5on potential.

What is happening at point X?

  Which is the correct defix tmns.j t*k(j)pn)9ynition of saltatory conduction?

Neuronal cells have special membranqxxe u,a4 0bs,e properties that allow their axons to propagate action potential from one x usx 0q,4,abecell 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 exocytosixq+ (fmk f 4cpu ld14hohlgok304s1+fs of neurotransmitters 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 restink wxove4-*t k *t)+5urgey9mqg potential?

  What is not a function of the myelin sheath?

Explain how the resting potential is maintained in a neurf aqvyn154/u yon.

The diagram represents a synaptic cleft between two neurons in an insect8 ec n:jg avj:2h09fhl)r )ycq's nervous system)c j:er hhlna80qg):29cv jyf.



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 7 dxll:6 bv(01eaewmfa 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 u71bld k(nwvxc (n*-n6dflnoc(m t9t5sed 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) we5(9l ktnbv 6n ntc(1folxd 7d nwm(c*-re 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 membranegkgyox)y e u1v3z 07x0 0vg2zo voltage over time during an action potential. Which letter represents the segment of the action potential when voltage-gated sodium channe gy73zzgxo0 0eoux0k 1 2vy)gvls are open and voltage-gated potassium channels are closed?

  Which two features are more abundant per unit length in a non-myelinate(l40)*syd4cguzz h swd neuron than )* 4lsuhygcd4 sz (wz0in a myelinated neuron?

  Which of the following is a/are correct y:s71k( l3vtvs;;xm6vq nee wdescription(s) of the relative speed impulses are conducted nyt : evs x6(;1m7vkwl esv3;qat?
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 prou/tqcih74 nul0i /jd .txh1*l cess that occurs in the membranes of neurons during a sta1*t/j h.4lild07qu /tcui hxnge of the action potential. What process does the diagram depict?

  The image shows neurons thatpvfniwz y:u );9u2g+ t are found in dog brains. What does letter X indicate?zy;u n9p2ft):+gv u wi

  The diagram shows two neurons of equal length and diameter. Which neuron will tq n 97xw7s*9ey wnx3alransfer an electrical impu qews x9*lwa n9x737nylse faster?

  Which triggers the release of neurotransmitters from tn/hmt :c6jw b,he presynaptic membrane?

  Which mode of transport do neurotransmitters ul, sg c9go1fz j4/;ykfse to travel across a synapse?

  Which statement explains why a nerve i hi g-5hno- i7ti; j:xfo2sxv1mpulse is electrical?

1.Explain why a resting poq w5if)e2 s-oatential 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.