6.5 Neurons and synapes

1.Which structure in the motor neuron is required for saltatory conduction? [Source: https://commons.wikimedia.org/wiki/File:Anatomy_and_physiology_of_animals_Motor_neuron.jpg]

2. What happens when an action potential reaches motor end plates?

3. Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is based on DNA sequences and the cladogram on the right is based on comparing protein sequences. What is the reason that cladograms based on DNA sequences are more reliable predictors of the phylogenetic relationship of species than cladograms based on protein sequences?

4. The diagram below shows part of the membrane of a neuron. What stage of the action potential does it depict?

5. Neurotransmitters are released into the synaptic cleft from the presynaptic neuron and travel to a receptor on the postsynaptic neuron membrane. Which processes are required for this to happen?

6. The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system. The graph shows the percentage of samples in which this bacterium showed resistance to six antibiotics over a period of ten years. What is a possible explanation for the total percentage resistance being larger than 100% in 2010?

7. If schizophrenia is caused by an overabundance of the neurotransmitters dopamine and serotonin in the synapses of some areas of the brain, which drug action could work in treating the symptoms?  

8. What is essential for conduction of nerve impulses to be saltatory?  

9. If schizophrenia is caused by an overabundance of the neurotransmitters dopamine and serotonin in the synapses of some areas of the brain, which drug action could work in treating the symptoms?

10. The decline in European honeybee (Apis mellifera) populations may be linked to neonicotinoid pesticides. What effect do these pesticides have on the nervous system of insects?  

11. What is the mechanism of sodium-potassium pumps in neurons that generates a resting potential by active transport?

12. What happens first when a neurotransmitter binds to a postsynaptic neuron?

13. What characterizes type I diabetes?

14. What is a feature of neurons?

15. What happens during synaptic transmission?

16. The diagram below shows the changes in membrane potential during an action potential. What best describes events indicated by the label X?  

17. The diagram below shows a motor neuron. What are the structures indicated by X, Y and Z?

18. The diagram below shows the changes in membrane potential during an action potential. What best describes events indicated by the label X?

19. Immediately after an action potential, which event causes the neuron membrane to repolarize?

20. What initiates an action potential along a neuron?

21. Which element or ion is required for transmission of a nerve impulse?

22. The diagram shows events at a synapse.   What is happening at the point labelled X?

23. What is a characteristic of axons in motor neurons?

24. Which response takes place when blood glucose levels are low?

25. During the menstrual cycle, what occurs in response to a fall in the progesterone level?

26. Between which structures do sensory neurons carry nerve impulses?  

27. Which term describes the phase of rapid entry of sodium ions (Na+) into an axon during an action potential?  

28. Between which structures do sensory neurons carry nerve impulses?

29. A process occurs in which the inside of a neuron develops a net positive charge compared with the outside. What is the name of this process?

30. In the diagram of synaptic transmission below, what is indicated by the letters X and Y?

31. The diagram below shows the changes in membrane potential during an action potential. What occurs at the stages labelled 1 and 2?

32. The graph below shows changes in membrane potential in an axon during the passage of an action potential. What is causing the decrease in membrane potential at point X?