AP BIOLOGY AA 1 NEURON STRUCTURE | NERVOUS STATION WORKSHEET

AP BIOLOGY AA 1 NEURON STRUCTURE | NERVOUS STATION WORKSHEET Station Response Sheet Name: ________ Model 1: 1. Model 1 is an illustration of two neurons. Label one of the neurons in the diagram with the following structures: Cell body or soma Axon Cell nucleus Synapse Dendrites → 2. Which structure(s) on the neuron in Model 1 would receive a signal from either a sensory cell (taste bud, touch receptor, retinal cell) or from another neuron? a. Dendrites would receive a signal from either a sensory cell or from another neuron. 3. Draw an arrow through the two cells in Model 1 to show the path of a nerve impulse if a message was being sent through the two neurons. Dendrites cell nucleus cell body/soma synapse axon Model 2: 1. Describe the cellular structure shown in detail in Model 2. a. The sodium-potassium pump moves the sodium and potassium ions across the cell membrane so that it can provide energy for the signal in the neuron. The sodium and potassium ions are balanced and it allows for action potential to be produced by nerve cells. 2. Identify each of these symbols in Model 2. phospholipid +¿ NA ¿ +¿ K ¿ sodiumpotassium pumps 3. Consider Model 2. a. Which side of the membrane has more sodium ions when the neuron is at rest? i. outside of cell b. Briefly explain why sodium ions cannot cross the membrane without the use of a protein channel. i. Sodium ions cannot cross the membrane without the use of a protein channel because the sodium ions themselves can’t diffuse through the membrane since it’s electrically charged. c. Which direction should sodium ions flow naturally if a channel is provided? i. They would go into the cell 4. Consider Model 2. a. Which side of the membrane has more potassium ions when the neuron is at rest? i. Inside of the cell. b. Which direction should potassium ions flow naturally if a channel is provided? i. outside of the cell. 5. The embedded proteins in Model 2 illustrate both active and passive transport. What evidence from Model 2 supports the idea that one of the types of embedded proteins use active transport? a. Since sodium ions can’t pass through the membrane an active transport is needed so that the sodium ions can pass through the membrane without any trouble. 6. Does the sodium/potassium ion pump move sodium ions into or out of the cell when activated? a. When it’s activated the sodium/potassium ion pump moves the sodium ions into the cell. 7. Does the sodium/potassium ion pump move potassium ions into or out of the cell when activated? a. The sodium/potassium ion pump moves potassium ions outside of the cell when activated. 8. What is the ratio of sodium ions to potassium ions that are moved through the sodium/ potassium ion pump each cycle? a. 3 sodium ions are pumped out of the cell for every 2 potassium ions. 9. If the sodium/potassium ion pump were to stop functioning, what would eventually happen to the concentration gradients of sodium and potassium ions across the membrane? Justify your answer with evidence from Model 2. a. If the sodium/potassium ion pump were to stop functioning there would be too much potassium ions on the inside and too much sodium ions on the outside of the cell. 10. The diagram in Model 2 shows a voltage or potential across the membrane. a. What is the resting membrane potential of a neuron? (Be sure to include units.) i. -70mV b. Propose an explanation for why there is an uneven distribution of charge across the membrane, resulting in a potential. i. There is an uneven distribution of charge across the membrane because the sodium/potassium pumps out 3 sodium ions out of cell for every 2 potassium ions resulting in an unequal distribution of ions across