AP Biology : Understanding Neural Cells

Study concepts, example questions & explanations for AP Biology

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Example Questions

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Example Question #621 : Ap Biology

What are diseases associated with demyelination?

Possible Answers:

Neurodegenerative diseases

Epilepsy

Anemia

HIV

Correct answer:

Neurodegenerative diseases

Explanation:

Demyelination of axons is associated with neurodegenerative diseases. The loss of myelination negatively impacts the ability of neurons to transmit signals throughout the body. Examples of demyelination diseases are multiple sclerosis and Guillain–Barre syndrome. HIV is a viral infection that attacks the immune system. Anemia is a blood disorder in which there are not enough functioning red blood cells to provide the body tissues with sufficient oxygen. Epilepsy is a disease that involves frequent seizures.

Example Question #622 : Ap Biology

What is true about saltatory conduction?

Possible Answers:

The signal is passed from one node of Ranvier to another

All of these

It is the method of action potential transmission in myelinated axons

It increases the rate of signal transmission 

Correct answer:

All of these

Explanation:

Saltatory conduction is a type of signal transmission in myelinated axons. Here, the action potential (wave of sodium ions) passes from one node of Ranvier to another, which increases the rate of transmission.

Example Question #623 : Ap Biology

What statement best defines the membrane potential?

Possible Answers:

The difference in electrical charge across a membrane is determined only by sodium ion concentration

The membrane potential in a cell never changes

Difference in electrical charge between the interior and exterior of the cell 

It is the electrical charge reached by action potential

Correct answer:

Difference in electrical charge between the interior and exterior of the cell 

Explanation:

Membrane potential is a term used to describe the difference in electrical charge across a cell membrane. This difference is determined by ion concentration inside and outside of the cell and can change due to ion-gated channels and ion pumps, among others. Membrane potential allows cells to transmit electrical signals. During an action potential, the membrane is said to be depolarized, which means the membrane potential becomes less negative.

Example Question #624 : Ap Biology

What is the resting potential of a cell?

Possible Answers:

The static membrane potential of a cell

The maximum difference in electrical charge across a membrane

Rapid rise and fall of membrane potential

Correct answer:

The static membrane potential of a cell

Explanation:

The resting potential of a cell is the relatively static membrane potential that serves as the baseline voltage of a cell, which is about  in neurons. The resting potential stands in opposition to the action potential.

Example Question #625 : Ap Biology

What does the threshold potential precede?

Possible Answers:

Action potential

Voltage

Membrane potential

Resting potential

Correct answer:

Action potential

Explanation:

The threshold potential of a cell is a specific membrane potential that is needed in order to initiate action potential. Therefore, threshold potential precedes action potential. Note that reaching the threshold potential triggers a positive feedback loop, causing more sodium to rush into the cell, further depolarizing the membrane potential.

Example Question #626 : Ap Biology

The axon hillock connects what two areas of a neuron?

Possible Answers:

Dendrite and synapse

Axon and soma

Axon and dendrite

Soma and dendrite

Correct answer:

Axon and soma

Explanation:

The axon hillock is the area of a neuron that connects the soma and axon. This is also the area of the of the neuron that "decides" whether an action potential would be initiated or not, depending on whether the cell has reached threshold or not.  

Example Question #121 : Types Of Cells And Tissues

What does not occur in the presynaptic terminal?

Possible Answers:

Recycling of unused neurotransmitters

Binding of neurotransmitters to receptors 

Exocytosis of neurotransmitters

Calcium influx

Correct answer:

Binding of neurotransmitters to receptors 

Explanation:

In the presynaptic terminal, the action potential causes an influx of calcium. Rising calcium levels stimulates exocytosis of neurotransmitters, which bind to post-synaptic receptors. Unused neurotransmitters are recycled by the pre-synaptic cell or degraded in the synaptic cleft.

Example Question #122 : Types Of Cells And Tissues

How is an electrical signal transmitted from a presynaptic terminal to a postsynaptic terminal?

Possible Answers:

Neither endocytosis of neurotransmitters by the postsynaptic terminal nor binding of neurotransmitters to receptors on the postsynaptic terminal

Endocytosis of neurotransmitters by the postsynaptic terminal

Binding of neurotransmitters to receptors on the postsynaptic terminal

Both endocytosis of neurotransmitters by the postsynaptic terminal and binding of neurotransmitters to receptors on the postsynaptic terminal

Correct answer:

Binding of neurotransmitters to receptors on the postsynaptic terminal

Explanation:

Signal transmission from presynaptic terminal to postsynaptic terminal occurs when neurotransmitters bind to receptors on the postsynaptic terminal. Once the neurotransmitter binds to the receptors on the postsynaptic neuron's cell membrane, the postsynaptic cell can be induced (excited) to fire another action potential, or inhibited based on the type of neurotransmitter and/or receptor that is bound.

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