Question 1

What is the basic structure of a neuron in the context of IB DP Biology?

Accepted Answer

In IB DP Biology, a neuron is described as a specialized cell that transmits nerve impulses. It consists of three main parts: the cell body (soma), dendrites, and an axon. The cell body contains the nucleus and is responsible for maintaining the cell's health. Dendrites are branched extensions that receive signals from other neurons, while the axon is a long projection that transmits signals to other neurons or muscles. The axon is often covered by a myelin sheath, which speeds up signal transmission.

Question 2

How do synapses facilitate communication between neurons?

Accepted Answer

Synapses are crucial for neuron-to-neuron communication. They are junctions where the axon terminal of one neuron meets the dendrite of another. When an electrical impulse reaches the axon terminal, it triggers the release of neurotransmitters into the synaptic cleft. These chemical messengers cross the cleft and bind to receptors on the receiving neuron's dendrite, initiating a new electrical impulse. This process allows for the transmission of information throughout the nervous system.

Question 3

What role do neurotransmitters play in synaptic transmission?

Accepted Answer

Neurotransmitters are chemical substances that play a key role in synaptic transmission. They are released from the presynaptic neuron into the synaptic cleft in response to an electrical impulse. Once released, they bind to specific receptors on the postsynaptic neuron, causing ion channels to open and generate a new electrical signal. This process is essential for the propagation of nerve impulses and communication within the nervous system. Common neurotransmitters include dopamine, serotonin, and acetylcholine.

Question 4

Why is the myelin sheath important for neuron function?

Accepted Answer

The myelin sheath is a fatty layer that surrounds the axons of many neurons. It is crucial for efficient neuron function because it acts as an insulator, allowing electrical impulses to travel more quickly along the axon. This rapid transmission is achieved through a process called saltatory conduction, where the impulse jumps between gaps in the myelin sheath known as nodes of Ranvier. This increases the speed and efficiency of neural communication, which is vital for proper functioning of the nervous system.

Question 5

How does the structure of a synapse ensure directional communication in neurons?

Accepted Answer

The structure of a synapse ensures directional communication by allowing signals to pass in one direction only—from the presynaptic neuron to the postsynaptic neuron. This is achieved through the release of neurotransmitters from the axon terminal of the presynaptic neuron into the synaptic cleft. These neurotransmitters then bind to receptors on the postsynaptic neuron, initiating a response. The unidirectional flow of information is crucial for maintaining organized and efficient communication within the nervous system.

Neurons and Synapses

Summary and Exam Tips for Neurons and Synapses

Exam Tips