Cell Biology Quiz: Vesicles and Mitochondria

Questions and Answers

Which of the following structures is primarily involved in the formation of chemical energy?

Microtubules

Neurofibrils

Lysosome

Mitochondria (correct)

What is the primary function of neurofibrils in a neuron?

Storing neurotransmitters

Transporting nutrients

Determining the shape of the neuron (correct)

Generating electrical impulses

Which structure is responsible for cellular waste management within the cell?

Lysosome (correct)

Microfilaments

Axon hillock

Centrioles

What type of filaments form a dense network beneath the plasma membrane and play a role in cell transport?

Microfilaments Signup and view all the answers

In which part of the neuron is the axon hillock located?

Cell body Signup and view all the answers

Which component of the neuron is described as having a fan-shaped structure?

Axon hillock Signup and view all the answers

What is the role of centrioles in the cell?

Participate in cell division and maintain microtubules Signup and view all the answers

What diameter range do microtubules typically have?

25 nm Signup and view all the answers

Which of the following statements accurately describes lipofuscin?

It appears as yellowish brown granules scattered in the cytoplasm. Signup and view all the answers

What is the main characteristic of the plasma membrane in a neuron?

Fluid and not well-defined Signup and view all the answers

What type of transport is associated with kinesin in neurons?

Rapid transport Signup and view all the answers

What characterizes slow transport in neurons?

Includes bulk movement of cytoplasm Signup and view all the answers

Which motor protein is primarily responsible for bringing organelles back to the cell body?

Dynein Signup and view all the answers

What is the maximum speed associated with rapid transport in neurons?

400 mm per day Signup and view all the answers

Which process involves the bulk movement of organelles in neurons?

Slow transport Signup and view all the answers

In the context of neural transport, what controls the direction and speed of movement?

Activation of motor proteins Signup and view all the answers

What is the role of adenosine triphosphate (ATP) in rapid transport?

It supplies energy for motor proteins Signup and view all the answers

Which statement best describes the difference between rapid and slow transport?

Slow transport involves the bulk movement of cytoplasm, while rapid transport does not. Signup and view all the answers

What is the primary neurotransmitter used in all skeletal neuromuscular junctions?

Acetylcholine Signup and view all the answers

Which process occurs first during the action of neurotransmitters?

Release of neurotransmitters Signup and view all the answers

What determines the excitatory or inhibitory effects of neurotransmitters on the postsynaptic membrane?

The summation of postsynaptic responses at different synapses Signup and view all the answers

During synaptic transmission, what role do calcium ions play?

Trigger the fusion of synaptic vesicles Signup and view all the answers

Which of the following neurotransmitters is NOT classified as an inhibitory neurotransmitter?

Glutamic acid Signup and view all the answers

What is the primary role of sodium ions during nerve cell excitation?

They diffuse into the cytoplasm to initiate depolarization. Signup and view all the answers

Which statement accurately describes the action potential?

It is a self-propagating electrical signal along the neuron. Signup and view all the answers

What characterizes the refractory period in nerve cells?

It occurs immediately after an action potential and prevents further potentials. Signup and view all the answers

How is the strength of an initial stimulus related to the subsequent depolarization?

A stronger stimulus results in a larger initial depolarization. Signup and view all the answers

What is a consequence of summated excitatory stimuli in neuron activity?

They can lead to a greater depolarization if sufficiently strong. Signup and view all the answers

Which type of molecular motor is believed to be involved in slow axonal transport?

Kinesin family. Signup and view all the answers

What is the primary function of sodium and potassium channels in the membrane?

They regulate the entry of ions in response to stimuli. Signup and view all the answers

Which of the following correctly describes the conduction of an action potential?

It spreads away from the initiation site along the neuron. Signup and view all the answers

What is the function of retrogade transport in nerve cells?

Responds to changes at the distal end of the axons Signup and view all the answers

Which structure on the neuron is considered the site where impulses are generated?

Axon hillock Signup and view all the answers

Which type of synapse is characterized by communication between the axon of one neuron and the soma of another?

Axosomatic Signup and view all the answers

What characteristic distinguishes larger diameter axons from smaller diameter axons?

Larger diameter axons conduct impulses rapidly Signup and view all the answers

What forms the plasma membrane surrounding the axon?

Axolemma Signup and view all the answers

What is the primary component of the axoplasm?

Cytoplasm Signup and view all the answers

Which of the following describes the function of varicosities in axons?

Release neurotransmitters at the synapse Signup and view all the answers

What best describes the directionality of synaptic communication?

One-directional at chemical synapses Signup and view all the answers

Study Notes

Mitochondria: Spherical, double-membraned organelles with cristae vital for chemical energy production; scattered throughout the cell.
Neurofibrils: Linear fibrils (10 nm) made of microfilament bundles that give shape to neurons; run parallel from dendrites through the cell body to the axon.
Microfilaments: Thin filaments (3–5 nm) forming a dense cytoskeletal network beneath the plasma membrane; involved in cell retraction and transport.
Microtubules: Larger linear tubes (25 nm) that facilitate cell transport; extend from dendrites through the cell body to the axon.
Lysosomes: Small vesicles (8 nm) acting as cell scavengers, containing primary, secondary, and residual forms; involved in waste processing.
Centrioles: Paired hollow cylinders of microtubules, localized to the cell body cytoplasm; play a role in cell division and microtubule maintenance.
Lipofuscin: Yellowish-brown granules scattered in the cytoplasm; they represent metabolic by-products derived from lysosomal activity.
Melanin: Yellowish-brown granules found in the substantia nigra of the midbrain; associated with dopamine formation.
Plasma Membrane: Fluid-like membrane facilitating the initiation and conduction of nerve impulses; characterized by rapid and slow axonal transports.

Impulse Conduction and Action Potentials

Depolarization: Occurs when Na+ ions diffuse into the cell cytoplasm due to neuronal excitation.
Action Potential: A brief occurrence lasting about 5 msec; spreads along the plasma membrane as a self-propagated nerve impulse.
Refractory Period: Nonexcitable state where a new action potential cannot be generated; helps regulate impulse frequency.
Sodium and Potassium Channels: Integral proteins that participate in the depolarization process; essential for maintaining ionic balance during nerve impulses.

Axon Structure and Function

Axon: Longest process extending from the cell body; conducts nerve impulses away from the neuron.
Axon Hillock: Conical elevation where the action potential is initiated.
Axon Terminals: Distal ends of axon branches where communication occurs with other neurons.
Varicosities: Swellings of autonomic axons resembling beads; involved in neurotransmitter release.
Axolemma and Axoplasm: Plasma membrane and cytoplasm of the axon, respectively; axoplasm lacks Nissl granules and Golgi complex.
Initial Segment: Most excitable part of the axon critical for action potential generation.

Synaptic Transmission

Synapse: Junction where neurons communicate; can be synapses between axon and dendrite (axodendritic), axon and soma (axosomatic), or axon to axon (axoaxonic).
Chemical Synapses: Involve neurotransmitter release, which diffuses across the synaptic cleft and binds to postsynaptic receptors; includes neurotransmitters like acetylcholine, dopamine, serotonin, and GABA.

Mechanism of Neurotransmitter Action

Neurotransmitters are released upon nerve impulse arrival, leading to calcium influx, synaptic vesicle fusion, and release into the extracellular fluid.
The effect on the postsynaptic neuron varies based on overall summation of excitatory and inhibitory signals; depolarization can trigger action potentials and propagate nerve impulses.

Transport Mechanisms

Rapid Transport: Achievable speeds of 100 to 400 mm per day using motor proteins kinesin (anterograde) and dynein (retrograde).
Slow Transport: Slower movement (0.1 to 3.0 mm per day) involving cytoplasm transport, primarily anterograde, likely mediated by a kinesin family motor.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on cellular structures in this quiz focusing on vesicles and mitochondria. Explore their shapes, functions, and the roles they play in the cell. Perfect for students studying cell biology or related subjects.