Neurochemistry Test – Questions and Answers | MCQ Quiz | OmpathStudy Kenya

Question 1

What neurotransmitter is associated with runner's high?

Accepted Answer

Endorphins — Endorphins are the body's natural opioids that create feelings of euphoria and pain relief. During intense exercise like running, the body releases endorphins, which bind to opioid receptors and produce the characteristic "runner's high" - a feeling of well-being and reduced pain perception. ---

Question 2

What neurotransmitter is associated with anxiety disorders?

Accepted Answer

GABA — GABA (Gamma-Aminobutyric Acid) is the primary inhibitory neurotransmitter in the brain. Low GABA activity is associated with increased anxiety, as GABA normally helps calm neural activity. Many anti-anxiety medications work by enhancing GABA function. ---

Question 3

Where do neurons store the genetic information they use to code and build all the proteins required for their functions?

Accepted Answer

In the nucleus — The nucleus contains the cell's DNA, which stores all genetic information. This DNA is transcribed into mRNA, which then travels to ribosomes for protein synthesis. The nucleus is the central control center for all cellular functions. ---

Question 4

Which of the following are major inhibitory neurotransmitters, causing inhibitory postsynaptic potentials (IPSPs)?

Accepted Answer

GABA and glycine — GABA is the major inhibitory neurotransmitter in the brain, while glycine is the major inhibitory neurotransmitter in the spinal cord. Both cause hyperpolarization of the postsynaptic membrane, making it less likely to fire an action potential. ---

Question 5

The effect of tetrodotoxin (puffer fish poison) on axons demonstrates

Accepted Answer

The role of sodium channels in depolarization — Tetrodotoxin specifically blocks voltage-gated sodium channels, preventing action potentials from occurring. This demonstrates that sodium influx through these channels is essential for depolarization and action potential generation. ---

Question 6

What neurotransmitter is associated with mood disorders?

Accepted Answer

Serotonin — Serotonin is strongly associated with mood regulation. Low serotonin levels are linked to depression, anxiety, and other mood disorders. SSRIs (Selective Serotonin Reuptake Inhibitors) are commonly prescribed antidepressants that increase serotonin availability. ---

Question 7

Which of the following is not true?

Accepted Answer

Neuron membranes have sodium/potassium ion pumps that take out potassium ions — This statement is incorrect. The sodium-potassium pump actually pumps potassium ions INTO the cell and sodium ions OUT of the cell (3 Na+ out, 2 K+ in). This maintains the concentration gradients necessary for the resting potential. ---

Question 8

What neurotransmitter is associated with insomnia?

Accepted Answer

Serotonin — Serotonin plays a crucial role in sleep regulation. It's a precursor to melatonin and helps regulate sleep-wake cycles. Imbalances in serotonin can lead to sleep disorders including insomnia. ---

Question 9

What neurotransmitter is associated with seizures?

Accepted Answer

Glutamate — Glutamate is the primary excitatory neurotransmitter in the brain. Excessive glutamate activity or insufficient GABA inhibition can lead to seizures, as the brain becomes hyperexcitable with uncontrolled neuronal firing. ---

Question 10

What is one of the functions of Dopamine?

Accepted Answer

Pleasure — Dopamine is central to the brain's reward system and pleasure pathways. It's released in response to rewarding experiences and motivates behavior toward pleasurable activities. This is why dopamine is often called the "feel-good" neurotransmitter. ---

Question 11

What is one of the functions of Endorphins?

Accepted Answer

Pleasure — Endorphins are the body's natural opioids that produce feelings of pleasure and well-being. They're released during exercise, stress, pain, and other activities, binding to opioid receptors to create euphoric feelings and reduce pain perception. ---

Question 12

What neurotransmitter is associated with Parkinson's disease?

Accepted Answer

Dopamine — Parkinson's disease is characterized by the death of dopamine-producing neurons in the substantia nigra. This leads to decreased dopamine levels, causing the characteristic motor symptoms like tremors, rigidity, and bradykinesia (slowness of movement). ---

Question 13

What neurotransmitter is associated with Alzheimer's disease?

Accepted Answer

Acetylcholine — Alzheimer's disease involves significant loss of acetylcholine-producing neurons, particularly affecting memory and cognitive function. Cholinesterase inhibitors, which increase acetylcholine availability, are used as treatments for Alzheimer's. ---

Question 14

Which of the following best discriminates between small-molecule neurotransmitters and peptide neurotransmitters?

Accepted Answer

Peptide neurotransmitter precursors and their enzymes are axonally transported in vesicles — Peptide neurotransmitters are synthesized in the cell body and transported down the axon in vesicles, while small-molecule neurotransmitters are typically synthesized locally at nerve terminals. This is a key distinguishing feature between these two types of neurotransmitters. ---

Question 15

Which neurotransmitter is released by the postganglionic neurons of the sympathetic nervous system?

Accepted Answer

Norepinephrine — Most postganglionic sympathetic neurons release norepinephrine (noradrenaline) as their neurotransmitter. This activates adrenergic receptors on target organs, producing the "fight or flight" response characteristic of sympathetic activation. ---

Question 16

Enkephalins are peptide neurotransmitters that function in the perception of pain. This is because

Accepted Answer

They interact with specific opioid receptor proteins to produce their effects — Enkephalins are endogenous opioid peptides that bind to opioid receptors (mu, delta, and kappa) to reduce pain perception. They work similarly to morphine and other opioid drugs by activating these same receptor systems. ---

Question 17

What determines the effect of neurotransmitter release on the post-synaptic neurons?

Accepted Answer

The postsynaptic receptors — The type of postsynaptic receptors determines whether the effect will be excitatory or inhibitory, and the magnitude of the response. The same neurotransmitter can have different effects depending on which receptors are present on the postsynaptic cell. ---

Question 18

A neuron cannot produce an action potential

Accepted Answer

Both b and d — During the absolute refractory period, sodium channels are inactivated and cannot be reopened regardless of stimulus strength. This ensures unidirectional propagation of action potentials and limits firing frequency. ---

Question 19

What would happen to the resting membrane potential of a neuron if sodium (Na+) channels were normally open in the membrane, but everything else was the same?

Accepted Answer

It would definitely be less negative than the normal resting potential — If sodium channels were normally open, sodium would continuously flow into the cell down its concentration gradient, making the inside less negative (more positive) than the normal resting potential of -65 mV. ---

Question 20

Conduction of action potentials is faster in myelinated axons. This happens mainly because these axons

Accepted Answer

Make use of faster internodal passive electrical conduction — Myelination allows for saltatory conduction, where the action potential "jumps" from node to node via fast passive electrical conduction through the myelinated segments, rather than having to actively propagate along the entire axon length. ---

Question 21

Synaptic autoreceptors normally

Accepted Answer

Reduce neurotransmitter release at a synapse — Autoreceptors provide negative feedback control. When activated by the neurotransmitter they respond to, they reduce further neurotransmitter release, serving as a self-regulating mechanism to prevent excessive synaptic activity. ---

Question 22

The process whereby the content of synaptic vesicles is released into the synaptic cleft/gap is called

Accepted Answer

Exocytosis — Exocytosis is the process by which synaptic vesicles fuse with the presynaptic membrane and release their neurotransmitter contents into the synaptic cleft. This is triggered by calcium influx following action potential arrival. ---

Question 23

Which channel membrane protein is specifically important in the process of neurotransmitter release?

Accepted Answer

Voltage-Dependent (gate — Voltage-gated calcium channels open when the action potential reaches the presynaptic terminal. The influx of calcium ions triggers the fusion of synaptic vesicles with the membrane, leading to neurotransmitter release via exocytosis. ---

Question 24

Small transmitter molecules are

Accepted Answer

Packaged in small synaptic vesicles — Small molecule neurotransmitters (like acetylcholine, dopamine, serotonin) are stored in small, clear synaptic vesicles, typically synthesized locally at nerve terminals, unlike peptide neurotransmitters which are made in the cell body. ---

Question 25

Which one of the following is not a criterion for small neurotransmitter (NT) status?

Accepted Answer

Packaged in large synaptic vesicles — Small molecule neurotransmitters are packaged in small synaptic vesicles, not large ones. Large dense-core vesicles are typically used for peptide neurotransmitters and neuromodulators. ---

Question 26

Serotonin-specific reuptake inhibitors (SSRIs) are widely prescribed to treat clinical depression. Which of the following procedures do you think would most likely worsen symptoms in untreated depressed patients?

Accepted Answer

Decrease the concentration of serotonin in the brain — Since depression is associated with low serotonin levels and SSRIs work by increasing serotonin availability, decreasing serotonin concentration would worsen depressive symptoms. SSRIs prevent serotonin reuptake, keeping more serotonin available in synapses.

Neurochemistry Test – Questions and Answers | MCQ Quiz | OmpathStudy Kenya

Questions, Answers & Explanations