Why Are High Levels of Radiation Fatal to Humans

question 37

Multiple Choice

Why are high levels of radiation fatal to humans?

• A) Radiation leads to permanent increases in the activity of DNA repair proteins.
• B) Radioactive atoms act as mutagens.
• C) Radiation increases the rate of DNA replication.
• D) Radiation inhibits cell division so that dead cells cannot be replaced.

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Definitions:

Presynaptic Terminal

The terminal segment of an axon responsible for discharging neurotransmitters into the synaptic gap, thereby facilitating communication with an adjacent neuron.

Postsynaptic Membrane

A specialized area of a cell membrane in a neuron, positioned after the synaptic gap, that receives signals from another neuron.

Acetylcholinesterase

An enzyme that breaks down acetylcholine, a neurotransmitter, in the synaptic cleft, effectively terminating the signal between nerve cells.

Synaptic Vesicles

Membrane-bound sacs in the presynaptic terminal of a neuron that store neurotransmitters which are released into the synaptic cleft during neurotransmission.