Exam 1: BIOS 251 BIOS251 Latest

Exam 1: BIOS 251 / BIOS251 (Latest

Update 2025 / 2026) Anatomy and Physiology I with Lab | Questions and Answers | 100% Correct | Grade A - Chamberlain

Question:

What are two signal transduction mechanisms

Answer:

intracellular receptor mediated responses

membrane-bound receptor mediated responses

some receptors are located inside the cell, others are membrane proteins

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Question:

actions of intracellular receptor-mediated messengers on target cell

Answer:

• messenger has to be able to diffuse into cell (i.e., lipid soluble)
• receptor can be in cytoplasm or in nucleus ---> alter protein synthesis

Question:

what are the 3 main membrane receptor mediated responses?

Answer:

channel-linked receptors enzyme-linked receptors G-protein-linked receptors 2 / 4

Question:

signal amplification via G protein

Answer:

many intracellular regulatory proteins from a few extracellular messengers

Question:

channel-linked receptors

Answer:

receptors that open/close ion channels in response to messenger binding = ligand (chemical) gated ion channels

Question:

ligand-gated channels

Answer:

• open or close in response to binding of ligand to receptor
• open channels correspond to increased permeability (allow diffusion of

ions)

• has two main categories

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Question:

what is a ligand

Answer:

messenger that binds to receptor/channel

Question:

what are the two main categories of ligand-gated channels

Answer:

fast and slow channels

Question:

fast channels

Answer:

receptor and channel are same protein

Question:

slow channels

Answer:

receptor coupled to channel by G protein

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