GRE Subject Test: Biochemistry, Cell, and Molecular Biology : Help with Receptors and Channels

Study concepts, example questions & explanations for GRE Subject Test: Biochemistry, Cell, and Molecular Biology

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All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources

1 Diagnostic Test 201 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #1 : Help With Receptors And Channels

Toll-like receptors (TLRs) are transmembrane receptors that have an extracellular leucine-rich region and an intracellular toll-interleukin region domain. What is the primary function of TLRs? 

Possible Answers:

Promote differentiation by recognizing notch ligands

Promote cell-cell adhesion 

Elicit innate immune responses by recognizing microbial associated molecular patterns

Bind epidermal growth factor to promote cell proliferation

Promote sex-specific organ growth by binding estrogen or testosterone 

Correct answer:

Elicit innate immune responses by recognizing microbial associated molecular patterns

Explanation:

The correct answer is elicit innate immune responses by recognizing microbial associated molecular patterns. TLRs are pattern recognition transmembrane receptors that recognize bacterial components, such as lipopolysaccharides and flagellin, and viral components such as single stranded DNA. Upon recognition by the leucine rich region, TLRs dimerize to facilitate signal transduction (via the toll-interleukin region domain) to downstream pathways to promote inflammation and recruitment of macrophages. 

Example Question #2 : Help With Receptors And Channels

Which of the following is not true concerning G protein-coupled receptors (GPCRs)?

Possible Answers:

They can recognize peptide hormones as their ligand.

All GPCRs will increase cAMP levels in the cell.

They are found on the outside of cell membranes.

They use GTP as energy when activated.

Correct answer:

All GPCRs will increase cAMP levels in the cell.

Explanation:

G protein coupled receptors are by far the largest class of cell surface receptors. They can respond to a large variety of extracellular signaling molecules, and can elicit a great deal of responses inside cells. With such diversity, it should come as no surprise that not all GPCRs will increase cAMP levels in the cell. In fact, many can display an inhibitory role, and decrease cAMP levels by preventing its production.

Example Question #3 : Help With Receptors And Channels

The sodium-potassium pump works by bringing sodium __________ cells and potassium __________ cells through the use of ATP.

Possible Answers:

out of . . . into

into . . . into 

None of these

into . . . out of

out of . . . out of

Correct answer:

out of . . . into

Explanation:

The sodium-potassium pump is a type of active transport that brings sodium out of the cell and potassium into the cell. This is in the opposite direction of their natural gradient. The fact that it is going in the opposite direction requires this pump to need energy, or, ATP.

All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources

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