GRE Subject Test: Biochemistry, Cell, and Molecular Biology : Help with Growth Factors

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

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Example Questions

Example Question #1 : Help With Growth Factors

Which of the following mutations in the EGF pathway could lead to increased proliferation of cells?

Possible Answers:

Mutation blocking EGF binding to EGFR

Mutation abolishing kinase activity of RAF

Mutation introducing hydrophillic domains in the hydrophobic region of EGFR 

Mutation causing constitutively phosphorylated Erk

Correct answer:

Mutation causing constitutively phosphorylated Erk

Explanation:

The phosphorylation of Erk is the final step of the protein cascade of EGF pathway, and phosphorylated Erk enters the nucleus to increase transcription of genes that induce proliferation. If Erk is constitutively active, it will likely lead to higher proliferation rate.

Preventing EGF from binding to EGFR or disrupting EGFR's ability to enter the membrane would abolish EGF pathway activity and reduce proliferation. Likewise, abolishing kinase activity of RAF would terminate the signal transduction and lead to reduced proliferation.

Example Question #2 : Help With Growth Factors

Production of which of the following cytokines is stimulated when the  concentration decreases in the circulatory system?

Possible Answers:

Interferon type II

Transforming growth factor beta 1

Tumor necrosis factor

Erythropoietin

Interleukin 2

Correct answer:

Erythropoietin

Explanation:

Erythropoietin, released by the kidney, stimulates the production of red blood cells, which becomes necessary if circulating  has decreased. Tumor necrosis factor stimulates systemic inflammation and regulates the immune system. Transforming growth factor beta 1 controls cell growth, proliferation, differentiation and other processes. Interferon type II modulates immune functions. Interleukin 2 also modulates the immune cells.

Example Question #3 : Help With Growth Factors

Which of the following growth factors is primarily produced by the kidney and is essential for the production of red blood cells?

Possible Answers:

Angiopoietin

Insulin-like growth factor

Erythropoietin

Myostatin

Fibroblast growth factor

Correct answer:

Erythropoietin

Explanation:

Erythropoietin is a glycoprotein that is crucial for the production of red blood cells, a process also called "erythropoiesis." Each of the other answers contains a growth factor, but none of these have a primary function in red blood cell production. 

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

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