All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
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?
Mutation abolishing kinase activity of RAF
Mutation blocking EGF binding to EGFR
Mutation causing constitutively phosphorylated Erk
Mutation introducing hydrophillic domains in the hydrophobic region of EGFR
Mutation causing constitutively phosphorylated Erk
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?
Tumor necrosis factor
Erythropoietin
Transforming growth factor beta 1
Interleukin 2
Interferon type II
Erythropoietin
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?
Myostatin
Angiopoietin
Erythropoietin
Insulin-like growth factor
Fibroblast growth factor
Erythropoietin
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.
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