GRE Subject Test: Biology : Understanding Determination and Differentiation

Study concepts, example questions & explanations for GRE Subject Test: Biology

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Example Questions

Example Question #1 : Developmental Stages And Events

During embryogenesis, the process in which a committed cell develops distinctive functions and characteristics is known as __________.

Possible Answers:

differentiation

determination

specification

induction

Correct answer:

differentiation

Explanation:

Once a committed cell begins to develop specialized functions, it is known as differentiation. Before a cell differentiates, it makes a commitment to a certain cell type, first by specification, which is reversible, and then by determination, which is irreversible. Once a cell is committed to a cell type, it undergoes differentiation to develop specific cell characteristics.

Induction is a process in which cells induce adjacent cells to commit to a certain cell type. 

Example Question #1 : Understanding Determination And Differentiation

What gene expression regulatory proteins control cell type specific genes and define cell identities that are indispensible in differentiation and development?

Possible Answers:

Pioneering transcription factors 

Master transcription factors

Chromatin remodelers

All of these answers

Mediator

Correct answer:

Master transcription factors

Explanation:

The correct answer is master transcription factors. The type of master transcription factor expressed in a cell depends on the ultimate cell type it will become. Master transcription factors have higher affinity for cell identity genes. Each cell type has a different profile of master transcription factors that are reliably expressed. Mediator facilitates binding and recuitment of many transcription factors. Chromatin remodelers change the epigenetic state in a cell, and pioneering transcription factors are the first factors to bind DNA, even in heterochromatin regions. 

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