All GRE Subject Test: Biology Resources
Example Questions
Example Question #91 : Animal Biology
During embryogenesis, the process in which a committed cell develops distinctive functions and characteristics is known as __________.
determination
differentiation
specification
induction
differentiation
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?
All of these answers
Pioneering transcription factors
Mediator
Chromatin remodelers
Master transcription factors
Master transcription factors
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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