Topic 4.5: Gene Expression (HL) Questions

What kind of molecule is a transcription factor?

State the stage of gene expression at which transcription factors act to control whether a gene is expressed.

Define the term epigenetic change.

A change to a cell switches a gene off but leaves the DNA base sequence exactly as it was. What kind of change is this?

State what is meant by the term epigenetics.

State the two processes that, together, make up the expression of a gene.

Which change to a gene is normally reversible?

Expression of a gene is often measured from the amount of mRNA it produces. State the relationship between the amount of mRNA from a gene and how strongly that gene is expressed.

Which list contains only environmental factors known to alter epigenetic marks?

At which stage is gene expression mainly controlled in a eukaryotic cell?

State what is meant by an epigenetic mark.

What does it mean to say that a gene is 'expressed'?

Which statement best describes an epigenetic change?

Which change is an epigenetic change rather than a mutation?

Define the term transcription factor.

Two genes are present in a cell, but only gene X is being transcribed and translated. Which conclusion is justified?

The diagram shows the control of a gene. In the top panel a transcription factor is bound and RNA polymerase transcribes the gene; in the absence of the right factor the gene is not read. What does the top panel represent? [Diagram: bio-gene-regulation]

Outline how histone modification controls whether a gene is expressed.

Every cell in a multicellular organism is produced by mitosis from a single zygote, so all the cells contain identical DNA. Explain how cells with identical DNA can develop into different cell types with different structures and functions.

Compare the effect of a mutation and the effect of an epigenetic change on the protein that a gene codes for.