Epigenetics

Question 1

Define Cellular Differentiation

Answer 1

Different cell types have distinct structure and function. Cells are controlled via gene expression – which genes are transcribed determines which proteins are translated, and therefore the function of the cell.

Question 2

Define Epigenetics

Answer 2

Epigenetics is a change in gene expression without changing the DNA code

Question 3

Types of epigenetic changes

Answer 3

transcription factors, histone modification, methylation, environmental factors

Question 4

Define and describe transcription factors

Answer 4

Specific proteins prevent the transcription of certain genes. Specific proteins promote transcription of certain genes.

Question 5

Define and describe histone modification

Answer 5

Eukaryotic DNA is wrapped around proteins called histones.
If the DNA is wrapped tightly around these histones the gene can’t be transcribed.
If the DNA is wrapped loosely around
these histones the gene can be
transcribed

Question 6

Define and describe methylation

Answer 6

The addition of methyl groups
to cytosine bases on DNA
prevents transcription
Many methyl groups reduces
ability for RNA polymerase to
bind, therefore less
transcription, leading to
decreased gene expression.
Less methyl groups means RNA
polymerase can bind, therefore
normal transcription, leading to
increased gene expression.

Question 7

define and describe environmental factors

Answer 7

The health of an organism, and exposure to chemicals, can change gene expression.

Question 8

Why do clones and environmental twins look different over time?

Answer 8

Identical twins will have
identical DNA codes, but
different epigenetic changes!
Each has been exposed to
different conditions, eaten
different foods, smoked/vaped
more or less (or even the same,
but had more changes due to
chance).
Even clones will exhibit
epigenetic differences.