Epigenetics

Question 1

What does methylation do?

Answer 1

Prevents transcription with the use of methyl groups attached to CpG site,DNA tightly packed

Question 2

What does acetylation do?

Answer 2

Increases transcription with the use of acetyl groups attaching to histones, DNA becomes more loose around the histone

Question 3

Meaning of polygenic

Answer 3

Characteristic determined by many genes at different loci
Characteristic showing continuous variation

Question 4

How epigenetic changes affect development of tissue in the embryo
(3 marks)

Answer 4

-DNA is wrapped around histones
-Acetylation, modification of histone affects binding of RNA polymerase.
-Methylation of DNA affects transcription of genes so gene expression altered.
-Different proteins synthesised

Question 5

Describe how cells become specialised
(3 marks)

Answer 5

-Chemical signals cause some genes to be activated
-Only activated genes are transcribed
-Proteins synthesised based on genes expressed, proteins determine structure of the cell

Question 6

What is a stem cell?

Answer 6

Cell that is undifferentiated
That can give rise to specialised cells

Question 7

What is totipotent?

Answer 7

Cell that can differentiate into all types of cells