Transcription factoprs

Question 1

What is it and what is needed for transcription

Answer 1

-Will only occur when a molecule from the cytoplasm enters the nucleus and binds to DNA in the nucleus
-They are proteins and each can bind to different base sequences
-Once bound transcription begins where mRNA is created to then be translated in the cytoplasm

Question 2

Example of a transcription factor

Answer 2

-Oestrogen , diffuses through cell membrane as a lipid and has a complementary shape to receptor so binds and causes it to change shape slightly which makes it complementary to DNA to initiate transcription

Question 3

Epigenetics

Answer 3

-heritable change in gene function without change in DNA base sequence which may be caused by environmental change which inhibits transcripiton

Question 4

Methylation of DNA

Answer 4

-Inhibits transcription as methyl group binds to cytosine preventing transcription factor binding

Question 5

Acetylation of histone proteins

Answer 5

-Decreased acetylation inhibits transcription
as acetyl removed makes histones more positive so more attracted to phosphate group

Question 6

RNAi interference

Answer 6

-Destroys MRNA molecule before transcription
DOne by
-one strand of sirna combining with another enzyme
-this complex binds to complementary base
-once bound enzyme cuts mrna so cannot be translated