3.8.2.2 Regulation of transcription and translation (Unit 8 Gene Expression) Flashcards
Molecules which regulate the expression of genes are called..
transcription factors
Where do transcription factors bind to regulate gene expression?
(upstream of the gene) Promoter region
What do transcription factors do to regulate gene expression?
encourage binding of RNA polymerase (turn on genes) or prevent RNA polymerase binding (turn off genes)
When a cell receives a signal to express a gene what does the transcription factor do?
moves from the cytoplasm to the nucleus
Can specialised cells change into other cell types?
Housekeeping genes e.g. genes involved in respiration
Name a hormone that can regulate transcription
oestrogen
What type of hormone is oestrogen?
steroid hormone
How can oestrogen enter the cell?
lipid soluble and diffused through the phospholipid bilayer
Transcription is when
DNA is copied into mRNA
Translation is when
mRNA is translated into a sequence of amino acids
What does oestrogen bind to to regulate transcription?
Complementary receptor site on the transcription factor
When oestrogen binds to the receptor on the transcription factor what happens?
The DNA binding site changes shape on the transcription factor is now able to bind to DNA (transcription activated)
Why is oestrogen able to bind the receptor on transcrption factor?
oestrogen has a complementary shape the the receptor
What property of oestrogen allows it to diffuse through the phospholipid bilayer?
lipid soluble
Who proposed the structure of DNA?
Watson and Crick
What is meant by epigenetics?
heritable changes in gene function without change the base sequence of DNA
What sort of environmental factors might influence phenotype?
stress, sunlight, chemical exposure, diet,
How is your DNA organised into chromosomes?
DNA wrapped around proteins called histones (forming chromatin)
DNA and histones are covered in chemicals known as ..
tags
Give examples of DNA tags
Methylation
Acetylation
(Phosphorylation)