Lecture 3 - Genetic Variation

Question 1

Define promoter region

Answer 1

Controls when we transcribe a gene into messenger RNA thats translated into proteins, controls the rate of expression of that gene

Question 2

What does RNA polymerase do?

Answer 2

Unwinds the DNA, access to the 2 strands, use one of the templates and creates the growing mRNA strand from that
Copies the antisense strand, when it approaches a STOP codon on the DNA, the RNA polymerase falls off, mRNA gets excreted from the nucleus into the cytoplasm and goes to the endosome gets taken up by ribosomal RNA and gets made into proteins

Question 3

What is eukaryotic gene regulation?

Answer 3

Controlled expression of a gene in a temporal (time) and spatial (space) manner
most common transcriptional regulation

Question 4

What is transcription?

Answer 4

Copying of DNA into a single stranded messenger RNA strand
forming mRNA
from DNA template, RNA polymerase makes mRNA strand
Translation - take mRNA and make it into proteins

Question 5

What is involved in transcription?

Answer 5

Need a DNA template
enzyme, DNA helicase (unwinds the double helix), DNA polymerase (reads the DNA)

Question 6

What is the role of transcription factors?

Answer 6

Have the ability to bind to DNA
Recognise specific DNA based sequence (transcription control elements)
Sequences of DNA that are recognised by particular families of proteins called TF

Question 7

What is chromatin?

Answer 7

exists in 2 structures
switches between the 2
Heterochromatin - densely packed nucleosome, not actively transcribed
euchromatin - extended appearance
being actively transcribed, acetylated histones
being unwound - region of chromosome with active gene transcription

Question 8

Where do transcription factors bind to?

Answer 8

Bind to the CAAT boc and GCGC box

Question 9

What is histone acetylation?

Answer 9

Adds histone groups, adds acetyl groups onto positively charged lysine residue
Positive charge is masked because it is blocked by the acetyl group so nothing to attract the DNA
DNA released around histones and unwinds allowing transcription factors in
Relaxes interaction of DNA with nucleotide

Question 10

What are histone deacetylases?

Answer 10

Remove acetyl group, HDAC - charge interact and DNA winds tightly again
Over and under expression of these enzymes affects the accessibility of DNA

Question 11

What do coactivator proteins do?

Answer 11

Unwind DNA - can expose DNA so we get transcription factors in and get RNA polymerase in so the DNA strand can make mRNA and then make a protein