25th Jan - Trx 1

Question 1

Outline the central dogma

Answer 1

DNA–> mRNA –> Protein

Question 2

Who proposed the concept of an ‘inevitable intermediate’ which would later be classified as mRNA?

Answer 2

Francis Crick

Question 3

Which RNA is encoded by Pol I?

Answer 3

rRNA

Question 4

Which RNA is encoded by Pol II?

Answer 4

mRNA

Question 5

Which RNA is encoded by Pol III?

Answer 5

tRNA and other e.g. 5SrRNA

Question 6

Does transcription require a primer?

Answer 6

No

Question 7

Where does Pol I transcription occur?

Answer 7

In the nucleolus

Question 8

Is Pol I highly regulated?

Answer 8

No

Question 9

Where is the promoter located in Pol III transcription?

Answer 9

Downstream of the TSS so the promoter forms part of the transcript

Question 10

What is chromatin?

Answer 10

DNA with histones

Question 11

How were histones discovered?

Answer 11

Digested DNA with non-specific micrococcal nuclease –> repeats of approximately 200bp indicating something was shielding the DNA

Question 12

How many bp of DNA wrap around a histone octamer?

Answer 12

147

Question 13

What are the subunits of a histone octamer?

Answer 13

(H2A, H2B, H3 and H4 ) x2

Question 14

What is the function of macro histone 2a?

Answer 14

X chromosome inactivation and transcriptional repression

Question 15

WHat is the function of histone H2AX?

Answer 15

It helps with DNA repair and recombination, they are deposited randomly across the genome and become phosphorylated at a site of DNA damage –> recruitment of DNA repair machinery

Question 16

Where is heterochromatin localised within the nucleus?

Answer 16

Around the edges of the nucleus

Question 17

How were transcription factories identified?

Answer 17

Using an immunofluorescence experiment in which Pol II was labeled with a fluorescent antibody.

Question 18

How were chromosome territories discovered by Kramer and Kramer?

Answer 18

Chromosome painting