Lectures 9, 10 & 11: Nuclei acids, proteins and the central dogma

Question 1

Purpose of DNA sequences, genes and proteins?

Answer 1

The DNA sequence encodes genes, genes encodes proteins, and proteins do the work in the cell.

Question 2

What are the pyrimidine nitrogenous bases?

Answer 2

Cytosine, Thymine in DNA, Uracil in RNA

Question 3

What are the purine nitrogenous bases?

Answer 3

Adenine and Guanine.

Question 4

What is the base pairing?

Answer 4

Adenine + Thymine and Guanine + Cytosine.

Question 5

Purpose of helicase?

Answer 5

Untwists dna to produce single stranded DNA.

Question 6

Topoisomerase?

Answer 6

Topoisomerase fixes the increased coiling in the DNA template.

Question 7

Single-strand binding protein?

Answer 7

Stabilises the single stranded template.

Question 8

DNA primase?

Answer 8

Synthesises RNA primer at 5’ end.

Question 9

DNA Polymerase III?

Answer 9

Uses parental DNA as a template and synthesises new DNA strand by adding nucleotides to an RNA primer or pre-existing DNA strand.

Question 10

DNA Polymerase I?

Answer 10

Removes RNA nucleotides of primer from 5’ end and replaces them with DNA nucleotides.

Question 11

DNA ligase?

Answer 11

Joins Okazaki fragments of lagging strand, joins 3’ end of DNA that replaces primer to rest of leading strand DNA.