Module 5: Genome replication & expression

Question 1

what is transformation

Answer 1

live cells can take up and incorporate naked DNA from lysed cell into their genomes

Question 2

what is a replicon

Answer 2

a unit of the genome that contains an origin of replication and in which DNA is replicated

Question 3

what is origin of replication

Answer 3

bacterial chromosomes are replicated starting from a single origin
- for circular chromosomes there is a single termination site
- replication forks = partially replicated chromosomes with two divergers

Question 4

what is transcription

Answer 4

the process by which DNA is copied (transcribed) to RNA
- most genes use mRNA to encode proteins and will undergo translation to translate the sequence of mRNA to a squence of amino acid during protein synthesis

Question 5

what are non coding RNAs

Answer 5

some genes that encode other types of RNA molecules that never are destined to be translated
- include RNA strands that are integral to ribosomes (rRNA) and transfer RNAs (tRNA that carry specific amino acids to the ribosomes for correct addition of growing protiens

Question 6

what is transcriptional regulation

Answer 6

dependednt on transcription having taken place

Question 7

what is a binding site

Answer 7

• region of their structure that has a DNA binding domain that has the affinity to a specific series of bases

Question 8

what is negative control

Answer 8

• arrangement where the binding of the regulatory protein to DNA inhibits transcriptional initiation
• repressor proteins and will bind to a specific site on DNA called operator

Question 9

what is positive control

Answer 9

• binding of the regulatory protein to DNA promotes transcriptional initiation
• activator proteins and will bind to a specific site on DNA called the activator binding site

Question 10

what is an inducer

Answer 10

an allosteric effector molecule that causes the repressor to fall off its binding site (allows the regulator gene to be transcribed)

Question 11

what is a corepressor

Answer 11

• allosteric effector that is required to be bound by the repressor before it can bind to its target

Question 12

what is attenuation

Answer 12

• alternative folding of the mRNA while its being formed, to either transcriptional termination signal or to not form a transcriptional termination signal.

Question 13

what are riboswitches

Answer 13

• sensors regions within mRNA 5’ untranslated regions that can undergo conformational changes (swap base pairing partener residues), depending on whether the RNA binds an allosteric effector molecule