Transcription And Translation (week 12)

Question 1

What is central dogma?

Answer 1

The idea that genetic information only flows in one direction. DNA → RNA → protein or just RNA → protein.

Question 2

What are the molecular machines involved in replication of DNA?

Answer 2

Transcription - RNA polymerase
Translation - ribosomes, tRNA

Question 3

What is a gene?

Answer 3

Genes are one functional unit.
They can code for functional RNA BUT not all genes code for proteins and not all RNA is translated.

Question 4

What is transcription?

Answer 4

DNA → mRNA

Question 5

What is translation?

Answer 5

mRNA → protein (tRNA used)

Question 6

How does gene expression differ between prokaryotes and eukaryotes?

Question 7

How does RNA processing in eukaryotes work?

Answer 7

• RNA is synthesised in the nucleus, and is then processed where it acquires a 5’ structure
• It is then transported through the nuclear wall
• Once inside the plane, translation can begin

Question 8

What are some differences between DNA and RNA?

Answer 8

• RNA has a C2 hydroxyl group
• uracil instead of thymine
• single stranded
• often forms stem loops
• can form other complex structures through Watson and crick, base pairing.

Question 9

RNA can contain nonstandard bases - what are some of these?

Answer 9

Inosine (mostly in tRNA)
Pseudouradine
Can have standard bases methylated

Question 10

What happens in the process of transcription?

Answer 10

1 - RNAP holoenzyme binds, directional l unwinds the DNA l formation of transcriptional bubble l strands separate l transcription initiates
2 - only 1 DNA strand is used as a template at a time I read 3’ to 5’ l RNA synthesis 5’ to 3’ l as transcriptional bubble advances the DNA helix reforms behind it
3 - sequence dependant, other factors involved l results in primary DNA release and dissociation of polymerase from DNA

Question 11

What is the process of translation?

Question 12

RNAP - what are the prokaryotic and eukaryotic differences?

Answer 12

Page 26 of notes

Question 13

How are functional proteins generated?

Answer 13

Central dogma is not sufficient to explain this → instead after gene expression there is a step called protein regulation. This occurs through post-translational modifications.

Question 14

Types of post translational modifications? (5 examples)

Answer 14

Phosphorylation
Methylation
Glycosylation
Ubiquitylation
Sumoylation