Genes - What they are and how we study them?

Question 1

Explain the central dogma of biology, namely DNA -> RNA -> protein.

Answer 1

DNA can become into RNA/protein but protein cannot become itself or into DNA/RNA.

Question 2

Explain the role of RNA polymerase in transcription.

Answer 2

• RNA polymerase synthesizes pre-mRNA (complementary to gene DNA sequence)
• can only move from 5’ to 3’,
• RNA polymerase 1 (rRNA),
• RNA polymerase 2 (mRNA),
• RNA polymerase 3 (tRNA),
• unable to recognise promoters efficiently without help,

Question 3

What is a gene?

Answer 3

• all of the DNA that is transcribed into RNA plus all of the cis-linked control regions
• they are required to ensure quantitatively appropriate tissue-specific expression of the final protein.

Question 4

What is a promoter?

Answer 4

• recruits RNA polymerase to DNA template, is a recognition sequence.

Question 5

What is the regulatory element?

Answer 5

• regulates recruitment of RNA polymerase

Question 6

What is a TATA box?

Answer 6

-Recruits general transcription factors/RNA polymerase

Question 7

What are exons?

Answer 7

Coding regions

Question 8

What are introns?

Answer 8

Non-coding regions

Question 9

Describe processing of mRNA (transcription)

Answer 9

• RNA polymerase recruited
• DNA helix unwinds
• RNA synthesis begins (elongation,termination)
• RNA polymerase dissociates

Question 10

Describe processing of mRNA (5’ capping)

Answer 10

Methylated cap is added to 5’ end and then transcription continues

Question 11

Describe processing of mRNA (3’ polyadenylation)

Answer 11

-Addition of poly tail/250 adenine molecules

Question 12

Describe processing of mRNA (splicing)

Answer 12

-Introns are taken out of the RNA transcribed via spliceosome/exons can be skipped or added to form isoforms