RNA processing

Question 1

Role of mRNA

Answer 1

• combines with ribosomes to direct protein synthesis, and carries genetic information from DNA to ribosomes

Question 2

Primary transcription in prokaryotes

Answer 2

• Primary transcript is mRNA
• Translation starts before transcription starts
• molecules of RNA code for different proteins, polycistronic RNA

Question 3

Primary transcription in eukaryotes

Answer 3

• transcription takes place in the nucleus
• translation takes place in the cytoplasm
  -RNA processing occurs

Question 4

RNA processing

Answer 4

• a process where the primary transcript gets converted into mRNA and then gets translated by the ribosome.

Question 5

Three chemical modifications during RNA processing

Answer 5

1. The 5’ end of the primary transcript is modified by adding a special nucleotide called a 5’ cap.
2. Polyadenylation, the addition of a string of nucleotides, the creation of a ponytail. ( on the end of mRNA stabilizes the molecule and helps export mRNA to the cytoplasm)
3. The removal of the non-coding regions of mRNA. Through RNA splicing

Question 6

What is a 5’ cap? what does it do?

Answer 6

• The 5’ helps add stabilizes mRNA
• located at the end of the mRNA

Question 7

Steps of RNA splicing:

Answer 7

1. the spliceosomes move introns closer to the 5’splice site.
2. The proximity of the intron causes the RNA to split and form a loop and a tail (latriat)
3. The lariat breaks down into induvial nucleotides

Question 8

Exons vs Introns

Answer 8

Exons: Protein coding regions
Introns: Non protein coding

Question 9

Ribosomal rRNA

Answer 9

Makes the most ribosomes crucial for translation. They are concentrated in the nucleus

Question 10

Transfer tRNA

Answer 10

carries individual amino acids used for translation

Question 11

MicroRNA (miRNA) and small interfering RNA (siRNA)

Answer 11

small regulatory molecules that can inhibit or destruct a transcript

Question 12

Alternative splicing

Answer 12

allows for different polypeptides to be made from a single gene.