RNA and RNA related-Processes

Question 1

What does it mean if mRNA is monocistronic?

Answer 1

Monocistronic mRNA encodes for only one protein. Eukaryotic mRNA is only monocistronic.

Question 2

What does it mean if mRNA is polycistronic?

Answer 2

Polycistronic mRNA is only found in prokaryotes and it encodes for multiple proteins.

Question 3

What function does Aminoacyl-tRNA synthetase do?

Answer 3

Aminoacyl-tRNA synthetase (ligase) utilizes ATP to attach an amino acid to the 3’ OH on the end of the tRNA (end of tRNA always ends with CCA).

• Once the amino acid has been attached to the tRNA, it is called an aminoacyl-tRNA or charged/activated.

Question 4

What is rRNA?

Answer 4

Ribosomal RNA (rRNA) is the RNA that composes ribozomes. It is synthesized in the nucleolus and is a major component of ribosomes. Many rRNA function as ribozymes. Ribosomal RNA leads the mRNA and grabes the correct tRNA. rRNA also catalyzes the formation of peptide bonds.

Question 5

What is the only start codon and the amino acid it encodes for?

Answer 5

The start codon is AUG which encodes for methionine.

Question 6

What are the 3 stop codons?

Answer 6

The three stop codons are:

1. UGA
2. UAA
3. UAG

Question 7

What is the wobble position?

Answer 7

The wobble position is the 3rd nucleotide in a codon. The 3rd nucleotide can generally change but still encode for the same amino acid.

Question 8

What is a point mutation and how many different types of point mutations are there?

Answer 8

A point mutation is when one base (nucleotide) is changed. There are 3 types of point mutations.

1. Silent mutation (same amino acid encoded)
2. Missense mutation (different amino acid encoded)
3. Nonsense mutation (stop codon produced)

Question 9

What is a frameshift mutation?

Answer 9

A frameshift mutation is when a base (nucleotide) is added or deleted. Serious change between the original protein and the mutated protein produced.