Final Exam - RNA - translation & transcription

Question 1

How is RNA processed in eukaryotic cells (after transcription)?

Answer 1

1. Capping - phosphates from GTP are placed on 5’ end
2. Poly A tail - 200-300 adenines are placed on 3’ end
3. Splicing - introns (don’t code for protein) are removed and exons (expressed regions coding for a protein) are joined together. Splicing occurs in SPLICESOMES, which are made up of SNURPS (small nuclear ribonucleoproteins)

Question 2

Point mutations

Answer 2

mis-sense mutation: if the point mutation results in a different amino acid (GGC –> GAC results in glycine to aspartate substitution

non-sense mutation: if the change results in a stop codon (UAA, UAG or UGA)

Question 3

Insertion or Deletion mutation

Answer 3

frameshift mutation: if one or more bases are inserted or deleted from the coding sequence
has the worst possible effects on protein sequence and function

Question 4

Inversion or translocation mutation

Answer 4

inversion: results from flipping the order of genes (ABC becomes CBA)
translocation: involves moving a part of chromosome from one place to another or to a different chromosome

Question 5

definition of gene

Answer 5

a DNA sequence that codes for a specific polypeptide chain