Microbiology: Types of Mutations and Mechanism of Action of Antibiotics

Running head: MICROBIOLOGY
Questions and Answers
Name of the Student
Name of the University
Author Note

1MICROBIOLOGY
Answer 1
1. Deletion- It refers to a kind of mutation that involves loss of a part of chromosome or
a particular fragment of the DNA, during DNA replication. The nucleotides that get
deleted range from one base to an entire chromosome (Auerbach, 2013).
TAC CAG ATA CAC TCC CCT GCT ACT → TAC TCC CCT GCT ACT
2. Insertion- This mutation refers to the addition of one or more than one nucleotides
into a certain DNA sequence. This commonly occurs in microsatellite portions due to
slipping of DNA polymerase. This is also a frameshift mutation since the addition of
five bases are resulting in a shift of the open reading frame.
TAC CAG ATA CAC TCC CCT GCT ACT → TAC CAG CGT ATA TAC ACT CCC
CTG CTA CT
3. Substitution- This mutation involves the exchange of one nucleotide base for another.
Such substitutions result in the change of one particular codon to another that encodes
for an altogether different amino acid and changes the protein produced. This is a
missense mutation since the initial second codon CAG coded for glutamine, while the
substituted one, CGG codes for arginine (Samocha et al., 2014).
TAC CAG ATA CAC TCC CCT GCT ACT → TAC CGG ATA CAC TCC CCT GCT
ACT
4. Nonsense- This refers to a kind of mutation where a sense codon is found to
correspond to one of the essential 20 amino acids that are encoded by the genetic
code, resulting in its change to chain termination codon.
TAC CAG ATA CAC TCC CCT GCT ACT → AUG GUC UAU GUG AGG GGA CGA
UGA (mRNA) → Met Val Tyr Val Arg Gly Arg Stop