The mRNA codon CUU codes for the amino acid leucine (leu). A mutation leaves the codon as CUC, what type of mutation is this? A) Chromosomal
B) Frameshift
C) Insertion
D) Silent

The change in the mRNA codon CUU to the codon CUC, product of a mutation, encodes for the same amino acid, leucine (leu), so it is a silent mutation (option).

Explanation:

A mutation in which a change in bases does not produce changes in the coding of an amino acid is called a silent mutation, since it does not influence changes in the structure or function of a protein.

The sequence of nitrogenous bases in the mRNA is organized into triplets, called codons, each of which encodes an amino acid.

There are 64 possible combinations for 4 nitrogenous bases to form codons, but there are only 20 amino acids. This means that an amino acid can be coded by several codons. In the case of leucine (Leu), it can be coded by the UUA, UUG, CUU, CUC, CUA and CUG codons.

A mutation of a base, without changes in the amino acid or its sequence in the proteins is a silent mutation.

The other options are not correct because:

    A. A chromosomal mutation involves the change in a DNA fragment.

    B. Frameshift or reading frame change occurs by insertion or deletion of nucleotides.

    C. Insertion in a mutation refers to the insertion of one or more nucleotides into a DNA molecule.

the answer would be 2, if crossing over doesn’t occur 2 out of 4 of the daughter cells will have that allele.

hope this : )