Why can a mutation affect the function of protein?
Because a protein's function is dependent on is shape, and a mutation may change the composition (the sequence of amino acids) of a protein, which may in turn cause the shape of the molecule to change.
Why does an insertion mutation usually cause more defects during protein synthesis than a point mutation?
A point mutation can affect the protein in a different ways. If the point change causes a silent mutation then it doesnt affect at all. When the point nucleotide change make a different amino acid, then it may alters the function of protein. If it make to forma a stop codon (TAA, TAG, TGA) then the protein synthesis stops at the point where it is changed.
The amino acid sequence is shifted, and this kind of mutation is called a frame shift mutation. All of the amino acid sequence after the mutation will be changed, which will cause a change in shape of the protein, which will then probably result in a nonfunctional protein, since the shape of a protein determines its function.
The function of a protein is determined by the sequence of amino acids in the protein. A genetic mutation can cause a change in the sequence of nitrogen bases in the DNA. This could cause an error in the sequence of amino acids in a protein, which can cause the protein to function improperly or not at all.