Generally speaking, which of the following mutations would most severely affect the protein coded for by a gene?a) a base substi
tution at the beginning of the geneb) a base substitution at the end of the genec) a frameshift deletion at the beginning of the gened) a frameshift deletion at the end of the gene
For A and B, a base substitution affects one of the three bases that comprise a codon, the DNA/RNA unit that corresponds to a particular amino acid. If one base is substituted, one codon and therefore one amino acid will be affected. Codons have built-in redundancy, so even by changing one base, the new codon sometimes still corresponds to the same amino acid. Therefore, a base substitution at most affects one amino acid, and sometimes doesn't affect it all.
Frameshift mutations cause a lot more trouble. These occur when you have a deletion or insertion that changes the number of bases in your gene. As a result, the "frame" of the codons changes (everything shifts one way or the other by the number of bases added/removed). This affects EVERY codon downstream of the mutation, so you can imagine that such a mutation would have a bigger effect the closer to the start of the gene it occurs. This is why C is correct.
Dead or diseased trees can serve as a food source for some birds because there are some insects which feed on these dead trees and these insects are eaten by some birds. The body of insects is made of protein so it is a good food for birds. The insects which lived in the dead and diseased trees and feed on it are termites and bugs. Termites are also known as white ants. They feed on dead bodies of plants.
