Biology Forums - Study Force

1.) What is a sex pilus and which cell type, F. ? or F+, would produce this structure.
(I think it is the F+ cell type but I"m not absolutely sure.)

2.) Does the phenotype of an organism automatically change when a change in genotype occurs? Why or why not? Can phenotype change without a change in genotype? In both cases, give some examples to support your answer.

Look at the following three types. The answer to: Does the phenotype of an organism automatically change when a change in genotype occurs? is No. Not all mutations automatically change the phenotype of the organism.

Silent mutations can have slightly modified protein structures or unmodified ones, as long as the nucleotide change does not result in any change of the phenotype.

Missense mutations are more restricted in that a nucleotide change results in a particular amino acid (codon) change. Although a missense mutation will change the amino acid sequence, this again may or may not change the structure of the protein.

A nonsense mutation is the most specific of all where the nucleotide sequence now contains an inserted non-native stop site. The premature halt of protein synthesis will result in a shortened protein structure.

hmmmm... Let's say an organism experiences a point mutation. Because a point mutation involves only a single base pair change, reversion is quite common relative to fixing a deletion of several nucleotides. Common in Bacteria are suppressor mutations, which suppress the initial mutation and restore the wild-type phenotype (but not genotype) of a point mutation. However, no analogous mechanism works to fix large-scale deletions.

So I agree with the answer above ^