Office Assistant Tasks. 1  Answer phones, direct calls and take messages. 2  Operate office machines; photocopiers and scanners, facsimile machines, voice mail systems and personal computers. 3  Maintain and update filing, inventory, mailing and database systems. 4  Open, sort and route incoming mail, answer correspondence and prepare outgoing mail.
DNA mutations happen when there are changes in the nucleotide sequence that makes up the strand of DNA. This can be caused by random mistakes in DNA replication or even an environmental influence like UV rays or chemicals.
A mutation is a change in a DNA sequence that alters the protein for which the DNA codes. Sometimes mutations occur due to damage from an outside source, such as ultraviolet radiation. Excess ultraviolet radiation from the sun sometimes causes mutations that lead a cell to become cancerous. Most mutations that damage a DNA strand are harmful. Other mutations occur due to deletion or insertion of DNA base pairs. One such deletion in humans confers HIV resistance or a delayed AIDS onset. Humans who are heterozygous for the mutation, meaning they possess one mutant gene and one normal gene, experience a slower progression of AIDS.