Their exons have been spliced out and discarded. A mutation consisting of deletion of nine base pairs from within a gene will have the effect of a. changing the reading frame and hence destroying the encoded protein. The aspect of retroviruses such as HIV that reverses part of the Central Dogma of molecular biology is that they can a. directly copy their RNA genome into multiple new RNA genomes. In eukaryotes, the initial stage of packing of DNA in nucleosomes is achieved by proteins known as a. cytochromes. The reason that a particular human gene is only expressed in certain cells, e.g. hemoglobin only in blood cells, is that a. the hemoglobin gene has been lost from the DNA of all other cell types.
Plasmids are a. single-stranded linear DNA molecules.
Restriction enzymes a. join segments of DNA together. Linus Pauling and Arthur Kornberg. Click here to return to the Biology 104 home page.