viruses are not considered to be living things, but they depend upon living cells for energy, reproduction, and protection at the expense of the cells that they invade.

the type of relationship described could best be classified as one of
a) commensalism.
b) mutualism.
c) parasitism.
d) resignation.

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. what is the significance of this finding? it will be important to include cysteine in the diet of the mice. cysteine residues are required for the formation of α helices and β pleated sheets. cysteine residues are involved in disulfide bridges that form tertiary structure. cysteine causes bends, or angles, to occur in the tertiary structure of proteins.