(Q002) The Earth's atmosphere Group of answer choices began as nitrogen and oxygen, left over from the solar nebula. acquires its carbon dioxide from photosynthesis by green plants. gets warmer as its carbon dioxide concentration goes down. became more oxygen-rich during the Proterozoic, after the evolution of photosynthetic organisms in the Archean.

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.