The function of a protein is determined by its shape. The shape of a protein is determined by its primary structure (sequence of amino acids.) The sequence of amino acids in a protein is determined by the sequence of nucleotides in the gene (DNA) encoding it.
'Red shift' is a key concept for astronomers. The term can be understood literally - the wavelength of the light is stretched, so the light is seen as 'shifted' towards the red part of the spectrum.
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Answer:
Chemicals that are secreted from antigen-presenting cells then activate helper T cells.
Explanation:
Mutation may occur if both copies of DNA molecules do not have the exact same sequence of nucleotides as the original DNA molecule. Mutation can also lead to further problems, in the future.
