Scientists are studying the structure and function of Receptor X, a single-polypeptide protein that is found in the membrane around certain types of cells. Receptor X contains no alpha-helices or beta sheets. A specific molecule outside the cells is recognized and bound by Receptor X. The binding of the molecule to Receptor X causes the cells to have a particular response. To study the structure and function of Receptor X, the scientists are altering the sequence of small sections of the receptor. Both the normal sequence of a five-amino acid section of Receptor X and an altered sequence that contains two amino acid substitutions are shown in Figure 1. A. H O H O H O H O -N-C-C-N-C-C-N-C-C-N-C-C-N-C-C- H CH H CH2 CH3 H CH H CH2 CH3 CH2 CH2 CH2 CH2 1. *NH3 . H O H O H O -N-C-C-N-C-C-N-C-C-N-C-C-N- -C- H CH H CH2 H CH H H HO CH3 CH2 CH2 H3C CH3 CH2 CH2 *NH3 H O H O H O H O -N-C-C-N-C-C-N-C-C-N-C-C-N- -C- H CH3 H3C H CH CH H H CH3 H3C CH2 CH3 CH3 Figure 1. (A) The normal sequence and (B) the altered sequence of a five-amino acid section of Receptor X B. (b) The change in the amino acid sequence illustrated in Figure 1 caused a change in the shape of Receptor X. Based on the R groups of the original and substituted amino acids, explain why Receptor X changed shape. B IU 0/10000 Word Limit (c) Using the template below that represents the four levels of protein structure, place an X on each level that is expected to be altered as a result of the amino acid substitutions shown in Figure 1. Primary Structure Secondary Structure Tertiary Structure Quaternary Structure The four levels of protein structure 1 Upload files (PDF, JPG, GIF, PNG, TXT, Word, Excel, Powerpoint, file formats supported)