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_____ Metal ions such as Zn^2+ and Fe^3+ are often needed by enzymes as A) isozy

ID: 506226 • Letter: #

Question

_____ Metal ions such as Zn^2+ and Fe^3+ are often needed by enzymes as A) isozymes. B) allosteres. C) inhibitors. D) cofactors. E) substrates. Fill in the blank. List the level of protein structure that is described. Choose from primary secondary, tertiary, or quaternary. _____ Hydrogen bonding among the amino acids in the protein backbone. _____ The sequence of amino acids in a protein or peptide. _____ Not disrupted by denaturation. _____ alpha helix. _____ Not all proteins have this level of structure. _____ Interactions among amino acid side chains.

Explanation / Answer

32. Answer: D (Cofactor)

Explanation: These are mostly inorganic or organic metallic compounds. They assist the enzymes during catalysis. The metal ions such as Zn2+ and Fe3+ are very common that are found in the cofactors.

Fill in the Blanks (Answers):

1) Answer: Secondary Structure

Explanation: Secondary structure of proteins contains alpha-helix and beta-sheets. Alpha-helix and beta-sheets are stabilized by H-bonds among the amino acids in the protein backbone.

2) Answer: Primary Structure

Explanation: Peptide bonds link the amino acid residues to form a polypeptide. The sequence of amino acids (covalently linked) in the protein backbone is called the primary structure.

3) Answer: Primary Structure

Explanation: During denaturation of a protein (e.g., in the stomach) only secondary, tertiary and quaternary structures are denatured.

4) Answer: Secondary Structure

Explanation: Secondary structure of proteins contains alpha-helix and beta-sheets.

5) Answer: Quaternary Structure

Explanation: All proteins have primary, secondary and tertiary structures but quaternary structures only form when there are more than one polypeptide chains in the protein form a complex.

6) Answer: Tertiary Structure

Explanation: Formation of tertiary structure occurs when interactions (H-bond, Van der Wall's, ionic or disulphide bonds) among the side chains of the amino acid residues in the polypeptide leads to the formation of 3-D structure.