Question

Complete the following statements
The quaternary structure of protein
A. Consists of four subunits , hence the name quaternary
B. Is unrelated to function of protein
C. May be either alpha or beta and depends on primary structure of subunits
D. Depends on covalent bondings on subunits

Answer 1

The three-dimensional arrangement of atoms in an amino acid-chain molecule is the structure of proteins. Proteins are polymers formed from amino acid sequences, the monomers of the polymer, specifically polypeptides. By tradition, rather than a protein, a chain under 30 amino acids is sometimes known as a peptide.

Complete Answer:
- Proteins are the end products of the process of decoding that begins with cellular DNA information. Proteins form structural and motor components in the cell as workhorses of the cell, and they serve as catalysts for nearly every biochemical reaction that occurs in living things.
- Conceptually, it is possible to understand protein structure at four stages. They are primary, secondary, quaternary and tertiary.
- All the covalent bonds between amino acids are included in the primary structure and are usually defined by the peptide-bonded amino acid sequence and disulphide bond locations. The relative spatial structure of the amino acids associated with it is unclear.
- The secondary structure refers to recurrent repeated space structures in the polypeptide chain of neighbouring amino acid residues.
- The tertiary structure refers to the spatial relationship in a polypeptide chain of all amino acids; it is a polypeptide 's entire three-dimensional structure.
- There is one additional level of structure called the quaternary structure for proteins with many polypeptide chains, which refers to the spatial relationship inside the membrane of the polypeptides or subunits.
- Multiple non-covalent interactions stabilise and direct the arrangement of proteins and protein subunits in three-dimensional complexes or quaternary structures. Alpha helices in globular proteins and beta sheets in fibrous proteins are the two most prominent quaternary structures of multisubunit proteins. The functional characteristics of multi-subunit proteins depend on the structure of the quaternary

The correct answer is option (C) Maybe either alpha or beta and depends on the primary structure of subunits.

Note: Proteins consisting of two or more similar or various polypeptide chains (subunits) occur in proteins. Since they have two or more subunits, these proteins are called oligomers. The quaternary structure describes the way in which the native protein is organised into subunits. Noncovalent forces keep subunits together; oligomeric proteins may therefore undergo rapid conformational changes that influence biological activity.