Question

the conformation or shape of a protein molecule directly determines its function. There are four orders of protein structure: primary, secondary, tertiary, and quaternary.

Answer 1

Proteins perform a surprising variety of essential functions in mammalian organisms . These may be grouped into dynamic and structural . Dynamic functions include transport, metabolic control, contraction , and catalysis of chemical transformations . In their structural functions , proteins provide the matrix for bone and connective tissue , giving structure and form to the human organism.

The primary structure (amino acid sequence) of a protein is required for an understanding of a protien structure , it's mechanism of action at amolecular level , and it's relationship to other proteins with similar physiological roles.The primary structure of insulin illustrates the value of this knowledge for understanding a prtein's biosynthesis and physiological forms . Insulin is produced in pancreatic islet cells as a single chain precursor,proinsulin.The polypeptide chain contains 86 amino acids and 3 intra chain cystine disulfide bonds . It is transformed into biologically active insulin by proteolytic modifications in it's primary structure as it is secreted from the islet cells.

There are four orders of protein structure : primary , secondary , tertiary and quaternary .

Primary structure of protein refers to the covalent stucture of a protein . It includes amino acid sequence and location of disulphide (cystine) bonds . Higher levels of protein organization refers to non covalently generated conformational properties of the primary structure . These higher levels of protein conformation and organization are defined as the secondary , tertiary , and quarternary structure of protein .

The secondary refers to the local three -dimentional folding of the polypeptide chain in the protein . The polypeptide chain in this context is the covalently inter connected atoms of the peptide bonds and alpha carbon linkages that sequentialy link the amino acid residues of the protein . Side chains are not considered at the level of secondary structure .

Tertiary structure refers to the three - dimensional structure of the poly peptide.It includes the conformational relationships in space of the side chains and the geometric relationship between distant regions of the polypeptide chain .

Quaternary structure refers to the struture and intractions of the noncovalent association of discrete polypeptide subunits into a multi subunit protein . Not all proteins have a quarternary structure .