In the processing of proinsulin into mature insulin,which of the following steps occurs?

The first clinical gene therapy was given for treating

With regard to insulin,choose the correct options.
$(a)$ $C$-peptide is not present in mature insulin.
$(b)$ The insulin produced by $rDNA$ technology has $C$-peptide.
$(c)$ The pro-insulin has $C$-peptide.
$(d)$ $A$-peptide and $B$-peptide of insulin are interconnected by disulphide bridges.
Choose the correct answer from the options given below.

$DNA$ probes are used in humans for

Many proteins are secreted in their inactive form. This is also true of many toxic proteins produced by microorganisms. Explain how this mechanism is useful for the organism producing the toxin?

Consider the following statements about insulin.
$I.$ Human insulin is made up of $51$ amino acids arranged in two polypeptide chains.
$II.$ The two polypeptide chains are interconnected by two disulphide bridges.
$III.$ In mammals,including humans,insulin is synthesised as a pro-hormone,which contains an extra stretch called the $C$-peptide.
$IV.$ $C$-peptide is not present in the mature insulin.
Which of the statements given above are correct?