STD 12 - 1. sexual reproduction in flowering plants — Biology STD 12 Science — Question

$I.$ Human insulin is made-up of $51$ amino acidsarranged in two polyperptide 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?

Here $A$ and $B$ refers to

$1.$ Viral $RNA$ replicates to form viral $DNA$ with the help of reverse transcriptase.

$2.$ The progeny viruses released in the blood attack other $T_H$ and destroy

$3.$ Viral $DNA$ gets incorporated into host cell's $DNA$ and produces virus particles

$4.$ Virus enters to macrophages

$R$ - Agrobacterium tumifaciens is a pathogens ofseveral dicot plants