Answer:
The correct answer is - regulation of the heavy metal and their toxicity.
Explanation:
Metallothionein is a group of cysteine-rich, small in size, and highly conserved proteins that bind to various metal ions and regulate their activity or toxicity in transcriptional level.
Metallothionein IIA is one of the metallothioneins that binds to heavy metal and helps cells to be protected from the toxicity of these heavy metals. These proteins are present in almost every eukaryotic organisms virtually. These proteins are highly induced to express highly in the present of heavy metals.
Thus, the correct answer is - regulation of the heavy metal and their toxicity.
The first, second, and fourth statements are correct.
Answer:
Adaptive immune defense system consists of lymphocytes like B-lymphocytes and T- lymphocytes. B-lymphocytes provides humoral immunity while T- lymphocytes provide cell-mediated immunity to the body.
99% of lymphocytes circulate freely in the blood and lymph. B lymphocytes differentiate into plasma B cells and B memory cells when interact with antigen presented by T helper cells.
Then plasma cells secrete antibodies in the circulation which binds to extracellular antigens through antigen-binding site. Then the bounded antigen is recognized by receptors present on phagocytic cells. This receptor binds the Fc region of antigen bounded antibody and destroy the antigen by phagocytosis.