Which vitamin is also called 'cobalamin'? MCQ with Answer and Explanation

Explanation:
Adrenocorticotropic Hormone (ACTH) is a peptide hormone secreted by the corticotroph cells of the anterior pituitary gland. Its primary target is the adrenal cortex (the outer layer of the adrenal glands). ACTH stimulates the growth of the adrenal cortex and the synthesis and secretion of its steroid hormones, primarily the glucocorticoids (like cortisol), and to a lesser extent, androgens and mineralocorticoids. ACTH secretion is controlled by Corticotropin-Releasing Hormone (CRH) from the hypothalamus and by the negative feedback of cortisol.

Explanation:
The nucleus is bounded by a double membrane called the nuclear envelope, not a single membrane. It houses the nucleolus, which is the site of ribosomal RNA synthesis. The nuclear envelope is perforated by nuclear pores that regulate the bidirectional transport of molecules, including the export of mRNA to the cytoplasm. Thus, statements 2 and 3 are correct.

Explanation:
Most bacteria possess a single circular double-stranded DNA molecule located in the nucleoid region. Some bacteria may also have linear chromosomes or multiple chromosomes, but the typical prokaryotic chromosome is circular. Eukaryotes have linear chromosomes. Plasmids are small, circular extra-chromosomal DNA in bacteria.