Which of the following eras is known as the 'Age of Reptiles'? MCQ with Answer and Explanation

Explanation:
Adenylyl cyclase converts ATP to cyclic AMP (cAMP), a second messenger. Phosphodiesterase breaks down cAMP, PKA is activated by cAMP, PLC produces IP₃ and DAG.

Explanation:
The placenta acts as a temporary endocrine gland, secreting hCG (which maintains the corpus luteum), hPL (which alters maternal metabolism for fetal growth), and high levels of estrogen and progesterone (which maintain the uterine lining and suppress further ovulation). Prolactin, however, is primarily secreted by the anterior pituitary gland, although its levels rise significantly during pregnancy to prepare the mammary glands for lactation.

Explanation:
The degeneracy of the genetic code refers to the fact that most amino acids are specified by more than one codon. For example, leucine is coded by six different codons (UUA, UUG, CUU, CUC, CUA, CUG). This redundancy is primarily due to the 'wobble' hypothesis, where the third base of the codon can have non-standard base pairing with the first base of the anticodon, allowing a single tRNA to recognize multiple codons.