Correct option is C
Explanation:
We need to match the terms related to gametogenesis and fertilization. Let's analyze each term:
A. Primordial germ cells
Match: ii. Posterior epiblast
Primordial germ cells are the precursors of gametes (sperm and eggs). These cells are initially located in the posterior epiblast during early development. They migrate towards the gonads later on, but their origin is in the posterior epiblast. Therefore, A-ii is correct.
B. Dictyate resting stage
Match: i. Luteinizing hormone
The dictyate resting stage occurs during oogenesis in female mammals, where primary oocytes are arrested in prophase I. The luteinizing hormone (LH) is crucial for the resumption of meiosis and the progression from this resting stage, signaling the activation of the oocyte. Therefore, B-i is correct.
C. Sodium channels
Match: iv. Block polyspermy
During fertilization, the sodium channels in the egg membrane open, which causes a sodium influx that changes the membrane potential. This change in the membrane potential prevents the entry of additional sperm, thus acting to block polyspermy. Therefore, C-iv is correct.
D. Protamine
Match: iii. Male pronuclei
Protamine is a protein that replaces histones in sperm DNA, allowing for the tight packaging of genetic material in sperm. After fertilization, the sperm’s DNA undergoes de-condensation to form the male pronucleus, which then fuses with the female pronucleus. Therefore, D-iii is correct.
