Columns X and Y list the terms associated with gametogenesis and fertilisation. Column X Column Y A Primordial germ cells i Luteinizing hormone B Dictyate resting stage ii Posterior epiblast C Sodium channels iii. Male pronuclei D Protamines iv Block polyspermy Which one of the following options represents all correct matches?
A - ii; B - i; C - iv; D - iii
Matching Gametogenesis and Fertilisation Terms
Let's analyze each term in Column X and find the best match in Column Y based on the processes of gametogenesis and fertilisation.
- Primordial germ cells: These are the precursor cells for gametes (sperm and eggs). In many organisms, they originate outside the developing gonad and migrate there. The epiblast is a layer of cells in the early embryo from which PGCs arise. Specifically, in mice, PGCs are first identified in the posterior epiblast.
- Dictyate resting stage: This is a prolonged prophase I stage of meiosis that occurs in primary oocytes. Oocytes enter this stage during fetal development and remain arrested until puberty. The surge of Luteinizing Hormone (LH) during the menstrual cycle triggers the completion of meiosis I, allowing the oocyte to proceed towards ovulation.
- Sodium channels: Ion channels like sodium channels play a crucial role in the fast block to polyspermy during fertilization. When the first sperm fuses with the egg membrane, it causes a rapid depolarization of the egg membrane due to the influx of ions, including sodium ions, which prevents other sperm from fusing immediately.
- Protamines: These are small, highly basic proteins found in the sperm nucleus of many animals, including mammals. They replace histones during spermiogenesis, leading to extreme condensation of the sperm DNA. After fertilization, when the sperm nucleus decondenses to form the male pronucleus, protamines are removed and replaced by maternal histones.
Based on these associations, we can match the terms:
- Primordial germ cells (A) are associated with the Posterior epiblast (ii).
- Dictyate resting stage (B) is related to Luteinizing hormone (i) because LH triggers the release from this arrest.
- Sodium channels (C) are involved in the Block polyspermy (iv), specifically the fast block.
- Protamines (D) are found in the sperm nucleus which becomes the Male pronucleus (iii).
Let's summarize the correct matches:
| Column X | Column Y | Match |
| A. Primordial germ cells | i. Luteinizing hormone | A - ii |
| B. Dictyate resting stage | ii. Posterior epiblast | B - i |
| C. Sodium channels | iii. Male pronuclei | C - iv |
| D. Protamines | iv. Block polyspermy | D - iii |
Therefore, the correct matching is A - ii, B - i, C - iv, D - iii.
Important Questions from System Physiology Animal
Which one of the following synaptic vesicles (as observed under transmission electron microscope) contains catecholamines?
Blood hemostasis is the interplay of several intrinsic and extrinsic factors. Deficiency of some of the blood clotting factors and their clinical manifestations are listed below.
Factors
Manifestations
A.
V
i.
Hageman trait
B.
VII
ii.
Hypoconvertemia
C.
IX
iii.
Hemophilia B
D.
XII
iv.
Parahemophilia
Which one of the following options represents all correct matches?
Nephrons are structural and functional units of the kidneys. Certain statements are made below about structure and function of a nephron.
A. P cells of the collecting duct are involved in Na+ reabsorption and vasopressin-stimulated water reabsorption.
B. P cells of the collecting duct are concerned with acid secretion and HCO3- transport.
C. I cells of the collecting duct are concerned with acid secretion and HCO3- transport.
D. The total length of the nephrons including collecting ducts ranges from 45 to 65 mm.
Which one of the following options has all correct statements?
The non-ciliated cuboidal epithelial cells in bronchioles that secrete important defense markers are called
Which one of the following factors inhibits renin secretion?
