Spermatocytogenesis, Biology

Assignment Help:

SPERMATOCYTOGENESIS

In this process four spermatid develop from one PGC.

(i) Multiplication phase

  1. The spermotogonia or sperm mother cells lie next to the basement membrane.
  2. These divide repeatedly by mitosis producing new sex cells.
  3. Some of these cells move towards the lumen of the seminiferous tubule and enter the growth phase.
  4. These are called primary spermatocytes while others produced by the mitotic division of spermatogonia remain in the original condition and continue to produce new spermatogonia throughout the reproductive life of the animal.

(ii) Growth phase

  1. The spermatogonia, formed as a result of repeated divisions of the primordial germ cells, stop dividing and prepare themselves for maturation division.
  2. They increase in size by accumulating nourishing material obtained from germinal cells.
  3. The enlarged cells are known as primary spermatocytes.
  4. Initially, the nucleus of each primary spermatocyte is of ordinary size, but soot it imbides material and enlarges considerably.
  5. At the end of growth phase, when the primary spermatocyte is ready to undergo first maturation division (i.e. the reduction division) its nucleus is much larger than that spermatogonial cell.

(iii) Maturation phase

  1. Each diploid primary spermatocyte undergoes the first maturation division which is a reduction division, with its long drawn out and complicated prophase.
  2. The pairing and spliting of homologons chromosomes take place during zygotene and pachytene and this leads to the formation of tetrads. Due to crossing over, the exchange of homologus chromosomes also take place.
  3. According to some, all these chromosomal events are completed in the growth phase only, so that during first maturation division the chromosomes are equally distributed to the two daughter cells.
  4. As a result of reduction division, the two cells formed are haploid. These haploid cells are called secondary spermatocytes.
  5. The secondary spermatocytes undergo second maturation division which is a simple mitotic division.
  6. As a result, each secondary spermatocyte divides into two equal cells, called spermatids.
  7. In the end of maturation phase four haploid spermatids are formed from each, diploid primary spermatocyte.

Related Discussions:- Spermatocytogenesis

What are some factors that can lead to protein denaturation, What are some ...

What are some factors that can lead to protein denaturation? Protein denaturation can be caused by temperature variation, pH change, alters in the concentration of surrounding

Theories to explain fine structure of chromosome, THEORIES TO EXPLAIN FINE ...

THEORIES TO EXPLAIN FINE STRUCTURE OF CHROMOSOME (1 ) Multistranded theory Steffenson 1959 - each chromosome composed of two chromatids (Half Chromosome) and each chromat

Define interaction of vitamin k with vitamins a and e, Define Interaction o...

Define Interaction of Vitamin K with Vitamins A and E? Excess vitamin A interferes with vitamin K absorption while the a-tocopherol or vitamin E, as we have already studied ear

What is the host factors of implants, What is the Host Factors of implants ...

What is the Host Factors of implants These factors are very important and it is essential for the clinician to keep these in mind during the diagnosis and treatment planning st

Explain the characteristics of agar- agar, Explain the Characteristics of A...

Explain the Characteristics of Agar- Agar? There are many characteristics, which make agar-agar, an ideal solidifying agent. These are: (a) It has high gel strength, so it c

Metabolism of lipids, The three main forms of fat found in food are glyceri...

The three main forms of fat found in food are glycerides (principally triacylglycerol [triglyceride], the form in which fat is stored for fuel), the phospholipids, and the sterols

Matlab, Write up your own Matlab program to do the job described by Show"...

Write up your own Matlab program to do the job described by Show">http://www.avatar.se/molbioinfo2001/dynprog/adv_dynamic.html Show a few examples, your code does work. You wil

Indications for surgery-pulmonary regurgitation, Indications for Surgery : ...

Indications for Surgery : Patients usually present with fatigue, dyspnoea and ventricular arrhythmias. If they have additional tricuspid regurgitation, pulmonary valve replacement

Why do protease-supplying cells of the stomach, Q Why do protease-supplying...

Q Why do protease-supplying cells of the stomach and of the pancreas make only precursors of the active proteolytic enzymes? The stomach and the pancreas make zymogens of the p

Explain about non-surgical therapy, Non-Surgical Therapy The most conse...

Non-Surgical Therapy The most conservative approach to treatment involves non-surgical therapy. This treatment modality includes three subcategories: a) Pharmacological ther

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd