Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
MEIOSIS
Every organism is mortal, It becomes old and wornout with advancing age (= ageing ) and ultimately dies ,Before death however ,it reproduces its own kind, so that its race species continues, Many protozoan and some lower metazoans reproduce asexually by mitosis .Inheritance in these is obviously uniparental some protozoans and most metazoans perpetuate their species by sexual reproduction . Inheritance in these is therefore biparental, because reproduction involves union of two sex cells or gametes ( male gametic cell or sperm and femal gametic cells or ovum), producing a single cells called zygote, from the zygote , then arises the entire multicellular body of a new progeny by its repeated mitotic division and different iation of resultant cells into the different types.
If the gametes were diploid like all body (= somatic) ,cell the zygote would have twice the number of diploid chromosomes (tetraploid -4 x or 4n and the number would go on multiplying in that order generation after generation .No species can survive if its karyotype multiplies in this way, Hence to prevent this situation ,sex cells or gametes are made to possess a single set of chromosomes i.e. only half the number of chromosomes present in the karyotpye ,This single set is called haploid or monoploid (x or n) gametic set in contrast to the diploid ( 2x or 2n) karyotypic or somatic set of chromosomes .
The haploid sex cells are formed insexual organs i.e. gonads (testes in males and ovaries in females ) from diploid germinal cells by a specialized process called gametogenesis (spermatogenesis in males and oogenesis in females) This process necessarily involves a single duplication of chromosomes but two consecutive cell division. The second division is mitotic but the first one is a special type of reduction cell division called meiosis (Gr meioum =to diminish ) which bring about the aforesaid reduction in chromosomal number to half in the resultant gametes . Conventionally , the two division are designated as first and second meiosis.
i want to online research biology projects
Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4
Q. Define Myocardial infraction and stress testing? Prediction of disease is one of the primary functions of stress testing. We would like to be able to predict in each patient
How to increase in sodium conductance A complete motor neuron is removed from a frog and placed in normal physiological saline at 1 AM. The neuron is healthy. At 2 AM, the ph
SPECIE S CONCEPT - According to Davis and Heywood species define as assemblage of individuals with morphological features in common and separable from other such assembla
#question.WRITE THE CHARACTER AND CLASSIFICATION OF MOLLUSCA ?
What is the meaning of Trocophore? This free-swimming ciliated larval stage is found in numerous animal phyla including Mollusca and Annelida. Larvae has a unique circle of pre
Explain Need For Microbiological Analysis of Environment Samples? Once the food is harvested, it passes through various operating steps before reaching the consumer. These step
Palliative Procedures i) This consists of enlarging the existing for a men ovale by putting a baloon through the defect (baloon septostomy) so that interatrial mixing of blo
why is blood called a fluid connective tissue ?
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd