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!
Fusion of Egg and Sperm Pro-Nuclei
The fusion of the sperm and egg which is the beginning of the fertilization process is completed with the fusion of the male and female pronuclei to from the zygote nucleus called synkaryon. Usually the nuclear fusion occurs between 10 to 20 minutes after attachment of the sperms to the egg. In sea urchins the completion of second meiotic division occurs after the entry of the sperm and the resulting haploid egg nucleus is known as female pronucleus. The sperm nucleus after its entry into the ovum is known as male pronucleus. After its entry in the ovum there is a breakdown in the sperm nuclear envelop, decondensation of chromatin and the formation of the pronuclear envelope.
In sea urchins at the completion of meiosis the female pronucleus is located in the central region of the egg and the male nucleus is located initially in the cortical region of the egg at the site of its entry. Before the fusion of the pronuclei, the sperm pronucleus has to migrate a considerable distance through the egg cytoplasm. In sea urchins a structure called sperm aster mediates this movement of the pronucleus. The sperm aster is a complex of long microtubules that radiate from the paired sperm centrioles. The centrioles which enter into the egg along with the sperm nucleus form the microtubule organising centre for the sperm aster. The microtubules of the sperm aster push the male pronucleus towards the centre of the egg. The astral microtubules also contact female pronucleus and pull it abruptly towards the male pronucleus. This activity continues until the two pronuclei are displaced to the centre of the egg where they fuse to form the synkaryon.
Some plants and animals originate food contain toxic substances. Some pulses and legumes contain a number of toxic substances such as protease inhibitors, lathyrogens, and flavism
A small family was traveling in the car when a minor accident happened. The children in the back seats were wearing lap belts, but still sustained numerous bruises about the abdome
What are the "chiasms" of homologous chromosomes seen in prophase I? Chiasms are intersections of two tracts in the form of X. The chiasms seen in prophase I are chromosome
what is the remedy of infertility
Explain the Nutritional Changes and Requirement - Geriatric Nutrition? Nutrition is affected in two way -due to the changes in physiological function with aging having effect
Q. What are the cells responsible for the production of antibodies? The cells that produce antibodies that is the cells of the humoral immune system are the B lymphocytes (B ce
a) What is biological magnification? b) Describe how DDT as a water pollutant undergoes biological magnification?
Explain the interaction of vitamin a with Proteins? Proteins: The protein status of an individual influences vitamin A status and transport because an inadequate protein intake
Cardiac Cycle Cardiac cycle has two phases-systole and diastole. Ventricular systole and diastole occur as a result of depolarization and chamber volume and pressure. The di
how animals respiratory
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