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!
Egg - Synergids
The three cells of the egg apparatus are arranged in triangular fashion with the egg sharing a common wall with the two synergids and the central cell. In the egg the wall is thicker at the micropylar end and is absent at the chalazal end. At this end the lateral walls of the egg cell appear to join the central cell wall. The egg cell wall is traversed by plasmodesmata on the sides of the two synergids and the central cell but not at its outer face. The egg cell becomes highly polarized early in its development. Polarity is expressed by the aggregation of cytoplasmic elements at the chalazal end of the cell. The micropylar end of the cell is occupied by a large vacuole. Thus, the distribution of the vacuole and cytoplasm in the egg cell is just the opposite of that in the synergids.
The ultra structure of the egg cytoplasm indicates that it is inactive. The mitochondria show only a few cristae. But for Zea mays, dictyosomes are either absent (Epidendrum) or are only a few in numbers. Where present, the dictyosomes exhibit an inactive state. Plastids are present in the egg; they often contain a striking difference from the male gametes. The egg cytoplasm is rich in ribosomes. In Plumbago capensis where the embryo sac lacks synergids. However many finger- like wall projections arise at the micropylar end of the egg cell. They resemble the filiform apparatus of the synergids. In this plant the egg cell seems to have taken over the role of synergids in addition to its own gametic function.
extracellular signals and their characteristics
Q. What is the substance produced in the liver that acts in the small intestine during digestion? How does that substance act in the digestive process? Bile is an emulsifier li
Cardiac Output - Circulation The cardiac output can be determined in a number of ways. The most common method is the Fick's principle. A. Fick a German physiologist in 1870 de
Classification of Viruses No evolutionary or phylogenetic exist between viruses. A nature system of classification cannot, therefore, be devised for viruses. Holmes (1948)
List the requirements of implant materials. a) Biologically compatibility: an ideal implant material will elicit mainly physiological reactions within the surrounding tissues (
GENETIC TERMINOLOGY (i) Gene - Mendel used the term factor for a gene. A gene is the unit of DNA responsible for the appearance and inheritance of character. (ii)
Question 1 Discuss how would you perform antiglobulin test? Add a note on it clinical importance. What are the precautions to be taken while performing the test? Question 2 E
What is telophase? Telophase is the cell divides apart and screws itself.
Food Applications Dextran can be used in food products, as it is capable of moisture retention and inhibition of crystallization of sugar. The properties of dextran as gelling
In certain instances differences in the morphology of genitalia between species make it impossible for normal mating to occur, and sympatric species tend to remain isolated. When t
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