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.
Amylopectin Amylopectin forms a branched structure with about 30 glucose units in a chain among branches. There are usually slightly more 'outer' unbranched chains (called A-c
Animal Tissue A tissue is a group of cells that are similar in structure, origin and function. Tissue word coined by Bichat (Father of Histology). Histology term
Cystic fibrosis (CF) is caused by a variety of mutations in the CFTR gene. Imagine you have identified a new single-base pair mutation (A→T) in an exon of the CFTR gene. You wish t
Q. What are worm infections? The Worm infections are human diseases caused by nematodes(roundworms) or platyhelminthes (flatworms).
Xerarch - Kinds of Succession When the succession takes place in drier area, i.e., the succession progresses from xeric to mesic conditions. It is further subdivided as:
What has caused evolution? 1) Different individuals have dissimilar characteristics 2) These differences result in altering abilities to reproduce under local circumstances
After the pollination how does fecundation occur in angiosperms? In these plants is fecundation dependent on water? After the pollination one of the sperm nuclei from the polle
Abscisic Acid Abscisic acid (ABA) as a naturally occurring growth inhibitor was discovered through independent investigations of different physiological phenomena in two diffe
What is vision? Why is vision important for life on earth? Vision is the ability of some living beings to perceive, to differentiate and to interpret luminous stimuli. Visio
DO I GET MY ANSWERS RIGHT AWAY?
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