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!
Female Gametophyte
The development of a female gametophyte is initiated with the enlargement of one of the megaspores (usually the one close to the chalaza in a linear tetrad) followed by three mitotic divisions. Thus, the female gametophyte, also called the embryo sac is almost always a 7-celled or 8-nucleate structure. The eight nuclei thus formed organize into the egg apparatus, central cell with two polar nuclei and three antipodal cells. This mode of embryo sac development occurs in the majority of flowering plants.
There are variations from this mode of female gametophyte development. In order to visualize these deviations let us recall the formation of megaspore tetrad. Out of the four megaspores, three degenerate and only one participates in the formation of embryo sac. This mode of development of female gametophyte is known as the monosporic type. In some plants, two megaspores out of four participate. For example, if after meiosis, the lower or the upper dyad produces the embryo sac and the other degenerates, the development is termed bisporic. Sometimes, cell plate formation does not occur after any of the meiotic divisions and all the four megaspore nuclei contribute to embryo sac formation. 'This is called tetrasporic type of development. Depending upon the orientation and subsequent behavior of the megaspore nuclei and their derivatives, the tetrasporic gametophyte may be of several types.
When ATP gives energy to the cellular metabolism it loses one of its phosphates and ADP reappears. ADP can also lose more phosphates and produce AMP (adenosine monophosphate) o
With the help of reaction briefly explain the oxidative phase of the pentose phosphate pathway. The oxidative branch of the pathway generates NADPH and pentose-5 phosphate, th
Molecular Hydrogen N 2 -fixing organisms also produce a membrane bound enzyme called uptake-hydrogenase under N 2 -fixing condition. The physiological significance of the pres
Chloroplasts Like mitochondria, chloroplasts are also distinctive organelles of eucaryotic cell. But they are found only in plant cells. Chloroplasts contain membranes forming
How does the intensity of facilitated diffusion vary in relation to the concentration of the moved substance? What is the limiting factor? Like simple diffusion facilitated dif
Assignment on CAM
1. Compute the mean energy per nuclear disintegration, A, for 99m TC if 2.0 x 10 9 Bq of this isotope is injected into a patient. Assume that one-half of the administered dose is
Increase in population size is known as population growth. It depends upon number of persons added to the population and number of persons lost from the population. Addition in pop
Implementation The planned goals and strategies are translated into nursing intervention by means of the nursing care plan. It is essential that the client and family par
how trematodes/nematodes adapt to their parasitic mode of feeding
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd