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!
Corpus Allatum and Juvenile Hormone
The corpora allata are rounded glands attached to the posterior side of every corpus cardiacum making a compact body just behind the brain. In a few (Hemiptera, higher Diptera) they are fused to make a single median structure. Experiments by Wigglesworth have shown that the CA secretes a hormone that determines the character of each larval instar by limiting the degree of differentiation in the direction of the development of the adult. He named this hormone like juvenile hormone (JH). This is also known as neotenic (youth substance), (Wigglesworth 1954) and gonadotropic hormone (Engelmann 1957). The juvenile hormone is identical in structure to terpenes. A large number of compounds with juvenile hormone activity have been isolated and several have been synthesized. Some synthetic ones appear much more potent than the naturally occurring ones. The juvenile hormones make sure the occurrence of larval moults and inhibit metamorphosis. Its existence or nonexistence determines whether the larva will moult into a larval/pupal stage or into adult stage. The main natural hormone isolated from the adult male Hyalophora cecropia moth has the following structure Figure.
Figure: Juvenile hormone isolated from Cecropia moth
The role of the corpus allatum and the juvenile hormones in metamorphosis has been proved via various experiments. It has been observed that if an extra corpora allata from a second stage larva is transplanted to the fourth instar last larval instar as compared to the moult does not generate a pupa or adult, instead an oversized larva develops. Removal of corpora allata early in larval life results in premature metamorphosis.
Flagellated Protozoan These are protozoan that move by means of one or more flagella and include the largest number of species, about 6,800. Asexual reproduction is by
Determine the type of bandage The most common type of bandage is the gauze bandage, a simple woven strip of material which comes in different widths and lengths.
what is phulum cnideria
Development of Fruit Concurrent with the development of the seed(s), the ovary is transformed into a fruit. The fruit protects the seeds and allows their release or germinati
To "express" a gene is to make it to function properly. A gene which encodes a protein will, when expressed, be transcribed or translated to produce that particular protein. A gene
Lipids All animal tissues contain lipids or fats as essential components of cell membrane. It is also stored in certain tissues. Lipids are body's chief source of energy and
Describe in detail about the unicellular eukaryotes Animal cel1.s and many types of unicellular eukaryotes contain centrioles, which are cylindrical in structure, about 0.15 m
Define about the Absorption of Iron? Before it can be absorbed, iron whether it is in the form of haem or non-haem must be released from the food matrices where it is bond with
What are the typical vegetation and the typical fauna of the deserts? The predominant fauna of desert ecosystems is produced by reptiles, as lizards and snakes, terrestrial art
Procedure For Define Percentage of reducing and total sugar by fehling soxhlet? 1. Standard titration (Standardization of Fehling's solution) - Titrate 10 ml of Fehling's solut
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