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!
Cell Theory
The invention of the compound microscope in the 17th century stimulated the interest in living things not visible to the naked eyes. Thus, Robert Hooke discovered 'cells' in 1665 by examining cork slices (,under a crude microscope. He was actually describing the spaces occupied by the cells limited by the cellulose walls. Hooke and his contemporaries also described cells from other plants and animals.
Figure: A generalized plant (a) and animal (b) cell. No one cell of either plant (a) or animal (b) has all the characteristics shorn in these composite figures. Both these are
However, cell theory, one of the greatest and most basic generalizations of biology, was formulated only about 200 years later. Two German investigators, Schleiden a botanist (1838), and Schwann, a zoologist (1839) are credited with presenting independently the first concise, yet comprehensive, statements about the cell. They pointed out that, "All plants and. animals are made up of small fundamental units called cells and that some organisms are unicellular and others, multicellular." Subsequent researched to the expansion of this concept by including further information on cells. We know that cells are surrounded by cell membrane and contain cytoplasm and nucleus and, most importantly, cells divide into roughly equal daughter cells by a process called cell division. Thus it became known that new cells come into existence only by the division of previously existing cells. In other words, cells do not arise by spontaneous generation from nonliving matter. It follows that all cells living today can trace their ancestry back to those which existed in ancient times.
Q. Can you show the Systems of classification plants? The development of angiosperm classification has been one of the most fascinating subject. A study of sequential events le
Express the term in brief - Protonephridia. An osmoregulatory-excretory structure found in some invertebrates. Also known as a flamecell, this tubule is closed at its distal en
Q. What is the evolutionary importance of pteridophytes? As the first pteridophytes, tracheophytes were also the first plants to extensively colonize the terrestrial environmen
Pathophysiology The exact mechanism of glomerulonephritis is still under investigation. The dies'ease is characterised by deposition of immune complexes consisting of anti
Define Behaviour change communication - iron deficiency anaemia? In communities that are illiterate and consequently ignorant of the consequences of nutrition disorders and the
Q. Show the Directly Visible Chemical Characters? Very few chemical substances in plants can be observed directly, but the few substances such, starch grains which are pres
why the excretory organ of prawn is called ''green gland''?
DEVELOPMENT OF PSYCHIATRIC NURSING IN OTHER COUNTRIES: Although the scientific findings rejected the belief that mental disturbance was the devil's work, the earliest asylums
Q. Explain Genetically Modified Organisms? Techniques that use gene modification through (a) recombinant DNA technology and (b) cellular techniques of introducing DNA into an o
Determine the term Clade? In cladistic taxonomy, how groups of animals are related to each other. It includes the ancestral group and all of the other groups, or lineages, of a
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