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.
Explain Herbicide tolerant crops in Evolutionary way Increased use of herbicide can result in increase in development of weed resistance to that herbicide either through
Nutritional and functional role of minerals in foods Essential elements including the main elements and a number of trace elements fulfill various functions: as electrolytes, a
cells are the smallest structural units of the living matter and is capable of functioning independently.
TYPES OF SPERM Mainly two types . (1) Flagellated Sperm - Generally all sperm are monoflagelated, but in todfish or opsonus sperm is biflagelated. (2) Non flagellated spe
excretary organ of whale
Q. What is Low Gradient Aortic Stenosis? One may come across patients who have severe left ventricular dysfunction and modest gradients across aortic valve. This situation may
when the father and the mother of a newborn baby possesses blood group ''O'' +ve,is it possible that the baby can have a blood group ''A'' +ve or ''B''+ve ? Conventionally it shoul
How does temperature affect the action of enzymes upon their substrates? There are explained temperature ranges under which enzymes operate and there is a specific temperature
Define the lens transparency in metabolism of lens. Lens Transparency: a. Transparency depends on avoidance of large transitions of refractory index. This is in other wor
what is he importance of proteins for living beings
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