Cell theory, Biology

Assignment Help:

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.

 

1299_Cell Theory.png

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.

 


Related Discussions:- Cell theory

Name the source gland of leutinising hormone, Name the source gland of leut...

Name the source gland of leutinising hormone (LH). State the other hormone along with which it acts on its target cells/organ. Give their two functions.

Define the v2 receptor antagonist, Define the V2 receptor antagonist A ...

Define the V2 receptor antagonist A new drug named ANTI-V2R has been developed that is a V2 receptor antagonist.  When ANTI-V2R binds to a V2 receptor, there is no binding of v

Coa to succinate in the citric acid cycle, Name the high-energy complex gen...

Name the high-energy complex generated during the conversion of succinyl CoA to succinate in the citric acid cycle GTP  or  ATP is  the high-energy  complex generated during th

Name groups of living beings that form the protist kingdom, Which are the g...

Which are the groups of living beings that form the protist kingdom? The protist kingdom contains protozoans and algae. (Two groups of fungi with same characteristics to protoz

Mitochondria, Mitochondria Mitochondria are commonly known as the "pow...

Mitochondria Mitochondria are commonly known as the "power house" of cells. These are the distinct organelles of all eucaryotic cells, plants, fungi and some protists. In the

Cell theory, Cell theory is one of the four (or five) unifying concepts in...

Cell theory is one of the four (or five) unifying concepts in the biology. The cell theory states that all the living things are composed of at least one cell and that cell is the

Explain adverse effects of enfuvirtide, Adverse effects of Enfuvirtide ...

Adverse effects of Enfuvirtide Almost all patients make local injection site reactions to enfuvirtide, usually having of mild or moderate pain, erythema, induration, nodules an

Secretion of hormones, Secretion of Hormones The secretion of most hor...

Secretion of Hormones The secretion of most hormones (except steroid) is by the process of exocytosis. Figure summarises the formation, transport, release and reconstitution o

Provide the definition of health care, Provide the Definition of Health Car...

Provide the Definition of Health Care? Health care involves much more than just medical care and can be defined as "multitude of services provided to individuals or communities

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd