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

Effects of long term malnutrition on adults, Effects of long term malnutrit...

Effects of long term malnutrition on adults In adults, once the stored carbohydrates and fats are used up, the body starts using proteins to generate energy. These protei

Explain functions of proteins, Explain Functions of proteins Functions ...

Explain Functions of proteins Functions of proteins are included herewith. These include: Source of energy: Constituent amino acids can be deaminated and metabolized to

Describe the methods of assessment, Describe the Methods of Assessment ...

Describe the Methods of Assessment The four general principles outlined above, that is, adaptation, brain and behaviour, context, and development serve as the foundation for th

Define thrombospondin polymorphisms, Q. Define Thrombospondin Polymorphisms...

Q. Define Thrombospondin Polymorphisms Thrombospondin polymorphisms may present an initial insight into our understanding of the genetic contribution to coronary atherosclerosi

Define comprehensive dietary management regime of patient, Define Comprehen...

Define Comprehensive Dietary Management Regime of Patient? A comprehensive dietary management regime of the patient should be based on the patient profile as gathered pre and p

Describe the epithelial cells of the kidney proximal tubule, Epithelial cel...

Epithelial cells of the kidney proximal tubule ?   A.  The sodium-glucose co-transporter in the luminal membrane is responsible for the net flux of glucose from luminal space to

What are the uses of formycin b, What are the uses of formycin B? Formy...

What are the uses of formycin B? Formycin B is a drug used to demolish of intestinal parasites.

What are the main degenerative diseases of the heart, Q. What are the main ...

Q. What are the main degenerative diseases of the heart? The major degenerative diseases of the heart are heart failure, arrhythmias, valvular heart diseases, coronary insuffic

Extractive use of biodiversity, Q. Extractive use of biodiversity? This...

Q. Extractive use of biodiversity? This includes direct use such as harvesting of wild plant species for use as food, fuel, fodder, fibre, shelter or medicine and hunting anima

Educate the mothers regarding prevention of diarrhoea, Educate the Mothers ...

Educate the Mothers Regarding Prevention of Diarrhoea   While working  in the diarrhoea clinic, ward or community, your major responsibility as a nurse is to educate mothers re

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