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

Viruses, are viruses cellular organisms

are viruses cellular organisms

Chronic aortic regurgitation-indications for surgery, Chronic Aortic Regurg...

Chronic Aortic Regurgitation :  Several factors have to be taken into account before recommending surgery. These include severity of symptoms and LV function. With evidence o

What is enzyme kinetics, What is enzyme kinetics The study of the rate ...

What is enzyme kinetics The study of the rate at which an enzyme works is called enzyme kinetics.

Congenital defects related to kidney/upper urinary tract, Congenital Defect...

Congenital Defects Related to Kidney/Upper Urinary Tract i) Renal Agenesis  A new born baby with this condition may show low set ears, flat nose, prominent epicanthic

Differ from our current use of retroviruses, In what way may we be able to ...

In what way may we be able to take advantage of retrotransposons in human gene therapy? How would this differ from our current use of retroviruses?

Determine the term - neuropsychological approach, Determine the term - Neur...

Determine the term - Neuropsychological approach The neuropsychological approach relies on the use of tests in which poor performance may indicate either focal (localised) or d

Dfine integrated child development services (icds), Dfine Integrated Child ...

Dfine Integrated Child Development Services (ICDS)? The adolescent girl scheme under ICDS intends to cover school dropout girls, 11-18 years in age with a view to meet their ne

Oxidative decarboxylation of pyruvate, Oxidative decarboxylation of pyruvat...

Oxidative decarboxylation of pyruvate Oxidative decarboxylation ofpyruvate : This is an important step in tissues with high oxidative capacity such as cardiac muscle, whereby

Advantages and disadvantages of measurement of cell mass, Define Advantages...

Define Advantages and Disadvantages of Measurement of Cell Mass? Advantage 1. It is a useful technique for estimating fungal and actinomycetes growth. Disadvantages 1.

Explain the compartments of body water, Explain the Compartments of Body Wa...

Explain the Compartments of Body Water? Within the body, water is found in two major compartments. These are: - The intracellular compartment (inside the cell) - The extr

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