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

Define distribution of body iron in different compartments, Define Distribu...

Define Distribution of body iron in different compartments? In humans, the total quantity of iron in the body varies with haemoglobin concentration, body weight, gender and the

Pollination, how pollination occurs in Salvia?

how pollination occurs in Salvia?

Canine parvovirus infections, Canine parvovirus infections The canine p...

Canine parvovirus infections The canine parvovirus infections are caused by a virus, which belongs to the genus Parvovirus in the family Parvoviridae. This virus is similar to

Explain theory of evolution through natural selection, Explain Theory of Ev...

Explain Theory of Evolution through Natural Selection The third theory of evolution through natural selection was put forward jointly by Darwin, and Wallace in 1859. This theor

Ionosinin ic pathway , how ionosinic pathway ric acid from ammonia forms ...

how ionosinic pathway ric acid from ammonia forms u

Determine the factors affecting fertilizer requirements, Factors Affecting ...

Factors Affecting Fertilizer Requirements   The rapid increase in the use of fertilizers is based on the fact that large profits are obtained from the money invested in them. The

Difference between myosin and actin filaments, DIFFERENCE S BETWEEN MYOSIN...

DIFFERENCE S BETWEEN MYOSIN AND ACTIN FILAMENTS     Myosin filaments (primary filaments)   Actinfilament s (secondary filaments)

Define the recommended dietary allowances of vitamin k, Define the Recommen...

Define the Recommended Dietary Allowances of Vitamin K? Recommended dietary intakes have not been suggested for different age groups or gentler. The safe levels of intake have

Seed dispersal, what are the characteristics of the stages in seed dispersa...

what are the characteristics of the stages in seed dispersal

What is the etiology of cholera, Q. What is the etiology of cholera? T...

Q. What is the etiology of cholera? The most common cause of cholera is consumption of food or drinking water that has been contaminated with the bacteria. It is important to

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