cell theory states that all cells come from pre-existing cells.
cell theory states that all cells come from pre-existing cells.
cell theory states that all cells come from?
from pre-existing cells
in biology, cell theory is the historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells. cells are the basic unit of structure in all organisms and also the basic unit of reproduction. with continual improvements made to microscopes over time, magnification technology advanced enough to discover cells in the 17th century. this discovery is largely attributed to robert hooke, and began the scientific study of cells, also known as cell biology. over a century later, many debates about cells began amongst scientists. most of these debates involved the nature of cellular regeneration, and the idea of cells as a fundamental unit of life. cell theory was eventually formulated in 1839. this is usually credited to matthias schleiden and theodor schwann. however, many other scientists like rudolf virchow contributed to the theory. it was an important step in the movement away from spontaneous generation.
cell theory
cells, which were once invisible to the naked eye, were first seen in 17th century europe with the invention of the compound microscope. robert hooke was the first person to term the building block of all living organisms as "cells" after looking at cork. the cell theory states that all living things are made up of cells. the theory also states that both plants and animals are composed of cells which was confirmed by plant scientist, matthias schleiden and animal scientist, theodor schwann in 1839. 19 years later, rudolf virchow contributed to the cell theory, arguing that all cells come from the division of preexisting cells. in recent years, there have been many studies which question the cell theory. scientists have struggled to decide whether viruses are alive or not. viruses lack common characteristics of a living cell, such as membranes, cell organelles, and the ability to reproduce by themselves. viruses range from 0.005 to 0.03 micrometers in size whereas bacteria range from 1-5 micrometers. modern day cell biology research looks at different ways to culture and manipulate cells outside of a living body to further research in human anatomy and physiology, to derive treatments and other medications, etc. the techniques by which cells are studied have evolved. advancement in microscopic techniques and technology such as fluorescence microscopy, phase-contrast microscopy, dark field microscopy, confocal microscopy, cytometry, transmission electron microscopy, etc. have allowed scientists to get a better idea of the structure of cells.
cell biology