Topic 2: Cells 2.1 Cell Theory
2.1.1 Outline the Cell Theory * Living organisms are composed of one or more cells * Cells are the smallest unit of life * Cells must come from pre-existing living cells
2.1.2 Discuss the evidence for the cell theory
The cell theory has amassed tremendous credibility through the use of the microscope in the following: * Robert Hooke- studied cork and found little tiny compartments that he called cells * Antonie Van Leeuwenhoek- observed the first living cells, called them 'animalcules' meaning little animals * Schleiden- stated that plants are made of 'independent, separate beings' called cells * Schwaan- made a similar statement to Schleiden about animals
2.1.3 State that …ver más…

And peripheral blood stem cells, as well as cord blood stem cells, can be used in lieu of bone marrow, making being a donor FAR easier today than in decades past.
State that a virus is a non-cellular structure consisting of DNA or RNA surrounded by a protein coat. * Viruses are not cells. They are simple particles consisting of DNA and RNA wrapped in a protein coat. Viruses are not considered alive because they have no metabolism and they require a host to live. Viruses do not carry out all the functions of life, therefore they are not living.

Explain three advantages of using light microscopes.
Light microscopes * Display color instead of monochrome (black and white) images. * Provide a large field of view. * Facilitate preparation of sample material. * Allow for the examination of living material and the observation of movement. * Cheap in comparison to electron microscopes

Outline the advantages of using electron microscopes.
Electron microscopes: * Provide images of higher resolution and magnification than light microscopes. * Resolution refers to the ability to distinguish two objects as separate entities. * Magnification refers to the ability to increase the size of a viewed object.
Scanning Electron Microscopes (SEM) provide images of the specimen's surface while Transmission Electron Microscopes (TEM) provide images of a sample's interior. The resolution of an SEM is approximately half that