Biology Pt.2 Flashcards
Improvement with lens technology came with new understandings of the cell, what did Robert Brown Identify?
He identified the nucleus of the cell as being responsible for controlling the cell
What did Schleiden and Schwann do?
They observed plant and animal cells, and together proposed that all plant and animals are composed of cells (cells are the basic unit of life)
What did Rudolf Virchow do?
expanded on Schleiden and Schwanns theory of cells and believed that all cells come from pre-existing cells
What is the summary of cell theory (3 things)
1) all living things are made up of one or more cells
2) all living functions take place in cells making them the smallest unit of life
3) all cells are produced from pre-existing cells through the process of cell division (mitosis)
What are three things that affect the quality of an image in microscopy
Magnification - light microscopes used today can now magnify between 1000x-2000x
Contrast - the variation of shadow and color
Resolution - the ability to distinguish between two structures that are close together
How does Fluorescent Microscopy Work?
Fluorescent stains called GFP are introduced to the specimen, different cell structures absorb stains in different amounts
What are Brightfield Miscroscopes
Light passes through but has limited resolution
What does Confocal Technology do
uses lasers and computers to focus the light, the later reflects off of the object and back into the eyepiece
Why do fluorescent stains work better with confocal microscopes?
because they eliminate the blurriness of the reflected light
How does Electron Microscopy work?
it uses a fine beam of electrons instead of light, the electrons pass though different materials at different rates due to differences in density.
Instead of lenses, Electron Microscopy uses ________ _______ to focus on the image
Magnetic Fields
How do Transmission Electron Microscopes work? (TEM)
Electrons pass through the specimen and has 100x better magnification and resolution than the light microscope
It is difficult for Transmission Electron Microscopes (TEM) to produce ____ images
3D Images
In TEM microscopes, specimens are “fixed” and “stained,” what does this mean?
living specimens cant be observed
Scanning Electron Microscopes (SEM) are good for observing what?
surface features of specimens
