Chaper 2 Flashcards
What is a cell?
The smallest unit of all living organisms.
What is a tissue?
A group of similar cells
What is an organ?
Different tissues working together to carry out a function.
What is an organ system?
A group of organs working together to carry out a function.
Why are microscopes needed?
To discover microorganisms
To obtain a detailed image of cells
Study cell biology
What does a light microscope consist of?
A series of lenses and an eyepiece.
How does a light microscope work?
The light from the bulb travels through the condenser lens, then the specimen, up through the objective lens, and finally through the eyepiece lens into your eye.
How do you calculate total magnification?
eyepiece X objective
What is magnification?
How much larger an object appears compared to the actual size of the object.
What is resolution?
The ability to distinguish between two points that are very close together. The higher the resolution, the more detailed an image will appear.
Why do specimen need to be stained before using a microscope?
to better visualize cells and cell components under a microscope.
How does a TEM work?
Electron beam passes through very thinly prepared sample. More dense areas of the sample don’t allow the electrons through as easily. this allows the 2D image to be created.
magnification of x500,000
short wavelength
How does a SEM work?
Electrons directed onto the sample don’t pass through, but bounce off which creates a 3D image.
magnification of 100,000
short wavelength
How large are cells?
5-500 micrometers
How is actual size calculated?
image size/magnification
