B1 Cells And Organisation Flashcards
What is the formula for total magnification?
Total magnification = Eyepiece magnification x objective lens magnification
What is the formula triangle for magnification?
Image size
/
Magnification x size of real object
Resolving power
The measure of the ability to distinguish two separate points that are very close together
How do light microscopes magnify and what is their maximum magnification?
Uses a beam of light to form an image of an object and can magnify up to 2000 times
What are some advantages of the light microscope?
- Relatively cheap
- Easy to use
- Can be used almost anywhere
- Can magnify live specimens
What are the disadvantages of light microscopes?
Magnification isn’t very high: you can see cells and some structures but not the details of organelles
When was the electron microscope invented?
In the 1930s
How does an electron microscope work and what is the maximum magnification?
Electron microscopes use a beam of electrons to form an image and can magnify and object up to around 2,000,000 times
How many micrometres in a mm?
1000
How many micrometres in a nanometre?
1000
What’s the function of the cytoplasm
A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.
What is the function of the nucleus?
Contains genetic material, including DNA, which controls the cell’s activities.
What is the function of the cell membrane?
It controls the movement of substances in and out of the cell.
Mitochondria
Organelles that contain the enzymes for respiration, and where most energy is released in respiration.
Ribosomes
A tiny organelle where protein synthesis occurs.
