2.1 Cell structure Flashcards
Magnification and resolution of a light microscope
x1500
200 nm
Magnification and resolution of a TEM
> x500,000
0.5 nm
Magnification and resolution of a SEM
x500,000
3-10 nm
What is the image from a TEM
2D
Black and White
Organelles visible
What is the image from an SEM
3D
Black and White
Cell surface visible
Advantages/Disadvantages of light microscope
Cheap
Easy to use
Can view live cultures / tissues
2D images only
cannot view most organelles
Advantages/Disadvantages of TEM
More organelles can be seen
Very high magnification + resolution
Dead specimen
Very thin specimen
Lengthy treatment to produce thin specimens
Advantages/Disadvantages of SEM
External 3D structure
Lower resolution than TEM
Dead specimens
Why is staining used?
Increases the contrast between organelles so differnet organelles can be viewed
Increases the contrast so biological molecules can be seen
Function of the nucleus
Contains DNA
Controls production of mRNA
Starts mitosis
Function of nucleolus
Manufactures ribosomal RNA and assembles the ribosomes
Ribosomes pass through nuclear pores
Function of the Nuclear envelope
Double membrane
Contains nuclear pores - mRNA and ribosomes pass out and nucleotides pass in
Function of Rough Endoplasmic Reticulum
Transports proteins made on attached ribosomes
Function of Smooth Endoplasmic Reticulum
Lipid, carbohydrate and steroid synthesis - stored in the SER and transported when needed
Function of the Golgi apparatus
Modifies proteins and lipids before packaging them into Golgi vesicles