The Cell Flashcards
Cell theory principles
- All organisms are composed of one or more cells. Life processes occur in these cells.
- Cells are the basic units of organisation in all organisms.
- A cell can arise only by division of a previously existing cell.
Light microscopes operate using ____ light
visible
Light microscopes are able to resolve structures that are at least ____ apart
200 nm
Transmission electron microscopes resolve images ____ apart
0.2nm
Principles of scanning electron microscopes
Electrons are beamed on the surface of the specimen and reflected back. Other electrons from the specimen are released from the bombardment. Electrons are then amplified and transmitted to a screen to produce a 3D image.
The DNA within prokaryotes is and found in a region called
circular; the nucleoid
The double membrane surrounding the nucleus of eukaryotic cells is called
the nuclear envelope
Types of proteins in the plasma membrane
- Transport proteins - help ions and molecules move across the phospholipid bilayer
- Receptor proteins
Two main domains of prokaryotes
Bacteria and archaea
Bacterial cell walls are composed of
peptidoglycan
Function of the bacterial cell wall
Maintains shape of cell, protects the cell and prevents excessive loss or uptake of water.
Nucleolus
Region within the nucleus where synthesis of rRNA takes place
Nucleosome is composed of
DNA wrapped around histone proteins
Eukaryotic cells have an internal protein scaffold called
the cytoskeleton
T/F: Animal, fungi and plant cells possess a cell wall.
False, only fungi and plant cells possess a cell wall.
