2. Prokaryotes (cells without a nucleus) Flashcards
1
Q
What are the three domains?
A
Archaea, Bacteria and Eukarya
2
Q
What is a prokaryote?
A
A cell that does not have membrane enclosed internal compartments, particularly a nucleus.
3
Q
What is the basic structure that all prokaryotes have?
A
- Plasma membrane that encloses the cell
- Nucleoid where DNA Is located
- Cytoplasm
- Cytosol which is mostly water, dissolved ions and soluble macromolecules
- Ribosomes
4
Q
Do prokaryotes have a cell wall?
A
Most prokaryotes have a cell wall located outside the plasma membrane.
- Cell walls of most bacteria, but not archaea contain peptidoglycan.
- Some bacteria have another layer, the outer membrane (gram -)
5
Q
What is the filament of the flagellum made of in bacteria?
A
A protein called flagellin
6
Q
Is the bacterial flagella extracellular or intracellular?
A
Extracellular (not inside the cell membrane)
7
Q
How do prokaryotes divide?
A
By binary fission
- replication of circular molecule of DNA
- attachment of two DNA molecules to plasma membrane at 2 different places
- lengthening of cell
- division of the cell into two via a constriction process across the middle of the cell so that each new cell contains one molecule of DNA.
8
Q
Features of eukaryotic cells not seen in prokaryotes?
A
- Division of labour in the cytoplasm
- Nucleus and histones
- Endomembrane system
- ER
- Golgi complex
- Cytoskeleton
- Microtubules
- Microfilaments
- Intermediate filaments
- Motor proteins and movement
9
Q
What is the nucleolus?
A
Subregion of nucleolus where genes are transcribed.
