Prokaryotic Cells Flashcards
1
Q
How do prokaryotic cells replicate?
A
Binary Fission
2
Q
How do prokaryotic cells replicate by binary fission?
A
- Circular DNA molecule is replicated once. Plasmids are replicated multiple times
- Cell expands, each circular DNA molecule moves to an opposite end of the cell
- Cytoplasm divides and a new cell wall forms
- We end with two daughter cells. Each have one copy of circular DNA molecule but can have variable number of plasmids
3
Q
How do viruses replicate?
A
- Viruses are not living. Therefore, they cannot replicate via cell division
- Viruses use their attatchment proteins to bind to complemenrary receptor proteins on surface of the host cell
- They then inject their DNA/RNA into the host cell
- The host cell then uses its enzymes, ribosomes etc. to replicate the virus particles
4
Q
Basic Structure of a Prokaryotic Cell
A
8
- Cell Wall
- Plasma Membrane
- Cytoplasm
- Ribosomes
- Circular DNA
- Plasmids
- Capsule
- Flagellum
5
Q
Cell Wall
A
- Supports + strengthens the cell. Prevents it from changing shape
- Made of murein (glycoprotein)
6
Q
Plasma Membrane
A
- Made up of lipids + proteins
- Controls substances entering + leaving the cell
- Receptor molecules on surface, which can respond to chemicals such as hormones
7
Q
Cytoplasm
A
- No membrane bound organelles
8
Q
Ribosomes
A
- 70s ribosomes (smaller)
- No surrounding membrane
- Site of protien synthesis
- Free flowing in cytoplasm
- Contain RNA + protein
9
Q
Circular DNA
A
- Free floating in cytoplasm
- Not attached to any histone proteins
- One long coiled DNA strand
10
Q
Plasmids
A
- Bits of DNA not part of the original circular DNA molecule
- Some cells have many, some cells have none
- Can be passed between cells
- Contain genes e.g. gene for antibiotic resistance
11
Q
Capsule
A
- Made of secreted slime
2. Protects cell from attack of cells of immunse system
12
Q
Flagellum
A
- Long hair like structure
- Rotates to make cell move
- Some cells have none, some have many
13
Q
How many differences are there between eukaryotic cells (EC) and prokaryotic cells (PC)
A
- EC have membrane bound organelles in cytoplasm. PC do not
- DNA in EC is attached to histone proteins. DNA in PC is not attached to histone proteins
- EC have 80s ribosomes. PC have 70s ribosomes
- EC have nucleus. PC have no nuclues, just a molecule of circular DNA
- PC have plasmids. EC do not
- PC have flagella. EC do not
- PC have capsule. EC do not
- In EC, cell wall can be made of chitin or cellulose. In PC, made of murein
14
Q
Structure of virus
A
- Protein coat, capsid
- Core of genetic material
- Attatchment proteins (allow it to attach to host cell, viruses reproduce inside host cell)
15
Q
Viruses
A
Acellular. Non-living.
