1. Bacterial Ultrastructure
Plate 12
Bacterial Ultrastructure

2. Structure & Function Structure is directly related to function
What a structure does is reflected in what it looks like

3. Flagella Flagella – thin fibers made of protein
As proteins change shape the flagella moves in a whip-like manner
Can move cell or push material around

5. Capsule Secreted by cell and adheres to outer part of cell
Made of polysaccharides and protein
Stores nutrients
Protects against dehydration, harmful chemicals, & phagocytosis

6. Capsule Also called glycocalyx when it’s a looser consistency
Many bacteria that are harmful to humans have capsules

7. Cell Wall Provides cell with shape and a rigid framework
Offers some protection

8. Cell (Plasma) Membrane
Found between cytoplasm and cell wall
2 purposes:
allow passage of some materials
blocks passage of some materials

9. Pili Pili – short tube-like structures
Allow attachment to surfaces and transfer DNA between bacteria cells

10. Mesosome Mesosome – coiled inner surface of membrane
May act to attach DNA during replication
May be produced when cells are chemically fixed for electron microscopy

11. Nucleoid Nucleoid – dark area with nucleic acid
There isn’t a membrane around DNA in bacteria
Smaller areas with DNA are plasmids

12. Plasmids Plasmid – small loop of DNA
Several dozen plasmids may be found in cytoplasm

13. Cytoplasm & Ribosome
Cytoplasm – gel/solid material inside cell membrane
Chemical reactions and all other life activities take place in cytoplasm
Ribosome – site of protein synthesis, different (smaller) than eukaryotic ribosome

14. A review