1. Cell Structure and Function
Chapter 3

2. There are 2 types of cells
Prokaryotes
Eukaryotes

3. Prokaryotes
Do NOT have a membrane surrounding genetic material, therefore, can make proteins simultaneously when reading genetic code.
Lack some structures found in Eukaryotic cells

4. Eukaryotes Have a membrane surrounding their DNA, forming a NUCLEUS
Contain numerous internal membranes that have specific functions, called ORGANELLES

5. External Structures – Bacteria
Glycocalyces – Sugar based external surrounding firmly attached to cell’s surface.
Flagella – Tail like structure that propels bacteria (also found on sperm cells). Flow of hydrogen and sodium ions allows movement.
Fimbriae and Pili – Hair like structures that adhere to surfaces to move bacterium.

6. Cell Walls
Found in most prokaryotes – allows attachment to other cells and resistance to antimicrobial drugs.
Eg. Penicillin attacks cell walls of microbes
Peptidoglycan – Polysaccharide, divides cells into two types:
Gram-Positive (Thick layer of peptidoglycan)
Gram-Negative (Thin layer of peptidoglycan)

7. Cytoplasmic Membrane
Made up of a PHOSPHOLIPID BILAYER: outside is hydrophilic and inside is hydrophobic
Selectively Permeable, but naturally impermeable to large objects
Concentration Gradient – Concentration of sodium ions can attract and repel charged substances into and out of cells.

9. Diffusion
Simple Diffusion - When a small, non-polar molecule passes through a lipid bilayer.
Channel Diffusion - Channel proteins where material moves through an open, aqueous pore.
Facilitated diffusion - Type of passive transport that is dependent on single transport protein carriers.

10. Osmosis
Movement of water across a selectively permeable membrane driven by a difference in solute concentrations on the two sides of the membrane.

11. Cytoplasm Gelatinous material inside of a cell
Liquid portion is called CYTOSOL
Contains INCLUSIONS– Deposits of small compounds within the cytoplasm

12. Endospores Produced by Bacillus and Clostridium NOT FOR REPRODUCTION
Constitute a defensive strategy for hostile or unfavourable conditions

13. Nonmembranous Organelles
Ribosomes – Sites of protein synthesis
Cytoskeleton – Structure of proteins which gives cells structure and movement:
Microfilaments: Fine, thread-like protein fibers, 3-6 nm in diameter
Microtubules: Cylindrical tubes, nm in diameter
Intermediate filaments are about 10 nm diameter and provide tensile strength for the cell.

14. Archaea Glycocalyces
Same characteristics as bacterial glycocalyces

15. Archaea Flagella Similar to bacterial flagella
About half the thickness (10-14 nm)

16. Fimbriae and Hami Fimbriae – nonmotile, rodlike, sticky projections
Hami – Fimbria of archaea. Filament frays into 3 hooks. Used for attachment

17. Eukaryotic Glycocalyces
Most animal and protozoan cells lack cell walls
Glycocalyces are anchored through covalent bonds

18. Eukaryotic Cell Walls and Membranes
Cell walls of plants are made of cellulose
Cell walls of fungi are made of chitin or glucomannan
Cell walls of algae are made of cellulose, proteins, agar, carrageenan, silicates, algin, calcium carbonate, or a combination of the aforementioned
ALL have cytoplasmic membrane

19. Centrioles and Centrosome