MEMBRANE
1. CELL Properties:
a.
Thin, flexible membrane
b.
Semipermeable (selectively permeable) membrane
2. Function:
a.
Controls the movement of nutrients, wastes across the membrane
b.
Site of some metabolic reactions - production of energy
3. Composition:
a.
Phospholipids & proteins
b.
Structure of phospholipids:
1).
2).
4.
Phosphate head - hydrophilic
Fatty acid tails - hydrophobic
Bilayer of phospholipids forms cell membrane
a.
Proteins molecules:
1).
Some extend through both lipid layers forming pores
2).
Some adhere to inside of membrane - usually enzymes
3).
Some capable of movement between the lipid layers
b.
Fluid mosaic model - lipids in fluid state, structure is constantly
c.
Movement across the membrane
changing
1).
Passive transport - osmosis, diffusion, facilitated diffusion
2).
Active transport
. CYTOPLASM
1.
Properties:
a.
b.
2.
Viscous fluid
Consistency of egg whites
Function:
a.
Filling of cell (cell sap)
b.
Suspension medium
c.
Site of most metabolic processes
3.
Composition :
a.
80% water
b.
20% soluble substances - nutrients, wastes
NUCLEOID
1.
Properties :
a.
b.
2.
Long, circular
Highly folded, suspended in cytoplasm
Composition :
a.
DNA
b.
Single molecule
c.
3.
Lacks histones
Function :
a.
Control center of the cell
1).
2).
b.
Controls metabolism
Contains reproduction
Controls genetic code (inherited characteristics)
RIBOSOMES
1.
Properties :
a.
b.
2.
Large, dense granules
Scattered through out cytoplasm
Composition :
a.
b.
3.
RNA
Proteins
Function :
Sites of protein synthesis
F. INCLUSIONS
NUTRIENT (STORAGE) GRANULES
1.
Properties :
a.
b.
2.
Very small, numerous
Scattered through out cytoplasm
Function :
Storage of nutrients
3.
Composition :
Insoluble nutrients :
a.
glycogen
b.
phosphate (volutin)
c.
inorganic ions (minerals)
VACUOLES
1.
Scattered in cytoplasm
2.
Gases, lipid droplets
SPECIAL CELL STRUCTURES
CAPSULE, SLIME LAYER (GLYCOCALYX)
1.
Properties :
a.
Jelly-like layer secreted by cell
b.
Adheres to cell wall
c.
Capsule - thick layer, regular
Slime layer - thin layer, loose fitting, irregular
2.
Functions :
a.
Capsule
1).
2).
b.
Protects the bacterium from phagocytes
Enhances bacteriums ability to produce disease
Slime layer
1).
Protects the cells against drying
2).
to each other
Allows bacteria to adhere to surfaces in their environment or
(colonize)
3.
Composition:
a.
Polypeptides and polysaccharides
b.
Exact composition varies in each individual species
4.
Found only on some cocci, bacilli
5.
Will not absorb dyes, need special staining techniques to observe