Lecture 2 Flashcards
Cell Size (Av. 2 Micrometer)
High Surface to volume = Nutr./wste in/out quickly = rapid cell growth
Can occupy a small space
Cell Appearance
Bacillus (Rod)
Coccus (round)
Spirochete (spiral)
Singles, pairs, clusters, or chains
Cytoplasm
DNA site (Chromosome and plasmids)
Site of biochemical reactions
- Biosynthetic enzymes
- Nutrient Storage sites
- Ribosomes (protein synthesis)
Proc. vs. euc. ribosomes = Same function =/ Different structure
Neg. wall/envelope
A. PM
B. Peptidoglycan (thin) (one or two layers)
C. Outer Membrane
Pos. Wall/envelope
A. PM
B. Peptidoglycan (Thick) (Several dozen PG)
Plasma Membrane
Phospholipid Layer + Embedded proteins
Functions: Permeability Barrier: Leakage of cytoplasmic
Metabolic Proteins: Biosynthetic and energy generating proteins
Transport nutr. in/out
Peptidoglycan (PG)
Found only in bacteria (Not in eukaryotic cells)
2 units of carbs + 4 amino acids
PG
Broken by certain enzymes
Gram Strain based on structural difference of PG thickness
Outer Membrane (gram Neg. only)
Porins
Lipopolysaccharide (LPS) (3 part lipid + carb structure)
LPS / Endotoxin (Only in bacteria)
Lipid A anchors LPS to outer membrane (Causes shock, inflammation, fever)
O antigen is exposed in the environment (stimulates the immune system)
Non Pyrogenic
No Bacteria
Acid Fast Bacteria (eg. Mycobacterium tuberculosis)
Envelope = Inner membrane + Peptidoglycan + Mycolic acid outer layer
Mycolic acids:
Waxy fatty acids
Resistance to germicides, environmental stresses
Stains are difficult to remove => Acid - Fast
Atypical Bacteria
Mycoplasma
Chlamydia
Mycoplasma
- mild pneumonia
- no PG; OM -> single phospholipid membrane
Fragile due to lack of PG
Chlamydia
-No PG -> IM + OM
Fragile due to lack of PG
Flagella
Mobility
Pili (Fimriae)
Attaches
Sex pili: Bacteria Common pili (required to cause disease) = Eukaryotic cells and tissues
Capsular Polysaccharide
Surrounds entire cell
Appears slimy
Pathogenic/environmental bacteria
Protection
Attachment (biofilm)
Bio Film
Bacteria attached via Capsular Polysaccharide (Helps persist)
Single = Human infections Multi = Natural environments
60% of bacterial infections
Form on Medical devices (Hard to remove with antibiotics)
Bacteria Spores (endoSpores)
Bacteria cell (mostly gram positive) vegetative (growing) form into dormant form (spore)
triggered by environmental stress
DNA encased in PG coat
RESISTANT
