OSU Microbiology 4000 Midterm 1 Test
Questions and Answers.
Coccus - Answer spherical
Bacillus - Answer rod-shaped
Spiral (3 types) - Answer 1. Vibrio
2. Spirillum
3. Spirochete
Vibrio - Answer Curved
Spirillum - Answer wave-like like the noodles
spirochete - Answer corkscrew
Diplo- - Answer division in one plane; a pair (occurs with cocci and bacilli)
Strepto- - Answer Chains (occurs in bacilli and cocci)
Staphylo- - Answer clusters (occurs only with cocci)
tetrad - Answer cluster of 4 cocci
sarcinae - Answer cluster of 8 cocci
Monomorphic bacteria - Answer always exhibit one morphology (most bacteria fall into this
category)
Pleomorphic bacteria - Answer exhibit more than one morphology
Examples of pleomorphic bacteria - Answer 1. Rhizobium
2. corynebacterium
, Glycocalyx - Answer 1. Made up of polysaccharides (sugars) and a few proteins (polypeptides)
2. Usually sticky
3. Located outside cell wall
Capsule - Answer (prevents phagocytosis by host cell)
A sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and
sometimes helping to glue the cell to surfaces.
Slime layer - Answer glycocalyx is unorganized and loosely attached to cell wall; allows cells
to attach (i.e. to teeth or intestinal wall)
General functions of glycocalyx - Answer 1. Absorbs h2o from surroundings to prevent
dehydration
2. Energy source when nutrients are unavailable
size of a eukaryote vs. bacteria - Answer typical eukaryote= 100X bigger than bacteria
(prokaryote)
Functions of cell wall - Answer 1. prevents osmotic lysis, rigidity, shape
2. composition and structure
3 components of peptidoglycan - Answer 1. Disaccharide polymer/glycan backbone (NAG,
NAM arranged in alternating fashion form 1 row of polymer)
2. Tetrapeptide side chains always attached to NAM
3. Peptide cross-bridges (attach to 2 hanging chains; belong to 2 different rows of
polysaccharide)
Peptidoglycan thickness - Answer Gm+ Thick (stains purple)
Gm- Thin plus outer membrane (stains pink/red)
Teichoic acids - Answer Present in Gm+ bacteria
Composition of outer membrane in Gm- bacteria - Answer 1. Lipopolysaccharides (LPS):
*O polysaccharide (antigenic variation)
*Lipid A (endotoxin-causes body to go into shock)
Questions and Answers.
Coccus - Answer spherical
Bacillus - Answer rod-shaped
Spiral (3 types) - Answer 1. Vibrio
2. Spirillum
3. Spirochete
Vibrio - Answer Curved
Spirillum - Answer wave-like like the noodles
spirochete - Answer corkscrew
Diplo- - Answer division in one plane; a pair (occurs with cocci and bacilli)
Strepto- - Answer Chains (occurs in bacilli and cocci)
Staphylo- - Answer clusters (occurs only with cocci)
tetrad - Answer cluster of 4 cocci
sarcinae - Answer cluster of 8 cocci
Monomorphic bacteria - Answer always exhibit one morphology (most bacteria fall into this
category)
Pleomorphic bacteria - Answer exhibit more than one morphology
Examples of pleomorphic bacteria - Answer 1. Rhizobium
2. corynebacterium
, Glycocalyx - Answer 1. Made up of polysaccharides (sugars) and a few proteins (polypeptides)
2. Usually sticky
3. Located outside cell wall
Capsule - Answer (prevents phagocytosis by host cell)
A sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and
sometimes helping to glue the cell to surfaces.
Slime layer - Answer glycocalyx is unorganized and loosely attached to cell wall; allows cells
to attach (i.e. to teeth or intestinal wall)
General functions of glycocalyx - Answer 1. Absorbs h2o from surroundings to prevent
dehydration
2. Energy source when nutrients are unavailable
size of a eukaryote vs. bacteria - Answer typical eukaryote= 100X bigger than bacteria
(prokaryote)
Functions of cell wall - Answer 1. prevents osmotic lysis, rigidity, shape
2. composition and structure
3 components of peptidoglycan - Answer 1. Disaccharide polymer/glycan backbone (NAG,
NAM arranged in alternating fashion form 1 row of polymer)
2. Tetrapeptide side chains always attached to NAM
3. Peptide cross-bridges (attach to 2 hanging chains; belong to 2 different rows of
polysaccharide)
Peptidoglycan thickness - Answer Gm+ Thick (stains purple)
Gm- Thin plus outer membrane (stains pink/red)
Teichoic acids - Answer Present in Gm+ bacteria
Composition of outer membrane in Gm- bacteria - Answer 1. Lipopolysaccharides (LPS):
*O polysaccharide (antigenic variation)
*Lipid A (endotoxin-causes body to go into shock)
