MICRO 401 EXAM 1 QUESTIONS AND VERIFIED
ANSWERS
What is microbiology? - Answers - The study of organisms too small to be seen with the
unaided eye
What are four types of microorganisms? - Answers - Bacteria, fungi, parasites and
viruses
What are two cell types? - Answers - Prokaryote (bacteria, algae)
Eukaryote (animals, fungi)
Differ in structure and complexity, similar in that they have the same metabolic reactions
taking place
Describe the structural organization of a bacterial cell.. - Answers - Appendages
(flagella, fimbriae, common pili, sex pilus)
Cell envelope (glycocalyx- slime layers or capsule, cell wall, cell membrane)
Cytoplasm (cell pool, nucleoid, plasmids, ribosomes, inclusion bodies)
Endospores
What is flagella? - Answers - Motility. Directed movement influences by positive and
negative chemotaxis. Composed of multiple units of the protein flagellin.
What is a virulent factor? List some examples.. - Answers - Virulent- factors that are
advantageous to pathogenisis
Examples: flagella, fimbriae or pili, slime layer or capsule, toxin production, plasmids,
and endospores
What are fimbriae or common pili? - Answers - Frimbriae are present in a higher amount
than pili. Multiple units composed of the protein pilin. The terminal unit has the ability to
stick to substances on surfaces and enable the bacteria to adhere
What is a sex pilus? - Answers - Elongate, rigid, hollow tubular structure through which
DNA may be transferred. Limiting factor is the proximity of the two cells
What are the two types of cell envelopes/glycocalyx? - Answers - Slime layer- loose
soluble sheild non-uniform in density or thickness that protects cell from dehydration
and nutrient loss
Capsule: thick gelatinous polymer firmly attached to cell wall contributed to bacterial
virulence by protecting bacteria from phagocytosis and destruction by certain WBC's
Describe the cell wall.. - Answers - Rigid net-likematric of great strength that covers the
entire cell and maintains the cell shape, protects cell from osmotic lysis, thickness
, depends on if gram (+) or (-), and the primary component if the heteropolymer
peptidoglycan
What is petidoglycan? - Answers - Long polysaccharide chains of two repeating
disaccharides (glycan chains)- NAG and NAM. Glycan chains are cross-linked by short
tetrapeptides between NAM subunits
Describe gram negative cell wall.. - Answers - Outer membrane: largest part, external to
peptidoglycan layer, semipermiable, phospholipid bilayer, contains specialized proteins
(lipopolysaccharides, lipoprotein- imbedded in outer membrane and attaches to
peptidoglycan, porin protein-spans whole bilayer allows anything in regardless of
charge.)
Periplasmic space: narrow gap between inner and outer membrane, contains
degradative or hydrolytic enzymes, also contains the single peptidoglycan layer.
More complex than gram (+)
Describe gram positive cell wall.. - Answers - Multiple layers of peptidoglycan (90%)
Acidic polysaccharides (10%)- teichoic and lipoteichoic acid, span the pepidoglycan
layers reinforcing cross linking between glycan chains therefore increasing the rigidity of
the call and allow/assist in the transport of ions across the wall. More rigid than gram (-)
What is the cell membrane? - Answers - Phospholipid bilayer containing integral and
peripheral proteins.
What are the primary functions of the cell membrane? - Answers - Retains the
cytoplasm and is a selectively permeable barrier. Site of metabolic activities attributable
to organelles in eukaryotes (synthesis reactions, transport system, secretions)
What is the cytoplasm? - Answers - Internal matrix contained inside the cell membrane,
70-80% water
What is cell pool? - Answers - Complex mix of nutrient- carbohydrates, amino acids,
fatty acids and inorganic molecules. Components are building blocks for cell synthesis
and sources of energy
What is the nucleoid? - Answers - Single circle of double stranded DNA with specialized
proteins. Nonuniform dense region, contains genetic information for cell structure and
function, not enclosed by a membrane
What are plasmids? - Answers - Circular extrachomosomal strands of DNA found in
most but not all bacterial. They encode a variety of protective traits or selective
advantages such as antibiotic resistance, production of toxins and production of
enzymes
What are ribosomes? - Answers - Granules of RNA and proteins that function as sited
for protein synthesis. Found free in the cytoplasm or attached to inner membrane
ANSWERS
What is microbiology? - Answers - The study of organisms too small to be seen with the
unaided eye
What are four types of microorganisms? - Answers - Bacteria, fungi, parasites and
viruses
What are two cell types? - Answers - Prokaryote (bacteria, algae)
Eukaryote (animals, fungi)
Differ in structure and complexity, similar in that they have the same metabolic reactions
taking place
Describe the structural organization of a bacterial cell.. - Answers - Appendages
(flagella, fimbriae, common pili, sex pilus)
Cell envelope (glycocalyx- slime layers or capsule, cell wall, cell membrane)
Cytoplasm (cell pool, nucleoid, plasmids, ribosomes, inclusion bodies)
Endospores
What is flagella? - Answers - Motility. Directed movement influences by positive and
negative chemotaxis. Composed of multiple units of the protein flagellin.
What is a virulent factor? List some examples.. - Answers - Virulent- factors that are
advantageous to pathogenisis
Examples: flagella, fimbriae or pili, slime layer or capsule, toxin production, plasmids,
and endospores
What are fimbriae or common pili? - Answers - Frimbriae are present in a higher amount
than pili. Multiple units composed of the protein pilin. The terminal unit has the ability to
stick to substances on surfaces and enable the bacteria to adhere
What is a sex pilus? - Answers - Elongate, rigid, hollow tubular structure through which
DNA may be transferred. Limiting factor is the proximity of the two cells
What are the two types of cell envelopes/glycocalyx? - Answers - Slime layer- loose
soluble sheild non-uniform in density or thickness that protects cell from dehydration
and nutrient loss
Capsule: thick gelatinous polymer firmly attached to cell wall contributed to bacterial
virulence by protecting bacteria from phagocytosis and destruction by certain WBC's
Describe the cell wall.. - Answers - Rigid net-likematric of great strength that covers the
entire cell and maintains the cell shape, protects cell from osmotic lysis, thickness
, depends on if gram (+) or (-), and the primary component if the heteropolymer
peptidoglycan
What is petidoglycan? - Answers - Long polysaccharide chains of two repeating
disaccharides (glycan chains)- NAG and NAM. Glycan chains are cross-linked by short
tetrapeptides between NAM subunits
Describe gram negative cell wall.. - Answers - Outer membrane: largest part, external to
peptidoglycan layer, semipermiable, phospholipid bilayer, contains specialized proteins
(lipopolysaccharides, lipoprotein- imbedded in outer membrane and attaches to
peptidoglycan, porin protein-spans whole bilayer allows anything in regardless of
charge.)
Periplasmic space: narrow gap between inner and outer membrane, contains
degradative or hydrolytic enzymes, also contains the single peptidoglycan layer.
More complex than gram (+)
Describe gram positive cell wall.. - Answers - Multiple layers of peptidoglycan (90%)
Acidic polysaccharides (10%)- teichoic and lipoteichoic acid, span the pepidoglycan
layers reinforcing cross linking between glycan chains therefore increasing the rigidity of
the call and allow/assist in the transport of ions across the wall. More rigid than gram (-)
What is the cell membrane? - Answers - Phospholipid bilayer containing integral and
peripheral proteins.
What are the primary functions of the cell membrane? - Answers - Retains the
cytoplasm and is a selectively permeable barrier. Site of metabolic activities attributable
to organelles in eukaryotes (synthesis reactions, transport system, secretions)
What is the cytoplasm? - Answers - Internal matrix contained inside the cell membrane,
70-80% water
What is cell pool? - Answers - Complex mix of nutrient- carbohydrates, amino acids,
fatty acids and inorganic molecules. Components are building blocks for cell synthesis
and sources of energy
What is the nucleoid? - Answers - Single circle of double stranded DNA with specialized
proteins. Nonuniform dense region, contains genetic information for cell structure and
function, not enclosed by a membrane
What are plasmids? - Answers - Circular extrachomosomal strands of DNA found in
most but not all bacterial. They encode a variety of protective traits or selective
advantages such as antibiotic resistance, production of toxins and production of
enzymes
What are ribosomes? - Answers - Granules of RNA and proteins that function as sited
for protein synthesis. Found free in the cytoplasm or attached to inner membrane
