51 Questions
What is the general organization of a bacterial cell?
Cell membrane and cytoplasm
Which bacterial structure is responsible for protecting the cell from lysis due to changes in osmotic pressure?
Capsule
What is the main function of the bacterial cell wall?
Provide structural support and shape to the cell
Which component of the bacterial cell envelope is associated with adherence to host cells and tissues?
Pili/fimbriae
What is the function of the plasma membrane in bacteria?
Barrier against aqueous ions
What is the main function of peptidoglycan?
Structural support and shape
Where is cardiolipin found in bacteria?
In the plasma membrane
Which components of the bacterial cell wall differ between different types and species of bacteria?
Peptidoglycan layer
What is the main function of the outer membrane in Gram-negative bacteria and Chlamydiaceae?
Selective barrier and protection against lysis
What is present in the outer leaflet of the outer membrane?
Lipopolysaccharide (LPS)
How does the outer membrane contribute to host mimicry and antigenic variation?
Via sugars (O-antigen) and proteins
What is the function of the periplasm in bacteria?
Protection against osmotic lysis via solutes
What is the major function of capsules in bacteria?
Antiphagocytic activity
Which component is responsible for adhesion to surfaces and biofilm formation in bacteria?
Slime
What is the main function of pili/fimbriae in bacteria?
Adhesion to host cell receptors
What is the role of the 'K' antigen in some serotyping schemes of bacteria?
Vaccine target
Which drug prevents the recycling of bactoprenol-PP during peptidoglycan synthesis?
Bacitracin
What is inhibited by Fosfomycin during peptidoglycan synthesis?
MurA
Which drug inhibits alanine racemase and D-ala-D-ala synthetase during peptidoglycan synthesis?
Cycloserine
What does Tunicamycin prevent during peptidoglycan synthesis?
NAM-P to Und-P transfer
Which antibacterial enzyme cleaves the bond between NAG and NAM in peptidoglycan?
Lysozyme
What is the primary function of the plasma membrane in bacteria?
Control over osmotic balance
Which component forms a 3D multilayered net in the peptidoglycan structure?
Peptide tail
What is the role of cardiolipin in the plasma membrane of bacteria?
Barrier against aqueous ions
Where is the outer membrane absent in some genera or species of bacteria?
Gram-positive bacteria
What type of bacteria has a variable outer membrane structure used for differentiating strains or species?
Gram-negative bacteria
What is added in phase II of PG biosynthesis in the presence of a bridge peptide?
Pentaglycine bridge
Where does monomer production for PG biosynthesis occur?
Cytoplasm
What is used for the production of many extracellular polysaccharides in phase I of PG biosynthesis?
Bactoprenol-PP
What is responsible for incorporating the new monomer into the PG macromolecule in phase III of PG biosynthesis?
Transglycosylases
Which type of drug inhibits transpeptidases and leads to cell lysis as autolysins continue to function by weakening the new peptidoglycan?
$\beta$-lactams (penicillins, cephalosporins, etc.)
Which of the following bacterial genera is Gram-negative?
Salmonella
What is a characteristic feature of the outer membrane of Gram-negative bacteria?
Containment of crystal violet during Gram staining
Which type of bacteria has a cell wall structure that includes mycolic acids?
Mycobacterium
Which staining technique is specifically used for acid-fast bacteria?
Ziehl-Neelsen stain
Which bacterial genus is known for its resistance to chemicals and antibiotics due to its unique cell wall components?
Bacteroides
What is the main function of Penicillin-binding proteins (PBPs) in the peptidoglycan (PG) biosynthetic process?
Cleaving PG crosslinks to allow cell growth and separation
Which bacteria have an outer membrane with lipopolysaccharides (LPS) but no peptidoglycan (PG)?
Chlamydia and Chlamydophila
What is the main role of the protein layer in the context of bacterial cell wall biosynthesis?
Providing structural support to the bacterial cell wall
Why is the Gram stain not useful for visualizing spirochetes such as Treponema and Borrelia?
They have a very thin structure that is not visible by light microscopy
Which enzyme is responsible for removing the last D-alanine from peptide tails that have not been crosslinked in peptidoglycan (PG)?
DD-carboxypeptidase
What is the main function of peptidoglycan in bacteria?
Protection against osmotic lysis
Which statement best describes the biological effects of peptidoglycan?
Unique to bacteria and induces cytokines
What role do teichoic and lipoteichoic acids play in Gram-positive bacteria?
Regulation of autolysis
Which bacterial component is involved in adherence to host cells and tissues?
Peptidoglycan
What is the general role of adhesins in bacteria?
Facilitating adherence to host cells and tissues
Which component is a specific type of peptidoglycan fragment targeting ciliated respiratory epithelial cells?
Cytotoxin
What is the primary effect of teichoic and lipoteichoic acids in Gram-positive bacteria?
Regulation of autolysis
What is the function of PAMPs (Pathogen Associated Molecular Patterns) in bacteria?
Inducing cytokines like IL-1, IL-6, GCSF, TNF
What distinguishes teichoic and lipoteichoic acids from peptidoglycan in their role within Gram-positive bacteria?
Regulation of autolysis
What is the key function of adhesins in bacteria?
Facilitating adherence to host cells and tissues
Test your knowledge of bacterial structure and organization, including general organization, outer membrane, and differentiating strains or species. This quiz covers material from pp. 61-64, 347-357 of Sherri's 6th edition, along with chapters on various organisms and basic microbiology texts.
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