Biology of Infectious Agents BIOL 314
Test Questions and Correct Answers.
How do bacteria survive in the body? - Answer Bacteria survive by utilizing their cytoplasmic
membrane, cell walls, DNA replication, motility, and mechanisms of adaptation.
What is the significance of the cytoplasmic membrane in bacteria? - Answer The cytoplasmic
membrane performs functions typically divided among eukaryotic plasma membranes and
organelles, including oxidative metabolism and nutrient transport.
What challenges do microbes face in nutrient acquisition? - Answer Microbes adapt to feast
or famine conditions, must adhere to surfaces to resist washout, and develop resistance to
damaging agents like chemicals, radiation, heat, and antibiotics.
What are siderophores and their role in microbial growth? - Answer Siderophores are small
molecules produced by microbes to chelate iron from the environment or host, essential for
microbial growth.
What is the Gram staining process and its significance? - Answer Gram staining, developed
by Dr. H. C. J. Gram in 1884, differentiates bacteria into Gram-positive (purple) and Gram-
negative (pink) based on their cell wall properties.
What distinguishes Gram-positive bacteria from Gram-negative bacteria? - Answer Gram-
positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin
peptidoglycan layer and an outer membrane.
What is peptidoglycan and its role in bacterial cells? - Answer Peptidoglycan is a polymer of
glycan strands crosslinked by peptides, providing strength and rigidity to bacterial cell walls.
What are the protective functions of peptidoglycan? - Answer Peptidoglycan protects
bacteria from osmotic pressures, lysis, bile digestion, and phagocytosis.
What is the structure and function of lipopolysaccharide (LPS) in Gram-negative bacteria? -
Answer LPS is found in the outer membrane of Gram-negative bacteria, consisting of Lipid A,
core polysaccharide, and O-antigen, and acts as an endotoxin.
What is the role of the outer membrane in Gram-negative bacteria? - Answer The outer
membrane protects the cytoplasmic membrane from damaging chemicals and is chemically
distinct from typical biological membranes.
Test Questions and Correct Answers.
How do bacteria survive in the body? - Answer Bacteria survive by utilizing their cytoplasmic
membrane, cell walls, DNA replication, motility, and mechanisms of adaptation.
What is the significance of the cytoplasmic membrane in bacteria? - Answer The cytoplasmic
membrane performs functions typically divided among eukaryotic plasma membranes and
organelles, including oxidative metabolism and nutrient transport.
What challenges do microbes face in nutrient acquisition? - Answer Microbes adapt to feast
or famine conditions, must adhere to surfaces to resist washout, and develop resistance to
damaging agents like chemicals, radiation, heat, and antibiotics.
What are siderophores and their role in microbial growth? - Answer Siderophores are small
molecules produced by microbes to chelate iron from the environment or host, essential for
microbial growth.
What is the Gram staining process and its significance? - Answer Gram staining, developed
by Dr. H. C. J. Gram in 1884, differentiates bacteria into Gram-positive (purple) and Gram-
negative (pink) based on their cell wall properties.
What distinguishes Gram-positive bacteria from Gram-negative bacteria? - Answer Gram-
positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin
peptidoglycan layer and an outer membrane.
What is peptidoglycan and its role in bacterial cells? - Answer Peptidoglycan is a polymer of
glycan strands crosslinked by peptides, providing strength and rigidity to bacterial cell walls.
What are the protective functions of peptidoglycan? - Answer Peptidoglycan protects
bacteria from osmotic pressures, lysis, bile digestion, and phagocytosis.
What is the structure and function of lipopolysaccharide (LPS) in Gram-negative bacteria? -
Answer LPS is found in the outer membrane of Gram-negative bacteria, consisting of Lipid A,
core polysaccharide, and O-antigen, and acts as an endotoxin.
What is the role of the outer membrane in Gram-negative bacteria? - Answer The outer
membrane protects the cytoplasmic membrane from damaging chemicals and is chemically
distinct from typical biological membranes.
