Microbiology

Question 1

Please give the function and chemical composition for the following structure: Peptidoglycan

Answer 1

Function: Gives rigid support, protects against osmotic pressure

Chemical Composition: Sugar backbone with peptide side chains cross-linked by transpeptidase

Question 2

Please give the function and chemical composition for the following structure: Cell wall/ cell membrane (gram positive)

Answer 2

Function: Major surface antigen

Chemical Composition: Peptidoglycan for support. Lipoteichoic acid induces TNF and IL-1

Question 3

Please give the function and chemical composition for the following structure: Outer membrane (gram negatives)

Answer 3

Function: Site of endotoxin (lipopolysaccharide [LPS]); major surface antigen

Chemical Composition: Lipid A induces TNF and IL-1; O polysaccharide is the antigen

Question 4

Please give the function and chemical composition for the following structure: Plasma membrane

Answer 4

Function: Site of oxidative and transport enzymes.

Chemical Composition: Phospholipid bilayer.

Question 5

Please give the function and chemical composition for the following structure: Ribosome

Answer 5

Function: Protein synthesis

Chemical Composition: 50S and 30S subunit

Question 6

Please give the function and chemical composition for the following structure: Periplasm

Answer 6

Function: Space between the cytoplasmic membrane and outer membrane in gram-negative bacteria

Chemical Composition: Contains many hydrolytic enzymes, including beta-lactamases

Question 7

Please give the function and chemical composition for the following structure: Capsule

Answer 7

Function: Protects against phagocytosis

Chemical Composition: Polysaccharide (except Bacillus anthracis, which contains D-glutamate)

Question 8

Please give the function and chemical composition for the following structure: Pilus/fimbria

Answer 8

Function: Mediate adherence of bacteria to cell surface; sex pilus forms attachment between 2 bacteria during conjugation

Chemical Composition: Glycoprotein

Question 9

Please give the function and chemical composition for the following structure: Flagellum

Answer 9

Function: Motility

Chemical Composition: Protein

Question 10

Please give the function and chemical composition for the following structure: Spore

Answer 10

Function: Resistant to dehydration, heat, and chemicals.

Chemical Composition: Keratin-like coat; dipicolinic acid; peptidoglycan

Question 11

Please give the function and chemical composition for the following structure: Plasmid

Answer 11

Function: Contains a variety of genes for antibiotic resistance, enzymes, and toxin

Chemical Composition: DNA

Question 12

Please give the function and chemical composition for the following structure: Glycocalyx

Answer 12

Function: Mediates adherence to surfaces, especially foreign surfaces (e.g., indwelling catheters).

Chemical Composition: Polysaccharide