BIO 109 EXAM QUESTIONS AND
ANSWERS
difference between an endotoxin and exotoxin? - ANSWER-endotocin: a
lipopolysaccharaide of outer membrane of gram - bacteria-released when bacteria
die and their cell walls break down
exotoxins: proteins secreted by certain bacteria and other organismsex: chlorea,
botulism
The evolution of antibiotic resistant strains of bacteria is on the rise. Explain why. -
ANSWER-- the rapid reproduction of bacteria enables genes conferring resistance to
multiply quickly throughout bacterial populations as a result of natural selection
people don't finish their antibiotics- only creating resistant bacteria rather than killing
them off
Why are Gram-negative pathogens generally more threatening than Gram-positive
ones? - ANSWER-Gram negative have complex structures ( outer membrane
protects against host defenses, resistant to typical antibiotics, LPS "liposaccharides"
that are toxic)
How does penicillin inhibit prokaryotic growth? - ANSWER-Inhibits x-link formation
(peptidoglycan) and interferes with cell wall function.
What is a capsule and what is its function? - ANSWER-Sticky layer of
polysaccharides
Protects against dehydration
Enables prokaryotes to connect with other substrates (cell wall)
What are fimbriae? - ANSWER-hairlike appendages that allow for attachment
major differences between prokaryotes and eukaryotes? - ANSWER-- peptidoglycan
cell wall
- unicellular
- no membrane bound organelles
- have pili and fimbriae (for adhesion), flagella (propulsion)
- smaller cell sizes
What is a plasmid - ANSWER-circular piece of DNA
How do the antibiotics erythromycin and tetracycline inhibit bacterial growth? -
ANSWER-Erythromycin inhibits bacterial protein synthesis by reversibly binding with
their 50 S ribosomal subunit, thus blocking the formation of new peptide bonds.
Tetracyclines probably penetrate bacterial cells by passive diffusion and inhibit
bacterial growth by interfering with protein synthesis or by destroying the membrane.
What is horizontal gene transfer? - ANSWER-movement of one or more genes from
one species to another
ANSWERS
difference between an endotoxin and exotoxin? - ANSWER-endotocin: a
lipopolysaccharaide of outer membrane of gram - bacteria-released when bacteria
die and their cell walls break down
exotoxins: proteins secreted by certain bacteria and other organismsex: chlorea,
botulism
The evolution of antibiotic resistant strains of bacteria is on the rise. Explain why. -
ANSWER-- the rapid reproduction of bacteria enables genes conferring resistance to
multiply quickly throughout bacterial populations as a result of natural selection
people don't finish their antibiotics- only creating resistant bacteria rather than killing
them off
Why are Gram-negative pathogens generally more threatening than Gram-positive
ones? - ANSWER-Gram negative have complex structures ( outer membrane
protects against host defenses, resistant to typical antibiotics, LPS "liposaccharides"
that are toxic)
How does penicillin inhibit prokaryotic growth? - ANSWER-Inhibits x-link formation
(peptidoglycan) and interferes with cell wall function.
What is a capsule and what is its function? - ANSWER-Sticky layer of
polysaccharides
Protects against dehydration
Enables prokaryotes to connect with other substrates (cell wall)
What are fimbriae? - ANSWER-hairlike appendages that allow for attachment
major differences between prokaryotes and eukaryotes? - ANSWER-- peptidoglycan
cell wall
- unicellular
- no membrane bound organelles
- have pili and fimbriae (for adhesion), flagella (propulsion)
- smaller cell sizes
What is a plasmid - ANSWER-circular piece of DNA
How do the antibiotics erythromycin and tetracycline inhibit bacterial growth? -
ANSWER-Erythromycin inhibits bacterial protein synthesis by reversibly binding with
their 50 S ribosomal subunit, thus blocking the formation of new peptide bonds.
Tetracyclines probably penetrate bacterial cells by passive diffusion and inhibit
bacterial growth by interfering with protein synthesis or by destroying the membrane.
What is horizontal gene transfer? - ANSWER-movement of one or more genes from
one species to another
