MCB 100 EXAM 2 QUESTIONS & ANSWERS
What are flexible, spiral-shaped bacteria called?
a. Spirilla
b. Pleomorphic
c. Spirochetes
d. Bacilli - Answers -c. Spirochetes
Correct! Flexible, spiral-shaped bacteria are called spirochetes.
What function do bacterial endospores perform?
a. They reproduce asexually.
b. They survive in unfavorable conditions.
c. They cause disease in people.
d. They reproduce sexually. - Answers -b. They survive in unfavorable conditions.
Correct! Endospores are highly resistant to unfavorable environmental conditions.
What type of arrangement forms when multiple planes of division occur randomly in
cocci?
a. Tetrads
b. Diplococci
c. Staphylococci
d. Streptococci - Answers -c. Staphylococci
Correct! Staphylococcal arrangements occur when multiple planes of cell division occur
randomly.
What type of arrangement occurs when bacilli divide by snapping division?
a. Streptobacilli
b. Diplobacilli
c. Single bacilli
d. Palisades and V-shapes - Answers -d. Palisades and V-shapes
Correct! After dividing by snapping division, daughter cells remain attached and form
palisades and V-shapes.
What is the main basis for classifying prokaryotes in Bergey's Manual of Systematic
Bacteriology?
, a. Biochemical test results
b. Prokaryotic morphology
c. rRNA sequences
d. Cell arrangement - Answers -c. rRNA sequences
Correct! The use of rRNA sequences in taxonomy is an attempt to reflect evolutionary
relationships between organisms and forms the basis for prokaryotic classification.
In which of these ways do archaea differ from bacteria?
a. Archaea lack peptidoglycan in their cell walls.
b. Archaea are all extremophiles.
c. Archaeal cytoplasmic membranes' lipids contain straight hydrocarbon chains.
d. The initial amino acid in the peptides of archaea is N-formylmethionine. - Answers -a.
Archaea lack peptidoglycan in their cell walls.
Correct! Archaea do not have peptidoglycan in their cell walls.
What is the difference between halophiles and thermophiles?
a. Both halophiles and thermophiles require high temperature for growth.
b. Halophiles require high temperatures (greater than 45°C) and thermophiles require
high salt concentrations (greater than 9%) for optimal growth.
c. Both halophiles and thermophiles require high salt concentrations for growth.
d. Halophiles require high salt concentrations (greater than 9%) and thermophiles
require high temperatures (greater than 45°C) for optimal growth. - Answers -d.
Halophiles require high salt concentrations (greater than 9%) and thermophiles require
high temperatures (greater than 45°C) for optimal growth.
Correct! Halophiles require high salt concentrations, and thermophiles require high
temperatures for growth.
What is a potential role of methanogens in global warming?
a.Methanogens produce methane, which traps more heat than carbon dioxide and may
contribute to global warming.
b. Methanogens convert carbon dioxide into methane, removing carbon dioxide from the
atmosphere and effectively decreasing global warming.
c. Methanogens convert methane gas produced by organic waste into carbon dioxide,
decreasing global warming.
d. The methane that methanogens produce during sludge digestion of wastewater
treatment is burned so that it does not contribute to global warning. - Answers -a.
Methanogens produce methane, which traps more heat than carbon dioxide and may
contribute to global warming.
What are flexible, spiral-shaped bacteria called?
a. Spirilla
b. Pleomorphic
c. Spirochetes
d. Bacilli - Answers -c. Spirochetes
Correct! Flexible, spiral-shaped bacteria are called spirochetes.
What function do bacterial endospores perform?
a. They reproduce asexually.
b. They survive in unfavorable conditions.
c. They cause disease in people.
d. They reproduce sexually. - Answers -b. They survive in unfavorable conditions.
Correct! Endospores are highly resistant to unfavorable environmental conditions.
What type of arrangement forms when multiple planes of division occur randomly in
cocci?
a. Tetrads
b. Diplococci
c. Staphylococci
d. Streptococci - Answers -c. Staphylococci
Correct! Staphylococcal arrangements occur when multiple planes of cell division occur
randomly.
What type of arrangement occurs when bacilli divide by snapping division?
a. Streptobacilli
b. Diplobacilli
c. Single bacilli
d. Palisades and V-shapes - Answers -d. Palisades and V-shapes
Correct! After dividing by snapping division, daughter cells remain attached and form
palisades and V-shapes.
What is the main basis for classifying prokaryotes in Bergey's Manual of Systematic
Bacteriology?
, a. Biochemical test results
b. Prokaryotic morphology
c. rRNA sequences
d. Cell arrangement - Answers -c. rRNA sequences
Correct! The use of rRNA sequences in taxonomy is an attempt to reflect evolutionary
relationships between organisms and forms the basis for prokaryotic classification.
In which of these ways do archaea differ from bacteria?
a. Archaea lack peptidoglycan in their cell walls.
b. Archaea are all extremophiles.
c. Archaeal cytoplasmic membranes' lipids contain straight hydrocarbon chains.
d. The initial amino acid in the peptides of archaea is N-formylmethionine. - Answers -a.
Archaea lack peptidoglycan in their cell walls.
Correct! Archaea do not have peptidoglycan in their cell walls.
What is the difference between halophiles and thermophiles?
a. Both halophiles and thermophiles require high temperature for growth.
b. Halophiles require high temperatures (greater than 45°C) and thermophiles require
high salt concentrations (greater than 9%) for optimal growth.
c. Both halophiles and thermophiles require high salt concentrations for growth.
d. Halophiles require high salt concentrations (greater than 9%) and thermophiles
require high temperatures (greater than 45°C) for optimal growth. - Answers -d.
Halophiles require high salt concentrations (greater than 9%) and thermophiles require
high temperatures (greater than 45°C) for optimal growth.
Correct! Halophiles require high salt concentrations, and thermophiles require high
temperatures for growth.
What is a potential role of methanogens in global warming?
a.Methanogens produce methane, which traps more heat than carbon dioxide and may
contribute to global warming.
b. Methanogens convert carbon dioxide into methane, removing carbon dioxide from the
atmosphere and effectively decreasing global warming.
c. Methanogens convert methane gas produced by organic waste into carbon dioxide,
decreasing global warming.
d. The methane that methanogens produce during sludge digestion of wastewater
treatment is burned so that it does not contribute to global warning. - Answers -a.
Methanogens produce methane, which traps more heat than carbon dioxide and may
contribute to global warming.
