BI 234: Lecture Exam QUESTIONS WITH
VERIFIED ANSWERS NEW VERSION
UPDATE 2024-2025 GRADED A.
what is the slime layer?
- ANSWER loose, water-soluble glycocalyx
-Allows prokaryotes to attach to surfaces
What are flagella?
- ANSWER -Responsible for movement
What compose flagella?
- ANSWER -Filament, hook and basal body
-basal body anchors the filament and hook to cell wall
what are the different orientations of flagella?
- ANSWER Monotrichous
Amphitrichous
Lophoptrichous
Peritrichous
How many rings are present in the basal body of gram negative flagella?
- ANSWER 4
How many rings are present in the basal body of gram positive flagella?
- ANSWER 2
what is the motion called that bacteria move?
- ANSWER run and tumble
What are fimbriae? - ANSWER hairlike appendages that allow for attachment
-shorter than flagella
what are pili?
- ANSWER -Special type of fimbriae
-Transfer DNA from one cell to another
Purpose of cell wall?
- ANSWER -Provide shape and structure and protect from osmotic forces
what composes cell walls of bacteria?
- ANSWER peptidoglycan
,What are the characteristics of gram-positive cell walls?
- ANSWER -Thick layer of peptidoglycan
-Contain teichoic and lipteichoic acids
What are the characteristics of gram-neg cell walls?
- ANSWER -Thin layer of peptidoglycan
What is the bilayer membrane outside of the peptidoglycan of gram neg bacteria? -
ANSWER -contains phospholipids, proteins and lipopolysaccharies
What is significant about lipid A?
- ANSWER can cause fever, vasodilation, inflammation, shock and blood clotting
What is the fluid mosaic model?
- ANSWER states that a membrane is a fluid structure with a "mosaic" of various
proteins embedded in it
-phospholipid bilayer
What are integral proteins?
- ANSWER penetrate the hydrophobic interior of the lipid bilayer
What are peripheral proteins?
- ANSWER bound to the surface of the membrane
what is the function of the cytoplasmic membranes? - ANSWER -Controls passage of
substances into and out of the cell
-Harvests ligh energy in photosynthetic bacteria
-selectively permeable
-naturally impermeable to most substances
-Proteins allow substances to cross membrane
-Maintains concentration and electrical gradients
What happens to a cell in a hypertonic solution?
- ANSWER cell shrinks
What happens to a cell in a hypotonic solution - ANSWER cell swells
What is a nucleoid?
- ANSWER A dense region of DNA in a prokaryotic cell.
What is the structure/number of the bacterial chromosome? - ANSWER circular, double-
stranded DNA molecule condensed into a structure called the nucleoid, which has no
nuclear membrane
What are plasmids?
,- ANSWER Plasmids are small loops of extra DNA that aren't part of the chromosome.
Plasmids contain genes for things like drug resistance and can be passed between
bacteria.
What is an endospore?
- ANSWER a dormant, tough, and temporarily non-reproductive structure produced by
certain bacteria.
-defense strategy against unfavorable conditions
What activates an endospore?
- ANSWER When bacteria is stressed/nutrients are limited
What two genera of bacteria produce endospores? - ANSWER Bacillus and Clostridium
What is the endosymbiotic theory?
- ANSWER Eukaryotes formed from union of small aerobic prokaryotes with larger
anaerobic prokaryotes
What organisms does the endosymbiotic theory apply to?
- ANSWER Aerobic prokaryotes evolved into mitochondria
What are the 6 basic shapes of prokaryotic cells?
- ANSWER - Coccus
- Bacillus
- Vibrio
- Spirillum
- Spirochete
- Filament
What is pleomorphic?
- ANSWER organisms that are variable in shape
What is the most common process of prokaryotic reproduction? - ANSWER Binary
fission
what is binary fission?
- ANSWER A form of asexual reproduction in which the parent divides into two
approximately equal parts
What are other methods of prokaryotic reproduction?
- ANSWER Snapping division
Budding
What is snapping division?
- ANSWER A variation of binary division, which occurs in some Gram positive cells.
, What are the common arrangements of cocci?
- ANSWER Diplo
Streptococci (chains)
Tetrads
Sarcinae
Staphylococcus
What are the different arrangements of bacilli?
- ANSWER -Single
-Diplobacilli: pair of cells with ends attached
-Streptobacilli: chain of several cells
-Palisades: cells of a chain remain partially attached by a small hinge region at the ends
How do archaea differ from bacteria?
- ANSWER a. Archaea lack peptidoglycan in their cell walls, a substance that is found
in the cell walls of most bacteria.
b. Archaea can live in more extreme environments than most bacteria can tolerate.
c. Even more metabolic diversity is seen within the archaea than in the bacteria.
What are the common features of archaea?
- ANSWER - lack true peptidoglycan
- cell membrane lipids have branched hydrocarbon chains
- AUG codon codes for methionine
-reproduce by binary fission, budding or fragmentation
-not known to cause disease
What are thermophiles?
- ANSWER heat loving microbes
-DNA RNA cytoplasmic membranes and proteins do not function properly below 45
degrees celcius
-Thermococcus and pyrodictium
What are hyperthermophiles?
- ANSWER some Archaea that grow at temperatures above 80C, some over 100C.
What are halophiles?
- ANSWER salt loving archaea
What are methanogens? - ANSWER the largest group of archaea; produce methane
gas from organic waste, which is useful in sewage treatment
-Some live in colons of animals
-One of primary sources of environmental methane
What are photosynthetic lamellae?
- ANSWER contained within phototrophs
-
VERIFIED ANSWERS NEW VERSION
UPDATE 2024-2025 GRADED A.
what is the slime layer?
- ANSWER loose, water-soluble glycocalyx
-Allows prokaryotes to attach to surfaces
What are flagella?
- ANSWER -Responsible for movement
What compose flagella?
- ANSWER -Filament, hook and basal body
-basal body anchors the filament and hook to cell wall
what are the different orientations of flagella?
- ANSWER Monotrichous
Amphitrichous
Lophoptrichous
Peritrichous
How many rings are present in the basal body of gram negative flagella?
- ANSWER 4
How many rings are present in the basal body of gram positive flagella?
- ANSWER 2
what is the motion called that bacteria move?
- ANSWER run and tumble
What are fimbriae? - ANSWER hairlike appendages that allow for attachment
-shorter than flagella
what are pili?
- ANSWER -Special type of fimbriae
-Transfer DNA from one cell to another
Purpose of cell wall?
- ANSWER -Provide shape and structure and protect from osmotic forces
what composes cell walls of bacteria?
- ANSWER peptidoglycan
,What are the characteristics of gram-positive cell walls?
- ANSWER -Thick layer of peptidoglycan
-Contain teichoic and lipteichoic acids
What are the characteristics of gram-neg cell walls?
- ANSWER -Thin layer of peptidoglycan
What is the bilayer membrane outside of the peptidoglycan of gram neg bacteria? -
ANSWER -contains phospholipids, proteins and lipopolysaccharies
What is significant about lipid A?
- ANSWER can cause fever, vasodilation, inflammation, shock and blood clotting
What is the fluid mosaic model?
- ANSWER states that a membrane is a fluid structure with a "mosaic" of various
proteins embedded in it
-phospholipid bilayer
What are integral proteins?
- ANSWER penetrate the hydrophobic interior of the lipid bilayer
What are peripheral proteins?
- ANSWER bound to the surface of the membrane
what is the function of the cytoplasmic membranes? - ANSWER -Controls passage of
substances into and out of the cell
-Harvests ligh energy in photosynthetic bacteria
-selectively permeable
-naturally impermeable to most substances
-Proteins allow substances to cross membrane
-Maintains concentration and electrical gradients
What happens to a cell in a hypertonic solution?
- ANSWER cell shrinks
What happens to a cell in a hypotonic solution - ANSWER cell swells
What is a nucleoid?
- ANSWER A dense region of DNA in a prokaryotic cell.
What is the structure/number of the bacterial chromosome? - ANSWER circular, double-
stranded DNA molecule condensed into a structure called the nucleoid, which has no
nuclear membrane
What are plasmids?
,- ANSWER Plasmids are small loops of extra DNA that aren't part of the chromosome.
Plasmids contain genes for things like drug resistance and can be passed between
bacteria.
What is an endospore?
- ANSWER a dormant, tough, and temporarily non-reproductive structure produced by
certain bacteria.
-defense strategy against unfavorable conditions
What activates an endospore?
- ANSWER When bacteria is stressed/nutrients are limited
What two genera of bacteria produce endospores? - ANSWER Bacillus and Clostridium
What is the endosymbiotic theory?
- ANSWER Eukaryotes formed from union of small aerobic prokaryotes with larger
anaerobic prokaryotes
What organisms does the endosymbiotic theory apply to?
- ANSWER Aerobic prokaryotes evolved into mitochondria
What are the 6 basic shapes of prokaryotic cells?
- ANSWER - Coccus
- Bacillus
- Vibrio
- Spirillum
- Spirochete
- Filament
What is pleomorphic?
- ANSWER organisms that are variable in shape
What is the most common process of prokaryotic reproduction? - ANSWER Binary
fission
what is binary fission?
- ANSWER A form of asexual reproduction in which the parent divides into two
approximately equal parts
What are other methods of prokaryotic reproduction?
- ANSWER Snapping division
Budding
What is snapping division?
- ANSWER A variation of binary division, which occurs in some Gram positive cells.
, What are the common arrangements of cocci?
- ANSWER Diplo
Streptococci (chains)
Tetrads
Sarcinae
Staphylococcus
What are the different arrangements of bacilli?
- ANSWER -Single
-Diplobacilli: pair of cells with ends attached
-Streptobacilli: chain of several cells
-Palisades: cells of a chain remain partially attached by a small hinge region at the ends
How do archaea differ from bacteria?
- ANSWER a. Archaea lack peptidoglycan in their cell walls, a substance that is found
in the cell walls of most bacteria.
b. Archaea can live in more extreme environments than most bacteria can tolerate.
c. Even more metabolic diversity is seen within the archaea than in the bacteria.
What are the common features of archaea?
- ANSWER - lack true peptidoglycan
- cell membrane lipids have branched hydrocarbon chains
- AUG codon codes for methionine
-reproduce by binary fission, budding or fragmentation
-not known to cause disease
What are thermophiles?
- ANSWER heat loving microbes
-DNA RNA cytoplasmic membranes and proteins do not function properly below 45
degrees celcius
-Thermococcus and pyrodictium
What are hyperthermophiles?
- ANSWER some Archaea that grow at temperatures above 80C, some over 100C.
What are halophiles?
- ANSWER salt loving archaea
What are methanogens? - ANSWER the largest group of archaea; produce methane
gas from organic waste, which is useful in sewage treatment
-Some live in colons of animals
-One of primary sources of environmental methane
What are photosynthetic lamellae?
- ANSWER contained within phototrophs
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