Micro Ch 3- Practice
Which of the following contribute to the environmental resistance of bacterial endospores?
-Spore coat -Low water content of endospore -Presence of calcium dipicolinate -Lower pH
Which of the following is not part of the process by which an endospore transforms to become a vegetative cell?
Induction
A pathogenic bacterial species has mutated and is no longer able to synthesize a capsule. Which outcome would you predict?
The mutated bacteria will not be able to cause disease as readily
The movement of molecules across a membrane from an area of lower concentration to an area of higher concentration with the expenditure of energy is called
active transport
endospores are reproductive structures
false
Intracellular granules of organic or inorganic material that are stockpiled by bacteria for future use
inclusions
The cytoplasmic membrane of bacteria _________
-retains the cytoplasm and its contents -acts as a selectively permeable barrier, allowing some molecules to pass while preventing the movement of others -is the major site of ATP synthesis in aerobes
characteristics of active transport
-saturable uptake rate -use of ATP or a proton gradient as a source of metabolic energy -can move materials against a concentration gradient
Which of the following statements is true regarding pili and flagella assembly?
Pili grow when protein subunits are added to the base, whereas flagellin proteins are added to the tip of the flagella during growth.
Predict the change in surface area and volume of a spherical cell if the diameter of the cell doubles.
The surface area will increase by a factor of 4, while the volume will increase by a factor of 8.
Which of the following is not true of bacterial plasmids?
They are required for host growth and/or reproduction.
gram-positive bacteria have a thinner layer of peptidoglycan than gram-negative bacteria
false
_________ is the main part of the process through which a vegetative cell is formed from an endospore.
germination
bacterial cells that are variable in shape
pleomorphic
nitrogen can be obtained from either organic or inorganic sources
true
sporulation steps
1. replication of DNA 2. in-folding of the plasma membrane to enclose a copy of DNA, forming forespore and septum 3. engulfment of the forespore with a second membrane 4. deposition of spore cortex 5. spore coat formation 6. maturation and release of endospore
Which of the following statements is false regarding the differences between bacterial and eukaryotic cytoskeletal proteins?
Eukaryotic cells have cytoskeletal fibers comprised of tubulin and actin proteins, whereas bacterial cells lack cytoskeletal proteins.
Which of the following is not considered a micronutrient?
Magnesium (Mg)
A strain of Neisseria gonorrhoeae has undergone a mutation and is no longer able to make pili. Predict the most likely outcome.
The bacteria will become less virulent and will not be able to readily establish infection.
process by which an endospore transforms to become a vegetative cell
activation, germination, outgrowth
Lipids with polar and nonpolar ends are said to be _________
amphipathic
In many spirochetes, multiple flagella combine to form a bundle known as a(n) _________blank fibril, which winds around the cell and confers motility on the cell.
axial
Which of the following is not considered a macronutrient?
cobalt
Extracellular vesicles formed by Gram-positive cells are
cytoplasm surrounded by plasma membrane
endospores are resistant to most environmental stressors because they have ______ ____ complexed with calcium ions which stabilize DNA
dipicolinic acid
The lipopolysaccharide (LPS) that is found in the outer membrane of Gram-negative bacteria is also known as
endotoxin
Extracellular vesicles (EVs) derived from Gram-negative bacteria differ from those originating in Gram-positive bacteria in that Gram-positive EVs contain peptidoglycan, whereas those from Gram-negative organisms lack peptidoglycan.
false
Sedimentation coefficients are proportional to the molecular weight of a particle and are not affected by the volume and shape of the particle.
false
Zinc (Zn) is considered a macronutrient.
false
if you remove the peptidoglycan layer from a gram-positive cell, it would still stain purple with a gram stain
false
organisms usually have only a single transport system for a nutrient
false
rotation of bacterial flagella is powered by ATP hydrolysis
false
actinomycetes form long filaments called
hyphae
A new protein has been described that transports a growth factor across the plasma membrane. This protein is most likely a(n)
integral membrane protein
proteins that are embedded within the cytoplasmic membrane and not easily extracted
integral proteins
Elements that are required in relatively large amounts by microorganisms are called _________
macronutrients
nutrients that are used by bacteria in relatively large amounts
macronutrients
Chemotaxis is a process by which bacteria _________
move toward an attractant or away from a repellent
small circular DNA molecules capable of replicating and containing genes that are useful but not necessary to the bacterium
plasmids
_________ are the site of protein synthesis in the cell.
ribosomes
A _________ layer consists of diffuse unorganized polysaccharide material that lies outside the cell wall and is easily removed.
slime
flexible bacteria with a helical shape
spirochetes
process through which endospores are formed within a vegetative cell
sporulation
Transport of two different substances can be linked. If the transport is in the same direction it is called _________; if the transport is in opposite directions it is called _________
symport, antiport
Copper (Cu) is considered a micronutrient.
true
Different transport systems for the same nutrient that are part of the same organism are usually regulated in different ways.
true
Some photosynthetic aquatic bacteria produce gas vacuoles that lack a lipid-bound membrane in order to regulate their buoyancy
true
Sterol-like molecules called hopanoids are thought to be important for the structural integrity of many bacteria because of their suspected role in membrane stabilization.
true
endotoxic shock, resulting from the release of endotoxin by bacteria infecting a patient, is only caused by Gram-negative bacteria
true
prokaryotes were once described based on structures that were present in eukaryotes, but absent in prokaryotes
true
Twitching motility involves _________
type IV pili