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