Prescott's Microbiology Ch. 3

Match the definition with the word. 1) monotrichous 2) peritrichous 3) lophotrichous 4) amphitrichous a) a singe flagellum b) a single flagellum at each pole of an organism c) a cluster of flagella at one or both ends of an organism d) a relatively even distribution of flagella over the entire surface of the bacterium

1-a, 2-d, 3-c, 4-b

Order the following structures (layers) that a small molecule must pass through as it moves from outside of an encapsulated gram negative cell to the cytoplasm

1. Capsule 2. Outer membrane 3. Periplasm and Peptidoglycan 4. Plasma membrane

Endospores are resistant to most environmental stressors because they have _________ complexed with calcium ions which stabilize DNA.

Dipicolinic acid

During the assembly of the flagellar filament, the flagellin protein monomers assemble at the cell proximal base of the flagellum.

False

Endospores are reproductive structures.

False

Phosphorus can be obtained from organic sources only.

False

Sulfur can be obtained from inorganic sources only.

False

Zinc (Zn) is considered a macronutrient.

False

___________ is the main part of the process through which a vegetative cell is formed from an endospore.

Germination

Which of the following is not part of the process by which an endospore transforms to become a vegetative cell?

Induction

Which of the following protects bacteria from lysis in dilute solutions and helps to determine their cellular morphology or shape?

Peptidoglycan

__________ are the site of protein synthesis in the cell.

Ribosomes

All of the following are reasons why some scientists believe that the term "prokaryote" is a somewhat artificial designation and should be discarded except

Some bacteria have 80S ribosomes.

Motile bacteria have been placed in an environment with a gradient of a chemical attractant. Which of the following behaviors would you predict?

The bacteria will both reduce tumbling frequency and increase run duration in the direction of the chemical.

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.

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.

Nutrients can be concentrated from dilute solutions by

active transport and group translocation.

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.

In many spirochetes, multiple flagella combine to form a bundle known as a(n) ____________ fibril, which winds around the cell and confers motility on the cell.

axial

Enzymes that are secreted out of the cell to aid in the acquisition and digestion of environmental nutrients are called __________.

exoenzymes

Intracellular granules of organic or inorganic material that are stockpiled by bacteria for future use are called ______________.

inclusions

Chemotaxis is a process by which bacteria

move toward an attractant or away from a repellent.

Bacteria that do not have a fixed shape are said to be ___________.

pleomorphic

Bacterial cells that are variable in shape are called

pleomorphic

Rigid bacteria with a helical cell shape are called

spirilla.

Flexible bacteria with a helical shape are called

spirochetes.

The genus of bacteria that undergoes cell division in random planes, forming grapelike clusters of round bacteria, are the _______________.

staphylococci or staphylococcus

A wide variety of microorganisms are commercially used to manufacture _________ for human consumption.

vitamins

Small organic molecules called __________ function as enzyme cofactors.

vitamins

Place the steps of sporulation in order

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 complex 5) Spore coat formation 6) Maturation and release of endospore

Bacterial and archaeal ribosomes are known as ________ ribosomes, based on their sedimentation coefficient.

70S

You have been studying the effect of a concentration gradient on the rate of transport of a nutrient into a bacterial cell. If a carrier protein is involved in the transport of this nutrient, which curve would you expect to see?

A

Which of the following processes can be used to bring nutrients into a cell against a concentration gradient?

Active transport

The cytoplasmic membrane of bacteria

All of the choices are correct.

The type III bacterial protein secretion machinery

All of the choices are correct.

Which of the following contribute to the environmental resistance of bacterial endospores?

All of the choices are correct.

Which of the following is a characteristic of active transport?

All of the choices are correct.

Which of the following is/are true of capsules?

All of the choices are correct.

Which of the following structures is NOT found in an endospore?

Capsule

Which of the following is not considered a macronutrient?

Cobalt (Co)

Which bacterial structure may survive if temperatures applied during food preservation processes are too low?

Endospores

Bacteria growing at lower temperatures have more saturated fatty acids in their membranes.

False

Gram-positive bacteria have a structurally and chemically more complex cell wall than gram-negative bacteria.

False

Gram-positive bacteria have a thinner layer of peptidoglycan than gram-negative bacteria.

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 any nutrient.

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

The cell membrane is a rigid structure that provides bacteria with their characteristic shapes.

False

The layers of peptidoglycan of the bacterial cell wall can be cross-linked by peptide intrabridges or by direct cross-linking.

False

The original differentiation of prokaryotes and eukaryotes was based on structures found in prokaryotes that are lacking in eukaryotes.

False

The rotation of bacterial flagella is powered by ATP hydrolysis.

False

___________ ______________ are required organic compounds because they are essential cell components or precursors of such components that cannot be synthesized by the organism.

Growth factors

All of the following statements about the periplasmic space are true except:

It is found only in gram-positive bacteria.

Which of the following is not considered a micronutrient?

Magnesium (Mg)

Which of the following is not a major class of growth factors?

Nucleic acids

_________ are carrier proteins embedded in the membrane that increase the rate of diffusion of specific molecules across selectively permeable membranes.

Permeases

_________ membranes allow some molecules to pass but not others.

Selectively permeable

___________ bind ferric iron and transport it into a bacterial cell.

Siderophores

How do spheroplasts and protosplasts differ?

Spheroplasts retain their outer membrane but protoplasts do not.

_________ is the process through which endospores are formed within a vegetative cell.

Sporulation

The concept of a prokaryote was first fully outlined in 1962 by

Stanier and Van Niel.

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.

Predict how the plasma membrane fatty acid composition would change as the temperature of the habitat of an aquatic bacterial species warms from 2 C to 15 C during the spring and summer months.

The percentage of saturated fatty acids would increase.

Which of the following is not true of bacterial plasmids?

They are required for host growth and/or reproduction.

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

Endotoxic shock, resulting from the release of endotoxin by bacteria infecting a patient, is only caused by Gram-negative bacteria.

True

Growth factors cannot be synthesized by the bacteria that use them and include amino acids, pyrimidines, and vitamins.

True

Nitrogen can be obtained from either organic or inorganic sources.

True

Permease proteins that aid in the transport of nutrients resemble enzymes in their specificity for the substance to be transported. Each carrier is selective and will transport only a closely related set of substances.

True

Prokaryotes were once described based on structures that were present in eukaryotes, but absent in prokaryotes.

True

Some photosynthetic bacteria produce gas vacuoles that regulate their buoyancy but contain no lipid.

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

The extreme insolubility of ferric iron leaves little free iron available for transport into bacterial cells.

True

The trace amounts of micronutrients needed by microorganisms are usually supplied as inadvertent contaminants in water and regular media components.

True

Lipids with polar and nonpolar ends are said to be

amphipathic.

Export of flagellin subunits is mediated by

an apparatus in the basal body of the flagellum that is related to the type III secretion pathway.

The term used to describe bacteria that are rod-shaped is

bacillus.

Bacterial flagella are composed of three parts: the _________ body, which is embedded in the cell, the hook, and the ___________, which is the longest part of the flagellum.

basal; filament

Twitching or gliding motility involves

both type IV pili and movement of slime can be involved in twitching or gliding motility.

A _________ is a polysaccharide layer that lies outside the cell wall and is not easilt removed.

capsule

Sortase is a protein enzyme of bacteria that

catalyzes covalent attachment of some surface proteins to peptidoglycan.

The term used to describe bacteria that are intermediate in shape between spherical and rod-shaped is

coccobacilli.

The term used to describe bacteria that have a spherical shape is

coccus.

Endospores represent a challenge to the fields of industrial and medical microbiology because

endospores are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive, and endospore-forming organisms are often dangerous pathogens.

The lipopolysaccharide (LPS) that is found in the outer membrane of gram-negative bacteria is also known as

endotoxin.

The movement of molecules across a membrane from an area of higher concentration to an area of lower concentration with the use of carrier molecule embedded in the membrane is called

facilitated diffusion.

The most widely accepted current model for membrane structures is called the _____________________ model.

fluid mosaic

You discover a new transport system used by a newly discovered bacterial species. The sugars that are transported using this system phosphorylated as they enter the bacterial species cell. You would describe this transport system as a(n) ____________.

group translocation

Molecules or regions of molecules that readily interact with water are said to be __________, whereas molecules or regions of molecules that are insoluble in water or do not readily interact with water are said to be hydrophobic.

hydrophilic

Actinomycetes form long filaments called ___________.

hyphae

Proteins that are embedded within the cytoplasmic membrane and not easily extracted are called _________ proteins.

integral

A new protein has been described that transports a growth factor across the plasma membrane. This protein is most likely a/an:

integral membrane protein.

Although penicillin inhibits peptidoglycan synthesis, bacterial cells will continue to grow normally in the presence of penicillin in a(n)______environment.

isotonic

Nutrients that are used by bacteria in relatively large amounts are ____________.

macronutrients

Elements that are required in relatively large amounts by microorganisms are called

macronutrients.

Some species of aquatic bacteria use inclusion bodies known as ________ to orient themselves in Earth's magnetic field.

magnetosomes

A branched network of hyphae formed by the Actinomycetes is called a ______________.

mycelium

Bacteria have a region of the cytoplasm known as the __________, which is not bounded by a membrane but contains the chromosome.

nucleiod

movement of molecules from an area of high concentration to an area of lower concentration without the participation of specific carrier molecules is called

passive diffusion.

Proteins that are loosely associated with the cytoplasmic membrane are called ________ proteins.

peripheral

Proteinacious projections from the surface of a bacterium that are used to mediate conjugation are called sex __________, whereas projections that mediate attachment to surfaces such as host cells are called __________.

pili; fimbriae

Small circular DNA molecules capable of replicating and containing genes that are useful but not necessary to the bacterium are called __________.

plasmids

Shrinkage of the plasma membrane away from the cell wall when the bacterium is placed in a hypertonic environment is called

plasmolysis.

The power used by most bacterial flagellar motors is produced by

proton motive force (PMF).

The bacterium E. coli swims in a straight line, called a _________, for a few seconds; then it stops, tumbles, then swims away in a new direction.

run

Many bacteria facilitate the uptake of iron by secreting low molecular weight molecules, called __________, to form complexes with the iron that can then be readily transported into the cell.

siderophores

A __________ layer consists of diffuse unorganized polysaccharide material that lies outside the cell wall and is easily removed.

slime

When the cell wall is removed from a Gram-negative bacterium without removing the outer membrane, the resulting form is called a(n) __________.

spheroplast

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

Square planar arrangement of cells that forms when round bacteria remain attached to each other during reproduction are called

tetrads.

The term to describe bacteria that are shaped like curved rods is

vibrio.