Microbio chapter 3

Which of the following is a characteristic 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 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/are true of capsules?

-They help bacteria escape phagocytosis by host cells. -They retain water and help prevent desiccation of the bacteria. -They prevent entry of many bacterial viruses.

Phosphorus can be obtained from organic sources only. (T/F)

False

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.

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.

Chemotaxis is a process by which bacteria _________.

move toward an attractant or away from a repellent

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

siderophores

Rigid bacteria with a helical cell shape are called _________.

spirilla

Germination is one process by which bacterial cells can reproduce. (T/F)

False

Gram-positive bacteria have a structurally and chemically more complex cell wall than Gram-negative bacteria. (T/F)

False

Gram-positive bacteria have a thinner layer of peptidoglycan than Gram-negative bacteria. (T/F)

False

If you remove the peptidoglycan layer from a Gram-positive cell, it would still stain purple with a Gram stain. (T/F)

False

Organisms usually have only a single transport system for any nutrient. (T/F)

False

Which of the following is a component of the outer membrane in Gram-negative bacteria that results in septic shock upon entering the bloodstream?

Lipolysaccharide

How do spheroplasts and protosplasts differ?

Spheroplasts retain their outer membrane but protoplasts do not.

A __________ is a polysaccharide layer that lies outside the cell wall and is not easily removed.

capsule

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

endotocin

Actinomycetes form long filaments called ___________.

hyphae

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

tetrads

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

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

70s

The rotation of bacterial flagella is powered by ATP hydrolysis. (T/F)

False

Which of the following bacterial structures are most directly linked to swimming motility in chemotaxis?

Flagella

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 is not a major class of growth factors?

Nucleic acids

When analyzing the outer membrane of Gram-negative bacteria, which part of lipopolysaccharide induces an antibody response?

O antigen

__________ 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

__________ 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 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 how the plasma membrane fatty acid composition would change as the temperature of the habitat of an aquatic bacterial species warms from 2oC to 15oC 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.

Complete bacterial ribosomes are comprised of approximately 55 proteins and three molecules of ribosomal RNA. (T/F)

True

Different transport systems for the same nutrient that are part of the same organism are usually regulated in different ways. (T/F)

True

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

True

Growth factors are molecules that cannot be synthesized by the bacteria that use them and include amino acids, pyrimidines, and vitamins. (T/F)

True

Nutrients can be concentrated from dilute solutions by _________.

active transport and group translocation

When observing flagella distribution patterns, bacteria with a single flagellum at each pole are called _________ bacteria.

amphitrichous

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

bacillus

Capsules and slime layers are networks of polysaccharides that can extend from the bacterial surface. Both capsules and slime layers can be encompassed by the general term _________.

glycocalyx

_______ are the site of protein synthesis in the cell.

ribosomes

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

vitamins

Small organic molecules called __________ function as enzyme cofactors.

vitamins

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

Active transport

Why is boiling at standard temperature and pressure an inadequate method of processing for canned foods?

Boiling to 100°C will kill vegetative C. botulinum cells, but any spores will survive to temperatures of 120°C.

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

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.

Bacteria growing at lower temperatures have more saturated fatty acids in their membranes. (T/F)

False

During the assembly of the flagellar filament, the flagellin protein monomers assemble from the base of the flagellum within the cell envelope. (T/F)

False

Endospores are reproductive structures. (T/F)

False

Sedimentation coefficients are proportional to the molecular weight of a particle and are not affected by the volume and shape of the particle. (T/F)

False

Sulfur can be obtained from inorganic sources only. (T/F)

False

The cell membrane is a rigid structure that provides bacteria with their characteristic shapes. (T/F)

False

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

False

The original differentiation of prokaryotes and eukaryotes was based on structures found in prokaryotes that are lacking in eukaryotes. (T/F)

False

Zinc (Zn) is considered a macronutrient. (T/F)

False

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

Germination

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

Growth factors

Which of the following is not considered a micronutrient?

Magnesium (Mg)

Which of the following statements is false regarding why some scientists believe that the term "prokaryote" is a somewhat artificial designation?

Some bacteria have 80s ribosomes

Which of the following statements is FALSE when comparing bacterial and eukaryotic cytoskeletal proteins?

The cytoskeletal proteins found in bacterial cells are structurally and functionally unrelated to those found in eukaryotic cells.

Copper (Cu) is considered a micronutrient. (T/F)

True

Nitrogen can be obtained from either organic or inorganic sources. (T/F)

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. (T/F)

True

Prokaryotes were once described based on structures that were present in eukaryotes, but absent in prokaryotes. (T/F)

True

Some photosynthetic aquatic bacteria produce gas vacuoles that lack a lipid-bound membrane in order to regulate their buoyancy. (T/F)

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. (T/F)

True

The extreme insolubility of ferric iron leaves little free iron available for transport into bacterial cells. (T/F)

True

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

True

Twitching motility involves _________.

Type IV pili

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

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

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

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

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

capsule

Sortase is a protein enzyme of bacteria that _________.

catalyzes covalent attachment of some surface proteins to peptidoglycan

Bacterial endospores are protected from chemicals and various lytic enzymes due to the presence of the spore layer called the ________.

coat

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

The movement of dissolved solutes from a region of higher concentration to a region of lower concentration is called __________.

diffusion

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

dipicolinic acid

Clostridium botulinum, which produces a toxin that causes botulism, is a major concern of the food industry due to its production of an extremely heat-resistant ________.

endospore

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

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

exoenzymes

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 _________.

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 are phosphorylated as they enter the bacterial cell. You would describe this transport system as a(n) ___________.

group translocation

Some molecules needed for survival cannot be synthesized by the cell but instead must be obtained from the environment. These types of molecules include vitamins and amino acids and are collectively called ______ ______.

growth factors

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 __________.

hydrophilic; hydrophobic

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

inclusions

Nutrient uptake and diffusion of molecules into the bacterial cell become more efficient as the surface area-to-volume ratio _________.

increases

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(n) _________.

integral membrane protein

Discovery of the bacterial cytoskeletal protein FtsZ provided an important link in the evolution of cells since __________.

is was also discovered in mitochondria and chloroplasts

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

isotonic

All of the following statements about the periplasmic space are true except __________.

it is found only in Gram-positive bacteria

Bacterial movement toward or away from a chemical is often described as a "random biased walk" due to the fact that __________.

it still tumbles to change direction but it occurs less often than in the absence of a chemical, and runs more creating an overall net motion in one direction

The plasma membrane must possess mechanisms for getting nutrients into the cell. Nutrients such as oxygen and hydrogen are needed in relatively large amounts and are referred to as _________.

macroelements

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

macronutrients

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

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.

nucleoid

The germination process of an endospore into a vegetative cell involves core enzymes becoming active due to increased water levels resulting in the ________ stage.

outgrowth

The movement of molecules from an area of higher concentration to an area of lower concentration without the participation of specific carrier molecules is called _________.

passive diffusion

In the Gram-positive bacterial cell wall, the tetrapeptides that extend from the peptidoglycan layers are linked by ________.

peptide interbridges

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

peptidoglycan

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

peripheral

Proteinaceous 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

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

pleomorphic

Bacterial cells that are variable in shape are called _________.

pleomorphic

The power used by most bacterial flagellar motors is produced by __________.

proton motive force (PMF)

The bacterial flagellum is driven to rotate by protons moving down a charge and pH gradient and the energy provided is called the _________ ___________ ____________.

proton motive forces

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

Many bacteria have overcome the difficulty of iron uptake by secreting low molecular weight iron-binding proteins called _________.

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

Flexible bacteria with a helical shape are called _________.

spriochetes

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

staphylococci

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

Structural differences between Gram-positive and Gram-negative bacteria are observed following the Gram-staining procedure since __________.

the thick layer of peptidoglycan in Gram-positive bacteria is dehydrated during the alcohol step, thus acting as an impermeability barrier retaining the crystal violet/iodine complex

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

vibrio