Microbiology Chapter 3

The number of proteins associated with the bacterial ribosome is well characterized; there are approximately 55 proteins total— _____ in the small subunit and ____ in the large.

-21 -34

Bacterial cells contain thousands of ribosomes that carry out _____________. Some are located in the cytoplasm and others are attached to the ______________.

-translation -plasma membrane

Two flagella extends from two different cell "poles" to power locomotion.

Amphitrichous

Protein and chromosome positioning

Bactofillin

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

Responsible for bacterial attachment to surfaces

Fimbriae

Responsible for locomotion

Flagellum

Cell division

FtsZ

Contains compounds that aid in buoyancy

Gas vesicle

carry genes for enzymes

Metabolic plasmids

Helps determine shape of cell

MreB

Several flagella extending from all cell "sides" to power locomotion.

Peritrichous

carry antibiotic resistance genes

R plasmids

Involved in protein synthesis

Ribosome

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 statement about flagellar structure is TRUE?

The filament extends out of the cell.

heat treatment prepares spores for germination

activation

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

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

increases

In addition, there is an _________________ external to the Gram-negative bacterial peptidoglycan layer.

outer membrane

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 force

Twitching motility involves _________.

type IV pili

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

vitamins

The bacterial ribosome is smaller than those found in eukaryotes. It is designated as a ______________

70s ribosome

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

Capsule

Contains genetic information required for survival

Chromosome

A dormant cell state

Endospore

Gram-positive bacteria have flagella with four basal body rings, while those of Gram-negative bacteria have only two. T/F

False

In an endospore, the protein coat forms a layer external to the exosporium. T/F

False

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

False

Several flagella extending from one cell "pole" to power locomotion.

Lophotrichous

A single flagellum extends from the cell to power locomotion.

Monotrichous

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

O antigen

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

Segregates chromosomes and plasmids

ParA

Gliding motility in bacteria involves which of the following?

Specialized cell-surface proteins and slimy polysaccharides

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

Sporulation

The rate of diffusion of a molecule into a cell is affected by which of the following factors?

Steep concentration gradient with a high amount of the molecule outside the cell

Spirochetes move in a screw-like manner that is mediated by bundles of flagella located in the cell's periplasmic space. T/F

True

Spore formation is initiated when there is a scarcity of nutrients. T/F

True

carry virulence genes

Virulence plasmids

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

amphitrichous

The bacterial flagellum moves _________.

by rotation that is powered by the proton motive force

The spore layer containing peptidoglycan is the __________.

cortex

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

diffusion

When discussing a ribosome's size, the "s" stands for Svedberg unit; a measure of how fast a particle travels when centrifuged. The greater the number, the __________ it travels.

faster

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

In endospore formation, when DNA condenses and aligns itself in the center of the cell, the cell is called a(n) __________.

mother cell

core enzymes become active due to increased water levels

outgrowth

Finally, bouyancy in aquatic bacteria is mediated by _____________, while certain bacteria accumulate magnetite in ________________ that can detect natural magnetic fields.

-gas vacuoles -magnetosomes

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

Nucleic acids are synthesized from inorganic inclusions called _______________________, while specialized photosynthetic bacteria can store energy as _________________.

-polyphosphate granules -sulfur globules

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

Iron is required by bacteria for metabolic activities. Put the following steps in order to review the bacterial method of iron uptake for the cell.

1. Iron scarce in environment 2. Bacteria secretes siderophore 3. Iron-siderophore complex binds cell surface protein 4. Iron-siderophore complex enters cell via ABC transporter

Place the steps of sporulation in the correct 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 cortex 5. Spore coat formation 6. Maturation and release of endospore

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

70S

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)

produce bacteriocins

Col plasmids

transfer DNA from one cell to another

Conjugative plasmids

Involved in cell division and controlling cell shape

Cytoskeleton

Germination is one process by which bacterial cells can reproduce. 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

Most substances are able to undergo passive diffusion across the plasma membrane in order to enter a cell. 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

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

Lipopolysaccharide

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

Peptidoglycan

flagella spread over the entire surface of the bacterium

Peritrichous

Extrachromosomal DNA molecules

Plasmid

one flagellum at one end of the bacterium

Polar

_______ are the site of protein synthesis in the cell.

Ribosomes

Responsible for transferring DNA from one bacterial cell to another

Sex pilus

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

Siderophores

Contains high-molecular weight polymers

Storage granules

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.

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.

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

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

Lipids with polar and nonpolar ends are said to be _________.

amphipathic

Another type of inclusion, which photosynthetic microbes often use to store carbon dioxide and the enzyme RuBisCO, is the ________________.

carboxysome

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

coat

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

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

endotoxin

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

flagella

germinant receptor proteins detect sugars or amino acids

germination

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

A rod with the same S/V ratio as a cocci can have _______________ uptake across its cytoplasmic membrane than the cocci.

greater nutrient

Epulopiscium fishelsoni has a ________________ plasma membrane to increase its S/V ratio to compensate for its large size.

highly convoluted

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

inclusions

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

Bacterial cells that are variable in shape are called _________.

pleomorphic

Inclusions containing carbon are most commonly in the form of _______________ and can be commercially used to create biodegradable plastics.

poly-beta-hydroxybutyrate

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

Movement of molecules from areas of higher concentration to areas of lower concentration

simple diffusion

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

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

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

A cocci with the same volume as a rod has a __________ S/V ratio than does the rod.

lower

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

In bacteria, as the surface area-to-volume ratio increases, nutrient uptake becomes ______________.

more efficient

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

mycelium

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

This structure contains only a thin layer of _______________.

peptidoglycan

The two layer cell wall of Gram-negative bacteria is separated from the plasma membrane by the ____________________.

periplasmic space

The addition of alcohol during the Gram-staining procedure causes decolorization of Gram-negative bacteria and the addition of safranin results in ________ cells.

pink

The cell wall of Gram-negative bacterial cells is external to the _______________.

plasma membrane

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

pleomorphic

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

vibrio

Small organic molecules called __________ function as enzyme cofactors.

vitamins