The concept of a prokaryote was first fully outlined in 1962 by |
Stanier and Van Niel |
The genus of bacteria that undergoes cell division in random planes, forming grapelike clusters of round bacteria, are the __________. |
staphylococci |
Bacteria that do not have a fixed shape are said to be __________. |
pleomorphic |
A branched network of hyphae formed by the Actinomycetes is called a __________. |
mycelium |
Actinomycetes form long filaments called ___________. |
hyphae |
The term used to describe bacteria that are intermediate in shape between spherical and rodshaped is |
coccobacilli. |
Bacterial cells that are variable in shape are called |
pleomorphic. |
Square planar arrangement of cells that forms when round bacteria remain attached to each other during reproduction are called |
tetrads. |
Flexible bacteria with a helical shape are called |
spirochetes. |
Rigid bacteria with a helical cell shape are called |
spirilla. |
The term used to describe bacteria that are shaped like curved rods is |
vibrio. |
The term used to describe bacteria that are rod shaped is |
bacillus. |
The term used to describe bacteria that have a spherical shape is |
coccus. |
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 cytoplasmic membrane of bacteria |
A. retains the cytoplasm and its contents., B. acts as a selectively permeable barrier, allowing some molecules to pass while preventing the movement of others., C. is the major site of ATP synthesis in aerobes. |
The lipopolysaccharide (LPS) that is found in the outer membrane of gram-negative bacteria is also known as |
endotoxin. |
Which of the following is/are true of capsules? |
A. They help bacteria escape phagocytosis by host cells., B. They retain water and help prevent desiccation of the bacteria., C. They prevent entry of many bacterial viruses. |
Proteins that are loosely associated with the cytoplasmic membrane are called __________proteins. |
peripheral |
Proteins that are embedded within the cytoplasmic membrane and not easily extracted are called __________ proteins. |
integral |
Shrinkage of the plasma membrane away from the cell wall when the bacterium is placed in a hypertonic environment is called |
plasmolysis. |
Lipids with polar and nonpolar ends are said to be |
amphipathic. |
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. |
Which of the following protects bacteria from lysis in dilute solutions and helps to determine their cellular morphology or shape? |
peptidoglycan |
Sortase is a protein enzyme of bacteria that |
catalyzes covalent attachment of some surface proteins to peptidoglycan. |
The cell membrane is a rigid structure that provides bacteria with their characteristic shapes. |
FALSE |
Gram-positive bacteria have a thinner layer of peptidoglycan than gram-negative bacteria. |
FALSE |
Gram-positive bacteria have a structurally and chemically more complex cell wall than gramnegative bacteria. |
FALSE |
Bacteria growing at lower temperatures have more saturated fatty acids in their membranes. |
FALSE |
When the cell wall is removed from a Gram-negative bacterium without removing the outer membrane, the resulting form is called a(n) __________. |
spheroplast |
Enzymes that are secreted out of the cell to aid in the acquisition and digestion of environmental nutrients are called __________. |
exoenzymes |
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 |
A __________ layer consists of diffuse unorganized polysaccharide material that lies outside the cell wall and is easily removed. |
slime |
A __________ is a polysaccharide layer that lies outside the cell wall and is not easily removed. |
capsule |
A(n) __________ layer is a layer of protein or glycoprotein that exhibits a pattern resembling floor tiles. |
S |
The most widely accepted current model for membrane structures is called the __________model. |
fluid mosaic |
The layers of peptidoglycan of the bacterial cell wall can be cross-linked by peptide intrabridges or by direct cross-linking. |
FALSE |
A feature unique to some archaeal plasma membranes is that they may |
consist of a lipid monolayer. |
Cell walls of most Archaea and bacteria contain peptidoglycan. |
FALSE |
_______ is a peptidoglycan-like molecule found in the cell walls of some archaea. |
Pseudomurein |
The hydrocarbons found in the membranes of archaea are identical to those found in bacteria. |
FALSE |
Which of the following is not true of bacterial plasmids? |
They are required for host growth and/or reproduction. |
Some photosynthetic bacteria produce gas vacuoles that regulate their buoyancy but contain no lipid. |
TRUE |
Intracellular granules of organic or inorganic material that are stockpiled by bacteria for future use are called __________. |
inclusions |
Bacteria have a region of the cytoplasm known as the __________, which is not bounded by a membrane but contains the chromosome. |
nucleoid |
Small circular DNA molecules capable of replicating and containing genes that are useful but not necessary to the bacterium are called __________. |
plasmids |
Some species of aquatic bacteria use inclusion bodies known as ________ to orient themselves in Earth’s magnetic field. |
magnetosomes |
Bacterial and archaeal ribosomes are known as _____ ribosomes, based on their sedimentation coefficient. |
70S |
_______ are the site of protein synthesis in the cell. |
Ribosomes |
Sedimentation coefficients are proportional to the molecular weight of a particle and are not affected by the volume and shape of the particle. |
FALSE |
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 |
The type III bacterial protein secretion machinery: |
A. has a needlelike structure through which proteins are secreted., B. includes structural features that may be evolutionarily related to the basal bodies of bacterial flagella., C. is found in gram-negative bacteria. |
Export of flagellin subunits is mediated by |
an apparatus in the basal body of the flagellum that is related to the type III secretion |
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 |
During the assembly of the flagellar filament, the flagellin protein monomers assemble at the cell proximal base of the flagellum. |
FALSE |
Archaeal flagella are superficially similar to bacterial flagella, although archaeal flagella are much thicker than bacterial flagella. |
FALSE |
Matching: Match the definition with the word. 1) monotrichous, 2) peritrichous, 3) lophotrichous, 4) amphitrichous: |
1-a, 2-d, 3-c, 4-b |
The power used by most flagellar motors is produced by |
proton motive force (PMF) |
Chemotaxis is a process by which bacteria |
move toward an attractant or away from a repellent. |
The rotation of bacterial flagella is powered by ATP hydrolysis. |
FALSE |
The bacterium E. coli swims in a straight line, called a __________, for a few seconds; then it stops, __________, then swims away in a new direction. |
run, tumbles |
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 |
Twitching or gliding motility involves |
both type IV pili and movement of slime can be involved in twitching or gliding motility. |
Endospores represent a challenge to the fields of industrial and medical microbiology because |
endospores are resistant to harsh environments, thus allowing survival of endo-sporeforming organisms under conditions in which non-endospore-forming cells would not survive, and endospore-forming organisms are often dangerous pathogens |
__________ is the process through which endospores are formed within a vegetative cell. |
Sporulation |
__________ is the main part of the process through which a vegetative cell is formed from an endospore. |
Germination |
Chapter 3 Microbiology
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