homework #1
A tuft of flagella from a single site is referred to as a _____ arrangement, whereas flagella dispersed over the surface of the cell is referred to as _____.
Lophotrichous, Peritrichous
which appendages act as channels to transfer nutrients such as amino acids and electrons?
Nanotubes
the name given to a structure external to and bound tightly to the cell wall, that is made of polysaccharides and glycoproteins and contributes to the pathogenicity of the organism, is the ___.
capsule
which cell structure is designed to provide shape, support and resistance to osmotic pressure?
cell wall
which structure accounts for the different results of the gram stain?
cell wall
the two main components of the cell envelope in most bacteria are the
cell wall and cell membrane
streptococci have cells arranged in ___ of a few hundreds of cells
chains
During ______, bacterial cells move by flagellar motion in response to chemical signals.
chemotaxis
the transfer of genetic material through pili is termed
conjugation
which process involves the transfer of genetic material through pili?
conjugation
the innermost layer of the cell envelope is always the ___.
cytoplasmic membrane
which is true regarding all bacterial cells? a) all contain a cell wall b) all are motile c) all cause disease d) all lack a nucleus
d) all lack a nucleus
___ possess DNA enclosed in a nucleus and membrane-bound organelles whereas ___ and archaea are prokaryotes and therefore do not encase their DNA organelles in a membrane. a) eukaryotes; fungi b) bacteria; protista c) bacteria; eukaryotes d) eukaryotes; bacteria
d) eukaryotes; bacteria
Cocci that associate in pairs are referred to as
diplococci
cellular arrangement in cocci varies from cells that associate in pairs, called___, to those found in long chains called ___.
diplococci; streptococci
many bacteria can generate ___ in the absence of oxygen by sharing electrons with substances in the environment such as iron.
energy
For bacteria to move, the flagella ___ rotate(s) 360 degrees.
filament and hook
the bacterial cellular appendages responsible for the mutual clinging of cells that lead to biofilm formation are ___.
fimbriae
which appendage provides the ability to attach to surfaces and other cells
fimbriae
The basal body, hook, and filament are components of ______ in bacteria.
flagella
appendages that propel bacterial cells through an aqueous environment include axial filaments and ___.
flagella
capsules and slime layers are both types of ___.
glycocalyx
the colonization of the non-living materials like catheters, intrauterine devices, and a teal pacemakers is the result of which bacterial structure?
glycocalyx
the protective covering called the ___ develops as a coating of repeating polysaccharide or glycoprotein units.
glycocalyx
which type of cell walls are thicker?
gram positive
which common staining technique distinguishes between groups of bacterial cells based on the composition of their cell walls?
gram stain
to determine whether bacterial cells are motile, they can be observed microscopically in a ___ drop slide.
hanging
many bacteria can generate their energy in the absence of oxygen by sharing electrons with substances in the environment such as ___.
iron
an enzyme found in tears and saliva termed ___ acts to hydrolyze the glycan chains in peptidoglycan
lysozyme
an average sized bacterium is about one ___.
micrometer
A cell wall and some form of glycocalyx are found in ______ bacterial cells. a) most b) few c) all
most
which term refers to the capacity of a cell to swim greeley through an aqueous environment through self-propulsion?
motility
bacteria that are close in proximity may communicate via structures known as nanotubes or ___.
nanowires
to move away from a potentially harmful compound by a flagellar motion is referred to as ___ chemotaxis.
negative
when cells in a chain remain partially attached by a hinge region at the ends and the cells fold back each other forming a row of cells orientated side by side, it is described as a ___ arrangement
palisade
cells oriented in a ___ arrangement result from having a hinge region between cells so that the cells fold back on eachother
palisades
peptidoglycan is composed of long glycan chains cross-linked by
peptide fragments
The strength and rigidity of the cell wall is due to
peptidoglycan
antibiotics of the penicillin class act on ___, so that the cell wall is compromised and the cell will lyse
peptidoglycan
bacterial cells are protected from rupturing in hypotonic conditions by the rigidity of the ___.
peptidoglycan cell wall
capsules protect against bacteria against immune cells generally referred to as __.
phagocytes
What host defense is prevented by the capsule of some pathogenic bacteria?
phagocytosis by white blood cells
An appendage which forms a channel for the exchange of genetic material during bacterial conjugation is called a ___________
pili
Small proteinaceous appendages in gram-negative bacteria that function in DNA exchange are called conjugation _____.
pili
a ___ is a hollow, protein tube that facilitates the transfer of genetic material between bacterial cells.
pilus
streptococci in the moth can produce a surface slime that permits attachment to teeth and results in the formation of ___.
plaque
a pilus is composed of
protein
the bacterial S layer is composed of a single layer with thousands of copies of a single ___ linked together.
protein
A pilus is a _____ structure on the surface of many bacteria.
rigid tubular
the bacterial flagellum moves by
rotating 360 degrees
counterclockwise rotation of the flagellum causes a bacterial cell to swim or ___ towards a stimulus, interrupted by clockwise rotation in which the cell ___ and changes its coutse
run; tumbles
counterclockwise rotations by flagella that propel a cell forward are called ___, whereas clockwise rotations that cause the cell to stop and change its course are called ___.
run; tumbles
one way to detect motility in the laboratory is to stab cells into what kind of medium?
semisolid
bacteria function as organisms comprised of ___.
single cells
some bacteria have structures called ___ that are not found in all bacterial cells. a) pili b) ribosomes c) chromosomes d) cytoskeletons
a) pili
order the following cellular structures, from the outside to inside, placing the outermost layer at the top of the list.
Glycocalyx Outer membrane Cell wall Cytoplasmic membrane
which of the following statements regarding bacterial flagella are correct? -amphitrichous flagella are located at both ends of the cell -all spirilla have flagella -bacteria with the coccus shape do not have flagella -polar flagella are located randomly on the cell surface
- All spirilla have flagella. - Amphitrichous flagella are located at both ends of the cell.
the glycocalyx is important in the ability of bacteria to cause infection because it ___.
-Allows the bacteria to adhere well to medical devices -Allows for the formation of biofilms
which of the following are attributes of bacterial cells but not of eukaryotic cells? -cell wall made of cellulose -DNA is free within the cell -membrane bound organlles such as mitochondria -cell wall made of peptidoglycan -DNA enclosed in membrane-bound nucleus -no membrane-bound organelles within the cell
-DNA is free within the cell -cell wall made of of peptidoglycan -no membrane-bound organelles within the cell
which of the following are types of flagella arrangements with more than one flagellum? -monotrichous -amphitrichous -lophotrichous -peritritchous
-amphitrichous -lophotrichous -peritritchous
identify the correct statements regarding bacterial flagella -monotrichous flagella are located at both ends of the cell -spirilla do not have flagella -bacteria with the coccus shape sometimes have flagella -polar flagella are located at the ends of a cell
-bacteria with the coccus shape sometimes have flagella -polar flagella are located at the ends of a cell
which of the following are part of the cell envelope, including components found in some but not all bacteria? -cell wall -outer membrane -cytoplasmic membrane -nuclear membrane -cytoskeleton
-cell wall -outer membrane -cytoplasmic membrane
what three roles do teichoic and lipoteichoic acid play in gram positive cells? -contributes to charge of the cell surface -enlargement of the cell wall during division -production of ATP -cause endotoxic shock if released in human host -maintenance of the cell wall
-cell wall maintenance -enlargement during cell division -contribute to charge of the cell surface
which three structures are possessed by ALL bacteria? -flagella -cell wall -chromosomes -ribosomes -cell membrane
-chromosomes -ribosomes -cell membrane
All of these appendages provide motility to bacteria EXCEPT ______. -fimbriae -nanowires -flagella -axial filaments -pili
-fimbriae -nanowires -pili
which two of the following are functions of the fimbriae found covering in bacterial cells?
-formation of biofilms -colonization of epithelial cells
the important factors that determine the arrangement of the bacterial cells are ___.
-how the cells remain attached after division -the pattern of cell division
the functions of the cell wall include
-maintaining the shape of the bacterium -preventing destruction with changes in osmotic pressure
identify the correct statements regarding chemotaxis -the fuel for the flagellum is ATP -nutrient receptors for the cell are located in the cytoplasmic membrane -negative chemotaxis is movement of a cell in the direction of nutrients -the fuel for the flagellum causes the filament to rotate
-nutrient receptors for the cell are located in the cytoplasmic membrane -the fuel for the flagellum causes the filament to rotate
which three of the following are specific structures found in some, but not all, bacteria? a) cytoskeleton b) cytoplasmic membrane c) ribosomes d) fimbriae e) outer membrane f) endospores
-outer membrane -fimbriae -endospores
which appendages provide attachment points or channels, rather than motility? -pili -flagella -fimbriae -nanotubes -axial filaments
-pili -fimbriae -nanotubes
choose the characteristics that are different between eukaryotes and bacteria/archaea -chemical structure of DNA nucleotides -presence of organelles -general cell membrane structure -cell wall composition
-presence of organelles -cell wall composition
biofilms are medically significant because they can adhere to the surfaces of ___.
-teeth -plastic catheters
identify the correct statements regarding bacterial and archaeal flagella -the flagellar filament is composed of nucleic acid -the flagellar filament is usually shorter than the bacterial cell -the archaeal flagellum is dramatically different from the bacterial flagellum -the basal body of the flagellum is anchored to the cell wall
-the archaeal flagellum is dramatically different from the bacterial flagellum -the basal body of the flagellum is anchored to the cell wall
which statements regarding bacterial and archaeal flagella are correct? -the flagella filament can be many times linger than the bacterial cell -the basal body of the flagellum is anchored to the cell wall -the archaea flagellum is virtually identical to the bacterial flagellum -the flagella filament is composed of polysaccharide
-the flagella filament can be many times longer than the cell -the basal body of the flagellum is anchored to the cell wall
which two of the following functions of the type IV pilus? -protects from desiccation -attach to surfaces -conduct electrical currents -transfer genetic material
-transfer genetic material -attach to surfaces
bacteria that are spatially close to one another may be able to communicate via which two of the following methods ? a) via light modulation b) via nanowires c) genetically d) via sound e) chemically
-via nanowires -chemically
which of the following are functions of the glycocalyx?
adherence, protection
which of the following describes the function of fimbriae?
adhesion
a periplasmic flagellum found in some spirochete bacteria is called a(n) ___ filament
axial
twisting of flexing of spirochete bacteria is attributed to the ___.
axial filaments
the pattern of cell division and how cells remain attached after division both affect ___. a) the presence of nanowires b) cellular arrangement c) whether the cells are in a biofilm d) the shape of individual cells
b) cellular arrangement
which term describes a grouping of 8, 16, or more cells that forms a cubical packet? a) streptococcus b) sarcina c) staphylococcus d) diplodocus
b) sarcina
peptidoglycan is a component of the cell wall in ___.
bacteria
the bacterial flagellum is composed of ___.
basal body, hook, filament
the assemblage of cells occurring in a matrix secreted by the members is termed by ___.
biofilm
each of the following is found in all bacterial cells except ___. a) cytoplasm b) ribosomes c) a glycocalyx d) a cytoplasmic membrane
c) a glycocalyx
which of the following structures is external and can protect the bacterial cell from various immune responses? a) flagella b) cell wall c) capsule d) cell membrane
c) capsule
the majority of bacterial cells have all of the following features EXCEPT ___. a) genetic material b) a cell wall made of peptidoglycan c) a nucleus d) one or more chromosomes
c) nucleus
which term means that a cell wall can have various shapes? a) coccobacillus b) variability c) plemoporphic
c) plemorphic
to protect the cell from dehydration and loss of nutrients, some bacteria are covered with a loose shield called a ___ ___.
slime layer
which prefix indicates cells that are arranged in chains?
strepto-
which of the following describes cocci in chains?
streptococci
which of the following are components of peptidoglycan?
sugar chains and short peptides
True or false: Mycoplasmas are pleomorphic because they do not contain a cell wall for shape.
true
true or false: bacteria that produce an S layer do so only when they are in a hostile environment.
true
many bacteria function as independent ___ organisms.
unicellular
structures found in a majority of, but not all, bacteria are a cell ___ and a surface coating called a(n) ___.
wall; glycocalyx
the cell envelope is composed of the cell ___ and the cell ___
wall; membrane
