Micro ch 4 Assignment Q's
The cortex is formed from _____.
peptidoglycan
Please select all of the following which are found in all cells regardless of cell type.
Cell membrane, cytoplasm, DNA
True or False: The thinner peptidoglycan layer of gram-positive bacteria allows the crystal-violet-iodine complex to leave the cell.
False
When is sporulation initiated by spore-forming bacteria?
when nutrients are depleted or conditions become adverse
The functions of the cell envelope include
Helping to determine the shape of a bacterial cell. Preventing rupture of the cell from increased internal pressure. Allowing the cell to regulate the transport of many molecules from the internal to external environment.
Of the photosynthetic bacteria, cyanobacteria produce ______ as a product of photosynthesis but the green and purple sulfur bacteria do not produce this substance.
Oxygen
In the final step of spore formation a _____ coat forms around the cortex.
Protein
Cytoskeleton
This structure is a network of protein polymers that helps stabilize the shape of the cell from within.
Granules
This structure stores inorganic compounds, such as sulfur and polyphosphate.
Inclusion bodies
This structure stores nutrients during periods of ample resources to compensate for times when nutrients are scarce.
Halophile
an organism that lives in an environment that contains high amounts of salt such as the Dead Sea
hyperthermophile
an organism that lives in extremely hot temperatures such as the hot springs of Yellowstone National Park
psychrophile
an organism that lives in very cold conditions, including temperatures below freezing
Archaea
are novel prokaryotic organisms that belong to their own superkingdom (domain).
The bacterial flagellum moves
by rotation that is powered by the proton motive force.
In the next phase of spore formation, _____ enters the cortex and _____ leaves the cortex.
calcium; water
A taxonomical outline of bacterial species based on shared evolutionary histories would be described as a
phylogenetic system.
This arrangement is formed when rod-shaped bacteria divide multiple times on their transverse planes and do not separate therefore the cells continue to be attached to each other.
streptobacilli
Please select all of the statements that are true about endospores.
-Bacterial endospores are highly resistant to heat, drying, and radiation. -Endospores can exist in the environment for indefinite periods of time. -Endospores resist boiling and therefore steam must be used to destroy endospores present in food.
Please select all of the following which are purposes of classification and taxonomy in the study of prokaryotes
-Classification and taxonomy can assist in identifying an unknown organism. -Classification and taxonomy can assist in studying the evolutionary origins of an organism. -Classification and taxonomy can assist in identifying a new species of organism.
Please select all of the following that are characteristics of archaea.
-prokaryotic -circular chromosome -contain long-chain, branched hydrocarbons in the cell membrane
Please select all of the characteristics that define life and living things
-the ability to synthesize new cell components or release energy through chemical reactions the ability to synthesize new cell components or release energy through chemical reactions -ability to respond to their environment ability to respond to their environment -ability to control the flow of some materials across cell boundaries
Which term(s) refer to cells without cell walls?
Mycoplasma sphereoplast protoplast
Please order the following choices to reflect the generalized anatomy of bacterial cells with "1" being the innermost cell component and "4" being the outermost cell component.
1. Cytoplasmic matrix 2. Cell membrane 3. Cell wall 4. glycocalyx
Please select all of the following which are contents of the cell cytoplasm.
Chromosome Ribosome Water
The best understood bacterial cytoskeletons are composed primarily of
Actin
After Gram's iodine is added, what color do the cells appear under a light microscope?
All cells appear purple
The cell envelope is the external covering that lies outside of the cell cytoplasm and is composed of the _______ and _______.
Cell membrane and cell wall
Ribosome
Composed of RNA and protein, this structure synthesizes new proteins.
Excess nutrients that the cell may store for later use may be found within
Cytoplasmic granules
Although they share many bacterial characteristics, members of the Domain Archaea are more closely related to Domain ? than to bacteria.
Eukarya
Characteristics that define archaea, however, include the presence of unique membrane ?, cell wall construction and composition and metabolic pathways.
Lipids
When spore formation begins, the vegetative cell is referred to as the ________.
Mother cell
Why must fresh cells be used when performing a Gram stain?
Old cells may not Gram stain properly.
For example, both archaea and eukaryotes share unique ? RNA sequences and their ribosomal subunit structures are similar as well.
Ribosomal
Ribosomes function primarily to
Synthesize protiens
This arrangement is formed when a coccus divides on perpendicular planes and results in four cocci being attached as a cluster of cells.
Tetrad
Chromosome
The structure which contains the essential DNA of the cell.
Plasmid
The structure which contains the nonessential DNA of the cell.
Which of the following explains why archaeons are extremophiles?
They are ancient, primitive organisms that adapt well to extreme conditions because they have retained characteristics of the cells that first evolved when Earth's conditions were far more extreme.
Acid fast cells
cells which contain a thick layer of mycolic acid or cord factor
Gram positive cells
cells which contain a thick layer of peptidoglycan and teichoic acids
Gram negative cells
cells which contain both an inner and outer membrane as well as a thin layer of peptidoglyan
Mycoplasms
cells which lack a cell wall with peptidoglycan but contain sterols to strengthen their cell membrane
The two groups of obligate intracellular bacteria are the ________, usually spread by contact, and the ________, usually transmitted by the bites of arthropods.
chlamydias; rickettsias
Flagella
composed of a filament, hook and basal body, these cell appendages provide movement to the cell
This arrangement is formed when two rod-shaped bacteria divide on the transverse plane and do not separate.
diplobacilli
This arrangement is formed when a coccus divides on a single plane and the two daughter cells remain attached.
diplococci
Which of the following correctly describe the color of different cells after using the Gram staining technique?
gram-negative—pink/red gram-positive—purple
Please select all of the characteristics that define life and living things.
heredity, growth and development and use of energy
Other than maintaining the shape of the cell, what is the primary function of the cell wall, and which component contributes most to this function?
maintaining strength; peptidoglycan
Bacterial species are defined in a fundamentally different way than mammalian species are. This is because
mammals reproduce sexually while bacteria reproduce asexually
This arrangement is formed when bacilli that are attached end to end fold back on each other to form rows of side-by-side cells.
palisades arrangement
The cell membrane is composed of _____________.
proteins dispersed throughout a phospholipid bilayer
When ethanol is applied correctly, gram-positive cells appear ____ and gram-negative cells appear _____.
purple; colorless
Choose the answer that best completes this statement's blanks in the correct order. When all the flagella on a cell rotate in a counterclockwise fashion, the cell is propelled forward in a movement known as a ____, but when the flagella reverse direction, the cell stops and changes course in an action known as a ____.
run; tumble
The developing spore is surrounded by
the membrane of the mother cell.
Such adaptations to their metabolic pathways allow archaea to live in extreme environments, such as areas with high levels of salt (halophiles) or high temperatures (?).
thermophiles
Axial filaments
these long, coiled threads provide movement to spirochetes
Pili
these long, tubular appendages allow cells to conjugate to other cells
Fimbriae
these short, bristle-like projections are used to attach the cell to other cells or surfaces
genetic techniques
these tests use DNA to determine the identity of an organism
serological analysis
these tests use antibody reactions to identify an organism or to determine relatedness
Morphology
these tests use cell shape and Gram reaction to classify organisms
bacterial physiology/biochemistry
these tests use the presence or absence of biochemical processes and enzymes to group organisms
glycocalyx
this is the general term which describes all the various coatings covering the surface of the cell
Capsule
this layer of polysaccharides and/or proteins is tightly bound to the cell and contributes to the cell's pathogenicity
Slime layer
this loosely attached, thin mucoid layer protects the cell from drying out or losing nutrients
peritrichous
this pattern consists of flagella randomly distributed around the cell
amphitrichous
this pattern has flagella at both poles of the cell
lophotrichous
this pattern has groups of flagella all originating from the same point on the cell
monotrichous
this pattern has one flagellum attached at one end of the cell
Polar
this type of flagella can be found at either or both ends of a cell
The primary function of the cell membrane is
to regulate the transport of molecules in and out of the cell.