Microbiology ch3 – Flashcards

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

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

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

 Actinomycetes form long filaments called ___________.  

True or False

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 Or False

The cell membrane is a rigid structure that provides bacteria with their characteristic shapes.  

True or False

Gram-positive bacteria have a thinner layer of peptidoglycan than gram-negative bacteria. 

True or false

Gram-positive bacteria have a structurally and chemically more complex cell wall than gram-negative bacteria. 

 Bacteria growing at lower temperatures have more saturated fatty acids in their membranes.  

When the cell wall is removed from a Gram-negative bacterium without removing the outer membrane, the resulting form is called a(n) __________.  

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

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 hydrophobic.  

A __________ layer consists of diffuse unorganized polysaccharide material that lies outside the cell wall and is easily removed.  

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

(p. 52)  _______ bind ferric iron and transport it into a bacterial cell.  

(p. 49)  Nutrients that are used by bacteria in relatively large amounts are _____.  

T/F

(p. 42)  Prokaryotes were once described based on structures that were present in eukaryotes, but absent in prokaryotes.  

(p. 52) 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) _____. 

 facillitated diffusion
micronutrient regulator
passive diffusion
group translocation

T/F

Growth factors cannot by synthesized by the bacteria that use them and include amino acids, pyrimidines, and vitamins.  

(p. 77)  Endospores are resistant to most environmental stressors because they have _____ complexed with calcium ions which stabilize DNA.  

(p. 77)  Which of the following structures is NOT found in an endospore?  
capsule
coat
 core
exosporium 

T/F

If you remove the peptidoglycan layer from a Gram positive cell, it would still stain purple with a Gram stain.  

The most widely accepted current model for membrane structures is called the __________ model.  

T/F

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

T/F

Some photosynthetic bacteria produce gas vacuoles that regulate their buoyancy but contain no lipid. 

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

 Bacteria have a region of the cytoplasm known as the __________, which is not bounded by a membrane but contains the chromosome.  

 Small circular DNA molecules capable of replicating and containing genes that are useful but not necessary to the bacterium are called __________.  

 Some species of aquatic bacteria use inclusion bodies known as ________ to orient themselves in Earth's magnetic field.  

_______ are the site of protein synthesis in the cell.  

T/F

 Sedimentation coefficients are proportional to the molecular weight of a particle and are not affected by the volume and shape of the particle.  

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.  

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 __________.  

T/F

During the assembly of the flagellar filament, the flagellin protein monomers assemble at the cell proximal base of the flagellum. 

monotrichous

peritrichous

lophotrichous

amphitrichous

T/F

The rotation of bacterial flagella is powered by ATP hydrolysis. 

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.  

 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.  

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

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

The concept of a prokaryote was first fully outlined in 1962 by   

 Watson and Crick.
Stanier and Van Niel.
Hersey and Chase.
Gilbert and Cech.

The term used to describe bacteria that are intermediate in shape between spherical and rod-shaped is  

cocci.
bacilli.
vibrio.
coccobacilli. 

Bacterial cells that are variable in shape are called 

 vibrio.
 pleomorphic.
coccobacilli.
hyphal.

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

 streptococci.
staphylococci.
 tetrads.
sarcinae.

Flexible bacteria with a helical shape are called 
vibrios.
spirilla.
spirochetes.
coccobacilli.

Rigid bacteria with a helical cell shape are called 
vibrios.
 spirilla.
 spirochetes.
coccobacilli.

Rigid bacteria with a helical cell shape are called 
vibrios.
 spirilla.
 spirochetes.
coccobacilli.

The term used to describe bacteria that are shaped like curved rods is 
 coccus.
 bacillus.
vibrio.
coccobacillus.

The term used to describe bacteria that are rod shaped is 
 coccus.
bacillus.
 vibrio.
coccobacillus.

The term used to describe bacteria that have a spherical shape is 
coccus.
bacillus.
vibrio.
coccobacillus.

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.
all of the choices.

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

 exotoxin.
teichoic acid.
murein.
endotoxin.

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.
all of the choices.

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

peripheral
  integral
 external
internal 

Proteins that are embedded within the cytoplasmic membrane and not easily extracted are called __________ proteins. 

 peripheral
integral
 external
 internal

Shrinkage of the plasma membrane away from the cell wall when the bacterium is placed in a hypertonic environment is called 

 osmolysis.
 plasmolysis.
 hydrolysis.
hypertonolysis.

Lipids with polar and nonpolar ends are said to be 

 amphipathic.
 amphibolic.
 bilateral.
none of the choices.

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

hypotonic
 isotonic
hypertonic
nonpolar

All of the following statements about the periplasmic space are true except:  

It is found only in gram-positive bacteria.
It is located between the plasma membrane and outer membrane of gram-negative bacteria.
It contains hydrolytic enzymes and binding proteins involved in nutrient acquisition.
All of the above are true. 

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

  plasma membrane
  peptidoglycan
  capsule
gas vacuoles 

Sortase is a protein enzyme of bacteria that 

plays a key role in directing proteins to the periplasm.
catalyzes covalent attachment of some surface proteins to peptidoglycan.
directs secretion of proteins across the outer membrane.
functions by transporting flagellum proteins to their extracellular site of assembly.

Which of the following is not true of bacterial plasmids? 

They can replicate independently of the chromosome.
They may carry genes for drug resistance.
They are required for host growth and/or reproduction.
They may carry genes that enhance survival of the bacterium under certain conditions.

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

The type III bacterial protein secretion machinery: 

has a needlelike structure through which proteins are secreted.
includes structural features that may be evolutionarily related to the basal bodies of bacterial flagella.
is found in gram-negative bacteria.
all of the choices are correct.

Export of flagellin subunits is mediated by  

  an apparatus in the basal body of the flagellum that is related to the type II secretion pathway.
  the type I secretion pathway.
  an apparatus in the basal body of the flagellum that is related to the type III secretion pathway.
  none of the above. 

The power used by most bacterial flagellar motors is produced by 

 synthesis of glucose.
 ATP hydrolysis.
 proton motive force (PMF).
 all of these.

Chemotaxis is a process by which bacteria 

 move toward an attractant or away from a repellent.
 avoid phagocytosis.
 respond metabolically to the presence of autoinducer molecules.
 move on solid surfaces by means of type IV fimbriae.

Twitching or gliding motility involves  

  type IV pili.
  axial fibrils.
  movement of slime.
  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

they are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive.
 endospore-forming organisms are often dangerous pathogens.
endospores are significantly smaller than vegetative cells.
 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.

Elements that are required in relatively large amounts by microorganisms are called 
 multivitamins.
 meganutrients.
 macronutrients.
 macromolecules.

Which of the following is not considered a macronutrient? 
 carbon (C)
 calcium (Ca)
 potassium (K)
 cobalt (Co)

Which of the following is not considered a micronutrient? 

 manganese (Mn)
 magnesium (Mg)
 zinc (Zn)
 copper (Cu)

T/F

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

T/F

Zinc (Zn) is considered a macronutrient. 

T/F

Copper (Cu) is considered a micronutrient. 

T/F

Sulfur can be obtained from inorganic sources only. 

T/F

Phosphorus can be obtained from organic sources only. 

T/F

Nitrogen can be obtained from either organic or inorganic sources. 

__________ __________ are required organic compounds because they are essential cell components or precursors of such components that cannot be synthesized by the organism. (2 words)  

Which of the following is not a major class of growth factors? 

 amino acids
 purines and pyrimidines
 vitamins
 nucleic acids

Small organic molecules called __________ function as enzyme cofactors.  

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

 vitamins
 sugars
 fatty acids
 none of the choices

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. 

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 __________. 

_________ are carrier proteins embedded in the membrane that increase the rate of diffusion of specific molecules across selectively permeable membranes. 

T/F

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

 Different transport systems for the same nutrient that are part of the same organism are usually regulated in different ways. 

T/F

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. 

The extreme insolubility of ferric iron leaves little free iron available for transport into bacterial cells. 

T/F

The extreme insolubility of ferric iron leaves little free iron available for transport into bacterial cells. 

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

 Active transport.
 Facilitated diffusion.
 Passive diffusion.
 Active transport and facilitated diffusion.

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.
 All of the choices.

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.
 osmosis.
 passive diffusion.
 active transport.

The movement of molecules across a membrane from an area of higher concentration to an area of lower concentration with the use of a carrier molecule embedded in the membrane is called 

 facilitated diffusion.
 osmosis.
 passive diffusion.
 active transport.

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 

 facilitated diffusion.
 osmosis.
 passive diffusion.
 active transport.

Nutrients can be concentrated from dilute solutions by 

 pinocytosis.
 endocytosis.
 active transport and group translocation.
 electron transport.

__________ membranes allow some molecules to pass but not others. 

 Permeable
 Inverted monolayer
 Selectively permeable
 Impermeable