Chapter 3 - Bacterial Cell Structure
Matching: Match the definition with the word. 1) monotrichous 2) peritrichous 3) lophotrichous 4) amphitrichous a. a single flagellum b. a single flagellum at each pole of an organism c. a cluster of flagella at one or both ends of an organism d. a relatively even distribution of flagella over the entire surface of the bacterium
1-a, 2-d, 3-c, 4-b
Order the following structures (layers) that a small molecule must pass through as it moves from outside of an encapsulated gram negative cell to the cytoplasm.
3 Periplasm and Peptidoglycan 4 Plasma membrane 1 Capsule 2 Outer membrane
Bacterial and archaeal ribosomes are known as _____ ribosomes, based on their sedimentation coefficient. A. 50S B. 30S C. 80S D. 70S
70S
Which of the following processes can be used to bring nutrients into a cell against a concentration gradient? A. Active transport B. Facilitated diffusion C. Passive diffusion D. Active transport and facilitated diffusion
Active transport
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. D. All of the choices are correct.
All of the choices are correct
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. D. All of the choices are correct.
All of the choices are correct
Which of the following is a characteristic of active transport? A. Saturable uptake rate B. Use of ATP or a proton gradient as a source of metabolic energy C. Can move materials against a concentration gradient D. All of the choices are correct.
All of the choices are correct.
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. D. All of the choices are correct.
All of the choices are correct.
Which of the following structures is NOT found in an endospore? A. Capsule B. Coat C. Core D. Exosporium
Capsule
Which of the following is not considered a macronutrient? A. Carbon (C) B. Calcium (Ca) C. Potassium (K) D. Cobalt (Co)
Cobalt (Co)
Endospores are resistant to most environmental stressors because they have _____ complexed with calcium ions which stabilize DNA.
Dipicolinic acid
Bacteria growing at lower temperatures have more saturated fatty acids in their membranes. (T/F)
False
During the assembly of the flagellar filament, the flagellin protein monomers assemble at the cell proximal base of the flagellum. (T/F)
False
Gram-positive bacteria have a structurally and chemically more complex cell wall than gram-negative bacteria. (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
Organisms usually have only a single transport system for any nutrient. (T/F)
False
Phosphorus can be obtained from organic sources only. (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
The layers of peptidoglycan of the bacterial cell wall can be cross-linked by peptide intrabridges or by direct cross-linking. (T/F)
False
The rotation of bacterial flagella is powered by ATP hydrolysis. (T/F)
False
Zinc (Zn) is considered a macronutrient. (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. (2 words)
Growth factors
All of the following statements about the periplasmic space are true except: A. It is found only in gram-positive bacteria. B. It is located between the plasma membrane and outer membrane of gram-negative bacteria. C. It contains hydrolytic enzymes and binding proteins involved in nutrient acquisition. D. All of the choices are true.
It is found only in gram-positive bacteria.
Which of the following is not considered a micronutrient? A. Manganese (Mn) B. Magnesium (Mg) C. Zinc (Zn) D. Copper (Cu)
Magnesium (Mg)
Which of the following is not a major class of growth factors? A. Amino acids B. Purines and pyrimidines C. Vitamins D. Nucleic acids
Nucleic acids
Which of the following protects bacteria from lysis in dilute solutions and helps to determine their cellular morphology or shape? A. Plasma membrane B. Peptidoglycan C. Capsule D. Gas vacuoles
Peptidoglycan
__________ are carrier proteins embedded in the membrane that increase the rate of diffusion of specific molecules across selectively permeable membranes.
Permeases
_______ are the site of protein synthesis in the cell.
Ribosomes
__________ membranes allow some molecules to pass but not others. A. Permeable B. Inverted monolayer C. Selectively permeable D. Impermeable
Selectively permeable
_______ bind ferric iron and transport it into a bacterial cell.
Siderophores
How do spheroplasts and protosplasts differ? A. Spheroplasts retain the peptidoglycan but protoplasts do not. B. Spheroplasts retain their outer membrane but protoplasts do not. C. There is no difference; these terms are synonyms. D. Spheroplasts form from cocci and protoplasts form from bacilli.
Spheroplasts retain their outer membrane but protoplasts do not.
The concept of a prokaryote was first fully outlined in 1962 by A. Watson and Crick. B. Stanier and Van Niel. C. Hershey and Chase. D. Gilbert and Cech.
Stanier and Van Niel.
Motile bacteria have been placed in an environment with a gradient of a chemical attractant. Which of the following behaviors would you predict? A. Bacteria will randomly switch back and forth between runs and tumbles. B. The bacteria will only exhibit runs away from the chemical. C. The bacteria will reduce tumbling frequency. D. The bacteria will reduce run duration in the direction of the chemical. E. The bacteria will both reduce tumbling frequency and increase run duration in the direction of the chemical.
The bacteria will both reduce tumbling frequency and increase run duration in the direction of the chemical.
A pathogenic bacterial species has mutated and is no longer able to synthesize a capsule. Which outcome would you predict? A. The mutated bacteria will be more virulent. B. The mutated bacteria will not be able to cause disease as readily. C. The mutated bacteria will be protected from plasmolysis in hypertonic environments. D. The mutated bacteria will undergo osmotic lysis in hypotonic environments.
The mutated bacteria will not be able to cause disease as readily
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. A. The percentage of saturated fatty acids would increase. B. The percentage of unsaturated fatty acids would increase. C. The percentage of saturated fatty acids would decrease. D. The percentage of saturated fatty acids would remain unchanged.
The percentage of saturated fatty acids would increase.
Which of the following is not true of bacterial plasmids? A. They can replicate independently of the chromosome. B. They may carry genes for drug resistance. C. They are required for host growth and/or reproduction. D. They may carry genes that enhance survival of the bacterium under certain conditions.
They are required for host growth and/or reproduction.
Copper (Cu) is considered a micronutrient. (T/F)
True
Different transport systems for the same nutrient that are part of the same organism are usually regulated in different ways. (T/F)
True
Growth factors cannot by synthesized by the bacteria that use them and include amino acids, pyrimidines, and vitamins. (T/F)
True
Nitrogen can be obtained from either organic or inorganic sources. (T/F)
True
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. (T/F)
True
Prokaryotes were once described based on structures that were present in eukaryotes, but absent in prokaryotes. (T/F)
True
Some photosynthetic bacteria produce gas vacuoles that regulate their buoyancy but contain no lipid. (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
The extreme insolubility of ferric iron leaves little free iron available for transport into bacterial cells. (T/F)
True
The trace amounts of micronutrients needed by microorganisms are usually supplied as inadvertent contaminants in water and regular media components. (T/F)
True
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 A. facilitated diffusion. B. osmosis. C. passive diffusion. D. active transport.
active transport
Nutrients can be concentrated from dilute solutions by A. pinocytosis. B. endocytosis. C. active transport and group translocation. D. electron transport.
active transport and group translocation.
Lipids with polar and nonpolar ends are said to be A. amphipathic. B. amphibolic. C. bilateral. D. None of the choices are correct.
amphipathic.
Export of flagellin subunits is mediated by A. an apparatus in the basal body of the flagellum that is related to the type II secretion pathway. B. the type I secretion pathway. C. an apparatus in the basal body of the flagellum that is related to the type III secretion pathway. D. None of the choices are correct.
an apparatus in the basal body of the flagellum that is related to the type III secretion pathway.
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
The term used to describe bacteria that are rod-shaped is A. coccus. B. bacillus. C. vibrio. D. coccobacillus
bacillus
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
Twitching or gliding motility involves A. type IV pili. B. axial fibrils. C. movement of slime. D. both type IV pili and movement of slime can be involved in twitching or gliding motility.
both type IV pili and movement of slime can be involved in twitching or gliding motility.
A __________ is a polysaccharide layer that lies outside the cell wall and is not easily removed.
capsule
Sortase is a protein enzyme of bacteria that A. plays a key role in directing proteins to the periplasm. B. catalyzes covalent attachment of some surface proteins to peptidoglycan. C. directs secretion of proteins across the outer membrane. D. functions by transporting flagellum proteins to their extracellular site of assembly.
catalyzes covalent attachment of some surface proteins to peptidoglycan.
The term used to describe bacteria that are intermediate in shape between spherical and rod-shaped is A. cocci. B. bacilli. C. vibrio. D. coccobacilli.
coccobacilli
The term used to describe bacteria that have a spherical shape is A. coccus. B. bacillus. C. vibrio. D. coccobacillus.
coccus
Endospores represent a challenge to the fields of industrial and medical microbiology because A. they are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive. B. endospore-forming organisms are often dangerous pathogens. C. endospores are significantly smaller than vegetative cells. D. 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.
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 A. exotoxin. B. teichoic acid. C. murein. D. endotoxin.
endotoxin
Enzymes that are secreted out of the cell to aid in the acquisition and digestion of environmental nutrients are called __________.
exoenzymes
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 A. facilitated diffusion. B. osmosis. C. passive diffusion. D. active transport
facilitated diffusion
The most widely accepted current model for membrane structures is called the __________ model.
fluid mosaic
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) _____. A. facillitated diffusion B. micronutrient regulator C. passive diffusion D. group translocation
group translocation
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.
hydrophilic
Actinomycetes form long filaments called ___________.
hyphae
Intracellular granules of organic or inorganic material that are stockpiled by bacteria for future use are called __________.
inclusions
Proteins that are embedded within the cytoplasmic membrane and not easily extracted are called __________ proteins. A. peripheral B. integral C. external D. internal
integral
Although penicillin inhibits peptidoglycan synthesis, bacterial cells will continue to grow normally in the presence of penicillin in a(n) __________ environment. A. hypotonic B. isotonic C. hypertonic D. nonpolar
isotonic
Elements that are required in relatively large amounts by microorganisms are called A. multivitamins. B. meganutrients. C. macronutrients. D. macromolecules.
macronutrients
Nutrients that are used by bacteria in relatively large amounts are _______________.
macronutrients
Some species of aquatic bacteria use inclusion bodies known as ________ to orient themselves in Earth's magnetic field.
magnetosomes
Chemotaxis is a process by which bacteria A. move toward an attractant or away from a repellent. B. avoid phagocytosis. C. respond metabolically to the presence of autoinducer molecules. D. move on solid surfaces by means of type IV fimbriae.
move toward an attractant or away from a repellent.
A branched network of hyphae formed by the Actinomycetes is called a __________.
mycelium
Bacteria have a region of the cytoplasm known as the __________, which is not bounded by a membrane but contains the chromosome.
nucleoid
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 A. facilitated diffusion. B. osmosis. C. passive diffusion. D. active transport.
passive diffusion
Proteins that are loosely associated with the cytoplasmic membrane are called __________ proteins. A. peripheral B. integral C. external D. internal
peripheral
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
Small circular DNA molecules capable of replicating and containing genes that are useful but not necessary to the bacterium are called __________.
plasmids
Shrinkage of the plasma membrane away from the cell wall when the bacterium is placed in a hypertonic environment is called A. osmolysis. B. plasmolysis. C. hydrolysis. D. hypertonolysis.
plasmolysis.
Bacteria that do not have a fixed shape are said to be __________.
pleomorphic
Bacterial cells that are variable in shape are called A. vibrio. B. pleomorphic. C. coccobacilli. D. hyphal.
pleomorphic.
The power used by most bacterial flagellar motors is produced by A. synthesis of glucose. B. ATP hydrolysis. C. proton motive force (PMF). D. All of the choices are correct.
proton motive force (PMF).
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.
run
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
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
Rigid bacteria with a helical cell shape are called A. vibrios. B. spirilla. C. spirochetes. D. coccobacilli.
spirilla
Flexible bacteria with a helical shape are called A. vibrios. B. spirilla. C. spirochetes. D. coccobacilli.
spirochetes
__________ is the process through which endospores are formed within a vegetative cell.
sporulation
The genus of bacteria that undergoes cell division in random planes, forming grapelike clusters of round bacteria, are the __________.
staphylococci or staphylococcus
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
Square planar arrangement of cells that forms when round bacteria remain attached to each other during reproduction are called A. streptococci. B. staphylococci. C. tetrads. D. sarcinae.
tetrads
The term used to describe bacteria that are shaped like curved rods is A. coccus. B. bacillus. C. vibrio. D. coccobacillus.
vibrio
A wide variety of microorganisms are commercially used to manufacture _________ for human consumption. A. vitamins B. sugars C. fatty acids D. none of the choices
vitamins
Small organic molecules called __________ function as enzyme cofactors.
vitamins
