Microbiology 20 Chapter 4
What is the difference between a true nucleus and a nucleoid?
A true nucleus is surrounded by a membrane whereas a nucleoid is not.
The heat resistance of bacterial endospores has been linked to high concentrations of which of the following?
Calcium dipicolinate
in endospores removes water and leaves the endospore very dehydrated.
Calcium dipicolinate
Which of the following structures is external and can protect the bacterial cell from various host immune responses?
Capsule
Which of the following is considered to be the basic unit of life?
Cell
All cells contain which of the following characteristics?
Cell membrane, Ribosomes, and Chromosomes
Which of the following prevents the rupture of bacterial cells by internal osmotic pressure?
Cell wall
Which of the following is the movement towards or away from a chemical stimulus?
Chemotaxis
All bacteria have a cell wall.
False
Fungal spores function in both survival and reproduction, while bacterial endospores function in survival only.
False
Gram-negative bacteria do not have peptidoglycan in their cell walls.
False
Iodine is the decolorizer in the Gram stain.
False
Prokaryotic cells contain developed organelles.
False
Treponema pallidum are rods that cause smallpox.
False
Using a cell phone in lab is permissible since it can be used for timing experiments.
False
Which of the following are small, circular pieces of DNA that exist independently within bacterial cytoplasm?
Plasmids
Identify the term for multiple shapes and sizes among cells of the same species.
Pleomorphism
Which of the following describes any arrangement of flagella where they are either attached at one or both ends of a bacterium?
Polar
In order to destroy endospore-forming bacteria in canned foods, canning is carried out under which of the following conditions?
Pressurized steam at 120οC for 20 minutes
Hot carbol fuchsin is the primary dye in the acid-fast stain.
True
If you observe rod-shaped, pink cells on a slide that had just been Gram stained, you can assume that their cell walls contain endotoxin.
True
Watches, bracelets, and rings should be removed prior to washing hands.
True
Identify the two important diseases caused by mycobacteria.
Tuberculosis and Leprosy
Neisseria gonorrhoeae binds to the epithelial cells of the reproductive tract by means of which of the following?
Type IV pili
Endotoxins (LPS) can stimulate fever and shock during which gram-negative infections?
Typhoid fever and Meningitis
Which is the active, growing state of endospore-forming bacteria?
Vegetative
Which of the following represent important safety procedures for microbiology students? (Select all that apply)
Wash your hands before and after laboratory procedures., Disinfect your lab bench at the beginning and end of the lab period., and Take extra care around the flame of a Bunsen burner by tying up hair and keeping it from combustibles.
All bacterial cells have
a chromosome.
flagella
composed of a filament, hook and basal body, these cell appendages provide movement to the cell
The transfer of DNA between bacterial cells is called
conjugation
Bacteria are able to attach to surfaces and other bacteria using the surface appendages known as
fimbriae or fimbria and pili or pilus
Bacterial appendages that provide attachment sites or channels are called
fimbriae or fimbria and pili or pilus
A bacterial cell exhibiting chemotaxis probably has
flagella.
The function of bacterial endospores is
for protection of genetic material during harsh conditions.
Which of the following attributes is true about bacterial ribosomes?
found in the cytoplasm, contains protein subunits, contains RNA subunits, and made of 50S and 30S subunits
All of the following structures contribute to the ability of pathogenic bacteria to cause disease, except
inclusions.
Which of the following should be worn at ALL times in the lab? (Select all that apply)
lab coat and closed-toed shoes
The outer membrane of Gram-negative bacteria is composed of phospholipids and __________.
lipopolysaccharide
Lab coats, gloves, face masks, and goggles are all examples of
personal protective equipment.
Which of the following items should be disposed of in a biohazard bag? (Select all that apply)
used agar plates, gloves used while working with infectious microorganisms, paper towels used to clean up a bacterial spill, and animal tissue
Soap should be applied to __________ hands.
wet
In addition to biofilms, some bacteria can produce hair-like appendages called __________ that allow them to adhere to inert surface.
pili or fimbriae
Bacterial pili are composed of the protein
pilin
The mycoplasmas are bacteria that naturally lack cell walls and as such, their cellular morphology is described as __________ because it varies so greatly.
pleomorphism
The cell membrane is composed of __________.
proteins dispersed throughout a phospholipid bilayer
The regulation of gene expression in a biofilm is referred to as:
quorum sensing
Which piece of equipment is routinely used for the decontamination of infectious laboratory waste?
steam autoclave
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
Ribosomes function primarily to
synthesize proteins.
In a typical Gram-positive bacterium, __________ are attached to the peptidoglycan. These molecules are polymers of ribitol or glycerol and phosphate.
teichoic acid
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.
Prokaryotic cells evolved on Earth about how many years ago?
3.5 billion years
A disinfectant is used on your work surface:
All of the answer choices are correct.
Endospores are
All of these choices are correct.
Which appendage(s) provide motility?
Axial filaments and Flagellum
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., and Endospores resist boiling and therefore steam must be used to destroy endospores present in food.
is the anaerobic, spore-forming bacterium that causes tetanus.
Clostridium, C., or C tetani
ribosome
Composed of RNA and protein, this structure synthesizes new proteins.
Pili are typically used for which of the following?
Conjugation
Capsules and slime layers are both types of which of the following?
Glycocalyx
spheroplast
Gram-negative cell that has lost its cell wall
protoplast
Gram-positive cell that has lost its cell wall
Which of the following are reasons for washing hands before and after lab activities? (Select all that apply)
Hands may be a source of contamination to the lab experiments., Hands may become contaminated with infectious bacteria during lab experiments., Hands may become stained during lab., and Hands may be contaminated with irritating chemicals during experiments.
Which of the following bores through the stomach lining and causes gastric ulcers?
Helicobacter pylori
Which of the following bacteria use their flagella to invade mucus membranes and cause infections?
Helicobacter pylori and Vibrio cholerae
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.
Which of the following are characteristics inherent to life?
Heredity, Metabolism, and Growth and development
Jackie went to the sink at the end of lab to wash her hands. After removing her watch and rings, she turned on the water, wet her hands, added soap and thoroughly rubbed and lathered her hands for 30 seconds, cleaning the backs of her hands, her fingernails, and between her fingers. She then turned off the water, and reached for the paper towels to dry her hands. Identify the correct statement below.
Jackie should have used paper towels to turn off the faucet.
Which of the following describes a single, polar flagellum?
Monotrichous
A bacterial genus that has waxy mycolic acid in the cell walls is
Mycobacterium.
The backbone of peptidoglycan is composed of alternating residues of N-acetyl muramic acid and __________.
N-acetylglucosamine
How many chromosomes do most bacteria contain?
One
Lysozyme digests which of the following in the bacterial cell wall?
Peptidoglycans
Which of the following bacteria could exhibit phototaxis?
Photosynthetic bacteria
Bacterial appendages can be divided into which two functional groups?
Provide attachment sites or channels and Provide motility
Bacteria called __________ display a serpentine mode of movement as a consequence of their periplasmic flagella called axial filaments.
Spirochetes
are spiral-shaped bacteria characterized by periplasmic flagella and display a worm-like mode of locomotion.
Spirochetes
Indicate each item that would be smaller than a typical E. coli cell.
Staphylococcus aureus cell and an Ebola virus
Please select all of the following which are contents of the cell cytoplasm.
chromosome, ribosome, and water
chromosome
The structure which contains the essential DNA of the cell.
plasmid
The structure which contains the nonessential DNA of the cell.
axial filaments
These long, coiled threads provide movement to spirochetes
Which statement is not a characteristic of biofilms?
They involve bacteria only.
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.
Branching filaments is a type of bacterial shape.
True
The best understood bacterial cytoskeletons are composed primarily of
actin.
The periplasmic space is
an important reaction site for substances entering and leaving the cell.
From the following list, choose all of the functions that can be performed by pili or fimbriae.
attachment to eukaryotic cells, biofilm formation, mating, and twitching motility
The two major types of prokaryotic cells are
bacteria and archaea
L form
bacteria that normally have a cell wall but can lose it during part of their life cycle
peptidoglycan; cell membrane
both gram-positive and gram-negative cells
The bacterial flagellum moves
by rotation that is powered by the proton motive force.
Which structure protects bacteria from being phagocytized?
capsule
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
Viruses are not considered living things because they only show signs of life when they are inside a host
cell or organism
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 peptidoglycan
mycoplasma
cells which lack a cell wall with peptidoglycan but contain sterols to strengthen their cell membrane
Excess nutrients that the cell may store for later use may be found within
cytoplasmic granules.
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
Chemical analysis of a bacterial cell structure detects calcium dipicolinic acid. What is the identity of this structure?
endospore
Lipopolysaccharide is an important cell wall component of
gram-negative bacteria.
lipopolysaccharide; outer membrane
gram-negative cells
Which of the following correctly describe the color of different cells after using the Gram staining technique?
gram-negative—pink/red and gram-positive—purple
teichoic acid
gram-positive cells
A prokaryotic cell wall that is primarily composed of peptidoglycan with small amounts of teichoic acid and lipoteichoic acid is
gram-positive.
Bacteria with small bunches of flagella emerging from the same site are said to be
lophotrichous.
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
Which term(s) refer to cells without cell walls?
mycoplasma, sphereoplast, and protoplast
Which of the following items should be disposed of in the Sharps container? (Select all that apply)
needles, glass pipettes, broken glass, and scalpel blades
Unlike eukaryotes, bacterial DNA is not enclosed by a nuclear membrane. Instead, bacterial DNA is condensed into a region called the __________.
nucleoid
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 molecule primarily responsible for the strength and stability of the bacterial cell wall is
peptidoglycan.
Which of the following represents size relationships from smallest to largest?
rhinovirus, Ebola virus, Staphylococcus cell, yeast cell, red blood cell, squamous epithelial cell
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 transfer of genes during bacterial conjugation involves rigid, tubular appendages called
sex pili.
The process of endospore formation is _____________, while the process of an endospore growing into a vegetative cell is ____________.
sporulation; germination
This arrangement is formed when a coccus divides on perpendicular planes and results in four cocci being attached as a cluster of cells.
tetrad
Which term is not used to describe bacterial cell shapes?
tetrad
The difference in cell wall structure of Mycobacterium and Nocardia compared to the typical gram-positive bacterial cell wall structure is
the predominance of unique, waxy lipids.
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
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
Which is the major component of cytoplasm?
Water
Which of the following items should be autoclaved? (Select all that apply)
glass culture tubes and hazardous chemicals
Which bacterial structure is most directly involved in the formation of a biofilm?
glycocalyx
Fungal spores function in _______, while bacterial spores function in _______.
reproduction; protection
Once a vegetative bacterial cell is committed to sporulation the cell is called a(n)
sporangium
How long should hands be lathered while washing?
20 seconds
What is the glycocalyx?
An extracellular coating that provides protection to the cell
Twisting or flexing of spirochete bacteria is attributed to which of the following?
Axial filaments
What biosafety levels do most introductory microbiology students work with?
BSL-1
is the rod-shaped, spore-forming bacterium that causes anthrax.
Bacillus anthracis
Which of the following bacteria can produce an S layer under harsh conditions?
Bacillus anthracis and Clostridium difficile
What are the three most common shapes of bacterial cells?
Bacillus, Spirillum, and Coccus
Peptidoglycan is a component of the cell wall of which of the following organisms?
Bacteria
What structural difference is found in gram-positive cells but not in gram-negative cells?
Single cell membrane
Which structure is most closely associated with biofilm formation?
Slime layer
Which type of glycocalyx is loosely attached to the bacterial cell and protects it from dehydration and loss of nutrients?
Slime layer
What is the name for corkscrew-shaped bacteria?
Spirochetes
One important factor that likely contributes to the recurring appearance of Mycobacterium abscessus infections was the ability of this bacterium to produce biofilms. What are biofilms and how could they contribute toward recurring infections?
Biofilms are communities of microbes that can attach to inert surfaces. These microbes secreted polymers (e.g. polysaccharides or glycoproteins) that form stable microbial communities. Biofilms are very adhesive and thus provide a way for bacteria to remain attached to water supply lines. In addition, biofilms provide protection from disinfectants, so as to enhance bacterial survival.
The canning food industry must be sure their process destroys which of the following bacteria that can cause food poisoning?
C. botulinum
What cell envelope component is not a static structure?
Cell membrane
Which of the following acts as a selective barrier between the internal and external contents of the cell?
Cell membrane
Identify the two main components of the cell envelope in most bacteria.
Cell wall and Cell membrane
Which of the following antibiotics affect the integrity of the cell wall of bacteria, thereby making them susceptible to lysis?
Cephalosporin and Penicillin
Elongated, rigid tubes on gram-negative bacteria that are involved in the transfer of DNA from one cell to another are called which of the following?
Conjugation pili
A palisades arrangement of cells is typical in which of the following bacteria?
Corynebacteria
Which of the following is the intracellular gelatinous solution?
Cytoplasm
Which of the following is the major factor that stimulates endospore formation?
Depletion of nutrients
Which of the following is formed during bacterial sporulation?
Endospore
True or false: Cell membranes are rigid, static structures that lend stability to cells.
False
Some bacteria can survive harsh environments by forming endospores. How do these structures allow bacteria to survive such nasty conditions?
High concentrations of calcium and dipicolinic acid keep spores relatively dehydrated, thus protecting them from the effects of heat. The cortex and spore coat are resistant to both radiation and chemical disinfectants.
Endotoxin is toxic to which of the following cells?
Human and other mammalian cells
What should be done to prepare or deal with a laboratory emergency? (Select all that apply)
Know the location of safety equipment such as the fire extinguisher., Notify your instructor regarding spills or nonemergency situations., and Call 911 if an emergency occurs.
The outer membrane of a gram-negative cell contains which of the following?
Lipopolysaccharide and Lipoprotein
Which of the following occurs when a cell breaks or ruptures?
Lysis
To what phylum does Mycobacterium abscessus belong? What are some other notable members of this taxonomic group?
Mycobacterium abscessus is part of the Actinobacteria. Other members of this group include Streptomyces, Corynebacterium, and Micrococcus.
Which of the statements below describe appropriate use of paper towels when washing hands? (Select all that apply)
Paper towels are used to dry hands after washing. and Paper towels are used to turn OFF the faucet.
The bulk of the Gram-positive cell wall is a homogeneous sheath of which of the following?
Peptidoglycan
Identify the area between the cell wall and cell membrane in gram-positive bacteria.
Periplasmic space
Which of the following describes a random arrangement of flagella distributed all over the bacterial cell?
Peritrichous
Identify the major structure component of the cell membrane.
Phospholipids
Which of the following describes the movement towards or away from light?
Phototaxis
Identify which of the following are external structures used primarily for direct contact interactions with other cells.
Pili and Fimbriae
Which of the following are functions of the bacterial cell membrane?
Provide a site for nutrient processing and synthesis, A barrier between the internal and external contents of the cell, and Provide a site for energy reactions
The presence of type IV pili cause a type of twitching movement in bacteria of which of the following genera?
Pseudomonas
is a behavior of biofilms which occurs when individual species alter the expression of their genes to cooperate with other cells in the biofilm.
Quorum sensing
A bacillus is a bacterial cell with which of the following shapes?
Rod
There are many microbes that constitute normal flora inside mouth. Some microbes that cause severe periodontal disease are anaerobic. How can such microbes exist inside the mouth, given how often air passes through oral cavity during talking, laughing, and breathing?
The dense biofilms formed within the oral cavity can be relatively oxygen-poor as compared to the surrounding environment. Microbes that dwell deep within spaces or pockets left behind after dental surgeries can also form anaerobic microenvironments.
Long hair should always be tied back when in the laboratory.
True
Please select all of the following which are found in all cells regardless of cell type.
cell membrane, cytoplasm, and DNA
Goggles or appropriate safety glasses protect the eyes from (Select all that apply)
chemical splashes, fumes of preservatives used on anatomy specimens., and UV exposure when using UV radiation in the laboratory
The cell envelope encloses the
cytoplasm
The cell membrane surrounds a complex solution of organic materials and salts that is referred to as
cytoplasm, cytoplasmic matrix, or cytosol
Lipopolysaccharide (LPS) is classified as is a(n)
endotoxin
Which of the following are potential hazards which you might encounter in the laboratory? (Select all that apply)
infectious microorganisms, open flames, hot surfaces, corrosive chemicals, and sharp tools or broken glass
LPS is the abbreviation for
lipopolysaccharide or lipopolysaccharides
Mycoplasma pneumoniae can cause illness when it adheres to the epithelial cells of the
lungs or lung
In prokaryotes, the chromosomal DNA is aggregated in a central area called the
nucleoid or nuclear region
The cell wall in bacteria is primarily composed of
peptidoglycan, PPG, or PG
The small, circular pieces of DNA of bacterial cells which can carry the traits for antibiotic resistance or toxin production are called
plasmids or plasmid
Mycoplasmas are known for causing primary atypical
pneumonia
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, ability to respond to their environment, and ability to control the flow of some materials across cell boundaries
