MICROBIOLOGY CHAPTER 3: BACTERIAL CELL STRUCTURE

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. Periplasm and Peptidoglycan Plasma membrane Capsule Outer membrane

1. Capsule 2. outer membrane 3. periplasm and peptidoglycan 4. plasma membrane

Place the steps of sporulation in the correct order. Replication of DNA Spore coat formation In-folding of the plasma membrane to enclose a copy of DNA, forming forespore and septum Maturation and release of endospore Deposition of spore cortex Engulfment of the forespore with a second membrane

1. REPLICATION of DNA 2. In folding of the plasma membrane to enclose a copy of DNA 3. Engulfment of the forespore with a second membrane 4. Deposition of spore cortex 5 Spore coat formation 6. Maturation and release of endospore

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

A. Active transport

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.

A. It is found only in gram-positive bacteria.

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.

A. The percentage of saturated fatty acids would increase.

Predict the change in surface area and volume of a spherical cell if the diameter of the cell doubles: A. The surface area will increase by a factor of 4, while the volume will increase by a factor of 8. B. The surface area will increase by a factor of 8 while the volume will increase by a factor of 4. C. The surface area and volume will both increase by a factor of 4. D. The surface area will increase by a factor of 2 and the volume will increase by a factor of 4

A. The surface area will increase by a factor of 4, while the volume will increase by a factor of 8.

Lipids with polar and nonpolar ends are said to be A. amphipathic. B. amphibolic. C. bilateral. D. None of the choices are correct.

A. amphipathic.

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

A. coccus

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.

A. facilitated diffusion.

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.

A. move toward an attractant or away from a repellent.

Proteins that are loosely associated with the cytoplasmic membrane are called __________ proteins. A. peripheral B. integral C. external D. internal

A. peripheral

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

A. vitamins

Which of the following structures is NOT found in an endospore? A. Capsule B. Coat C. Core D. Exosporium

A.capsule

Which bacterial structure may survive if temperatures applied during food preservation processes are too low? A. Flagella B. Endospores C. Plasma membranes D. Ribosomes

B. Endospores

Which of the following is not considered a micronutrient? A. Manganese (Mn) B. Magnesium (Mg) C. Zinc (Zn) D. Copper (Cu)

B. Magnesium (Mg)

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

B. Peptidoglycan

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.

B. 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.

B. Stanier and Van Niel.

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.

B. The mutated bacteria will not be able to cause disease as readily.

The term used to describe bacteria that are rod-shaped is A. coccus. B. bacillus. C. vibrio. D. coccobacillus.

B. bacillus.

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.

B. catalyzes covalent attachment of some surface proteins to peptidoglycan.

Proteins that are embedded within the cytoplasmic membrane and not easily extracted are called __________ proteins. A. peripheral B. integral C. external D. internal

B. 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

B. isotonic

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.

B. plasmolysis.

. Bacterial cells that are variable in shape are called A. vibrio. B. pleomorphic. C. coccobacilli. D. hyphal.

B. pleomorphic.

Rigid bacteria with a helical cell shape are called A. vibrios. B. spirilla. C. spirochetes. D. coccobacilli.

B. spirilla.

Which of the following is not part of the process by which an endospore transforms to become a vegetative cell? A. Germination B. Activation C. Induction D. Outgrowth

C. Induction

__________ membranes allow some molecules to pass but not others. A. Permeable B. Inverted monolayer C. Selectively permeable D. Impermeable

C. Selectively permeable

All of the following are reasons why some scientists believe that the term "prokaryote" is a somewhat artificial designation and should be discarded except A. Some bacteria have internal membranous structures. B. Some bacteria have their genetic material enclosed within a membrane. C. Some bacteria have 80S ribosomes. D. Many bacterial have cytoskeletal elements.

C. Some bacteria have 80S ribosomes.

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.

C. They are required for host growth and/or reproduction.

Nutrients can be concentrated from dilute solutions by A. pinocytosis. B. endocytosis. C. active transport and group translocation. D. electron transport.

C. active transport and group translocation.

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.

C. an apparatus in the basal body of the flagellum that is related to the type III secretion pathway.

4. A new protein has been described that transports a growth factor across the plasma membrane. This protein is most likely a/an: A. peripheral membrane protein, facing outward. B. peripheral membrane protein, facing the cytoplasmic side. C. integral membrane protein. D. cytoplasmic protein.

C. integral membrane protein.

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

C. macronutrients.

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.

C. passive diffusion.

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.

C. proton motive force (PMF).

Flexible bacteria with a helical shape are called A. vibrios. B. spirilla. C. spirochetes. D. coccobacilli.

C. spirochetes.

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

C. tetrads.

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

C. vibrio

Bacterial and archaeal ribosomes are known as _____ ribosomes, based on their sedimentation coefficient. A. 50S B. 30S C. 80S D. 70S

D. 70S

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

D. 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.

D. 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.

D. All of the choices are correct.

Which of the following is not considered a macronutrient? A. Carbon (C) B. Calcium (Ca) C. Potassium (K) D. Cobalt (Co)

D. Cobalt (Co)

Which of the following is not a major class of growth factors? A. Amino acids B. Purines and pyrimidines C. Vitamins D. Nucleic acids

D. Nucleic acids

A strain of Neisseria gonorrhoeae has undergone a mutation and is no longer able to make pili. Predict the most likely outcome. A. The bacterial strain will no longer be able to transport certain sugars into the cell. B. The bacteria will become more virulent and will more readily establish infection. C. The bacteria will become more resistant to antibiotics. D. The bacteria will become less virulent and will not be able to readily establish infection.

D. The bacteria will become less virulent and will not be able to readily establish infection.

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.

D. active transport.

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.

D. both type IV pili and movement of slime can be involved in twitching or gliding motility.

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.

D. coccobacilli.

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.

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.

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.

D. endotoxin.

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

D. group translocation

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 choices are correct

D.All choices are correct

Which of the following contribute to the environmental resistance of bacterial endospores? A. Spore coat B. Low water content of endospore C. Presence of calcium dipicolinate D. Lower pH E. All of the choices are correct.

E. All of the choices are correct.

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.

E. The bacteria will both reduce tumbling frequency and increase run duration in the direction of the chemical.

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

FALSE

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

FALSE

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

FALSE

Nitrogen can be obtained from either organic or inorganic sources. TF

FALSE

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

FALSE

Phosphorus can be obtained from organic sources only. TF

FALSE

Sulfur can be obtained from inorganic sources only TF

FALSE

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

FALSE

The original differentiation of prokaryotes and eukaryotes was based on structures found in prokaryotes that are lacking in eukaryotes. TF

FALSE

Zinc (Zn) is considered a macronutrient TF

FALSE

Endospores are reproductive structure TF

False

Copper (Cu) is considered a micronutrient.

TRUE

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

TRUE

Endotoxic shock, resulting from the release of endotoxin by bacteria infecting a patient, is only caused by Gram-negative bacteria. TF

TRUE

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

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. TF

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. TF

TRUE

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

TRUE

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

TRUE

Actinomycetes form long filaments called ___________.

hyphae

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

mycelium

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

pleomorphic

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

staphylococci or staphylococcus