Deck 3: Bacterial Cell Structure

Question 1

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

Answer 1

capsule

Question 2

_______ bind ferric iron and transport it into a bacterial cell.

Answer 2

Siderophores

Question 3

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

Answer 3

mycelium

Question 4

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

Question 5

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

Question 6

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.

Question 7

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

Question 8

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

Question 9

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

Question 10

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

Question 11

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

Question 12

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

Question 13

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

Question 14

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.

Question 15

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

Question 16

Actinomycetes form long filaments called ___________.

Question 17

Predict how the plasma membrane fatty acid composition would change as the temperature of the habitat of an aquatic bacterial species warms from 2^oC to 15^oC 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.

Question 18

Nutrients that are used by bacteria in relatively large amounts are _______________.

Question 19

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

Question 20

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

Question 21

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

Question 22

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

Question 23

Which of the following structures is NOT found in an endospore?

A)Capsule
B)Coat
C)Core
D)Exosporium

Question 24

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

Question 25

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

Question 26

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

Question 27

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

Question 28

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

Question 29

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

Question 30

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

Question 31

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.

Question 32

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

Question 33

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

Question 34

_______ are the site of protein synthesis in the cell.

Question 35

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 __________.

Question 36

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.

Question 37

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

Question 38

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

Question 39

The rotation of bacterial flagella is powered by ATP hydrolysis.

Question 40

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.

Question 41

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.

Question 42

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.

Question 43

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.

Question 44

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

A)peripheral
B)integral
C)external
D)internal

Question 45

Bacterial cells that are variable in shape are called

A)vibrio.
B)pleomorphic.
C)coccobacilli.
D)hyphal.

Question 46

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.

Question 47

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.

Question 48

Flexible bacteria with a helical shape are called

A)vibrios.
B)spirilla.
C)spirochetes.
D)coccobacilli.

Question 49

Lipids with polar and nonpolar ends are said to be

A)amphipathic.
B)amphibolic.
C)bilateral.
D) None of the choices are correct.

Question 50

The term used to describe bacteria that are rod-shaped is

A)coccus.
B)bacillus.
C)vibrio.
D)coccobacillus.

Question 51

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

A)peripheral
B)integral
C)external
D)internal

Question 52

The term used to describe bacteria that are shaped like curved rods is

A)coccus.
B)bacillus.
C)vibrio.
D)coccobacillus.

Question 53

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.

Question 54

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.

Question 55

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

Question 56

Rigid bacteria with a helical cell shape are called

A)vibrios.
B)spirilla.
C)spirochetes.
D)coccobacilli.

Question 57

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.

Question 58

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.

Question 59

The term used to describe bacteria that have a spherical shape is

A)coccus.
B)bacillus.
C)vibrio.
D)coccobacillus.

Question 60

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

Question 61

Which of the following is not considered a micronutrient?

A)Manganese (Mn)
B)Magnesium (Mg)
C)Zinc (Zn)
D)Copper (Cu)

Question 62

Copper (Cu)is considered a micronutrient.

Question 63

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.

Question 64

Elements that are required in relatively large amounts by microorganisms are called

A)multivitamins.
B)meganutrients.
C)macronutrients.
D)macromolecules.

Question 65

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

A)50S
B)30S
C)80S
D)70S

Question 66

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

A)Amino acids
B)Purines and pyrimidines
C)Vitamins
D)Nucleic acids

Question 67

Zinc (Zn)is considered a macronutrient.

Question 68

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.

Question 69

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.

Question 70

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.

Question 71

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.

Question 72

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.

Question 73

Phosphorus can be obtained from organic sources only.

Question 74

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

Question 75

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.

Question 76

Nitrogen can be obtained from either organic or inorganic sources.

Question 77

Sulfur can be obtained from inorganic sources only.

Question 78

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

Question 79

Which of the following is not considered a macronutrient?

A)Carbon (C)
B)Calcium (Ca)
C)Potassium (K)
D)Cobalt (Co)

Question 80

Small organic molecules called __________ function as enzyme cofactors.