Deck 2: Microbial Cell Structure and Function

Question 1

The cytoplasmic membrane could best be described as

A)an impermeable barrier.
B)a passive conduit for intracellular transport.
C)a highly selective permeability barrier.
D)a rigid structure that protects the cell.

Answer 1

C

Question 2

The lipopolysaccharide (LPS)layer is found ONLY in the cell walls of

A)gram-positive Bacteria.
B)gram-negative Bacteria.
C)Archaea.
D)Eukarya.

Answer 2

B

Question 3

Bacteria with type IV pili

A)possess tubular or stalk-like extensions of their cells.
B)likely exhibit twitching motility.
C)have capsules that promote dehydration.
D)live in aquatic environments.

Answer 3

B

Question 4

The morphology of a cell influences its

A)motility.
B)metabolism.
C)surface-to-volume ratio.
D)motility and surface-to-volume ratio.

Question 5

An organism of the genus Staphylococcus is ________,while an organism of the genus Spirochaeta is ________.

A)spherical / rod shaped
B)rod shaped / coiled
C)spherical / coiled
D)coiled / spherical

Question 6

Using phase contrast microscopy on a wet mount of live cells,you observe motile bacilli moving rapidly and randomly through the field of view,changing directions after a brief tumble and taking off in a different direction.These cells are exhibiting ________ motility.

A)twitching
B)swimming
C)gliding
D)twitching or gliding

Question 7

An endotoxin is

A)the toxic portion of the LPS.
B)a toxin produced within archaeal cells.
C)a toxin known for its primary attack on the epidermis of mammals.
D)a toxin produced in the periplasm of most bacteria.

Question 8

You have discovered a new microorganism,but you want to know if it is a eukaryote or a prokaryote.To investigate this question you prepare a slide with a simple stain and view it with a light microscope with a 40X objective lens and 10X ocular lens.You also prepare a control slide using Saccharomyces cerevisiae (a unicellular eukaryote).You can see the cells on your control slide,but you don't see cells when you look at your unknown microorganism.What can you conclude from this experiment?

A)The experiment failed to visualize the organism because the stain killed it.
B)Your new unknown microorganism is probably a virus.
C)The cells of the new unknown microorganism may be too small to see with the objective and ocular lenses you used.
D)The new unknown microorganism is probably an archaeon.

Question 9

You have discovered a new coccoid-shaped microorganism with no nucleus,a rigid cell wall,and a diameter of 2 µm.Chemical tests reveal that its cell wall does NOT contain peptidoglycan.The new microorganism is

A)most likely a bacterium.
B)most likely a eukaryote.
C)most likely an archaeon.
D)either a bacterium or an archaeon.

Question 10

In gram-positive Bacteria,the cell walls are composed mainly of thick ________ layers.

A)protein
B)poly-β-hydroxybutryic acid (PHB)
C)lipopolysaccharides (LPS)
D)peptidoglycan

Question 11

Which of the following statements is FALSE?

A)A flagellar protein subunit is flagellin.
B)In flagellar motion,the basal body acts as a motor.
C)Flagellar rotation generates ATP.
D)The hook is the wider region at the base of the flagellum.

Question 12

Hydrolytic enzymes function in the

A)initial degradation of nutrients.
B)transport of substrates within the cell.
C)chemotactic response,particularly in gram-negative Bacteria.
D)regeneration of the periplasm.

Question 13

Compared to Eukaryotes,Bacteria and Archaea have ________ surface-to-volume ratios,causing ________ nutrient exchange and growth rates.

A)lower / lower
B)lower / higher
C)higher / lower
D)higher / higher

Question 14

The terms "run" and "tumble" are generally associated with

A)eukaryotic cells.
B)nutrient transport.
C)chemotaxis.
D)clustering of certain rod-shaped bacteria.

Question 15

Bacteria stain as gram-positive or gram-negative because of differences in the cell

A)wall.
B)cytoplasm.
C)nucleus.
D)chromosome.

Question 16

The use of the Gram stain in microbiology is important because it differentiates

A)Bacteria from Archaea.
B)prokaryotic from eukaryotic cells.
C)bacterial cells with different types of cell walls.
D)archaeal cells with different types of metabolism.

Question 17

Nutrient transport requires energy because the nutrients must be transported into the cell against a concentration gradient.The energy required for nutrient transport is supplied by

A)ATP.
B)the proton motive force.
C)phosphoenol pyruvate.
D)ATP,the proton motive force,or phosphoenol pyruvate.

Question 18

Some archaea have unique phospholipids in their cytoplasmic membrane that

A)form a monolayer due to the presence of diglycerol tetraethers.
B)form a bilayer due to the presence of sterols.
C)form a stable ring structure due to the presence of crenarchaeol.
D)form a bilayer due to the presence of phosphatidylethanolamine.

Question 19

Carrier-mediated transport is necessary when

A)diffusion will not allow adequate amounts of a substance to enter the cell.
B)movement into the cell is against a concentration gradient.
C)the level of nutrients in nature is very low.
D)nutrient concentration is very low in the environment,is higher inside of the cell,or diffusion is not possible.

Question 20

You are given an electron micrograph of a bacterial cell.In the micrograph you can clearly see three thin layers of different densities surrounding the cell.Based on the micrograph,you can infer that this cell is ________ and would appear ________ after application of the Gram stain procedure.

A)gram-positive / purple
B)gram-negative / pink
C)gram-positive / pink
D)gram-negative / purple

Question 21

The membrane of a gas vesicle is composed of

A)various phospholipids.
B)proteins.
C)carbohydrates.
D)both glycoproteins and phospholipids.

Question 22

Which of the following statements is TRUE?

A)Fimbriae are generally shorter and more numerous than flagella.
B)Fimbriae enable cells to stick to surfaces.
C)Pili serve as receptors and facilitate genetic exchange between prokaryotic cells.
D)Fibriae are usually shorter than flagella and enable cells to adhere to surfaces,whereas pili are involved in genetic exchange.

Question 23

Where within a eukaryotic cell is ribosomal RNA (rRNA)synthesized?

A)cytoplasm
B)lysosome
C)mitochondrion
D)nucleolus

Question 24

The prokaryotic transport system that involves a substrate-binding protein,a membrane-integrated transporter,and an ATP-hydrolyzing protein is

A)the ABC transport system.
B)group translocation.
C)symport.
D)simple transport.

Question 25

Membrane-enclosed organelles,such as nuclei,lysosomes,endoplasmic reticulum,mitochondria,and chloroplasts,

A)form specialized compartments within eukaryotic cells for specific functions to occur.
B)increase the structural complexity of eukaryotic cells.
C)help large eukaryotic cells overcome the limitations of diffusion imposed by their large cell size.
D)increase structural complexity,help eukaryotes overcome diffusion limitation due to their size,and form specialized environments for specific functions to occur.

Question 26

Although the inner leaflet of the gram-negative outer membrane is composed mainly of phospholipids,the outer leaflet of the outer membrane contains

A)pseudopeptidoglycans.
B)lipoteichoic acids.
C)poly-β-hydroxybutyric acids (PHB).
D)lipopolysaccharides (LPS).

Question 27

The membrane-enclosed compartments that contain digestive enzymes in eukaryotic cells are called

A)cristae.
B)mitosomes.
C)lysosomes.
D)stromas.

Question 28

One of the many types of proteins found in the cytoplasmic membrane is involved in the chemotactic response and is called a

A)hydrolytic enzyme.
B)chemoreceptor.
C)binding protein.
D)porin.

Question 29

Electron microscopy has greater ________ than light microscopy,because the wavelengths of visible light are much larger than the wavelengths of electrons.

A)contrast
B)magnification
C)resolution
D)penetration

Question 30

Cellular inclusions in prokaryotic cells serve to

A)store energy rich compounds.
B)protect DNA.
C)position cells in the appropriate environment for survival.
D)store energy rich compounds and position cells in the appropriate environment for survival.

Question 31

Which is/are a function(s)of the cytoplasmic membrane in prokaryotes?

A)It functions as a permeability barrier.
B)It is an anchor for many proteins involved in bioenergetic reactions and transport.
C)It is a major site of energy conservation.
D)It serves as a permeability barrier,a docking station for proteins involved in bioenergetics reactions and transport,and a site for energy conservation.

Question 32

The lipids in the cytoplasmic membrane of Bacteria and ________ contain ester linkages,while the cytoplasmic membrane of ________ contain ether linkages.

A)Archaea / Eukarya
B)Archaea / fungi
C)Eukarya / prokaryotes
D)Eukarya / Archaea

Question 33

What is the biological function of endospores?

A)They are bacterial reproductive structures.
B)They enable organisms to endure extremes of temperature,drying,and nutrient depletion.
C)They transport toxins.
D)Endospores can serve as reproductive structures,enable survival in harsh environments,and transport toxins.

Question 34

________ are charged molecules that are partially responsible for the ________ charge of the gram-positive bacterial cell surface.

A)Diaminopimelic acids / positive
B)Teichoic acids / negative
C)Phospholipids / negative
D)Peptide interbridges / neutral

Question 35

Aquaporins are

A)water transport proteins.
B)molecules that prevent water from crossing a membrane.
C)enzymes involved in the generation of water within cells.
D)cations bound to water molecules.

Question 36

The Golgi complex functions to

A)modify and secrete proteins to the external environment.
B)sort proteins used within the cell.
C)both modify and sort proteins into those destined for secretion and those that function in membrane structures.
D)synthesize proteins.

Question 37

A major function of prokaryotic gas vesicles is to

A)confer buoyancy on cells by decreasing their density.
B)serve as a reservoir for oxygen and carbon dioxide.
C)keep the cell's organelles separated during flagellar motion.
D)store oxygen for aerobic growth when oxygen becomes depleted in the environment.

Question 38

When does endospore formation commence?

A)when bacterial growth ceases due to limitation of an essential nutrient
B)when the bacterium is undergoing binary fission
C)when bacteria are dividing exponentially
D)following bacterial death

Question 39

All eukaryotes contain

A)a membrane-enclosed nucleus.
B)mitochondria.
C)hydrogenosomes.
D)a nucleus,mitochondria,and hydrogenosomes.

Question 40

Mitochondria and hydrogenosomes are similar in that they both

A)are the site of energy production in eukaryotic cells.
B)evolved via endosymbiosis of bacterial cells.
C)are the site of aerobic respiration.
D)evolved via endosymbiosis and are sites for aerobic respiration and energy production.

Question 41

Using bright-field microscopy to look at a slide prepared with a basic dye you observe cells under 400X magnification with a clear inner compartment within the cell.The cell is most likely a(n)

A)prokaryote.
B)bacterium.
C)archaeon.
D)eukaryote.

Question 42

Smaller prokaryotic cells generally grow faster than larger ones due to a higher surface-area-to-volume ratio.

Question 43

In general,most cell inclusions function as energy reserves or as a reservoir of structural building blocks.

Question 44

ATP-binding cassette transport systems have high substrate affinity and thus help microorganisms survive in low nutrient environments.

Question 45

Both hydrophilic and charged molecules readily diffuse through the cytoplasmic membrane.

Question 46

Small acid-soluble proteins (SASPs)protect DNA from ultraviolet light and are found in high numbers within

A)gram-positive Bacteria.
B)endospores.
C)inclusion bodies.
D)gram-negative Bacteria.

Question 47

Which of the following types of microscopy can be used with live cells?

A)phase-contrast microscopy
B)transmission electron microscopy
C)bright-field microscopy
D)scanning electron microscopy

Question 48

Which of the following types of microscopy could be used to visualize the layers of the cell membrane and the cell wall?

A)phase-contrast microscopy
B)transmission electron microscopy
C)bright-field microscopy
D)confocal microscopy

Question 49

The peptide interbridge crosslinking between peptidoglycan layers is found ONLY in the cell walls of

A)Archaea.
B)Eukarya.
C)gram-positive Bacteria.
D)gram-negative Bacteria.

Question 50

The rigid layer that is present in the cell walls of Bacteria that is primarily responsible for the strength of the wall is known as

A)pseudomurein.
B)S-layer.
C)cellulose.
D)peptidoglycan.

Question 51

Despite the invariance of the peptidoglycan backbone's structure,there are more than 100 different types of peptidoglycan.

Question 52

Eukaryotes have ________ in their cytoplasmic membranes,which serve to strengthen and stabilize the membrane and make it less flexible.Many bacteria have similar molecules,known as ________,in their cytoplasmic membranes that have a similar role.

A)ether bonds / ester bonds
B)lipids / phospholipids
C)sterols / hopanoids
D)phospholipids / lipopolysaccharides

Question 53

Lysozyme is an enzyme that can ultimately lyse and kill eukaryotic cells by breaking β-1,4-glycosidic bonds in peptidoglycan.

Question 54

The energy source derived from the charge separation across the cytoplasmic membrane is referred to as

A)the proton motive force.
B)carbohydrate charging.
C)adenosine triphosphate.
D)the voltage source.

Question 55

Type IV pili are involved in

A)attachment of cells to surfaces.
B)twitching motility.
C)pathogenesis.
D)attachment to surfaces,twitching motility,and pathogenesis.

Question 56

Teichoic acids are commonly found in gram-negative cell walls.

Question 57

Some membrane proteins are involved in bioenergetic reactions,while others are involved in membrane transport.

Question 58

Some of the intestinal symptoms elicited by pathogens such as Salmonella,Shigella,and Escherichia are due to the presence of

A)pseudomurein.
B)S-layers.
C)lipopolysaccharides.
D)peptidoglycan.

Question 59

Based on the table of attributes given below,which of the following statements are FALSE about the two organisms? Characteristic Bacterium A Bacterium B
Endospore formation yes no
Capsule no yes
Type IV pili yes no
Flagella no no
Morphology bacillus bacillus

A)Bacterium A is more resistant to heat and ultraviolet light.
B)Bacterium B likely forms a slime layer better than Bacterium A.
C)Bacterium B is likely to exhibit motility.
D)Both bacteria may attach to surfaces.

Question 60

In general,lipids in archaeal cytoplasmic membranes lack true fatty acids.

Question 61

Electron microscopes have less resolving power than light microscopes.

Question 62

Chemotaxis is a sensory response affecting the rotational direction of the flagellar motor.

Question 63

Describe the mechanisms by which certain prokaryotes glide.What are the ecological advantages of gliding motility?

Question 64

What type of microscope would you use to visualize the internal structures of a chloroplast? Support your conclusion with evidence based on the size of the structures you want to see and the resolution and magnification power of different types of microscopes.

Question 65

Porins are channels in the outer membranes of gram-positive Bacteria.

Question 66

Why is energy required for nutrient transport? Give an example of a system that transports nutrients and describe what source of energy is used to move the nutrients into the cell.

Question 67

Macromolecules resulting from lysosomal digestion are used in cellular biosynthesis and energy generation.

Question 68

You have discovered a new bacterial strain that causes urinary tract infections.Closely related bacterial species cannot cause infections.You compare the strains and find that your new strain has structures composed of protein external to its cell wall.What structures might your new strain have that the other strains do not? Why?

Question 69

Explain the differences between uniporters,symporters,and antiporters.

Question 70

Compare and contrast the chemical composition and structure of the cytoplasmic membranes found in Bacteria and Archaea.What is the advantage of the archaeal membranes in relationship to the types of environments many archaea inhabit?

Question 71

Describe the makeup of the phospholipid bilayer.Include molecular orientation and proteins as well.

Question 72

A bacterial cell is interpreted as gram-positive when it forms purple insoluble crystal violet-iodine complexes within the cell during the Gram stain.

Question 73

Mitochondria and chloroplasts have their own DNA and ribosomes,which supports the endosymbiosis hypothesis.

Question 74

What is the function of an endospore and how is an endospore formed?

Question 75

In general,swimming is performed with flagella,whereas gliding uses other cellular components such as pili.

Question 76

You are studying swimming motility in a pathogenic bacillus.You create mutations in random genes and then test which mutations effect swimming motility by looking at the mutant cells under the microscope.One of the mutant bacteria can not swim anymore,but still rotates around in a one spot when you watch them.Using electron microscopy you discover that some parts of the flagella are still present in the cell wall,but no long flagella are visible.Which gene do you think is mutated (i.e.,missing)and which motility-related parts are still present in this mutant?

Question 77

Poly-β-hydroxybutyric acid (PHB)is a carbon- and energy-storing polymer.

Question 78

Construct a chart to show at least five major differences between the cytoplasmic membrane and cell wall of bacteria and archaea.What are the implications of these differences?

Question 79

Photoreceptors are analogous to chemoreceptors in that they are both proteinaceous sensors.

Question 80

Pathogenic bacteria that contain S-layers are protected against host defense mechanisms.