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Flashcards in Cell Structure [2] Deck (43):
1

What is lipid A?

It is the lipid which attaches to the core section of the polysaccharide in a lipid polysaccharide.

2

Which of the following molecules is shared by both Gram-positive and Gram-negative organisms?
A N-acetylmuramic acid
B lipopolysaccharide
C lipoteichoic acid
D lipid A

A

3

Amoxicillin is an antibiotic that inhibits the formation of peptide cross-links. Amoxicillin, therefore, would most likely inhibit the growth of __________.
A only Gram positive organisms
B neither Gram-positive nor Gram-negative organisms
C both Gram-positive and Gram-negative organisms
D only Gram-negative organisms

C

4


Porins are present in ______________bacteria because, in these organisms, molecules entering the cell must pass through an extra layer of ___________.
A Gram-positive; membrane
B Gram-negative; membrane
C Gram-positive; peptidoglycan
D Gram-negative; peptidoglycan
E both Gram-negative and Gram-positive; membrane

B

5

While staining a mixed culture of Gram-positive and Gram-negative bacteria, switching the order of steps 2 and 3 would result in ______________________.
A a change in the Gram reaction; Gram-negative cells would appear purple while Gram-positive cells would appear pink.
B all bacteria appearing pink
C all bacteria appearing clear
D all bacteria appearing purple

B

6

Axial filaments are found on
A staphylococci.
B rod-shaped bacilli.
C streptococci.
D spirochetes.

D

7

Teichoic acid molecules in Gram-positive cell walls include phosphate groups. Therefore, they will __________.
A bind other phosphate ions
B bind negative ions like Cl– and SO42–
C bind positive ions like Mg2+ and Ca2+
D not bind any ions

C

8

The presence of which of the components listed below would allow you to distinguish between a gram-positive or gram-negative cell wall?
A teichoic acids -- gram-positive
B N-acetylmuramic acid – gram-positive
C N-acetylglucosamine – gram-negative
D teiochic acids -- gram-negative

A

9

How are negative stains different from other types of stains?
A They stain the desired structure or specimen black.
B They stain the background, leaving the cells colorless.
C They stain more than one type of specimen.

B

10

What is the fundamental purpose of staining in light microscopy?
A To kill the specimen
B To increase the contrast and visibility of the specimen
C To make the specimen appear larger in the microscope
D To see the specimen without the aid of a microscope

B

11

Analysis of the second swab has confirmed that the causative organism is Streptococcus pyogenes, a gram-positive organism. Imagine that you are the technician looking at the Gram stain from Shelly’s culture. What would you expect to see as you look through the microscope?
A pink, rod-shaped organisms arranged in pairs
B purple, spherical-shaped organisms arranged in chainlike formations
C purple, spherical-shaped organisms arranged in grapelike clusters
D pink, spherical-shaped organisms arranged in chainlike formations

B

12

How will the prescribed penicillin kill S. pyogenes that is causing Shelly’s infection?

A Penicillin will attach to bacterial ribosomes and inhibit protein synthesis, which will lead to the death of S. pyogenes.
B Penicillin will interfere with peptidoglycan synthesis, ultimately weakening the cell wall and leading to cellular lysis.
C Penicillin will poke holes in the plasma membrane, weakening the cell and leading to cellular lysis.
D Penicillin will disrupt the outer membrane, leading to a loss of structural integrity and death of S. pyogenes.

B

13

Predict which type of organism would be more difficult to treat with antibiotics and why.
A gram-negative organisms -- thinner peptidoglycan layer
B gram-positive organisms -- thicker peptidoglycan layer
C gram-negative organisms -- extra layer of LPS
D gram-positive organisms -- no LPS laye

C

14

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

A

15

The lipopolysaccharide (LPS) layer is found ONLY in the cell walls of
A Archaea.
B gram-negative Bacteria.
C gram-positive Bacteria.
D Eukarya.

B

16

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

B

17

Some of the intestinal symptoms elicited by pathogens such as Salmonella, Shigella, and Escherichia are due to the presence of
A S-layers.
B peptidoglycan.
C lipopolysaccharides.
D pseudomurein.

C

18

Porins are channels in the outer membranes of gram-positive Bacteria.
A True
B False

B

19

Pathogenic bacteria that contain S-layers are protected against host defense mechanisms.
A True
B False

B
(S LAYERS, EXIST IN GRAM + AND -, AND ARCHAEA)
PROTECTIVE, ALLOW BINDING

20

Bacteria with type IV pili

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

C

21

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

C

22

Explain why the presence of a capsule or slime layer would benefit a bacterial cell.
A These outer layers prevent water from entering the cell, causing rapid dehydration.
B These outer layers can help the immune system recognize foreign organisms.
C These outer layers can aid in attachment to solid surfaces.
D These outer layers can prevent added virulence during a bacterial infection.

C

23

Which of the following types of bacterial cells would have only a single flagellum?
A Lophotrichous
B Monotrichous
C Lophotrichous and monotrichous
D Amphitrichous
E Peritrichous

B

24

Peritrichous bacteria make a run when
A the flagella turn counterclockwise and become bundled.
B the flagella turn clockwise and separate.
C the flagella turn counterclockwise and separate.
D the flagella turn clockwise and become bundled.

A

25

Which of the following types of bacterial cells would have flagella located at only one end of the cell?
A Monotrichous
B Lophotrichous and monotrichous
C Lophotrichous
D Amphitrichous
E Monotrichous and amphitrichous
F Peritrichous

B

26

Taxis is
A movement towards or away from a stimulus.
B caused by the undulating motion of a bacterium.
C another word for stimulus.
D another term for bacterial tumbling.

A

27

Which of the following terms refers to a bacterium moving towards a light source?
A Positive chemotaxis
B Positive phototaxis
C Negative chemotaxis
D Negative phototaxis

B

28

As a bacterium approaches a food source, one would expect
A runs to become more frequent.
B flagella to stop spinning.
C flagella to rotate clockwise more frequently.
D tumbles to become more frequent.

A

29

What structural part of a bacterial flagellum is composed of flagellin?
A Basal body
B Rod
C Filament
D Hook

C

30

How are Gram-positive and Gram-negative flagella different?
A Flagella are only found in Gram-negative bacteria.
B A Gram-positive flagellum has only two rings in its basal body; Gram-negatives each have four.
C A Gram-positive flagellum does not have a membrane covering its filament; A Gram-negative flagellum does.
D Each Gram-positive flagellum contains a hook; gram-negatives do not.

B
TWO RINGS FOR EACH PHOSPHOHEAD GROUP YOU PASS THROUGH

31

The rings
A are curved structures into which each filament inserts.
B are covered by a membrane.
C anchor the flagellum to the cell wall.
D are comprised of globular proteins called flagellin.

C

32

The basal body is comprised of which structural component(s) of flagella?
A Rings
B Hook
C Rod
D Rod and Rings
E Filament
F Rod and Hook

D

33

Pathogenic bacteria
A have a unique basal body structure.
B do not have flagella.
C are unique because they have a membrane covering the filament.
D can be identified and classified by differences in their flagellar proteins.

D

34

Cellular inclusions in prokaryotic cells serve to
A position cells in the appropriate environment for survival.
B store energy rich compounds.
C store energy rich compounds and position cells in the appropriate environment for survival.
D protect DNA.

C

35

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

A

36

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

C

37

The membrane of a gas vesicle is composed of
A carbohydrates.
B various phospholipids.
C both glycoproteins and phospholipids.
D proteins.

D

38

Predict why dipicolinic acid is only found in endospores and not vegetative cells.
A It binds free water and aids in transporting that water into vegetative cells, which would be detrimental to endospores.
B It binds to calcium ions to destabilize DNA at room temperature.
C It binds to calcium ions to stabilize DNA at room temperatures.
D It binds free water and aids in dehydration, which would be detrimental to vegetative cells

D

39

Predict why dipicolinic acid is only found in endospores and not vegetative cells.
A It binds free water and aids in transporting that water into vegetative cells, which would be detrimental to endospores.
B It binds to calcium ions to destabilize DNA at room temperature.
C It binds to calcium ions to stabilize DNA at room temperatures.
D It binds free water and aids in dehydration, which would be detrimental to vegetative cells

D

40

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

C

41

When does endospore formation commence?
A following bacterial death
B when bacterial growth ceases due to limitation of an essential nutrient
C when bacteria are dividing exponentially
D when the bacterium is undergoing binary fission

B

42


The energy source derived from the charge separation across the cytoplasmic membrane is referred to as
A the proton motive force.
B the voltage source.
C carbohydrate charging.
D adenosine triphosphate.

A

43

Small acid-soluble proteins (SASPs) protect DNA from ultraviolet light and are found in high numbers within
A inclusion bodies.
B endospores.
C gram-negative Bacteria.
D gram-positive Bacteria.

B