Microbiology Online Quiz #2

Teichoic acids are commonly found in gram-negative cell walls. A. True B. False

B. False

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

all bacteria appearing pink

Nonspecific permeases are not used for passive transport. allow only water to cross the cytoplasmic membrane. allow only one type of solute to pass through the membrane. allow a variety of molecules to cross the cytoplasmic membrane.

allow a variety of molecules to cross the cytoplasmic membrane.

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

anchor the flagellum to the cell wall.

Transport proteins can become saturated with solute, have high specificity for certain substances, undergo conformational (shape) changes, and are highly regulated by the cell. What other type of cellular proteins have these four general characteristics? flagella porins ribosomes enzymes

enzymes

Given that the cytoplasmic membrane has a fluid dynamic nature, with phospholipids and proteins able to move about within the bilayer structure, what force or structure keeps the membrane from falling apart? rigid sterol lipids hydrophilic/hydrophobic forces osmosis the proton motive force

hydrophilic/hydrophobic forces

An organism of the genus Staphylococcus is ________, while an organism of the genus Spirochaeta is ________. spherical / rod shaped coiled / spherical spherical / coiled rod shaped / coiled

spherical / coiled

Axial filaments are found on rod-shaped bacilli. spirochetes. staphylococci. streptococci.

spirochetes.

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

store energy rich compounds and position cells in the appropriate environment for survival.

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

A Gram-positive flagellum has only two rings in its basal body; Gram-negatives each have four.

Which of the following scenarios is an example of bacterial motility? A bacterium moving towards a food source A bacterium traveling through the air from a sneeze A bacterium being removed from the skin during hand washing

A bacterium moving towards a food source

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

A. True

The peptide inter-bridge cross-linking between peptidoglycan layers is found ONLY in the cell walls of A. gram-positive Bacteria. B. Archaea. C. gram-negative Bacteria. D. Eukarya.

A. gram-positive Bacteria.

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

A. peptidoglycan.

Why is ATP necessary for active transport? ATP is an important structural element of transport proteins. ATP is a constituent of the electrochemical gradient. ATP provides energy to transfer material against its concentration gradient. ATP is in higher concentrations inside of the cell.

ATP provides energy to transfer material against its concentration gradient.

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 ATP. ATP, the proton motive force, or phosphoenol pyruvate. phosphoenol pyruvate. the proton motive force.

ATP, the proton motive force, or phosphoenol pyruvate.

What would you expect to see if you forgot to perform step 2 of the Gram stain procedure? All bacteria would appear pink. All bacteria would appear purple. Gram-positive cells would appear purple and Gram-negative cells would appear pink. Gram-positive cells would appear pink and Gram-negative cells would appear purple.

All bacteria would appear pink.

What would you anticipate seeing if you accidentally switched crystal violet and safranin while performing a Gram stain? Gram-positive bacteria would appear pink and Gram-negative bacteria would appear purple. All bacteria would appear purple. All bacteria would appear pink. Gram-positive bacteria would appear purple and Gram-negative bacteria would appear pink.

All bacteria would appear purple.

Sodium and potassium ions need to be pumped simultaneously against their concentration gradients. Which one of the transport proteins would be most effective at this? Uniport Antiport Symport Any would work, as they can all pump ions out.

Antiport

Which type of active transport protein uses one protein to pump two different molecules? Symport Antiport Antiport and Symport Uniport, Antiport, and Symport Uniport

Antiport and Symport

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

B. False

Which molecule shown in the animation, the square or the circle, is moving against its concentration gradient? Neither; they are both moving with their respective concentration gradients. The square Both the circle and the square The circle

Both the circle and the square

How does water enter and exit a cell? By simple diffusion across the membrane By use of a peripheral transport protein By simple diffusion or by use of an integral transport protein By use of an integral transport protein

By simple diffusion or by use of an integral transport protein

Bacteria stain as gram-positive or gram-negative because of differences in the cell: A. chromosome. B. cytoplasm. C. wall. D. nucleus.

C. wall.

In gram-positive Bacteria, the cell walls are composed mainly of thick ________ layers. A. poly-β-hydroxybutryic acid (PHB) B. lipopolysaccharides (LPS) C. protein D. peptidoglycan

D. peptidoglycan

The lipids in the cytoplasmic membrane of Bacteria and ________ contain ester linkages, while the cytoplasmic membrane of ________ contain ether linkages. Archaea / fungi Eukarya / prokaryotes Eukarya / Archaea Archaea / Eukarya

Eukarya / Archaea

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

Filament

Which of the following statements about bacterial flagella is true? Bacteria can only rotate flagella clockwise. Bacteria can only rotate flagella counterclockwise. Flagella work by undulating. Flagella can rotate 360 degrees.

Flagella can rotate 360 degrees.

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

Gram-negative; membrane

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

It binds free water and aids in dehydration, which would be detrimental to vegetative cells.

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

Lophotrichous and monotrichous

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

Monotrichous

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

N-acetylmuramic acid

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

Positive phototaxis

Which of the following would not move freely across the cytoplasmic membrane? Small alcohols Positively charged hydrogen ions Dissolved oxygen Dissolved carbon dioxide

Positively charged hydrogen ions

The basal body is comprised of which structural component(s) of flagella? Rings Rod and Hook Rod and Rings Rod Hook Filament

Rod and Rings

How is simple diffusion different from other types of passive transport? Simple diffusion requires ATP. Simple diffusion is only the diffusion of water. Simple diffusion only brings material into the cell, not out of it. Simple diffusion does not require a permease.

Simple diffusion does not require a permease.

What type of transport uses two transport proteins? Uniport Antiport Symport None of the proteins do All of the proteins do

Symport

Which of the active transport types employs diffusion? Antiport Uniport and Antiport All types of active transport make use of some form of diffusion. Symport Uniport

Symport

Which type of active transport protein moves two molecules into the cell at the same time? Uniport Antiport Symport Antiport and Symport Uniport, Symport, and Antiport

Symport

What will happen to a cell that is placed in a solution containing a high concentration of sugar, a molecule that cannot pass across the cell membrane? The cell will pump the salt in the cytoplasm out of the cell via simple diffusion. The cell will lose its interior water, causing it to shrivel up and possibly die. The cell will swell up with water and burst.

The cell will lose its interior water, causing it to shrivel up and possibly die.

Why is no energy required in passive transport? Transport proteins move the molecules, so no energy is required. The membrane physically moves the molecules. The concentration gradient drives the movement.

The concentration gradient drives the movement.

Why are receptors on the cell surface necessary for bacterial movement? The receptors sense the stimulus and send signals to the flagella. The bacterium contains receptors that are sensitive to light. The receptors actually spin the flagella. The receptors physically alter shape to steer the bacterium.

The receptors sense the stimulus and send signals to the flagella.

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

They enable organisms to endure extremes of temperature, drying, and nutrient depletion.

What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass? They have both hydrophilic and hydrophobic regions. They are completely hydrophobic. They are completely hydrophilic. They are positively charged.

They have both hydrophilic and hydrophobic regions.

Why are ATPases associated with active transport proteins? They allow for the production of ATP that is needed during active transport. They help pump phosphate ions across the membrane to maintain the electrochemical gradient. They provide transport proteins with the energy needed to pump molecules against their concentration gradients. They are important only in symport proteins, because two are required. All of the above

They provide transport proteins with the energy needed to pump molecules against their concentration gradients.

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

True

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

True

Efflux pumps can be used to pump antibiotics out of a cell once they enter to protect the cell. This will be done against the concentration gradient of the antibiotic. Which of the active transports would most likely be used? Uniport Symport Antiport

Uniport

Which transport protein employs transporters that move molecules only in one direction? Uniport Symport Uniport and Symport Antiport Uniport and Antiport Uniport, Antiport, and Symport

Uniport and Symport

How is osmosis different from simple diffusion? Water cannot pass freely across the membrane. Water movement is driven by the concentration of solutes rather than its own concentration. Water requires a special permease. Water requires energy to move across a cytoplasmic membrane.

Water movement is driven by the concentration of solutes rather than its own concentration.

The cytoplasmic membrane could best be described as a highly selective permeability barrier. an impermeable barrier. a rigid structure that protects the cell. a passive conduit for intracellular transport.

a highly selective permeability barrier.

All eukaryotes contain a membrane-enclosed nucleus. hydrogenosomes. a nucleus, mitochondria, and hydrogenosomes. mitochondria.

a membrane-enclosed nucleus.

Which structural feature of Gram-positive bacteria enhances their ability to retain the crystal violet dye? an outer membrane a thick peptidoglycan layer a thin peptidoglycan layer All of the above contribute to a Gram-positive cell's ability to retain crystal violet.

a thick peptidoglycan layer

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

both Gram-positive and Gram-negative organisms

The Golgi complex functions to synthesize proteins. sort proteins used within the cell. modify and secrete proteins to the external environment. both modify and sort proteins into those destined for secretion and those that function in membrane structures.

both modify and sort proteins into those destined for secretion and those that function in membrane structures.

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

can be identified and classified by differences in their flagellar proteins.

One of the many types of proteins found in the cytoplasmic membrane is involved in the chemotactic response and is called a binding protein. chemoreceptor. hydrolytic enzyme. porin.

chemoreceptor.

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

endospores.

Identify which of the following is a major function of the cytoplasmic membrane. rigid shape defining layer energy conservation anchor for carbohydrates impermeable barrier

energy conservation

Which list contains the correct components of a bacterial flagellum? filament, hook, basal body filament, anchor, rotator filament, anchor, basal body filament, hook, rotator

filament, hook, basal body

Membrane-enclosed organelles, such as nuclei, lysosomes, endoplasmic reticulum, mitochondria, and chloroplasts, increase the structural complexity of eukaryotic cells. increase structural complexity, help eukaryotes overcome diffusion limitation due to their size, and form specialized environments for specific functions to occur. help large eukaryotic cells overcome the limitations of diffusion imposed by their large cell size. form specialized compartments within eukaryotic cells for specific functions to occur.

form specialized compartments within eukaryotic cells for specific functions to occur.

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

gram-negative Bacteria.

A glycoprotein can be used in enzymatic functions. is a type of peripheral protein. can be used as a receptor. is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.

is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.

The membrane-enclosed compartments that contain digestive enzymes in eukaryotic cells are called cristae. stromas. mitosomes. lysosomes.

lysosomes

Once equilibrium is reached, molecules no longer move. passive transport starts over to create a concentration gradient. the membrane permits all molecules to freely move across the membrane. molecules move, but there is no net movement in a particular direction.

molecules move, but there is no net movement in a particular direction.

The morphology of a cell influences its motility. metabolism. surface-to-volume ratio. motility and surface-to-volume ratio.

motility and surface-to-volume ratio.

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

movement towards or away from a stimulus.

Carrier-mediated transport is necessary when movement into the cell is against a concentration gradient. nutrient concentration is very low in the environment, is higher inside of the cell, or diffusion is not possible. the level of nutrients in nature is very low. diffusion will not allow adequate amounts of a substance to enter the cell.

nutrient concentration is very low in the environment, is higher inside of the cell, or diffusion is not possible.

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

runs to become more frequent.

Tumbles occur when the flagella rotate clockwise. the flagella rotate counterclockwise. the flagella undulate. the flagella stop rotating.

the flagella rotate clockwise.

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

the flagella turn counterclockwise and become bundled.

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

the proton motive force.

Transport proteins (transporters) require energy expenditure for each molecule of substrate transported. The reason for this energy requirement is __________. the solute must be forced through the hydrophobic membrane the solute must be chemically altered the solute must be transported against a concentration gradient the conformational shape of the solute must be changed during transport

the solute must be transported against a concentration gradient

Integral proteins are mostly involved in enzymatic function. receptors. transport function. recognition sites.

transport function.