Chapter 4 Homework

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

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 being removed from the skin during hand washing A bacterium moving towards a food source A bacterium traveling through the air from a sneeze

A bacterium moving towards a food source

Indicate the bacterial structures that are likely to be antigens, to which host antibodies bind, marking the invader for phagocytosis ribosomes cell wall plasmids fimbriae flagella nucleoid capsule

A. fimbriae C. cell wall D. capsule F. flagella

Identify antibacterial strategies that would likely be selectively toxic for bacteria. interfering with lysosomal function inhibition of peptidoglycan synthesis interfering with translation at 70s ribosomes inhibition of fimbriae synthesis inhibition of microtubule function

A. inhibition of peptidoglycan synthesis C. inhibition of fimbriae synthesis E. interfering with translation at 70s ribosomes

Which membrane transport mechanism requires ATP? facilitated diffusion osmosis simple diffusion active transport

Active Transport

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? Antiport Symport Antiport and Symport Uniport Uniport, Antiport, and Symport

Antiport and Symport

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

By simple diffusion or by use of an integral transport protein

Which of the following is found in the cytoplasm of prokaryotic cells but is ABSENT from the cytoplasm of eukaryotic cells? DNA water enzymes a cytoskeleton

DNA

Which of the following statements is TRUE? Endospores are for reproduction. A cell produces one endospore and keeps growing. A cell can produce many endospores. Endospores are easily stained in a Gram stain. Endospores allow a cell to survive environmental changes by producing a dormant period with no growth.

Endospores allow a cell to survive environmental changes by producing a dormant period with no growth.

There are some structures that are common to all prokaryotic cells, and others that are only found in some bacterial species or strains. Select the structures below that are found in all bacterial cells. cellwall nucleoid capsule ribosomes pilus (pili) fimbriae cytoplasm flagella plasma membrane

F. ribosomes G. plasma membrane H. cytoplasm I. nucleoid

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

Filament

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

Flagella can rotate 360 degrees.

Which type of solution would cause a bacterium with a weak or damaged cell wall to burst as water moves into the cell? a hypotonic solution a hypertonic solution an isotonic solution either a hypotonic or an isotonic solution

Hypotonic Solution

Which of the following statements accurately describes specific bacterial cell walls? Gram-negative bacterial cell walls contain teichoic acids, whereas the cell walls of gram-positive bacteria do not. In gram-negative bacteria, the thin layer of peptidoglycan is surrounded by an outer membrane made of phospholipids, lipopolysaccharides, and proteins. The cell walls of gram-negative bacteria contain many more layers of peptidoglycan than those of gram-positive bacteria. In bacteria with acid-fast cell walls, the carboxylic acid in the walls forms a layer outside a thin layer of hydrophilic polypeptides.

In gram-negative bacteria, the thin layer of peptidoglycan is surrounded by an outer membrane made of phospholipids, lipopolysaccharides, and proteins.

Which of the following molecules would be blocked by a cell membrane? Water Dissolved oxygen Simple alcohols Ions

Ions

What is the advantage to spirochetes of the corkscrew movement provided by axial filaments? It allows the cells to move more easily through viscous human tissues and fluids, such as mucus. It provides faster movement, allowing the spirochete to escape the cells of the immune system. It hides the flagella, so they are not as easily detected by the immune system. It makes spirochete cells more flexible, and prevents them from breaking as easily as bacillus-shaped bacteria.

It allows the cells to move more easily through viscous human tissues and fluids, such as mucus.

What is a hallmark of passive transport across cell membranes? It may involve the use of transport proteins. It cannot occur without assistance from an integral membrane protein. It occurs along an electrochemical gradient It requires the use of ATP. It occurs along an electrochemical gradient, and may involve the use of transport proteins.

It occurs along an electrochemical gradient, and may involve the use of transport proteins.

Which of the following statements regarding active transport is false? It requires ATP. It powers the diffusion of water across the cell membrane. It requires the use of a transport protein.

It powers the diffusion of water across the cell membrane.

A strain of Streptococcus pneumoniae is no longer able to synthesize its capsular polysaccharide. What is a likely outcome? It will not be able to appropriately transport ions across its plasma membrane It will no longer be able to carry out fermentation It will produce more potent toxins which damage the host It will be readily phagocytized upon entering the host It will no longer be motile

It will be readily phagocytized upon entering the host

A strain of Neisseria gonorrhoeae has been genetically altered and can no longer produce fimbriae. What is a likely outcome? It will no longer be able to secrete exotoxins. It will be unable to carry out aerobic respiration It will be readily phagocytized upon entering the host It will demonstrate increased resistance to antibiotics It will be unable to adhere to host tissue and establish infection

It will be unable to adhere to host tissue and establish infection

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

Lophotrichous and monotrichous

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

Monotrichous

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

Positive phototaxis

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

Positively charged hydrogen ions

How will the prescribed penicillin kill S. pyogenes that is causing Shelly's infection? Penicillin will disrupt the outer membrane, leading to a loss of structural integrity and death of S. pyogenes. Penicillin will attach to bacterial ribosomes and inhibit protein synthesis, which will lead to the death of S. pyogenes. Penicillin will poke holes in the plasma membrane, weakening the cell and leading to cellular lysis. Penicillin will interfere with peptidoglycan synthesis, ultimately weakening the cell wall and leading to cellular lysis.

Penicillin will interfere with peptidoglycan synthesis, ultimately weakening the cell wall and leading to cellular lysis.

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

Rod and Rings

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 swell up with water and burst. 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 lose its interior water, causing it to shrivel up and possibly die.

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

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

Symport

How do axial filaments differ from regular bacterial flagella? They do not function in cell movement. They do not rotate. The axial filament is located between the cell membrane and the outer membra

The axial filament is located between the cell membrane and the outer membrane.

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

The concentration gradient drives the movement

What effect will the penicillin have on Shelly's cells? There will be no impact on Shelly's cells because penicillin targets the flagella, which are found only in bacteria. The penicillin will not have any impact on Shelly's cells because it targets peptidoglycan, which is found only in bacteria. The penicillin will kill some of Shelly's cells because it targets the ribosomes, a structure found in both prokaryotes and eukaryotes. The penicillin will also kill some of Shelly's cells by disrupting the structure of the plasma membrane.

The penicillin will not have any impact on Shelly's cells because it targets peptidoglycan, which is found only in bacteria.

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

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

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 hydrophilic. They are completely hydrophobic. 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.

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

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

Transport function.

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 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

Uniport

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

Uniport and Symport

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

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

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

allow a variety of molecules to cross the cytoplasmic membrane.

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

anchor the flagellum to the cell membrane.

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

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

Which of the following is NOT characteristic of the glycocalyx found in bacteria? creates a slimy, slippery coating that prevents bacteria from attaching to surfaces if firmly attached, contributes to bacterial virulence a viscous coating surrounding the cell made of polysaccharide, polypeptide, or both a structure that can be visualized using an acidic negative stain and a basic counterstain

creates a slimy, slippery coating that prevents bacteria from attaching to surfaces

Axial filaments are composed of axial fibers. the outer membrane. endoflagella.

endoflagella.

Sequence the path of a solute from the external environment to the cytoplasm of a prokaryotic cell.

external environment --> capsule --> cell wall --> plasma membrane --> cytoplasm

You are observing a Gram stain of spherical-shaped microorganisms that are linked in a chain and stain purple. How would you describe these bacteria using the correct terminology for the cell shape and arrangement? gram-positive coccobacilli gram-positive streptococci gram-positive tetrads gram-negative staphylococci

gram-positive streptococci

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

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

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

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

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

movement towards or away from a stimulus.

Fimbriae and pili differ in that pili are used for motility. pili are used for transfer of DNA and motility. there are only one or two pili per cell. pili are used to transfer DNA. pili are used for attachment to surfaces.

pili are used for transfer of DNA and motility.

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? purple, spherical-shaped organisms arranged in chainlike formations pink, spherical-shaped organisms arranged in chainlike formations purple, spherical-shaped organisms arranged in grapelike clusters pink, rod-shaped organisms arranged in pairs

purple, spherical-shaped organisms arranged in chainlike formations

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

runs to become more frequent

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

spirochetes.

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

the flagella rotate clockwise.

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

the flagella turn counterclockwise and become bundled

Hydrophobic molecules would enter a cell through integral transport proteins. by passive transport directly across the membrane. by active transport directly across the membrane.

through integral transport proteins.

Which of the following eukaryotic organelles is correctly matched with its function? glycocalyx--transport flagellum--protection vacuole--storage of materials mitochondrion--protein synthesis

vacuole--storage of materials

A positively charged sodium ion would get stuck in the hydrophobic core of the membrane. would require the use of integral protein channels to pass through a cell membrane. freely diffuses directly across the cell membrane.

would require the use of integral protein channels to pass through a cell membrane.