Micro – Ch. 4 Part One – Flashcards

The immune response of a host against an invading bacterium is often triggered by surface components on the bacterium that are recognized as "non-self" or "foreign" by the host. These non-self components, often protein or polysaccharide in nature, are referred to as antigens. The host responds to these antigens by making antibodies that will react with invading bacteria and mark them or tag them for destruction by phagocytes. Indicate the bacterial structures that are likely to be antigens, to which host antibodies bind, marking the invader for phagocytosis fimbriae ribosomes cell wall plasmids flagella capsule nucleoid

An important characteristic of antibacterial drugs is their selective toxicity. If antibacterial drugs were not selectively toxic, then they would kill or interfere with the hosts' cells as well as bacterial cells. Examining cellular differences between bacterial (prokaryotic) cells and host (eukaryotic) cells suggests strategies to achieve selective toxicity. We can capitalize on these differences and take advantage of them in the design of antibacterial drugs Identify antibacterial strategies that would likely be selectively toxic for bacteria. inhibition of peptidoglycan synthesis interfering with lysosomal function inhibition of fimbriae synthesis interfering with translation at 70s ribosomes inhibition of microtubule function

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

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 demonstrate increased resistance to antibiotics It will be readily phagocytized upon entering the host It will be unable to adhere to host tissue and establish infection

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

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 neither Gram-positive nor Gram-negative organisms only Gram-negative organisms

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

How are Gram-positive and Gram-negative flagella different? 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. 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.

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.

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

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

Which of the following scenarios is an example of bacterial motility? 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

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

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 membrane.

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

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

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

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

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

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.

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

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

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

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

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

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.

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

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

How is osmosis different from simple diffusion? 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.

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.

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 is only the diffusion of water. Simple diffusion requires ATP.

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

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

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

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

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

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

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

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.

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

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? Symport Antiport Uniport

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.