BIOS 2320-Microbiology and Infectious Diseases (MasteringMicro Ch. 3)

Eukaryotic ribosomes are composed of 50S and 30S subunits. A. True B. False

B. False

Endospores survive a variety of harsh conditions in part because of the presence of A. hopanoids. B. lipopolysaccharide. C. dipicolinic acid. D. mycolic acid. E. glycoproteins.

C. dipicolinic acid.

Membrane rafts are found in the cytoplasmic membranes of A. bacteria only. B. archaea only. C. eukaryotes only. D. both archaea and bacteria. E. both archaea and eukaryotes.

C. eukaryotes only.

Cholesterols are typically found in ________ cytoplasmic membranes. A. archaeal B. prokaryotic C. eukaryotic D. bacterial E. both eukaryotic and prokaryotic

C. eukaryotic

Which type of active transport protein uses one protein to pump two different molecules? A. Uniport B. Uniport, Antiport, and Symport C. Symport D. Antiport and Symport E. Antiport

D. Antiport and Symport

________ may have pili. A. Eukaryotes B. Archaea C. Prokaryotes D. Bacteria E. Both eukaryotes and bacteria

D. Bacteria

Which of the following would contain teichoic acids? A. a Gram-negative cell wall B. a Gram-positive cell wall C. a pseudomurin cell wall D. the glycocalyx

B. a Gram-positive cell wall

Which of the following organisms is a prokaryote? A. fungus B. archaea C. algae D. protozoa E. both archaea and protozoa

B. archaea

The hami of some archaea are used for which of the following processes? A. reproduction B. attachment C. defense D. locomotion

B. attachment

Some bacteria have an outer layer called a ________ which allows them to adhere to surfaces and contributes to their ability to cause disease. A. pilus B. capsule C. flagellum D. cell wall E. LPS

B. capsule

Some bacteria have a water-soluble outer slime layer composed of A. lipoteichoic acid. B. carbohydrate. C. peptidoglycan. D. lipid. E. protein.

B. carbohydrate.

The bacterial ________ maintains the DNA in a specific location and facilitates the process of bacterial cell division. A. fimbriae B. cytoskeleton C. pilus D. nucleoid E. inclusion

B. cytoskeleton

Lipid-soluble molecules would be expected to cross the cytoplasmic membrane by which of the following processes? A. active transport B. diffusion C. group translocation D. facilitated diffusion E. osmosis

B. diffusion

If a eukaryotic cell suffers damage to its mitochondria, which of the following processes of life would be most immediately affected? A. reproduction B. energy production C. responsiveness D. growth

B. energy production

The accumulation of glucose 6-phosphate inside a bacterial cell via phosphorylation of glucose is an example of A. diffusion. B. group translocation. C. plasmolysis. D. facilitated diffusion. E. osmosis.

B. group translocation.

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

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

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

C. It powers the diffusion of water across the cell membrane.

A bacterial cell possesses a glycocalyx. Which of the following is FALSE? A. It will be less likely to dry out. B. It will be more pathogenic. C. It will be engulfed more quickly by defensive cells of the host. D. It will be able to attach to surfaces.

C. It will be engulfed more quickly by defensive cells of the host.

Which of the following is NOT a passive transport process? A. simple diffusion B. osmosis C. facilitated diffusion D. group translocation

D. group translocation

Part B One chain of alternating NAGs and NAMs is connected to another chain via _____. A. tetrapeptides B. enzymes C. lipids D. teichoic acids

A. tetrapeptides

A (capsule/slime layer/matrix) is a type of glycocalyx that is firmly attached to the cell.

capsule

The cell walls of eukaryotes are typically composed of (carbohydrates/peptidoglycan/glycoproteins).

carbohydrates

The reserve deposits of starch or other compounds found in many prokaryotic cells are called (vacuoles/inclusions/nucleoid).

inclusions

A structural molecule found in eukaryotic cytoskeletons, flagella, cilia, and centrioles is (flagellin/tubulin/fibrin).

tubulin

The presence of a cell (wall/membrane) enables bacterial and plant cells to resist the effects of hypotonic solutions.

wall

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

A. ATP provides energy to transfer material against its concentration gradient.

A periplasmic space is found in which of the following? A. Gram-negative cells only B. Gram-positive cells only C. both Gram-positive and Gram-negative cells D. neither Gram-positive nor Gram-negative cells

A. Gram-negative cells only

A bacterial cell stains positive with the acid-fast stain. Which of the following is FALSE? A. It has a cell wall that contains endotoxin. B. It may be a member of the genus Mycobacterium. C. It has a cell wall that contains waxy lipids. D. It will be difficult to stain this cell with the Gram stain.

A. It has a cell wall that contains endotoxin.

A bacterial cell is placed in distilled water. Which of the following will happen? A. The cell will gain water. B. There will be no net gain or loss of water in the cell. C. The cell will lose water. D. The cell will shrink.

A. The cell will gain water.

Bacterial protein synthesis can begin before the reading of the gene is complete. A. True B. False

A. True

Chloroplasts use light energy to produce ATP and carbohydrates. A. True B. False

A. True

The presence of a glycocalyx contributes to bacteria's ability to cause disease. A. True B. False

A. True

The processes illustrated in the figure are driven by electrochemical gradients. A. True B. False

A. True

Watch the Video Tutor on Bacterial Cell Walls and then answer the questions below. Part A Peptidoglycans are composed of sugars and _____. A. amino acids B. nucleic acids C. teichoic acids D. lipids

A. amino acids

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

A. anchor the flagellum to the cell membrane.

The flagella of archaea are similar to bacterial flagella but differ in that they A. are driven by ATP hydrolysis. B. lack a basal body. C. move like a whip. D. are anchored in the cytoplasm. E. are hollow.

A. are driven by ATP hydrolysis.

What is the function of the cellular structure indicated by "c" in the figure? *Figure of a bacterium* A. attach to surfaces and protect from dehydration B. serve as carbohydrate storage C. attach to surfaces only D. provide shape only E. protect from dehydration only

A. attach to surfaces and protect from dehydration

Which of the following contribute to the ability of archaea to survive in extreme environments? A. branched hydrocarbons with ether linkages B. phospholipids with monounsaturated fatty acids C. glycerols D. hopanoids E. both hopanoids and glycerols

A. branched hydrocarbons with ether linkages

Short, hairlike structures used only by eukaryotic cells for movement are called A. cilia. B. pseudopodia. C. fimbriae. D. flagella. E. pili.

A. cilia.

Part C Axial filaments are composed of A. endoflagella. B. axial fibers. C. the outer membrane.

A. endoflagella.

The filament and basal body are associated with which of the following external structures found in some bacterial cells? A. flagella B. fimbriae C. glycocalyx D. pili

A. flagella

Bacterial ________ are sites of metabolite storage. A. inclusions B. periplasm C. pili D. vacuoles E. nucleoids

A. inclusions

Which of the following is NOT a characteristic of all living things? A. motility B. growth C. reproduction D. responsiveness E. metabolism

A. motility

Which of the following would NOT be found in the cytoplasm of a bacterial cell? A. porins B. nucleoid C. endospores D. ribosomes

A. porins

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

A. spirochetes.

The endosymbiotic theory does NOT provide an explanation for A. the two membranes of the nuclear envelope. B. the cristae in mitochondria. C. the presence of DNA in chloroplasts. D. the double membrane of chloroplasts. E. the presence of ribosomes in mitochondria.

A. the two membranes of the nuclear envelope.

Bacterial ribosomes are composed of several polypeptides and A. three RNA molecules in two subunits. B. two RNA molecules in a single complex. C. two RNA molecules in two subunits. D. one large RNA molecule in a single complex. E. three RNA molecules in three subunits.

A. three RNA molecules in two subunits.

The glycocalyx of a eukaryotic cell performs all of the following functions EXCEPT A. transfer of genetic material between cells. B. anchoring cells to each other. C. strengthening the cell surface. D. protection against dehydration. E. cellular recognition and communication.

A. transfer of genetic material between cells.

Which of the following is NOT a component of bacterial flagella? A. tubulin B. basal body C. hook D. flagellin E. filament

A. tubulin

Part D Within the peptidoglycan layer, the crossbridges that connect the chains of alternating sugar molecules extend between _____. A. two N-acetylmuramic acid molecules B. an N-acetylmuramic acid and an N-acetylglucosamine C. two N-acetylglucosamine molecules D. two glucose molecules

A. two N-acetylmuramic acid molecules

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

B. A bacterium moving towards a food source

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

B. Both the circle and the square

Why is using antimicrobial drugs to kill large numbers of Gram-negative bacteria in a short period of time a cause for medical concern? A. Gram-negative bacteria often contain viruses that are released when they die. B. Dead Gram-negative cells release lipid A, which causes fever and other medical problems. C. Dead Gram-negative cells transform into Gram-positive cells, which release exotoxins D. Dead Gram-negative bacteria are more infectious than live Gram-negative bacteria

B. Dead Gram-negative cells release lipid A, which causes fever and other medical problems.

Archaea are similar to bacteria in having cytoplasmic membrane that are composed of phospholipids and hopanoids. A. True B. False

B. False

Lysosomes result from the endocytosis of food particles by eukaryotic cells. A. True B. False

B. False

Peroxisomes contain enzymes used to digest nutrients that have been brought into the cell through phagocytosis. A. True B. False

B. False

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

B. Flagella can rotate 360 degrees.

Which of the following prokaryotic cells contain an outer membrane? A. Gram-positive bacteria only B. Gram-negative bacteria only C. both Gram-positive and Gram-negative bacteria D. all prokaryotes E. archaea

B. Gram-negative bacteria only

Which of the following molecules would be blocked by a cell membrane? A. Water B. Ions C. Dissolved oxygen D. Simple alcohols

B. Ions

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

B. Lophotrichous and monotrichous

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

B. Monotrichous

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

B. Positively charged hydrogen ions

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

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

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

B. The concentration gradient drives the movement.

Which transport protein employs transporters that move molecules only in one direction? A. Antiport B. Uniport and Symport C. Uniport and Antiport D. Symport E. Uniport F. Uniport, Antiport, and Symport

B. Uniport and Symport

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

B. movement towards or away from a stimulus.

Which of the following chemical substances contributes to the unique characteristics of acid-fast bacteria? A. peptidoglycan B. mycolic acid C. lipoteichoic acid D. endotoxin E. N-acetylglucosamine

B. mycolic acid

Using a microscope, you observe an amoeba moving toward a food source. This is an example of A. growth. B. responsiveness. C. metabolism. D. reproduction. E. cellular structure.

B. responsiveness.

Peptidoglycan is a polymer of millions of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) sugars based on glucose molecules linked together in long chains cross-braced with four amino acids that link individual polymer chains together in a chain-link fence pattern. Layers of cross-braced NAG and NAM sheets are stacked vertically and held together by proteins with lipid anchors attached to the cell's cytoplasmic membrane to form a scaffold of sugars and proteins that is able to hold the bacterial cell's shape, even in response to extreme osmotic pressures. How would you expect a microbiology student to be able to describe the composition of peptidoglycan? What is the composition of the peptidoglycan layers found in the cell wall of bacteria? Pick the answer that lists the composition of the bacterial cell wall. A. amino acids, NAG, and NAM B. short amino acid chains, NAG, NAM, and some lipid proteins C. proteins and sugars D. NAG and NAM

B. short amino acid chains, NAG, NAM, and some lipid proteins

What types of molecules may NOT need transport proteins to be able to cross cytoplasmic membranes? A. small hydrophilic molecules B. small hydrophobic molecules C. nothing crosses cytoplasmic membranes without transport proteins D. large molecules E. ions

B. small hydrophobic molecules

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

B. the flagella turn counterclockwise and become bundled.

Lipid A is a component of A. cytoplasmic membranes. B. the outer membrane of Gram-negative bacteria. C. plant cell walls. D. Gram-positive bacterial membranes. E. bacterial glycocalyces.

B. the outer membrane of Gram-negative bacteria.

The archaea are similar to bacteria in all of the following aspects EXCEPT __________. A. their mechanism of cell division B. their ribosomal proteins C. their cytoskeleton D. their lack of membranous organelles

B. their ribosomal proteins

Integral proteins are mostly involved in A. recognition sites. B. transport function. C. enzymatic function. D. receptors.

B. transport function.

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

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

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

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

Which of the following statements concerning endocytosis is TRUE? A. This process occurs in both prokaryotes and eukaryotes. B. Endocytosis is a form of passive transport. C. Endocytosis produces a structure called a food vesicle. D. Waste products and secretions are exported from the cell during endocytosis. E. Phagocytosis is a type of endocytosis in which liquids are brought into the cell.

C. Endocytosis produces a structure called a food vesicle.

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

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

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

C. Simple diffusion does not require a permease.

Which type of active transport protein moves two molecules into the cell at the same time? A. Uniport B. Antiport C. Symport D. Antiport and Symport E. Uniport, Symport, and Antiport

C. 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? A. The cell will pump the salt in the cytoplasm out of the cell via simple diffusion. B. The cell will swell up with water and burst. C. The cell will lose its interior water, causing it to shrivel up and possibly die.

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

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

D. By simple diffusion or by use of an integral transport protein

Which of the following statements concerning osmosis is FALSE? A. Osmosis requires a selectively permeable membrane. B. Cells placed in hypotonic solutions will gain water. C. Crenation results when blood cells are placed in a hypertonic solution. D. During osmosis, water crosses to the side of the membrane with a lower solute concentration. E. Osmosis stops when the system reaches equilibrium.

D. During osmosis, water crosses to the side of the membrane with a lower solute concentration.

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

D. Filament

Which of the following may have cell walls containing teichoic acids? A. all prokaryotes B. both Gram-positive and Gram-negative bacteria C. Gram-negative bacteria only D. Gram-positive bacteria only E. archaea

D. Gram-positive bacteria only

Which of the following statements concerning conjugation pili is FALSE? A. Pili facilitate the transfer of DNA among bacterial cells. B. Pili are long, hollow tubules. C. Not all bacteria have pili. D. Pili are longer than fimbriae and flagella. E. A bacterial cell will usually have only one or two pili.

D. Pili are longer than fimbriae and flagella.

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

D. Positive phototaxis

Part F What role do the teichoic acids play within the cell wall of Gram-positive bacteria? A. They act as crossbridges, holding the peptides and sugar molecules together. B. They serve as pores allowing the passage of ions, nutrients, and amino acids into the cell. C. They serve as adhesins, allowing bacteria to bind to one another. D. They serve to stabilize the cell wall and hold it in place.

D. They serve to stabilize the cell wall and hold it in place.

Part E The peptidoglycan cell wall of bacteria is most analogous to _____. A. an impenetrable brick wall B. a sugary candy shell C. a rain coat D. a chain-link fence

D. a chain-link fence

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

D. allow a variety of molecules to cross the cytoplasmic membrane.

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

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

Which of the following is NOT a characteristic of a eukaryotic cell? A. presence of a nuclear envelope B. contain chromosomes composed of DNA and histones C. presence of membrane-bound organelles D. can undergo transcription and translation simultaneously

D. can undergo transcription and translation simultaneously

Endocytosis and exocytosis are means of transport used by A. bacteria. B. archaea. C. all prokaryotes. D. eukaryotes. E. nothing; no cells use both processes.

D. eukaryotes.

Which of the following would NOT be expected to be present in a biochemical analysis of an archaeal cell? A. phospholipids B. membrane proteins C. ribosomes D. peptidoglycan

D. peptidoglycan

The process of bringing a solid substance into a eukaryotic cell is known as __________. A. pseudopodia B. pinocytosis C. photosynthesis D. phagocytosis

D. phagocytosis

Which of the following is NOT a membranous organelle within a eukaryotic cell? A. nucleus B. chloroplast C. endoplasmic reticulum D. ribosome

D. ribosome

Archaeal flagella __________. A. do not contain a filament B. are powered by the flow of hydrogen ions across the membrane C. grow by the addition of subunits at the tip D. rotate as bacterial flagella do

D. rotate as bacterial flagella do

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

D. runs to become more frequent.

Which of the following is NOT a basic process of life? A. growth B. responsiveness C. metabolism D. sexual reproduction

D. sexual reproduction

Which of the following is NOT a component of eukaryotic cell walls? A. chitin B. silicates C. cellulose D. sterols

D. sterols

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

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

The cell walls of some ________ are composed of minerals such as calcium carbonate. A. fungi B. archaea C. bacteria D. bacteria and fungi E. algae

E. algae

Cytoplasmic membranes of ________ are composed of unbranched phospholipids. A. archaea B. bacteria C. eukaryotes D. prokaryotes E. bacteria and eukaryotes

E. bacteria and eukaryotes

ATP is expended in which of the following processes? A. diffusion B. facilitated diffusion C. group translocation D. active transport E. both active transport and group translocation

E. both active transport and group translocation

Which of the following processes requires a channel protein? A. facilitated diffusion only B. endocytosis only C. active transport only D. diffusion only E. both facilitated diffusion and active transport

E. both facilitated diffusion and active transport

Which of the following bacterial cell structures plays an important role in the creation of biofilms? A. flagella B. pili C. glycocalyces D. fimbriae E. both fimbriae and glycocalyces

E. both fimbriae and glycocalyces

Which of the following may be a component of bacterial cell walls? A. lipoteichoic acids B. tubulin C. carrageenan D. mycolic acid E. both lipoteichoic and mycolic acids

E. both lipoteichoic and mycolic acids

Part C One of the main differences between a Gram-positive and a Gram-negative bacterial cell wall is that the peptidoglycan portion of a Gram-positive cell wall is _____ as compared to a Gram-negative cell wall. A. positively charged B. more lipid rich C. composed of a greater percentage of NAGs than D. NAMs E. thicker

E. thicker

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

F. Rod and Rings

A cell wall is a requirement for all living bacteria. Choose True or False.

False

At this point in writing your tutorial, you have to find a way to get across to the students the importance of a cell wall to a bacterium. How do you convey that the bacterial cell will be at the mercy of its environment? The cell wall will need to act as a support mechanism to neutralize the inflow or outflow of water that would alter the shape of the cell. The cell cannot search out for a better place in the environment that has more available water; or if there is water that it has a high enough solute concentration that the cell will not gain water. Because that's the problem for a bacterial cell, it cannot control the tonicity due to solute concentrations in the surrounding water. Water will flow in or out depending on solute concentrations and the only thing a bacterial cell can do to keep from collapsing due to water loss or rupturing due to too much water coming in is to have a strong cell wall that will hold its shape regardless of the osmotic pressures. The rigidity of the cell wall will maintain a set shape regardless of water flow. The proteins and lipids that anchor the cytoplasmic membrane to the cell wall will tether the membrane to the peptidoglycan layer so that when environmental conditions result in the loss of water from the cell, the membrane will not collapse in on itself. Similarly, changes in environmental conditions that would result in the inflow of water would expand the volume of the cell to the limits of the cell wall and no more. The composition of the cell wall allows for the expansion and contraction of the cell wall in response to the gain or loss of water from the cell. Choose True or False.

False

The thickness of this sugar-protein scaffold of peptidoglycan can be used to separate most bacteria into two groups. In your tutorial, you want to illustrate to the students that the thickness of the peptidoglycan layer can be used by microbiologists to differentiate many bacteria by only using an easy staining method that all microbiologists will have to master. This staining procedure, known as the Gram stain, is based on the retention of dyes within the cell wall for a positive result or the rinsing away of the dyes and leakage of the membrane for a negative result. A thicker cell wall will allow for retention of dye crystals that will give the bacterial cell a blue-purple color (positive result), but the thinner cell walls will not allow for the retention of these crystals during rinsing, which will mean that these cells will then be colorless unless another dye that does not require interaction with the cell wall to maintain its retention is used (negative result). In addition to differences in cell wall thickness, Gram-positive and Gram-negative bacteria also differ in the proteins and lipids associated with their cell walls, as well as the composition of their cell membranes. Gram-positive walls are composed of an underlying cytoplasmic membrane, with the thick peptidoglycan layer on the outside offering support. Proteins anchor the membrane and the cell wall together to provide support and structure between the two. Gram-negative staining walls have a different layout. You try to explain in your tutorial that even though these bacteria stain "negative" they do have a thin layer of peptidoglycan sandwiched in between two lipid bilayer membranes. Place each attribute into the bin of the bacterial group it belongs to, based on whether the bacterium is a Gram-positive or a Gram-negative cell.

Gram-positive bacterial cell wall: thick layer of peptidoglycan teichoic acids single lipid bilayer membrane Gram-negative bacterial cell wall: thin layer of peptidoglycan lipopolysaccharides periplasmic space dual lipid bilayer membrane

Fragments of (LPS/NAM/NAG) released from Gram-negative bacteria into the bloodstream produce fever and shock.

LPS

The peptidoglycan cell wall and the one or two membranes present also impart a three-dimensional shape to the bacterial cell. The overall shape and arrangement of bacteria are genetically determined, so that each genus of bacteria has a characteristic shape (round, rod, spiral, etc.) and arrangements of the growing cell population (individual cells, chains of cells, or clustered cells). Drag the descriptive terms to the pictured bacterial shapes. Bin 1 - Image of a single round bacterium. Bin 2 - Image of a single rodishaped bacterium. Bin 3 - Image of a cluster of round bacteria. Bin 4 - Image of a string of rodishaped bacteria. Bin 5 - Image of a commaishaped bacterium. Bin 6 - Image of a corkscrewishaped bacterium.

1. coccus 2. bacillus 3. staphylococcus 4. streptobacillus 5. Vibrio 6. spirochete

Part H A patient is infected with Gram-negative bacteria and is experiencing only mild symptoms. When the patient is given an antibiotic causing lysis of the bacterial cells, he suddenly experiences an increase in inflammation and fever, as well as the formation of blood clots. What explanation best describes what happened? A. The antibiotic is toxic and is affecting the patient adversely. B. Any part of the bacterial cell wall released during lysis is seen as foreign and thereby elicits a severe immune response by the body's immune system. C. The lysis of the cells releases lipid A from the lipopolysaccharide layer. D. The lysis of the cells releases NAG and NAM from the cell wall.

C. The lysis of the cells releases lipid A from the lipopolysaccharide layer.

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

C. 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? A. They are completely hydrophobic. B. They are positively charged. C. They have both hydrophilic and hydrophobic regions. D. They are completely hydrophilic.

C. They have both hydrophilic and hydrophobic regions.

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

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

Which of the following is paired INCORRECTLY? A. archaea; protein cell wall B. plants; cellulose cell wall C. algae; glycocalyx D. bacteria; peptidoglycan cell wall E. fungi; polysaccharide cell wall

C. algae; glycocalyx

Which of the following never have cell walls? A. fungi B. bacteria C. animal cells D. algae E. archaea

C. animal cells

The cytoplasmic membranes of ________ may contain branched hydrocarbons. A. bacterial cells B. eukaryotic cells C. archaeal cells D. both bacterial and eukaryotic cells E. archaeal, bacterial, and eukaryotic cells

C. archaeal cells

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

C. by passive transport directly across the membrane.

The figure shows two cells with more dark dots inside them than outside. Arrows labeled H2O go inside the cells. One cell is very enlarged and bursts, while the second one is a little bit flattened and of a regular size. The cells illustrated in the figure are in a(n) ________ environment. A. isotonic B. fluid mosaic C. hypotonic D. passive E. hypertonic

C. hypotonic

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

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

Bacteria of the genus Mycoplasma lack cell walls. What sort of environment do they require for survival? A. hypotonic B. a biofilm C. isotonic D. low temperature E. hypertonic

C. isotonic

Part G The region between the outer and inner membranes of a Gram-negative bacterial cell is known as the __________, and it is the location of enzymes that assemble peptidoglycan. A. intramembranous space B. lipopolysaccharide layer C. periplasmic space D. cytoplasm

C. periplasmic space

Which of the following statements concerning the characteristics of life is FALSE? A. living things store metabolic energy in the form of chemicals such as ATP. B. organisms may not exhibit all of the characteristics of life at all times. C. reproduction is defined as an increase in the size of an organism. D. reproduction can occur asexually or sexually in living things. E. viruses have some, but not all, of the characteristics of living things.

C. reproduction is defined as an increase in the size of an organism.

Part A Tumbles occur when A. the flagella rotate counterclockwise. B. the flagella stop rotating. C. the flagella rotate clockwise. D. the flagella undulate.

C. the flagella rotate clockwise.

Chloroplasts differ from mitochondria in that the former have A. two lipid bilayers. B. cristae. C. thylakoids. D. DNA. E. 70S ribosomes.

C. thylakoids.

With the description of the different cell walls, membranes, and associated proteins set in the students' minds, you now need to introduce them to the idea that the cell wall can also act as a foundation to build things upon. Bacterial appendages require a strong foundation that will offer the support needed to move and function in a dynamic world. For example, flagella are long, whiplike protein structures that are used by many Gram-positive and Gram-negative bacteria for locomotion. In order to function effectively, a flagellum must be firmly anchored to the cell wall. How will you be able to get across the idea that the peptidoglycan cell wall is strong enough to support such a mechanism? With a protein rod that passes through the cell wall and protein rings used to anchor it in the membranes, these basal bodies are the rudimentary biological motors that use ATP power to spin the hook and the flagella attached to it. Bacterial flagella have a biological motor that spins within the cell wall and is powered by ATP. This allows the flagella to spin in a whiplike motion to propel the bacterium. Is this statement True or False? Choose the answer that you think is correct.

False