Unit 2 Exam

A pure culture consists of which of the following? a) one streak b) one species of microbe c) similar Gram stain reactions d) turbidity e) one genus of microbe

b) one species of microbe

Gallionella bacteria can get energy from the reaction Fe2+ → Fe3+. This reaction is an example of a) the Calvin-Benson cycle. b) oxidation. c) photophosphorylation. d) fermentation. e) reduction.

b) oxidation.

Which of the following physical methods of microbial control denatures proteins as a mechanism of action? View Available Hint(s) a) osmotic pressure b) incineration c) radiation d) boiling or autoclaving

d) boiling or autoclaving

Turbidity is an indirect measurement of bacterial growth that can be measured using a spectrophotometer. True/False

True

The reason that Staphylococcus aureus turns yellow on MSA is that __________. a) the microbes are salt-tolerant b) the microbes have fermented mannitol c) the microbes are resistant to eosin and methylene blue d) the microbes have fermented lactose e) the microbes are resistant to phenol red

b) the microbes have fermented mannitol

If an agar contains a dye or pH indicator in the presence of a sugar, it is generally considered _______ for those bacteria that may ferment the sugar over those that cannot. a) selective b) differential

b) differential

The ___________ aspect of MacConkey agar allows for the determination of which bacteria are lactose fermenters and which are not. a) selective b) differential

b) differential

The following reagents are used in the Gram stain. You could distinguish Gram-positive cells from Gram-negative cells after _______. a) iodine b) ethanol c) crystal violet d) impossible to determine e) This can be done after any of the reagents

b) ethanol

Which of the following chemical agents is used for sterilization? a) alcohol b) ethylene oxide c) soap d) phenolics e) chlorine

b) ethylene oxide

S. aureus S. pyogenes Nutrient Agar ++ ++ Nutrient Agar + 7.5% NaCl + - The data in the table indicate that S. aureus is a(n) a) aerobe. b) mesophile. c) halophile. d) facultative halophile. e) facultative anaerobe.

d) facultative halophile.

During which growth phase will gram-positive bacteria be most susceptible to penicillin? a) death phase b) stationary phase c) lag phase d) log phase e) The culture is equally susceptible during all phases

d) log phase

Microbes have very narrow optimum temperature ranges. Which of the following classifications of microbes are most likely to cause human disease, based on their temperature requirements? a) hyperthermophiles b) psychrophiles c) thermophiles d) mesophiles

d) mesophiles The temperature range of mesophiles overlaps that of normal human body temperature, allowing the greatest growth.

What is the primary purpose of the bacterial flagella? a) survival in harsh conditions b) genetic exchange c) avoiding immune defenses d) motility e) pathogenesis

d) motility

After acid-fast staining, an acid-fast cell will be __________. a) green b) brown c) colorless d) red e) blue

d) red

Leptospira would be placed in which of the phyla according to the taxonomic scheme used by your textbook: a) Gram negative Protobacteria b) Gram positive Firmicutes c) Gram positive Actinomycetes d) Chlamydiae e) Spirochaetes

e) Spirochaetes

What are cofactors and coenzymes?

Cofactor is any substance required to cooperate with an enzyme that catalyzes a specific reaction (Zn, Mg, Fe) Organic, loosely bound cofactors are called coenzymes, and play an accessory role in enzyme-catalyzed processes, often inside the active site. They both help achieve a better shape.

Halophiles

"salt-loving" archaea that live in environments that have very high salt concentrations

What modes of action are utilized by anti-microbial substances?

# of microbes Nature of microbes in population Temperature and pH of env't Concentration of agent Mode of action of agent Presence of solvents, interfering organic matter and inhibitors

Cytochromes

Proteins that play a key role in electron transport chains in mitochondria and chloroplasts.

Both respiration and photosynthesis require the use of an electron transport chain. True/False

True

A bacterium that can be found growing in a hot spring would be considered a ___________. a) Mesophile b) Psychrophile c) Thermophile

c) Thermophile

Eosin methylene blue (EMB) media are selective because of __________. a) mannitol b) phenol red c) the pH d) the dyes e) the agar

d) the dyes

Acidophiles

grow in acidic environments

Thermophiles

heat loving microbes

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

What factors influence the effectiveness of antimicrobial treatments?

- Concentration of the disinfectant - Organic matter - pH - Time

Cofactor

A nonprotein molecule or ion that is required for the proper functioning of an enzyme. My help catalyze a reaction by forming a bridge between an enzyme and its substrate.

Disinfection

A process that eliminates many or all microorganisms, with the exception of bacteria spores, from inanimate objects

Electron Transport Chain

A series of proteins in which the high-energy electrons from the Krebs cycle are used to convert ADP into ATP. NADH and FADH2 are oxidized, contributing the electrons they have carried from the substrates to a "cascade" of oxidation-reduction reactions involving a series of addition electron carriers. Energy from these reactions is used to generate a considerable amount of ATP.

Sanitizer

A substance or preparation for killing germs, designed for use especially on food-processing equipment.

Exoenzymes

An _____, or extracellular enzyme, is an enzyme that is secreted by a cell and functions outside of that cell. _____ are produced by both prokaryotic and eukaryotic cells and have been shown to be a crucial component of many biological processes.

Endoenzymes

An _____, or intracellular enzyme, is an enzyme that functions within the cell in which it was produced. Because the majority of enzymes fall within this category, the term is used primarily to differentiate a specific enzyme from an exoenzyme.

What is electron transport and how does the electron transport chain produce ATP?

An electron transport chain consists of a sequence of carrier molecules that are capable of oxidation and reduction. They shuttles electrons from NADH and FADH2 to molecular oxygen. ATP is generated through Chemiosmosis.

Coenzyme

An organic cofactor

Heterotrophs

An organism that obtains organic food molecules by eating other organisms or their by-products.

How is growth measured both directly and indirectly? What are the advantages and disadvantages of each?

Direct- measurement of the growth of microbial populations through measuring cell numbers, measuring the population's total mass (direct counts on small samples). Indirect- Not always necessary to count microbial cells to estimate their numbers

Noncompetitive Inhibition

Do not compete with the substrate for the enzyme's active site; instead , they interact with another part of the enzyme.

What happens during cellular respiration?

During cellular respiration, cells break down glucose and other molecules from food in the presence of oxygen, releasing energy.

At the end of Krebs Cycle, where is most of the energy from the original glucose molecule?

During the Krebs cycle, energy stored in pyruvate is transferred to NADH and FADH2, and some ATP is produced. These electron carriers will connect with the last portion of cellular respiration, depositing their electrons into the electron transport chain to drive synthesis of ATP molecules through oxidative phosphorylation.

Describe enzymes, and how is their function determined?

Enzymes are proteins, produced by living cells, that catalyze chemical reaction by lowering the activation energy. They are generally globular proteins with characteristic three-dimensional shapes. Enzymes are efficient, can operate at relatively low temperatures, and are subject to various cellular controls. When an enzyme and a substrate combine, the substrate is transformed, and the enzyme is recovered. Enzymes are characterized by specificity, which is a function of their active sites. Enzyme names usually end is -ASE.

Denaturation - protein structure

The loss of shape in a protein as a result of changes in temperature, pH, or exposure to chemicals. Ex: transformation of uncooked egg white to a hardend state by heat

Describe the type of media used in the growth of microbes?

The most common growth media for microorganisms are nutrient broths (liquid nutrient medium) or LB medium (lysogeny broth). Liquid media are often mixed with agar and poured via a sterile media dispenser into Petri dishes to solidify. These agar plates provide a solid medium on which microbes may be cultured.

Glycolysis

The oxidation of glucose to pyruvic acid with the production of some ATP and energy-containing NADH.

Photophosphorylation

The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis.

Sterilization

The process that completely destroys all microbial life, including spores.

Protonmotive Force

The proton motive force occurs when the cell membrane becomes energized due to electron transport reactions by the electron carriers embedded in it. Basically, this causes the cell to act like a tiny battery. Its energy can either be used right away to do work, like power flagella, or be stored for later in ATP.

Decarboxylation

The removal of CO2 from an amino acid

Deanimation

The removal of an amino group from an amino acid.

Oxidation

The removal of electrons (e-) from an atom or molecule, a reaction that often produces energy.

Krebs Cycle (Citric Acid Cycle)

The second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

Pyruvic Acid

The three-carbon compound that is produced during glycolysis and needed for both the aerobic and anaerobic pathways of cellular respiration that follow glycolysis.

Phosphorylation

The transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by _____. Organisms use three mechanisms of _____ to generate ATP from ADP.

How are microbes classified based on their use of oxygen? How can this be determined by growth?

Obligate aerobes - Require oxygen, Have no fermentative pathways. Generally produce superoxide dismutase Microaerophilic - Requires low but not full oxygen tension Facultative anaerobes - Will respire aerobically until oxygen is depleted and then ferment or respire anaerobically Obligate anaerobes - Lack superoxide dismutase. Generally lack catalase. Are fermenters. Can not use oxygen as terminal electron acceptor

Homolactic Fermentation

Organism that produces only lactic acid from fermentation ex: Streptococcus

Autotrophs

Organisms that are able to make their own food

Chemotrophs

Organisms that get energy from chemicals taken from the environment

Heterolactic Fermentation

Organisms that produce lactic acid as well as other acids or alcohols and often use the pentose phosphate pathway.

Enzyme Classification

Oxidoreductase: oxidation-reduction, in which oxygen and hydrogen are gained or lost Transferase: transfer functional groups, such as amino group, acetyl group, or phosphate group Hydrolase: hydrolysis (addition of water) Lyase: removal of atoms without hydrolysis Isomerase: rearrangement of atoms within a molecule Ligase: joining of molecules; uses ATP

Oxidative Phosphorylation

Part of the electron transport chain. A process occurring in the mitochondria that results in the formation of ATP from the flow of electrons across the inner membrane to bind with oxygen.

Anabolism

Pathways of synthesis reactions in living organisms are collectively called anabolic reactions or _____. biosynthetic; endergonic ex: combining of sugar molecules to form starch and of amino acids to form proteins

What is phosphorylation? Why is it important?

Phosphorylation is the addition of a phosphoryl group (PO3)− to a molecule. Oftentimes refers to ADP becoming ATP. It is important because Phosphorylation is the most common mechanism of regulating protein function and transmitting signals throughout the cell.

What happens when an enzyme is denatured?

They are no longer active and cannot function.

What are the major elements required for microbial growth, and how are they used by cells?

Warmth, moisture, pH levels and oxygen levels are the four big physical and chemical factors affecting microbial growth.

Fermentation

Releases energy from sugars or other organic molecules O2 is not required Two ATP molecules are produced by substrate-level phosphorylation Electrons removed from the substrate reduce NAD+ The final electron acceptor is a substance from inside the cell In lactic acid _____, pyruvic acid is reduced by NADH to lactic acid In alcohol _____, acetaldehyde is reduced by NADH to produce ethanol Heterolactic _____ can use the pentose phosphate pathway to produce lactic acid and ethanol

Antisepsis

Removing pathogens from living tissue

Anaerobic Respiration

Respiration that does not require oxygen

Aerobic Respiration

Respiration that requires oxygen

What is the purpose of using streak plates and pour plates?

Streak plates are used to isolate pure cultures. Pour plates can be used to determine the number of microbes/mL in a specimen.

3 General ways phosphorylation can occur

Substrate-Level Phosphorylatioin Oxidative Phosphorylation Photophosphorylation

Physical Growth Requirements

Temperature, pH, and osmostic pressure The minimum growth temperature is the lowest temperature at which a species will grow, the optimum growth temperature is the temperature the temperature at which it grows best, and the maximum growth temperature is the highest temperature at which growth is possible. Most bacteria grow best at a pH value between 6.5 and 7.5. In a hypertonic solution, most microbes undergo plasmolysis; halophiles can tolerate high salt concentrations.

Metabolism

The buildup and breakdown of nutrients within a cell. Two key players in metabolism are ENZYMES and ATP (adenosine triphosphate)

What is the difference between aerobic and anaerobic respiration?

The difference between aerobic and anaerobic respiration is that aerobic respiration requires oxygen while anaerobic respiration does not.

Acetyl CoA

The entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme.

ATP Synthase

The enzyme that catalyzes the reaction that adds a high-energy phosphate group to ADP which forms ATP

Reduction

The gain of one or more elections

Allosteric Inhibition

The inhibitor binds to a site other than the substrates binding site (the Allosteric Site).

ATP (energy coupling)

When complex molecules are split apart (catabolism), some of the energy is transferred to and trapped in ATP, and the rest is given off as heat. When simple molecules are combined to form complex molecules (anabolism), ATP provides the energy for synthesis, and again some energy is given off as heat.

Enzyme

_____ catalyze reactions for specific molecules called substrates. _____, which are generally proteins, may need other nonprotein molecules called cofactors to work.

Competitive Inhibition

_____ is a process by which a chemical substance has a shape that fits the active site of an enzyme and competes with the substrate, effectively inhibiting the enzyme.

Feedback Inhibition

_____ occurs when the end-product of a metabolic pathway inhibits an enzyme's activity near the start of the pathway A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

Lyophilization

a combination of freezing and drying; used to preserve microorganisms and other cells in a viable state for many years

-stasis

a period or state of inactivity or equilibrium.

Which of the following statements are TRUE? 1-Electron carriers are located at ribosomes. 2-ATP is a common intermediate between catabolic and anabolic pathways. 3-ATP is used for the long-term storage of energy and so is often found in storage granules. 4-Anaerobic organisms are capable of generating ATP via respiration. 5-ATP can be generated by the flow of protons across protein channels. a) 2, 4, 5 b) 2, 3, 5 c) 1, 3, 4 d) 1, 2, 3 e) All of the statements are true.

a) 2, 4, 5

You count 50 colony-forming units on the fourth plate that corresponds to the 10-4 dilution tube. How many bacteria would you estimate to be in the original sample? a) 5 x 10^5 bacteria per mL b) 5 x 10^5 bacteria total c) 50,000 bacteria per mL d) 50 x 10^-4 bacteria per mL

a) 5 x 10^5 bacteria per mL

For which of the following types of microbes would a microbiologist employ living host cells to support their growth? a) obligate intracellular organisms, such as chlamydia and viruses b) Campylobacteria sp. c) normal skin bacteria d) capnophiles

a) obligate intracellular organisms, such as chlamydia and viruses These organisms cannot grow on media but require living host cells when cultured.

If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar? a) pressure cooker at 121°C for 15 minutes b) hydrogen peroxide c) oven at 121°C for one hour d) boiling for one hour e) bleach

a) pressure cooker at 121°C for 15 minutes

In the Gram stain, the purpose of the ethanol decolorizer is to _______. a) remove the stain from Gram-negative cells b) stain Gram-positive cells c) disinfect the slide d) kill bacteria e) stain Gram-negative cells

a) remove the stain from Gram-negative cells

Selective media can be useful in isolating bacteria. Mannitol salt agar is selective because of its __________. a) salt content b) phenol red c) sugar content d) mannitol e) pH

a) salt content

An agar that uses a high salt concentration to limit the growth of one type of bacteria over another would be considered __________. a) selective b) differential

a) selective

An agar that uses the dye in crystal violet agar suppresses the growth of Gram-positive bacteria. This agar would be considered ______________. a) selective b) differential

a) selective

Bile salts in MacConkey agar allow for the agar to be _______ for the growth of enteric Gram-negative bacteria over Gram-positive bacteria. a) selective b) differential

a) selective

Consider a culture medium on which only gram-positive organisms such as Staphylococcus aureus colonies can grow due to an elevated NaCl level. A yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the pH as a result and changing the color of a pH indicator chemical. This type of medium would be referred to as a(n) a) selective and differential medium. b) differential medium. c) enrichment culture. d) differential and enrichment culture. e) selective medium.

a) selective and differential medium.

Which of the following pairs of microbe classification terms and optimal growth temperatures is mismatched? a) thermophile growth at 37°C b) psychrotroph growth at 22°C c) mesophile growth at 37°C d) psychrophile growth at 12°C e) hyperthermophiles growth at 95°C

a) thermophile growth at 37°C

When microbial control methods are used, microbes are destroyed at a constant rate; there is no instantaneous death of all the microbes present. That microbial death rate is influenced by all of the following factors EXCEPT __________. a) toxins produced by the microbe b) the time of exposure c) the number of microbes d) the microbial characteristics

a) toxins produced by the microbe

Disinfectant

any chemical agent used to destroy or inhibit the growth of harmful organisms

Which of the following is the best definition of oxidative phosphorylation? a) ATP is directly transferred from a substrate to ADP. b) A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP. c) Electrons are passed through a series of carriers to O2. d) Electrons are passed through a series of carriers to an organic compound.

b) A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP.

Which of the following regarding antimicrobial control agents is FALSE? a) Some agents kill by denaturing microbial cell proteins. b) A true antimicrobial control agent is equally effective against both bacteria and viruses. c) Some agents affect microbial cell membranes by dissolving lipids. d) Contaminating organic debris such as blood or sputum will decrease effectiveness. e)Some agents are utilized as both an antiseptic and a disinfectant.

b) A true antimicrobial control agent is equally effective against both bacteria and viruses.

Which of the following regarding antimicrobial control agents is FALSE? a) Some agents kill by denaturing microbial cell proteins. b) Alcohols effectively inactivate nonenveloped viruses by attacking lipids. c) Silver is used for treating antibiotic-resistant bacteria. d) Contaminating organic debris such as blood or sputum decrease effectiveness. e) Some agents affect microbial cell membranes by dissolving lipids.

b) Alcohols effectively inactivate nonenveloped viruses by attacking lipids.

Which of the following statements regarding metabolism is FALSE? a) Heat may be released in both anabolic and catabolic reactions. b) Anabolic reactions are degradative. c) ATP is formed in catabolic reactions. d) ADP is formed in anabolic reactions.

b) Anabolic reactions are degradative.

Glucose is broken down into two pyrucates. a) Anabolic Reaction b) Catabolic Reaction

b) Catabolic Reaction

Starches are digested into individual glucose molecules. a) Anabolic Reaction b) Catabolic Reaction

b) Catabolic Reaction

Where does the energy required for anabolic reactions come from? a) Heat b) Catabolic reactions c) Unused energy from metabolism

b) Catabolic reactions

How would a noncompetitive inhibitor interfere with a reaction involving the enzyme shown in the figure? a) It would bind to a. b) It would bind to b. c) It would bind to c. d) It would bind to d. e) The answer cannot be determined based on the information provided.

b) It would bind to b.

Which of the following statements is FALSE regarding the oxidation of proteins? a) After deamination of the protein, the organic acid enters the Krebs cycle. b) Microbes produce extracellular enzymes to reduce proteins to their fatty acid and glycerol components so that each component can enter the Krebs cycle. c) The amino group is removed through deamination and converted to nitrogenous waste, such as NH4+. d) Enzymes break down proteins into component amino acids.

b) Microbes produce extracellular enzymes to reduce proteins to their fatty acid and glycerol components so that each component can enter the Krebs cycle.

After Gram-staining a sample of Gram-negative bacteria, all the cells appear purple. What is the best explanation for this result? a) Not enough iodine was used. b) Not enough alcohol was used. c) Not enough safranin was used. d) Not enough crystal violet was used. e) The Gram-stain was properly prepared, and the color of this bacterial sample should be purple

b) Not enough alcohol was used.

Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol. The yeasts are growing well on the maltose medium but are not producing alcohol. What is the most likely explanation? a) The temperature is too low. b) O2 is in the medium. c) Not enough protein is provided. d) The temperature is too high. e) The maltose is toxic.

b) O2 is in the medium.

A bacterium with increased cholesterol in its cytoplasmic membrane to maintain membrane fluidity at extremely low temperatures would probably fall in the ______________class of bacteria. Psychrophile a) Mesophile b) Psychrophile c) Thermophile

b) Psychrophile

Thirty-six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample? a) 9 per milliliter b)18 per milliliter c) 36 per milliliter d) 72 per milliliter e)4 per milliliter

c) 36 per milliliter

In the pour-plate technique, 63 colonies were found on the plate where 1ml of a 1:100,000 dilution was plated. How many colony-forming units per ml were there? a) 6.3 x 10^4 CFU/ml b) 6.3 x 10^5 CFU/ml c) 6.3 x 10^6 CFU/ml d) 6.3 x 10^7 CFU/ml e) 6.3 x 10^8 CFU/ml

c) 6.3 x 10^6 CFU/ml

After performing a Gram stain, both purple cocci and red rods are observed. What is the best explanation for this observation? a) The culture used was too old. b) The alcohol was not left on long enough. c) A mixed-culture was Gram-stained. d) The alcohol was left on for too long. e) The cells were distorted by the fixing process.

c) A mixed-culture was Gram-stained.

Why do all enzymatic reactions need activation energy? a) Energy is required by an enzyme so that it can be reused. b) Energy allows only the substrate to bind. c) Energy is required to disrupt a substrate's stable electron configuration. d) Energy is needed for the enzyme to find its substrate.

c) Energy is required to disrupt a substrate's stable electron configuration.

What is meant by the statement "Enzymes are biological catalysts"? a) Enzymes produce biological organisms. b) Enzymes are products of biological systems. c) Enzymes speed up the chemical reactions in living cells. d) Enzymes produce products useful for biology.

c) Enzymes speed up the chemical reactions in living cells.

Which of the following is a limitation of the autoclave? a) It cannot kill endospores. b) It requires an excessively long time to achieve sterilization. c) It cannot be used with heat-labile materials. d) It cannot inactivate viruses. e) It cannot be used with glassware.

c) It cannot be used with heat-labile materials.

Which of the following statements about photophosphorylation is FALSE? a) Light liberates an electron from chlorophyll. b) Energy from oxidation reactions is used to generate ATP from ADP. c) It requires CO2. d) It occurs in photosynthesizing cells. e) The oxidation of carrier molecules releases energy.

c) It requires CO2.

Which of the following is an example of an acid-fast pathogen? a) Escherichia coli b) Streptococcus pyogenes c) Mycobacterium leprae d) Candida albicans e) Staphylococcus aureus

c) Mycobacterium leprae

Why are acid-fast bacteria difficult to stain? a) Their cell walls are composed of peptidoglycan. b) They are pathogenic. c) Their cell walls contain a mycolic acid lipid. d) Their cell walls contain carbohydrates. e) They have an outer member.

c) Their cell walls contain a mycolic acid lipid.

The _________ bacteria have evolved to grow and excel in temperatures that denature most protein and kill most organisms. a) Mesophile b) Psychrophile c) Thermophile

c) Thermophile

In one hospital, Pseudomonas aeruginosa serotype 10 infected the biliary tract of 10 percent of 1300 patients who underwent gastrointestinal endoscopic procedures. After each use, endoscopes were washed with an automatic reprocessor that flushed detergent and glutaraldehyde through the endoscopes, followed by a tap water rinse. P. aeruginosa serotype 10 was not isolated from the detergent, glutaraldehyde, or tap water. What was the source of the infections? a) bacterial cell walls in the water b) contaminated disinfectant c) a biofilm in the reprocessor d) fecal contamination of the bile ducts e) None of the answers is correct.

c) a biofilm in the reprocessor

Which of the following does NOT describe a colony? a) a visible growth on a streak plate b) an outcome on a successful streak plate c) a mixture of microbes in an environment d) used to develop a pure culture e) one kind of bacterium

c) a mixture of microbes in an environment

Which of the following terms refers to pathways that can function both in anabolism and catabolism? a) chemiosmotic pathways b) homolactic fermentation pathways c) amphibolic pathways d) light-dependent pathways

c) amphibolic pathways

The reactions involved in producing larger compounds from smaller compounds is called a) catabolism. b) metabolism. c) anabolism.

c) anabolism.

Which of the following pairs of terms is mismatched? a) fungicide kills yeasts and molds b) sterilant destroys all living microorganisms c) bacteriostatic kills vegetative bacterial cells d) germicide kills microbes e) virucide inactivates viruses

c) bacteriostatic kills vegetative bacterial cells

Sterilize your loop __________. a) after fixing the smear b) before transferring bacteria c) before and after transferring bacteria d) after picking up bacteria but before putting them on the slide e) after transferring bacteria

c) before and after transferring bacteria

Which biochemical process is NOT used during glycolysis? a) substrate-level phosphorylation b) enzymatic reactions c) beta oxidation d) oxidation-reduction e) carbohydrate catabolism

c) beta oxidation

Dyes such as phenol red or methylene blue are used in culture media to __________. a) inhibit motility b) see microbes c) detect pH changes due to metabolism d) stain microbes e) kill bacteria

c) detect pH changes due to metabolism

Which of the following is an advantage of the standard plate count? a) can be performed on very dilute samples, such as lake water b) provides immediate results c) determines the number of viable cells d) can be used to count heat-sensitive bacteria e) can readily count cells that form aggregates

c) determines the number of viable cells

In the streak-plate technique, the intent is to isolate bacteria by dilution in theory by __________. a) using a pipette b) dilution in water blanks c) dilution on a solid surface d) separating cells within the solid surface

c) dilution on a solid surface

The term aerotolerant anaerobe refers to an organism that a) requires less oxygen than is present in air. b) is killed by oxygen. c) does not use oxygen but tolerates it. d) tolerates normal atmospheric nitrogen gas levels. e) requires more oxygen than is present in air.

c) does not use oxygen but tolerates it.

Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt? a) anaerobes b) hyperthermophiles c) facultative halophiles d) thermophiles e) psychrophiles

c) facultative halophiles

Which of the following methods used to count microbes is correctly identified as direct or indirect? a) plate count--indirect measurement b) dry weight--direct measurement c) filtration--direct method d) turbidity--direct method

c) filtration--direct method A specific volume of fluid is filtered through a membrane, which is then placed on media and allowed to grow, representing a direct count of the viable cells

Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes? a) pasteurization c) freezing d) nonionizing radiation e) ionizing radiation f) lyophilization

c) freezing

A ribosome of a eukcaryotic cell differs from the ribosome of a prokaryotic cell in that only the eukaryotic cell: a) forms polyribosomes b) is 70s in size c) functions in protein synthesis d) is found on intracellular membranes e) is found free in the cytoplasm

c) functions in protein synthesis

Which stain is used to distinguish differences between the cell walls of medically important bacteria? a) simple stain b) acridine orange c) gram stain d) negative stain e) Sudan black stain

c) gram stain

Malachite green and safranin are used in the endospore stain. The endospores will be __________. a) colorless b) black c) green d) green and red e) red

c) green

Salts and sugars work to preserve foods by creating a a) hypotonic environment. b) depletion of nutrients. c) hypertonic environment. d) lower pH. e) lower osmotic pressure.

c) hypertonic environment

Which of the following microbial diseases can be diagnosed using the acid-fast stain? a) AIDS and measles b) strep throat and endocarditis c) leprosy and tuberculosis d) cholera and dysentery e) bubonic plague and influenza

c) leprosy and tuberculosis

Which of the following phases of the bacterial growth curve is matched with the correct definition? a) lag phase--the phase in which the death of organisms exceeds the creation of new cells and the curve declines b) stationary phase--the phase in which cells are not dividing very rapidly as they acclimatize to a new environment c) log phase--the phase in which organisms are actively dividing and the generation time is constant d) death phase--the phase in which the curve is flat; microbial deaths balance the number of new cells

c) log phase--the phase in which organisms are actively dividing and the generation time is constant This is the steep upward slope of the bacterial growth curve, where organisms are rapidly multiplying.

Which of the following media are NOT selective or differential? a) MSA media b) EMB media c) nutrient agar d) None of these are both selective and differential media. e) All of these are both selective and differential media.

c) nutrient agar

Which of the following is NOT necessary for respiration? a) quinones b) flavoproteins c) oxygen d) cytochromes e) a source of electrons

c) oxygen

Cyanobacteria are a type of a) chemoautotroph. b) chemoheterotroph. c) photoautotroph. d) photoheterotroph.

c) photoautotroph.

After Gram staining, a gram-negative cell will be _______. a) colorless b) purple c) red d) brown e) green

c) red

In the acid-fast stain, after being stained with carbolfuchsin, all cells will be __________. a) blue b) colorless c) red d) brown e) green

c) red

Which process is best for the short-term storage of bacterial cultures? a) lyophilization b) deep-freezing c) refrigeration d)freeze-drying

c) refrigeration Refrigeration is the best short-term storage method for microbes. Refrigeration slows down metabolic activity, but the microbes can be quickly revived at optimum temperatures.

Which of the following is an advantage of the direct microscopic count? a) requires a large number of cells b) can easily distinguish live from dead cells c) requires no incubation time d) can readily count organisms that are motile e) sample volume is unknown

c) requires no incubation time

The antimicrobial activity of chlorine is due to which of the following? a) the formation of ozone b) the formation of a hypochlorite ion c) the formation of hypochlorous acid d) disruption of the plasma membrane e) the formation of hydrochloric acid

c) the formation of hypochlorous acid

Which of the following is the best definition of fermentation? a) the production of energy by both substrate and oxidative phosphorylation b) the complete catabolism of glucose to CO2 and H2O c) the partial oxidation of glucose with organic molecules serving as electron acceptors d) the partial reduction of glucose to pyruvic acid e) the production of energy by oxidative-level phosphorylation

c) the partial oxidation of glucose with organic molecules serving as electron acceptors

Assume you inoculated 100 cells, with a generation time of 20 minutes, into 100 ml of nutrient broth. You then inoculated 100 cells of the same species into 200 ml of nutrient broth. After incubation for 4 hours, you can reasonably expect to have a) more cells in the 200 ml. b) more cells in the 100 ml. c) the same number of cells in both. d) The answer cannot be determined based on the information provided.

c) the same number of cells in both.

Which of the following pairs is mismatched? a) plasma sterilization free radicals b) ionizing radiation hydroxyl radicals c) ultraviolet radiation desiccation d) ozone takes electrons from substances e) supercritical fluids CO2

c) ultraviolet radiation desiccation

Facultative Anaerobes

can live with or without oxygen

Aerotolerant Anaerobes

can tolerate oxygen and grow in its presence even though they cannot use it

Psycrophiles

cold loving microbes

Chemically Defined Media

composed of exact amounts of pure chemicals

How much will a culture be diluted if 1 ml of the cell suspension is added to 99 ml of diluent? a) 1:9.9 b) 1:10 c) 1:99 d) 1:100 e) 1:199

d) 1:100

Which of the following is true of anabolic reactions? a) Anabolic and catabolic reactions both build complex organic molecules from simpler ones; however, anabolic reactions use ATP, whereas catabolic reactions transfer energy to create ATP. b) Anabolic reactions produce energy, which is used to convert ADP to ATP. c) Anabolic reactions break down complex organic compounds into simpler ones. d) Anabolic reactions use ATP and small substrates as building blocks to synthesize larger molecules.

d) Anabolic reactions use ATP and small substrates as building blocks to synthesize larger molecules.

Which of the following matches enzyme components with their correct definition and/or function? a) Apoenzymes are typically inorganic molecules, such as iron, zinc, or magnesium. b) Apoenzymes are the non-protein component of an enzyme. c) Cofactors are the protein components of enzymes. d) Coenzymes are the organic cofactors important to enzyme activity.

d) Coenzymes are the organic cofactors important to enzyme activity.

Which of the following sequences arranges the steps of the Gram stain into the correct order? a) Crystal violet → Alcohol → Safranin → Iodine b) Safranin → Iodine → Alcohol → Crystal violet c) Crystal violet → Iodine → Safranin → Alcohol d) Crystal violet → Iodine → Alcohol → Safranin e) Iodine → Crystal violet → Alcohol → Safranin

d) Crystal violet → Iodine → Alcohol → Safranin

Which of the following best describes the pattern of microbial death? a) All the cells in a culture die at once. b) The pattern varies depending on the species. c) Not all of the cells in a culture are killed. d) The cells in a population die at a constant rate. e) The pattern varies depending on the antimicrobial agent.

d) The cells in a population die at a constant rate.

Microbes are often identified using biochemical tests that detect specific enzymes of metabolic pathways. E. coli typically ferments lactose, whereas Shigella does not. If a pure culture of each bacterium was placed in a tube containing lactose as the only food source, and a chemical indicator changed color after a pH change, what would the tubes look like after the bacteria were incubated? a) Both tubes would show the evidence of lactose fermentation by turning acidic and changing the pH indicator. b) Neither tube will show any change. c) Both tubes would show the evidence of lactose fermentation by turning alkaline. d) The tube with E. coli would indicate a pH change, and the Shigella tube would indicate no change.

d) The tube with E. coli would indicate a pH change, and the Shigella tube would indicate no change.

A capsule is located __________. a) just below the cell membrane b) inside the cell c) between the wall and the membrane d) around the outside of the cell, exterior to the cell wall

d) around the outside of the cell, exterior to the cell wall

Patients with indwelling catheters (long-term tubes inserted into body orifices for drainage, such as through the urethra and into the urinary bladder) are susceptible to infections because a) bacteria cause infections. b) their immune systems are weakened. c) infections can be transmitted from other people. d) biofilms develop on catheters. e) injected solutions are contaminated.

d) biofilms develop on catheters.

The purpose of acid alcohol in the acid-fast stain is to __________. a) stain Gram-negative cells b) disinfect the slide c) stain the cells d) decolorize non-acid-fast cells e) kill bacteria

d) decolorize non-acid-fast cells

Heat is used to make the stain enter the thick walls of __________. a) Gram-positive bacteria b) flagella c) cells with capsules d) endospores e) all bacteria

d) endospores

Which one of the following is most resistant to chemical biocides? a) gram-positive bacteria b) mycobacteria c) viruses with lipid envelopes d) gram-negative bacteria e) protozoan cysts

d) gram-negative bacteria

Ethylene oxide a) is a good antiseptic. b) is not sporicidal. c) requires high heat to be effective. d) is a sterilizing agent. e) is the active chemical in household bleach.

d) is a sterilizing agent.

The use of amino acids to make proteins a) involves the production of ATP. b) is an example of catabolism. c) is a completely efficient reaction. d) is an example of anabolism.

d) is an example of anabolism.

In metabolism, energy that is not used a) is used to break down large molecules into smaller ones. b) is stored in the form of ATP. c) is used to build up large compounds from smaller ones. d) is given off as heat.

d) is given off as heat.

Which of the following characteristics is NOT TRUE of a plasmid: a) it is a circular piece of DNA b) it can be transferred from cell to cell c) it is found in bacteria d) it is required for normal cell function

d) it is required for normal cell function

Microbial control methods usually target any of the following microbial structures EXCEPT which one? a) plasma membrane permeability b) microbial proteins c) nucleic acids d) mitochondria

d) mitochondria

What is the expected result from an acid-fast stain of sputum from a tuberculosis patient? a) red and blue cocci b) blue cocci c) blue bacilli d) red bacilli e) red cocci

d) red bacilli

In the acid-fast stain, the purpose of the methylene blue is to __________. a) disinfect the slide b) kill bacteria c) remove the stain from non acid-fast cells d) stain the acid-fast cells e) stain non-acid-fast cells

d) stain the acid-fast cells

Bone and tendons for transplant are decontaminated by a) peroxygens. b) glutaraldehyde. c) ethylene oxide. d) supercritical fluids. e) plasma sterilization.

d) supercritical fluids.

Identification of microorganisms by base ratio analysis would use: a) fermentation testing b) ability of the organism to digest complex nutrients c) presence of oxidase in the organism d) the C+G content of the organism

d) the C+G content of the organism

The organism that produces an exotoxin that allows the organism to invade previously healthy connective tissue is: a) Clostridium tetany b) Clostridium botulinum c) Clostridium difficile d) the agent that causes gas gangrene e) the agent that causes anthrax

d) the agent that causes gas gangrene

-cide

denoting a person or substance that kills

In the spread-plate technique, 120 colonies were found on the plate where 100 µl (0.1 ml) of a 1:100,000 dilution was plated. How many colony-forming units per ml were there? a) 1.2 x 10^4 CFU/ml b) 1.2 x 10^5 CFU/ml c) 1.2 x 10^6 CFU/ml d) 1.2 x 10^7 CFU/ml e) 1.2 x 10^8 CFU/ml

e) 1.2 x 10^8 CFU/ml

An experiment began with 4 cells and ended with 128 cells. How many generations did the cells go through? a) 64 b) 32 c) 6 d) 4 e) 5

e) 5

Most fungi grow best at pH a) 1 b) 7 c) 14 d) 9 e) 5

e) 5

Most bacteria grow best at pH a) 5 b) 14 c) 9 d) 1 e) 7

e) 7

Which concentration of ethanol is the most effective bactericide? a) 30 percent b) 40 percent c) 100 percent d) 50 percent e) 70 percent

e) 70 percent

If cells are grown in media containing amino acids labeled with radioactive nitrogen (15N), most of the radioactivity will be found in the cells' a) DNA. b) DNA and phospholipids. c) phospholipids. d) proteins. e) DNA and proteins.

e) DNA and proteins.

After the Gram stain, microbial cells appear as red rods. What is the best description of these cells? a) Gram-positive bacilli b) Gram-negative cocci c) Gram-positive cocci d) Gram-negative eukaryotes e) Gram-negative bacilli

e) Gram-negative bacilli

In noncyclic photophosphorylation, O2 is released from a) CO2. b) chlorophyll. c) C6H12O6. d) sunlight. e) H2O.

e) H2O.

Which of the following statements about anaerobic respiration is FALSE? a) Only part of the Krebs cycle is utilized. b) It requires cytochromes. c) It yields lower amounts of ATP when compared to aerobic respiration. d) It generates ATP. e) It involves the reduction of an organic final electron acceptor.

e) It involves the reduction of an organic final electron acceptor.

What is the fate of pyruvic acid in an organism that uses aerobic respiration? a) It is catabolized in glycolysis. b) It is reduced to lactic acid. c) It reacts with oxaloacetate to form citrate. d) It is oxidized in the electron transport chain. e) It is converted into acetyl CoA.

e) It is converted into acetyl CoA.

All of the following factors contribute to hospital-acquired infections EXCEPT a) invasive procedures can provide a portal of entry for bacteria. b) some bacteria metabolize disinfectants. c)gram-negative bacteria are often resistant to disinfectants. d) bacteria may be present in commercial products such as mouthwash. e) None of the answers is correct; all of these factors may contribute to hospital-acquired infection.

e) None of the answers is correct; all of these factors may contribute to hospital-acquired infection.

After Gram-staining a sample of Gram-positive bacteria, all the cells appear red. What is the best explanation for this result? a) The iodine was left on too long. b) The crystal violet was left on too long. c) The Gram-stain was properly prepared, and the color of this bacterial sample should be red. d) The safranin was left on too long. e) The alcohol was left on too long.

e) The alcohol was left on too long.

In order to improve resolution, one can: a) use immersion oil b) increase the amount of light c) increase the wave length of light d) use UV light e) both A and B f) both A and C g) both A and D

e) both A and B

A strictly fermentative bacterium produces energy a) only in the absence of oxygen. b) only in the presence of oxygen. c) by aerobic respiration only. d) by fermentation or aerobic respiration. e) by glycolysis only.

e) by glycolysis only.

An unwanted organism in a streak plate is called a(n) __________. a) pathogen b) virus c) colony d) outlier e) contaminant

e) contaminant

Which of the following is an example of a metabolic activity that could be used to measure microbial growth? a) most probable number (MPN) b) standard plate count c) turbidity d) direct microscopic count e) glucose consumption

e) glucose consumption

All of the following are methods of food preservation EXCEPT a) desiccation. b) osmotic pressure. c) high pressure. d) ionizing radiation. e) microwaves.

e) microwaves.

What term best describes a microbial cell with a single flagellum at one end? a) non-motile b) amphitrichous c) peritrichous d) lophotrichous e) monotrichous

e) monotrichous

The acid-fast stain is used to identify __________. a) prokaryotic and eukaryotic cells b) rod-shaped cells c) most bacterial cells d) Gram-positive and Gram-negative cells e) mycobacteria

e) mycobacteria

Which of the following does NOT achieve sterilization? a) ethylene oxide b) supercritical fluids c) dry heat d) autoclave e) pasteurization

e) pasteurization

In the Gram stain, after staining with crystal violet, all cells will be _______. a) colorless b) green c) brown d) red e) purple

e) purple

Which of the following is the best definition of generation time? a) the duration of log phase b) the minimum rate of doubling c) the time needed for nuclear division d) the length of time needed for lag phase e) the length of time needed for a cell to divide

e) the length of time needed for a cell to divide

Complex Media

extracts and digests of yeasts, meat, or plants

Sanitation

maintaining a clean condition in order to promote hygiene and prevent disease

Inoculum

microbes that are introduced into a culture medium to initiate growth

Mesophiles

moderate temperature loving microbes

Obligate Anaerobes

organisms that cannot live where molecular oxygen is present

Phototrophs

organisms that get energy from light

Degerming

removal of microbes from a limited area

Obilgate Aerobes

require oxygen to survive

What are toxic forms of oxygen? What ways do microbes protect themselves from these substances?

singlet oxygen superoxide radical peroxide anion hydroxyl radical Organisms protect themselves form toxic forms of oxygen by the use of antioxidants, vitamins C and E. These antioxidants provide electrons that reduce toxic forms of oxygen.

Antiseptic

substance that prevents infection

Commercial Sterilization

sufficient heat treatment to kill endospores of Clostridium botulinum in canned food

Selective Media

suppress growth of unwanted bacteria and encourage growth of desired microbes

Dehydrogenation

the loss of hydrogen atoms from a substrate

Generation Time

the time required for the bacterial population to double in cell number

sepsis

toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection

A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained a) 54,000 cells per milliliter. b) 5,400 cells per milliliter. c) 540 cells per milliliter. d) 540,000 cells per milliliter. e) 54 cells per milliliter.

54,000 cells per milliliter.

NAD (Nicotinamide Adenine Dinucleotide)

A coenzyme present in all cells that helps enzymes transfer electrons during the redox reactions of metabolism.

Chemical Sterilants

-paracetic acid 0.2% -acetic acid -formaldehyde -glutaraldehyde -hypochlorous acid

What is the mechanism and function of feedback inhibition?

.This mechanism stops the cell from making more of a substance than it needs and thereby wasting chemical resources. Generally acts on the first enzyme in a metabolic pathway (similar to shutting down an assembly line by stopping the first worker).

Substrate Level Phsophorylation

ATP formed by transferring a phosphate group directly to ADP from a substrate.

Chemiosmosis

ATP synthesis using the electron transport chain. It involves oxidative phosphorlyation.

Microaerophiles

Aerobes that require Oxygen levels from 2-10% and have a limited ability to detoxify Hydrogen Peroxide and Superoxide Radicals

In what ways can the activity of enzymes be affected and controlled?

At high temperatures, enzymes undergo denaturation and lose their catalytic properties; at low temperatures, the reaction rate decreases. The pH at which enzymatic activity is maximal is known as the optimum pH. Enzymatic activity increases as substrate concentration increases until the enzymes are saturated. Competitive inhibitors compete with the normal substrate for the active site of the enzyme. Noncompetitive inhibitors act on other parts of the apoenzyme or on the cofactor and decrease the enzyme's ability to combine with the normal substrate.

Chemical Growth Requirement

Carbon Nitrogen, sulfur, and phosphorus: Nitrogen, sulfur, and phosphorus Trace elements Vitamins and amino acids Oxygen

CO2 Fixation

Carbon fixation or сarbon assimilation is the conversion process of inorganic carbon (carbon dioxide) to organic compounds by living organisms. (photosynthesis)

Catabolism

Decomposition reactions that occur in living organisms are collectively called catabolic reactions or _____. degradative;exergonic ex: the breakdown of sucrose (table sugar) into simpler sugars, glucose and fructose, during digestion

How do we describe the pattern of death of microorganisms?

Depends on the... - Number of microbes - Environment (organic matter, temperature, biofilms) - Time of exposure - Microbial characteristics

Any process that destroys the non-spore forming contaminants on inanimate objects is sterilization. True/False

False

Desiccation is a reliable form of sterilization. True/False

False

Most pathogenic bacteria are thermophiles. True/False

False

The pH of the medium has no effect on the activity of the disinfectant being applied. True/False

False

The use of enzymes is necessary to increase the activation energy requirements of a chemical reaction. True/False

False

What important process is achieved in both fermentation and respiration?

Fermentation and cellular respiration are alike in that they both begin with a series of reactions known as glycolysis, which breaks glucose molecules into smaller pyruvate molecules. They are also similar in that during both processes, ATP is produced for the cell to use.

What happens in fermentation and how is it different from respiration? (Where do we get the most energy?)

Fermentation releases energy from sugars or other organic molecules by oxidation. It is different from respiration because O2 is not required in fermentation. We get most energy from respiration.

Describe the two uses of filtration

Filtration is the passage of liquid or gas through a filter with pores small enough to retain microbes. Microbes an be removed from air by high-efficiency particulate air (HEPA) filters. Membrane filters composed of cellulose esters are commonly used to filter out bacteria, viruses, and even large proteins.

What is glycolysis and where does it occur in the cell? What are the starting products, and what are the final products?

Glycolysis is the oxidation of glucose to pyruvic acid with the production of some ATP and energy containing NADH. The most common pathway for the oxidation of glucose. Pyruvic acid is the end-product. Glycolysis yields two ATP and two NADH molecules are produced from one glucose molecule. It occurs in the cytoplasm.

Describe the differences between ionizing and non-ionizing radiation. What are the uses of each?

Ionizing radiation - gamma rays, x rays, electron beams - it ionizes water, which forms hydroxyl radicals, and these react with the DNA and damages it Nonionizing radiation - UV light - the UV light damages the DNA

Describe the four phases of growth

Lag phase, log phase, stationary phase, and death phase. Lag phase is where there is little or no change in the number of cells, but metabolic activity is high. Log phase is where the bacteria multiply at the fastest rate possible under the conditions provided. Stationary phase is where there is an equilibrium between cell division and death. Death phase is where the number of deaths exceeds the number of new cells formed

What methods are used to preserve/store microbes?

Microbes can be stored in a refrigerator for short term storage. Deep freezing and freeze drying are used for long term storing.

Capnophiles

Microbes that grow better at high CO2 concentrations

A mordant is used to make bacterial flagella wider and thus easier to see. True/False

True

Agar is used as a solidifying agent in microbiological media since few bacteria can degrade it. True/False

True

Agars can be used to select for growth of certain types of bacteria and then allow for you to identify the different bacteria that can grow on the plate. These agars may be considered both selective and differential. True/False

True

An isolated colony on a streak plate contains millions (or even billions) of identical cells all arising from one initial cell. True/False

True

Autoclaving is the most effective method of moist heat sterilization. True/False

True

Bacterial growth refers to an increase in the numbers of cells in a bacterial culture. True/False

True

Carbon fixation occurs during the light-independent phase of photosynthesis. True/False

True

Catabolic reactions are generally degradative and hydrolytic. True/False

True

Endospores are hard to stain. True/Fals

True

Filtration methods, followed by growth of the bacteria trapped on the filters in growth media, are used to count bacteria present in very low concentrations, such as in lakes and streams. True/False

True

Glycolysis is utilized by cells in both respiration and fermentation. True/False

True

In general, ATP is generated in catabolic pathways and expended in anabolic pathways. True/False

True

Pseudomonas has been found growing in quaternary ammonium compounds (quats). True/False

True

Which of the following is true of aerobic respiration compared to anaerobic respiration? a) Aerobic respiration uses oxygen as a final electron acceptor, whereas anaerobic respiration uses an inorganic molecule other than oxygen as the final electron acceptor. b) Aerobic respiration uses oxygen as a final electron acceptor, whereas anaerobic respiration uses an organic molecule. c) Aerobic respiration is less efficient than all forms of anaerobic respiration, producing less ATP and larger end-products. d) Aerobic respiration and anaerobic respiration both require oxygen as a final electron acceptor.

a) Aerobic respiration uses oxygen as a final electron acceptor, whereas anaerobic respiration uses an inorganic molecule other than oxygen as the final electron acceptor.

A uracil base is added to an mRNA strand by RNA polymerase. a) Anabolic Reaction b) Catabolic Reaction

a) Anabolic Reaction

Ammonia is added to glutamate to form glutamine. Anabolic a) Anabolic Reaction b) Catabolic Reaction

a) Anabolic Reaction

Four amino acids are linked together to form a tetrapeptide. a) Anabolic Reaction b) Catabolic Reaction

a) Anabolic Reaction

Ribose and inorganic phosphate are bonded to form a nuvleotide. a) Anabolic Reaction b) Catabolic Reaction

a) Anabolic Reaction

Why are enzymes important to biological systems? a) Enzymes decrease the amount of activation energy required for chemical reactions to occur. b) Enzymes prevent unwanted chemical by-products from forming. c) Enzymes are reuseable. d) Enzymes increase the energy barrier required of chemical reactions.

a) Enzymes decrease the amount of activation energy required for chemical reactions to occur.

A bacterium that is a common cause of human infections but is also part of our microflora would have to be in the ____________class of bacteria. a) Mesophile b) Psychrophile c) Thermophile

a) Mesophile

Which of the following has a cell wall that is rich in lipids? a) Mycobacteria b) Mycoplasma c) speroplasts d) protoplasts e) none of the above because the cell wall is made of proteins

a) Mycobacteria

Which of the following statements correctly summarizes the enzymatic reactions to reactive oxygen species? a) Superoxide dismutase detoxifies superoxides and converts them into hydrogen peroxide and oxygen. Catalase then converts the hydrogen peroxide into water and oxygen. b) Superoxide dismutase detoxifies singlet oxygen and converts it into hydrogen peroxide and oxygen. Catalase then converts the hydrogen peroxide into water and oxygen. c) Superoxide dismutase detoxifies superoxides and converts them into hydrogen peroxide and oxygen. Catalase uses NADH to convert the hydrogen peroxide into water and NAD+. d) Superoxide dismutase detoxifies superoxides and converts them into water and oxygen. Catalase then converts the hydrogen peroxide into water and oxygen.

a) Superoxide dismutase detoxifies superoxides and converts them into hydrogen peroxide and oxygen. Catalase then converts the hydrogen peroxide into water and oxygen.

Contaminated hospital equipment represents a difficult environment to control harmful microbial growth. Regarding influences that affect disinfection of hospital equipment, which of the following is an accurate statement? a) The cell walls of gram-negative bacteria are especially resistant to many chemicals that are used destroy microbes. b) Antimicrobial agents work best under reduced temperatures. c) Biofilms, often found contaminating hospital equipment, are relatively simple targets for biocides to reach effectively. d) The presence of organic matter, such as dried blood or protein, will not affect the action of antimicrobial agents.

a) The cell walls of gram-negative bacteria are especially resistant to many chemicals that are used destroy microbes.

Which of the following techniques is NOT used to isolate bacteria and develop a pure culture? a) a mixed broth culture tube b) streak-plate technique c) pour-plate technique d) spread-plate technique e) None of the listed responses is correct.

a) a mixed broth culture tube

Acid-fast refers to cells that __________. a) are not decolorized by acid alcohol b) tolerate alkaline conditions c) survive in acid d) appear purple e) produce acids by fermentation

a) are not decolorized by acid alcohol

Which enzyme catalyzes the reaction: 2H2O2 → 2H2O + O2? a) catalase b) oxidase c) peroxidase d) superoxide dismutase

a) catalase

Which of the following uses CO2 for carbon and H2 for energy? a) chemoautotroph b) chemoheterotroph c) photoautotroph d) photoheterotroph

a) chemoautotroph

Congo red and acid fuchsin are used in the capsule stain. The capsules will be __________. a) colorless b) pink c) black d) green e) red

a) colorless

An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n) a) disinfectant. b) fungicide. c) antiseptic. d) aseptic. e) virucide.

a) disinfectant.

A medically important organism that is described as fastidious would be grown on: a) enriched medium b) selective media c) differential media d) general purpose media

a) enriched medium

The process of cellular differentiation that produces a vegetative cell from an endospore is known as: a) germination b) common among the bacilli c) sporogenesis d) common among the cocci

a) germination

Oxidizing agents include all of the following EXCEPT a) glutaraldehyde. b) hydrogen peroxide. c) iodine. d) ozone. e) chlorine.

a) glutaraldehyde.

Streak plates are useful in microbiology to __________. a) isolate bacteria and develop pure cultures b) quantify the number of bacteria c) measure turbidity d) determine cell shape e) identify bacteria

a) isolate bacteria and develop pure cultures

Which of the following is NOT a direct method to measure microbial growth? a) metabolic activity b) most probable number (MPN) c) direct microscopic count d) filtration on a support membrane followed by incubation on medium e) standard plate count

a) metabolic activity

What aspects of biofilm formation and the interaction of bacteria within the biofilm would allow for the survival of the bacteria in the presence of the sanitizing solutions? a) The interaction of the bacteria within the biofilm mimics that seen in eukaryotic tissues and allows the cells have specific roles. b) Quorum sensing within the biofilm allows bacteria to respond to other bacteria and alter their enzyme expression. c) Formation of a biofilm may allow for the survival of the bacteria that are at the base of the biofilm, farthest away from any chemicals found within the environment. d) The matrix of the biofilm aids in retention of nutrients and sequestration of the bacteria from environmental stresses such as chemical sanitizers.

b) Quorum sensing within the biofilm allows bacteria to respond to other bacteria and alter their enzyme expression. c) Formation of a biofilm may allow for the survival of the bacteria that are at the base of the biofilm, farthest away from any chemicals found within the environment. d) The matrix of the biofilm aids in retention of nutrients and sequestration of the bacteria from environmental stresses such as chemical sanitizers.

Motility can be determined by all of the following EXCEPT __________. a) a flagella stain b) a Gram stain c) a semisolid agar deep d) a hanging drop e) a wet mount

b) a Gram stain

A Gram stain is done on _______. a) all types of cells b) a heat-fixed smear of bacteria c) only Gram-negative bacteria d) live bacteria e) only Gram-positive bacteria

b) a heat-fixed smear of bacteria

The purpose of iodine in the Gram stain is to _______. a) disinfect the slide b) act as a mordant and form a large complex with crystal violet c) kill bacteria d) stain Gram-negative cells e) stain the cells

b) act as a mordant and form a large complex with crystal violet

The main advantage of a spread plate over a streak plate is that the spread plate __________. a) requires fewer reagents b) allows for the calculation of cell numbers c) is much faster d) gives isolated colonies e) allows more types of microbes to be cultured

b) allows for the calculation of cell numbers

Most bacteria reproduce by a) aerial hyphae. b) binary fission. c) fragmentation. d) budding. e) mitosis.

b) binary fission.

Which of the following uses glucose for carbon and energy? a) chemoautotroph b) chemoheterotroph c) photoautotroph d) photoheterotroph

b) chemoheterotroph

Which of the following compounds is NOT an enzyme? a) sucrase b) coenzyme A c) dehydrogenase d) β-galactosidase e) cellulase

b) coenzyme A

A culture medium consisting of agar, peptone, and beef heart is a a) differential medium. b) complex medium. c) chemically defined medium. d) selective medium. e) reducing medium.

b) complex medium.

The following reagents are used in the Gram stain. Which reagent is used in the first step? a) safranin b) crystal violet c) ethanol d) iodine e) They can be used in any order.

b) crystal violet

A blood agar plate contains sheep red blood cells and allows for the determination of hemolytic capabilities for all bacteria that grow on the agar. This would make this type of agar___________. a) selective b) differential

b) differential

An agar that allows for the distinction of bacteria based on metabolism would be considered _______________. a) selective b) differential

b) differential

EMB agar uses lactose and two dyes that allow it to be ___________ between the blue-black colonies of E. coli and the pinkish colonies of all other enteric bacteria. a) selective b) differential

b) differential

In cellular respiration of glucose, what are the three principal stages? a) chemiosmosis, photophosphorylation, and reduction b) glycolysis, Krebs cycle, and the electron transport chain c) fermentation, Krebs cycle, and electron transport chain d) Calvin-Benson cycle, electron transport chain, and glycolysis

b) glycolysis, Krebs cycle, and the electron transport chain

Surface-active agents act by decreasing surface tension so that microbes can be more easily removed. All of the following agents use this mechanism of action EXCEPT __________. a) quaternary ammonium compounds (quats) b) halogens c) soaps and detergents d) acid-anionic sanitizers

b) halogens

Bacteria tend to stain more readily with basic dyes because bacteria: a) contain large amounts of alkaline substances b) have cytoplasm that is packed with RNA c) are neutral d) have thick cell walls e) have a lot of lipids in the cell wall

b) have cytoplasm that is packed with RNA also contains a large amount of acidic substances

If some cells in a pure culture of Staphylococcus epidermidis stain blue, and some cells stain red, the bacteria are _______. a) Gram-negative b) impossible to determine because of a staining error c) lacking cell walls d) Gram-positive e) two-tone

b) impossible to determine because of a staining error

An iodophor is a(n) a) form of formaldehyde. b) iodine mixed with a surfactant. c) phenol. d) quaternary ammonium compound. e) agent that reduces oxygen.

b) iodine mixed with a surfactant.

Which of the following is the best method to sterilize heat-labile solutions? a) freezing b) membrane filtration c) autoclave d) dry heat e) pasteurization

b) membrane filtration

The source of nutrients in nutrient agar is a) peptone and NaCl. b) peptone and beef extract. c) gelatin. d) agar. e) agar and NaCl.

b) peptone and beef extract.

Which organism is NOT correctly matched to its energy source? a) chemoautotroph-NH3 b) photoautotroph - CO2 c) photoheterotroph - light d) chemoautotroph - Fe2+ e) chemoheterotroph - glucose

b) photoautotroph - CO2

In which of the following techniques will microbial colonies form within the actual agar of the plate? a) streak-plate b) pour-plate c) spread-plate d) all three of the listed techniques e) none of the listed techniques

b) pour-plate