Micro Final Tests

An organism that can exist in both oxygen and oxygen-free environments is a/an:

a) aerobe

b) obligate aerobe

c) facultative anaerobe

d) microaerophile

e) obligate anaerobe

c) facultative anaerobe

An organism that uses CO2 for its carbon needs and sunlight for its energy needs would be termed a:

a) photoautotroph

b) chemoheterotroph

c) photoheterotroph

d) chemoautotroph

a) photoautotroph

The term facultative refers to:

a) the ability to exist in a wide range of conditions

b) existing in a very narrow niche

c) using chemicals for energy production

d) using light for energy production

e) using oxygen for metabolism

a) the ability to exist in a wide range of conditions

You inoculate a bacterium into three tubes of nutrient broth medium containing added salt: 0.5% NaCl, 5% NaCl, 15%NaCl. After incubation, you notice significant turbidity in the 15% NaCl medium and modest turbidity in the 5% NaCl medium. There is no growth in the third tube. This organism would be termed:

a) psychrophilic

b) osmophobic

c) halophilic

d) barophilic

c) halophilic

Cultures of a bacterial species were incubated in several locations: a refrigerator, out on a lab benchtop, a 37C incubator, and in a 50C incubator. After incubation, there was no growth at 37C or 50C, slight growth out on the bench top and abundant growth at refrigeration. What term should be used for this species:

a) mesophile

b) thermophile

c) psychrophile

d) anaerobe

e) halophile

c) psychrophile

A microbiology student notices that a fluid thioglycolate medium (FTM) tube is very turbid at the bottom and clear throughout the rest of the tube. What should she conclude?

a) the broth is sterile

b) the organisms are microaerophilic

c) the organisms are facultative anaerobes

d) the organisms are aerobes

e) none of the above

e) none of the above

Bacteria that are able to grow in humans and cause disease would be classified as:

a) psychrophiles

b) mesophiles

c) thermophiles

d) hyperthermophiles

b) mesophiles

The cell wall will help prevent the cell from bursting in ______ conditions.

a) hypertonic

b) hypotonic

c) isotonic

d) mesotonic

b) hypotonic

Which of the following organisms would find hypotonic conditions the most damaging?

a) bacteria

b) algae

c) fungi

d) protists

d) protists

Diffusion of water through a semipermeable membrane is called:

a) endocytosis

b) diffusion

c) active transport

d) facilitated diffusion

e) osmosis

e) osmosis

Which of the following mechanisms can a cell use to transport a substance from an area of high concentration to an area of lower concentration:

a) facilitated diffusion

b) simple diffusion

c) osmosis

d) any of the above

d) any of the above

Bacteria living in a freshwater stream that are transferred to ocean water would:

a) be in an isotonic solution

b) be in a hypotonic solution

c) gain water

d) become dehydrated due to the loss of water

d) become dehydrated due to the loss of water

The term used to describe the sum of all chemical reactions within a cell is:

a) catabolism

b) redox reactions

c) phosphorylation

d) metabolism

e) cellular respiration

d) metabolism

Enzymes are:

a) broken down in reactions that require energy input

b) proteins that act as catalysts

c) used up in chemical reactions

d) not needed for catabolic reactions

b) proteins that act as catalysts

How is ATP generated in the reaction from ADP?

a) fermentation

b) photophosphorylation

c) oxidative phosphorylation

d) substrate-level phosphorylation

d) substrate-level phosphorylation

Which of the following statements about NAD+ is true?

a) NAD+ is reduced to NADH during glycolysis, the intermediate step and the Krebs cycle

b) the NAD+ is reduced to NADH only during glycolysis and the Krebs cycle

c) NAD+ is oxidized to NADH during glycolysis, the intermediate, and the Krebs cycle

d) In the absence of NAD+, glycolysis can still function

a) NAD+ is reduced to NADH during glycolysis, the intermediate step and the Krebs cycle

The Krebs Cycle produces:

a) ATP and CO2

b) CO2 and NADH

c) NADH, FADH2, and ATP

d) NADH, FADH2, ATP, and CO2

d) NADH, FADH2, ATP, and CO2

Substrate-level phosphorylation occurs in:

a) glycolysis and the electron transport chain

b) photosynthesis and glycolysis

c) glycolysis and the Krebs cycle

d) Krebs cycle and the electron transport chain

e) all of the choices are correct

c) glycolysis and the Krebs cycle

_____ produces the majority of the _____ total molecules of ATP generated form one molecule of glucose during bacterial fermentation.

a) glycolysis, 38

b) glycolysis, 2

c) Krebs cycle, 2

d) electron transport chain, 38

b) glycolysis, 2

In prokaryotic microbes, the electron transport chain is located in the:

a) cell/plasma membrane

b) mitochondria

c) ribosomes

d) cytoplasm

a) cell/plasma membrane

You discover a new organelle and think it is involved in metabolic reactions. You isolate the organelle and incubate it with various molecules and determine the changes in the amount of molecules, with the results shown. Which metabolic process do you conclude is taking place in the organelle?

glucose = no change

CO2 = increase

O2 = no change

ATP = increase

NADH = increase

FADH2 = increase

a) glycolysis

b) Krebs cycle

c) electron transport chain in respiration

d) light reactions of photosynthesis

b) Krebs cycle

Animals breathe in air containing oxygen and breathe out air with less oxygen and more carbon dioxide. The carbon comes from:

a) glycolysis

b) the Krebs cycle and intermediate step

c) the electron transport chain

d) all of the above

b) the Krebs cycle and intermediate step

The pathway of aerobic respiration that produces the most ATP per molecule of glucose is:

a) the electron transport chain

b) the Krebs cycle

c) glycolysis

d) lactic acid fermentation

a) the electron transport chain

During aerobic cellular respiration, the final electron acceptor is:

a) pyruvic acid

b) oxygen

c) nitrate

d) FAD

b) oxygen

All of the following pertain to glycolysis except:

a) it occurs without oxygen

b) it ends with formation of pyruvic acid

c) it occurs during fermentation

d) it degrades glucose to CO2 and H2O

e) it involves reduction of NAD

d) it degrades glucose to CO2 and H2O

As the electron transport chain carriers shuttle electrons, they actively pump _____ into the outer membrane compartment setting up a concentration gradient called the proton motive force:

a) ATP

b) hydrogen ions

c) oxygen

d) NADH

b) hydrogen ions

In which stage of aerobic respiration is water produced?

a) glycolysis

b) intermediate step

c) the Krebs cycle

d) the electron transport chain

d) the electron transport chain

Which of the following is not true of true anaerobic respiration?

a) It involves glycolysis

b) it generates some ATP

c) it utilizes an electron transport system

d) it uses the same final electron acceptor as aerobic respiration

d) it uses the same final electron acceptor as aerobic respiration

Glycolysis and the Krebs cycle yield 10 molecules of glucose. How many molecules of ATP will be made from these NADH molecules in the electron transport system?

a) 10

b) 38

c) 36

d) 2

e) 30

e) 30

What step in aerobic respiration produces pyruvate?

glycolysis

What step in aerobic cellular respiration requires oxidation-reduction reactions.

glycolysis, the intermediate step, the Krebs cycle, and the electron transport chain

What step in aerobic cellular respiration makes ATP?

glycolysis, the Krebs cycle, and the electron transport chain

What step in aerobic cellular respiration uses oxidative phosphorylation?

the electron transport chain

Which step in aerobic cellular respiration produces full electron carriers?

glycolysis, the intermediate step, and the Krebs cycle

Which step in aerobic cellular respiration requires oxygen?

the electron transport chain

Which step in aerobic cellular respiration reduces FAD to FADH2?

the Krebs cycle

Autoclaves are effective sterilization tools because:

a) they denature cells via extreme pressure

b) they affect all bacteria equally

c) they allow the temperature of steam to exceed 100C

d) they target the removal of pathogens

c) they allow the temperature of steam to exceed 100C

The process that destroys or removes all microorganisms including bacterial endospores is:

a) disinfection

b) sterilization

c) decontamination

d) any of the above, depending on the circumstances

b) sterilization

The use of chemical agents directly on inanimate surfaces to destroy or inhibit pathogens is:

a) disinfection

b) sterilization

c) antisepsis

d) sanitization

a) disinfection

Which of the following factors will influence effectiveness of microbial agents?

a) the number of microorganisms

b) the kind of microorganisms

c) the concentration of the agent

d) the mode of action of the agent

e) all of the above will influence the effectiveness

e) all of the above will influence the effectiveness

The lowest temperature needed to kill or inactivate all microbes in 10 minutes is the:

a) thermal death point (TDP)

b) thermal death time (TDT)

c) sporicidal time

d) death phase point

a) thermal death point (TDP)

Which of the following is the target of antimicrobial agents except:

a) cells walls

b) cell membranes

c) ribosomes

d) nucleic acid production

e) cytoplasm

e) cytoplasm

Placing organisms at 4C is:

a) bacteriocidal

b) bacteriostatic

c) decontamination

d) sterilization

b) bacteriostatic

Which of the following statements is true:

a) dry heat is less efficient than moist heat

b) dry heat cannot sterilize

c) dry heat includes intermittent steam

d) dry heat is used in devices called autoclaves

e) dry heat will sterilize at 121C for 15 minutes

a) dry heat is less efficient than moist heat

The alcohol wipe is used on a patient’s skin before an injection is an example of:

a) antisepsis

b) disinfection

c) sterilization

d) decontamination

e) sanitization

a) antisepsis

Disinfection of beverages such as apple juice and milk is optimally achieved by:

a) chlorination

b) filtration

c) pasteurization

d) moist heat autoclave

e) boiling water

c) pasteurization

Physical agents for controlling microbial growth include all of the following except:

a) ultraviolet radiation

b) boiling water

c) pasteurization

d) hydrogen peroxide

d) hydrogen peroxide

In lab, inoculating loops are sterilized using:

a) moist heat

b) chemicals

c) incineration

d) filtration

c) incineration

Which of the following represents the use of osmotic pressure as a microbial control method?

a) bleaching a kitchen counter

b) salting meat

c) rinsing of a cut with Betadine

d) exposing dental equipment to UV light

b) salting meat

Choose the microbial control method that neither inhibits nor kills microbes, but instead physically removes them from liquids or air:

a) desiccation

b) lyophilization

c) filtration

d) irradiation

c) filtration

Surfactants work by:

a) coating the organism preventing interaction with its environment

b) blocking transport into the organism

c) blocking transport out of the organism

d) disrupting plasma membrane integrity

d) disrupting plasma membrane integrity

Selective toxicity refers to:

a) damage to pathogenic organisms

b) damage to prokaryotic cell membranes

c) damage to target organisms but not the cells of the host

d) damage to nucleic acids

c) damage to target organisms but not the cells of the host

Substances that are naturally produced by certain microorganisms that can inhibit or destroy other microorganisms are called:

a) antibiotics

b) narrow-spectrum drugs

c) synthetic drugs

d) broad-spectrum drugs

a) antibiotics

There are fewer antifungals, antiprotozoal, and antihelminth drugs compared to antibacterial drugs because fungi, protozoa, and helminths:

a) do not cause many human infections

b) are not affected by antimicrobials

c) are so similar to human cells that drug selective toxicity is difficult

d) are parasites found inside human cells

e) because their cells have fewer target sites compared to bacteria

c) are so similar to human cells that drug selective toxicity is difficult

The antibiotic erythromycin binds to the 30S ribosomal subunit which causes the ribosome to be unable to move along the mRNA. This is an example of an antibiotic that inhibits gene expression by disrupting:

a) replication

b) transcription

c) translation

d) recombination

c) transcription

Each of the following target bacterial ribosomes except:

a) streptomycin

b) polymyxins

c) tetracycline

d) erythromycin

b) polymyxins

What drug is used in cases of penicillin and methicillin resistance and also used to treat endocarditis?

a) penicillin G

b) vancomycin

c) tetracycline

d) erythromycin

b) vancomycin

Antimicrobials effective against a wide variety of microbial types are termed:

a) narrow-spectrum drugs

b) semisynthetic drugs

c) synthetic drugs

d) broad-spectrum drugs

d) broad-spectrum drugs

The use of a drug to prevent imminent infection is called:

a) competitive inhibition

b) synergism

c) prebiotics

d) prophylaxis

e) antibiotics

d) prophylaxis

What molecule will allow some bacteria to be resistant to many penicillins?

a) synercid

b) penicillinase

c) aztreonam

d) clavulanic acid

e) imipenem

b) penicillinase

Which of the following practices would help limit drug resistance by microorganisms?

a) Patients complying with physicians’ guidelines by taking the correct dosage of a prescribed drug, by the best route, for the appropriate period

b) eliminating the addition of antimicrobials to animal feeds

c) for some combinations of drugs, administration of two or more drugs together

d) physicians making an accurate diagnosis and prescribing drug therapy rather than using a “shotgun” antimicrobial therapy

e) all of the above

e) all of the above

If pathogen A is less sensitive to an erithromycin disc on a Kirby-Bauer plate compared to pathogen B, then pathogen B will have a(n) _____ zone of inhibition compared to pathogen A.

a) smaller

b) equal

c) larger

c) larger

A superinfection results from:

a) buildup of a drug to toxic levels in the patient

b) the wrong drug administered to the patient

c) an immune system reaction to the drug

d) decrease in most normal microbiota with overgrowth of an unaffected species

e) all of the above

d) decrease in most normal microbiota with overgrowth of an unaffected species

True/False: bacteria cannot have resistance to a drug that it has never been exposed to

False

True/False: pasteurization makes beverages safe for consumption through a sterilization procedure involving heat

False

True/False: HEPA filters are not used to remove microbes from the air only from liquids.

False

The minimum sterilizing conditions in a steam autoclave are _____ for _____ at _____.

15 psi, 15 minutes, 121C

Sulfa drugs inhibit bacteria by blocking the synthesis of _____ and work with no side effects because mammals must get this substance from their diet.

folic acid

What is the mode of action for the antibiotic Polymixins?

disrupts the plasma membrane

What is the mode of action for the antibiotic rifampin?

inhibits nucleic acid synthesis

What is the mode of action for the antibiotic tetracycline?

inhibits protein sysnthesis

What is the mode of action for the antibiotic penicillin?

inhibits cell wall synthesis

What is the mode of action for the antibiotic erythromycin?

inhibits protein synthesis

What is the mode of action for the antibiotic bacitracin?

inhibits cell wall synthesis

What is the mode of action for the antibiotic ciprofloxacin?

inhibits nucleic acid synthesis

List 5 different mechanisms that bacteria have developed to become drug-resistant against humans?

1) Bacteria will use a different metabolic pathway than the one the drug blocked

2) Bacteria will use enzymes (penicillinase) to cleave a portion of the drug

3) Bacteria will alter ribosomal binding sites so the drug can no longer bind to them

4) Bacteria will use drug pumps to pump drugs out of the cell

5) Bacteria will change substrate binding sites to decrease drug permeability

A relatively nerdy microbiologist describes an organism as 1) chemoheterotrophic, 2) microaerophilic, 3) psychrophilic, 4) halotolerant, and 5) bacillus. Translate this description into plain english.

1) Chemoheterotrophic indicates that the organisms obtains its energy from chemical compounds and uses organic compounds as its food source.

2) Microaerophilic indicates that they live/grow in atmospheric conditions where concentrations of oxygen in lower (~10%).

3) Psychrophilic indicates that they live/grow in extremely cold conditions.

4) Halotolerant indicates that they live/grow in saline conditions.

5) Bacillus indicates that they are rod-shaped

Draw and label the 4 phases of a bacterial growth curve. Then, describe what is happening in the culture as it passes through each phase and why.

1) Lag phase: during this phase, there is little to no growth as bacteria are new to their environment. This is an adjustment period.

2) Exponential phase: Bacteria are accustomed to their environment. Nutrients are readily available, so they have the resources they need to grow exponentially.

3) Stationary phase: Nutrients are greatly depleted, and organic wastes are building in the environment. New growth = death rate.

4) Death phase: Nutrients are completely depleted, and no new growth occurs. We see an exponential death rate occur. No nutrients = no growth.

Regarding early life on Earth:

a) it is impossible to determine which type of life appeared first

b) Microbial life existed for billions of years before plant and animal life

c) microbial life existed long beofre animals but has been around for about the same amount of time as plants

d) microbial life, plant life, and animal life all appeared at about the same time

b) microbial life existed for billions of years before plant and animal life

All microorganisms are best defined as organisms that:

a) cause human disease

b) lack a cell nucleus

c) are infectious particles

d) are too small to be seen with the unaided eye

d) are too small to be seen with the unaided eye

Which Domain would an organism with a cell wall containing peptidoglycan belong to?

a) Archaea

b) Eukarya

c) Bacteria

d) Archaea or Bacteria

c) Bacteria

The structure that confers structural strength on the cell and protects it from osmotic lysis is known at the:

a) cytoplasmic membrane

b) cell wall

c) outer membrane

d) cytoplasm

b) cell wall

Which of the following is in the correct order from the most general to the most specific?

a) species - genus - family - order - class - phylym

b) species - genus - order - class - family - phylum

c) phylum - class - order - family - genus - species

d) phylum - family - class - order - genus - species

c) phylum - class - order - family - genus - species

When assigning a scientific name to an organism:

a) the species name is capitalized

b) the species name can be abbreviated

c) the genus is italicized and the species is underlined

d) both genus and species names are italicized or underlined

d) both genus and species names are italicized or underlined

An organism of the genus Staphylococcus will be _____, while the spirillum bacteria will be _____.

a) spherical/rod shaped

b) coiled/spherical

c) spherical/coiled

d) rod shaped/spherical

c) spherical/coiled

A chain of rod-shaped cells would be called a(n)?

a) palisades

b) Streptococcus

c) Staphylococcus

d) Streptobacillus

d) Streptobacillus

In what way are bacteria and eukaryotes the same?

a) always have a cell wall for rigidity

b) contain a nucleus to hold DNA

c) possess a cell membrane

d) contain membrane-bound organelles

c) possess a cell membrane

Which of the following is a unique characteristic of viruses that distinguishes them from the other major groups of microorganisms?

a) lack cell structure

b) cannot be seen without a microscope

c) cause human disease

d) lack a nucleus

e) contain genetic material

a) lack cell structure

Which of the following is found in eukaryotic cells but not in prokaryotic cells?

a) nucleus

b) mitochondria

c) endoplasmic reticulum

d) all of the above

d) all of the above

The process by which two cells arise from one in most prokaryotes is known as:

a) conjugation

b) meiosis

c) binary fission

d) mitosis

c) binary fission

Which external structure protects bacteria from phagocytosis?

a) fimbriae

b) capsule

c) cell membrane

d) slime layer

b) capsule

Which of the following is not a characteristic of bacteria?

a) DNA is free in the cytoplasm

b) Ribosomes are present at the site of protein synthesis

c) the cell wall is made up of peptidoglycan

d) organelles termed mitochondria are the site of ATP synthesis

d) organelles termed mitochondria are the site of ATP synthesis

The outcome of the gram stain is based on differences in the cell’s:

a) ribosomes

b) inclusions

c) cell wall

d) cell membrane

c) cell wall

During the gran stain, gram _____ cells do not decolorize when the alcohol is applied.

a) positive

b) negative

c) both positive and negative

d) neither positive nor negative

a) positive

A prokaryotic cell wall that has primarily peptidoglycan with small amounts of teichoic acid and lipoteichoic acid is:

a) Gram-negative

b) Gram-positive

c) archaea

d) spheroplast

b) gram-positive

All of the following structures contribute to the ability of pathogenic bacteria to cause disease except the:

a) ribosomes

b) capsule

c) slime layer

d) outer membrane of gram-negative cell walls

a) ribosomes

Lipopolysaccharide (LPS) is an important cell wall component of:

a) Gram-negative bacteria

b) Gram-positive bacteria

c) acid fast bacteria

d) mycoplasmas

a) Gram-negative bacteria

The bacterial chromosome:

a) is located in the cell membrane

b) contains all the cell’s plasmids

c) is part of the nucleoid

d) forms a single linear strand of DNA

c) is part of the nucleoid

Which of the following is mismatched?

a) ribosomes - protein synthesis

b) fimbriae - passing genes horizontally to another bacteria

c) plasma membrane - phospholipid bilayer used for selective permeability

d) nucleoid - hereditary material

b) fimbriae - passing genes horizontally to another bacteria

Plasmids:

a) are found in all bacteria

b) are essential for survival

c) cannot be passed between organisms

d) are often the site of pathogenic genes

d) are often the site of pathogenic genes