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Chapter 5 - Microbial Metabolism Chapter 6 - Microbial Growth Chapter 7 - The Control of Microbial Growth

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elizabeth.merner
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Question 1 of 30

1

A medium that contains yeast extract, glucose, and peptones would be a(n)

Select one of the following:

  • complex medium

  • selective medium

  • anaerobic medium

  • chemically defined medium

Explanation

Question 2 of 30

1

A bacterial suspension produces a turbidity reading that corresponds to 5 x 107 CFU/ml. A viable plate count of the same suspension produces a concentration of only 1 x 105 CFU/ml. You most correctly conclude that

Select one of the following:

  • you forgot to use the 500x multiplier that is always a part of computing viable counts.

  • turbidity is an indirect counting method and is inherently inaccurate.

  • most of the cells in the suspension are dead.

  • the suspension is safe to drink.

Explanation

Question 3 of 30

1

In metabolism, ______ reactions liberate energy used to make ATP, whereas ______ reactions require energy supplied by the hydrolysis of ATP.

Select one of the following:

  • anabolic, catabolic

  • catabolic, anabolic

  • biosynthetic, degradative

Explanation

Question 4 of 30

1

The ATP made by oxidative phosphorylation

Select one of the following:

  • is powered by chemiosmosis using a proton gradient.

  • is made at large transmembrane proteins called ATP synthases.

  • represents most of the energy made during respiration.

  • all of the above.

Explanation

Question 5 of 30

1

Why are both the temperatures and times involved in hot air sterilization higher than those involved in steam sterilization?

Select one of the following:

  • Heat transfer is more efficient when water is involved.

  • Desiccated organisms are harder to kill.

  • Microbes have more organic material to eat in ovens.

  • Microbes are hydrophobic.

Explanation

Question 6 of 30

1

At which phase of microbial growth is the growth rate identical to the death rate?

Select one of the following:

  • lag phase

  • death phase

  • stationary phase

  • log phase

Explanation

Question 7 of 30

1

A bacterial growth experiment began with 100 cells and ended with 409,600 cells. How many generations occurred?

Select one of the following:

  • 3

  • 6

  • 24

  • 12 [Log (409,600) - Log (100)]/log 2=12, See Appendix B

Explanation

Question 8 of 30

1

During Glycolysis

Select one of the following:

  • ATP is generated by substrate-level phosphorylation

  • carbon dioxide is produced.

  • oxygen is consumed.

  • all of the above.

Explanation

Question 9 of 30

1

Suppose you have a suspension of C. botulinum endospores that has a decimal reduction time (DRT) of 1.5 minutes at 121 °C. If you had 1 x 10 6 endospores, how long (at 121 °C ) would it take to reduce this number to a single organism?

Select one of the following:

  • 12 minutes

  • 3 minutes

  • 9 minutes

  • 6 minutes

Explanation

Question 10 of 30

1

The process of destroying vegetative pathogens on living tissue is most correctly called

Select one of the following:

  • disinfection.

  • sanitization.

  • sterilization.

  • antisepsis.

Explanation

Question 11 of 30

1

What type of organism would have an optimum growth temperature at about 12 °C?

Select one of the following:

  • psychrophile

  • psychrotroph

  • thermophile

  • mesophile

Explanation

Question 12 of 30

1

Plasmas, supercritical fluids, and peroxygens are all

Select one of the following:

  • obsolete microbial control methods.

  • new methods used to sterilize.

  • used to grow bacteria.

  • commonly used in surgeries.

Explanation

Question 13 of 30

1

The most important products of the Krebs cycle are

Select one of the following:

  • citric acid and pyruvic acid.

  • ATP and water.

  • NADH and FADH2.

  • carbon dioxide and water.

Explanation

Question 14 of 30

1

The method of preserving bacterial cultures that involves sublimation is

Select one of the following:

  • drying.

  • deep-freezing.

  • lyophilization.

  • refrigeration.

Explanation

Question 15 of 30

1

The germicidal action of chlorine is due to the formation of

Select one of the following:

  • hypochlorous acid.

  • sodium chloride.

  • free oxygen.

  • ozone.

Explanation

Question 16 of 30

1

The net yield of ATP equivalents from one turn of the Krebs cycle (starting with acetyl-CoA) is

Select one of the following:

  • 12

  • 36

  • 24

  • 6

Explanation

Question 17 of 30

1

The most common physical method of microbial control in foods is

Select one of the following:

  • heat treatment or low temperatures.

  • pressure.

  • radiation.

  • filtration.

Explanation

Question 18 of 30

1

The most resistant microbe (of the ones listed) to chemical biocides is

Select one of the following:

  • protozoan cysts.

  • mycobacteria.

  • bacterial endospores.

  • viruses without envelopes.

Explanation

Question 19 of 30

1

A bacterostatic agent

Select one of the following:

  • causes bacteria to grow.

  • kills bacteria using an electric charge.

  • kills bacteria.

  • inhibits the growth of bacteria.

Explanation

Question 20 of 30

1

Flavoproteins, cytochromes, and ubiquinones are all part of

Select one of the following:

  • the electron transport chain.

  • the pentose phosphate pathway

  • glycolysis.

  • the Krebs cycle.

Explanation

Question 21 of 30

1

Phenolics, biguanides, halogens, alcohols, and probably quaternary ammonium compounds (Quats) all cause damage to the cell’s

Select one of the following:

  • wall

  • nucleic acids

  • capsule

  • plasma membrane

Explanation

Question 22 of 30

1

Radiation does most of its lethal damage by causing breaks in, or changes to the microbe’s

Select one of the following:

  • plasma membrane.

  • cell wall

  • DNA

  • flagella

Explanation

Question 23 of 30

1

Which of the following is not a common end product of a microbial fermentation?

Select one of the following:

  • ethyl alcohol

  • lactic acid

  • glucose

  • CO2

Explanation

Question 24 of 30

1

Organisms that grow deep in the bottom of the ocean (no light) next to hydrogen sulfide vents (source of energy), and are able to fix CO2 in the seawater, would be referred to as

Select one of the following:

  • photoheterotrophs.

  • photoautotrophs.

  • chemoautotrophs.

  • chemoheterotrophs.

Explanation

Question 25 of 30

1

Which type of organism is indifferent to either the presence or absence of oxygen?

Select one of the following:

  • mircoaerophile

  • obligate anaerobe

  • facultative anaerobe

  • aerotolerant anaerobe

Explanation

Question 26 of 30

1

During photosynthesis, the main products of the light-dependent reactions are ________, whereas the main products of light-independent reactions are __________.

Select one of the following:

  • chlorophyll/NADPH and O2

  • lipids/proteins

  • sugars/ATP and water

  • ATP, O2, and NADPH/sugars

Explanation

Question 27 of 30

1

Enzymes

Select one of the following:

  • raise the temperature of a chemical reaction.

  • are permanently altered by a chemical reaction.

  • lower the activation energy of a chemical reaction.

  • lower the energy difference between the reactants and products.

Explanation

Question 28 of 30

1

Five bacterial cells with a generation time of 15 minutes were allowed to grow for 8 hours. How many cells are present?

Select one of the following:

  • 5 million

  • 3.20 × 108

  • 4.29 × 109

  • 2.15 × 1010

Explanation

Question 29 of 30

1

A sample of milk is diluted 1:2,000,000 and 1 ml samples of this dilution are plated in duplicate. The average plate count is 50 CFU. How many CFU/ml are present in the undiluted milk?

Select one of the following:

  • 50,000,000

  • 100,000,000

  • 10,000,000

  • 500,000,000

Explanation

Question 30 of 30

1

Blood agar containing an antibiotic that inhibits gram-positive organisms, would most correctly be called

Select one of the following:

  • selective.

  • anaerobic.

  • both selective and differential

  • differential

Explanation

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