Extra Credit Review HW Chapters 6-9 Questions

Aerotolerant anaerobes:

1. Tolerate normal atmospheric nitrogen gas levels.

2. Are killed by oxygen.

3. Do not use oxygen but can tolerate it.

4. Require more oxygen than is present in air.

5. Require less oxygen than is present in air.

3

According to the operon model, for the synthesis of an inducible gene to occur, the ________.

1. substrate must bind to the enzyme

2. end-product must not be in excess

3. protein repressor must not be synthesized

4. substrate must bind to the protein repressor

5. protein repressor must bind to the operator

4

All of the following methods are effective for destroying prions except:

1. Proteases

2. Incineration

3. Boiling

4. NaOH + autoclaving at 134°C

5. None of the answers are correct; each of these will destroy prions

3

Which of the following is NOT a product of transcription?

1. rRNA

2. a new strand of DNA

3. tRNA

4. mRNA

2

The biosafety level (BSL) for most introductory microbiology laboratories is

1. BSL-1.

2. BSL-2.

3. BSL-3.

4. BSL-4.

1

An advantage of cDNA over genomic DNA is that it ________.

1. does not contain exons

2. is easy to isolate

3. can form very large DNA fragment

4. contains selectable markers

5. does not contain introns

5

A gene is ________.

1. any random segment of DNA

2. the RNA product of a transcribed section of DNA

3. a three-nucleotide segment of DNA that code for an amino acid

4. a sequence of nucleotides in DNA that codes for a functional product

5. a sequence of nucleotides in RNA that codes for a functional product

4

Often, 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:

1. Injected solutions are contaminated.

2. Their immune systems are weakened.

3. Bacteria cause infections.

4. Infections can be transmitted from other people.

5. Biofilms develop on catheters.

5

If cells are grown in media containing amino acids labeled with radioactive nitrogen (15N), most of the radioactivity will be found in the cells'

1. DNA.

2. DNA and phospholipids.

3. proteins.

4. DNA and proteins.

5. phospholipids.

4

Which of the following is NOT a desired characteristic of DNA vectors used in gene cloning procedures?

1. may replicate in several species

2. circular form of DNA or integrates into the host chromosome

3. has a selectable marker

4. large size

5. self-replication

4

A sample of milk is tested for its bacterial content in a plate count assay. A 1 ml sample of the milk is diluted in a 1:10 serial dilutions. 1ml 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 ________ cells per milliliter.

1. 54

2. 5,400

3. 540

4. 540,000

5. 54,000

5

If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar?

1. pressure cooker at 121°C for 15 minutes

2. bleach

3. hydrogen peroxide

4. boiling for one hour

5. oven at 121°C for one hour

1

Which enzyme catalyzes the biochemical reaction: 2H2O2 → 2H2O + O2?

1. Catalase

2. Oxidase

3. Peroxidase

4. Superoxide dismutase

1

Culture 1: F+, leucine+, histidine+

Culture 2: F-, leucine-, histidine-

In the table, if culture 1 mutates to Hfr, what will be the result of conjugation between the two cultures?

1. 1 will become F+, leu+, his+; 2 will become F+, leu+, his+

2. They will both remain the same.

3. 1 will remain the same; recombination may occur in 2

4. 1 will become F-, leu+, his+; 2 will become Hfr, leu+, his+

5. The answer cannot be determined based on the information provided.

3

Which of the following statements best describes the pattern of microbial death?

1. The pattern varies depending on the antimicrobial agent.

2. The cells in a population die at a constant rate.

3. All the cells in a culture die at once.

4. Not all of the cells in a culture are killed.

5. The pattern varies depending on the species.

2

Most fungi grow best at pH

1. 5.

2. 14.

3. 9.

4. 7.

5. 1.

1

An experiment began with 4 bacterial cells in log phase and ended with 128 cells. How many times the cells divided?

1. 32

2. 64

3. 6

4. 4

5. 5

5

The fact that people continue to be concerned about the safety of DNA technology can be attributed to which of the following?

1. Both that it is impossible to prove something is safe under all conditions and that science can only provide supporting evidence for hypotheses.

2. Science can definitively disprove hypotheses but can only provide supporting evidence for hypotheses.

3. There is mounting scientific evidence that DNA technology is unsafe.

4. People are suspicious of science, in general.

5. It is impossible to prove something is safe under all conceivable conditions.

1

A kitchen countertop has a spill of vegetable oil that was wiped up but a film remains. What should be the next step in disinfecting this surface?

1. isopropanol

2. 10% bleach

3. chlorhexidine containing solution

4. spray a disinfectant that contains a heavy metal

5. warm soapy scrub

5

The reaction catalyzed by reverse transcriptase is

1. tRNA → mRNA.

2. mRNA → cDNA.

3. DNA → DNA.

4. mRNA → protein.

5. DNA → mRNA.

2

If you knew the sequence of nucleotides within a gene, which one of the following could you determine with the most accuracy?

1. the tertiary structure of the protein

2. the quaternary structure of the protein

3. the secondary structure of the protein

4. the primary structure of the protein

5. The answer cannot be determined based on the information provided.

4

Microorganisms placed in a high concentration of salt and sugar environment will undergo osmotic lysis.

1. True

2. False

2

Which of the following pairs of terms is mismatched?

1. fungicide – kills yeasts and molds

2. germicide – kills microbes

3. bacteriostatic – kills vegetative bacterial cells

4. sterilant – destroys all living microorganisms

5. virucide – inactivates viruses

3

A culture medium consisting of agar, peptone, and beef heart is a ________ medium.

1. chemically defined

2. differential

3. reducing

4. complex

5. selective

4

During which growth phase will gram-positive bacteria be most susceptible to penicillin?

1. death phase

2. stationary phase

3. log phase

4. lag phase

5. The culture is equally susceptible during all phases.

3

In the figure, which model of the lac operon correctly shows RNA polymerase, lactose, and repressor protein when the structural genes are being transcribed?

1. a

2. b

3. c

4. d

5. e

4

A suspension of 10⁶ Bacillus cereus endospores was put in a hot-air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown.

In the figure, the thermal death point for this culture is

1. 30 minutes.

2. 50°C.

3. 15 minutes.

4. 170°C.

5. The answer cannot be determined based on the information provided

5

In the figure, which line best depicts a facultative anaerobe in the absence of O2?

1. a

2. b

3. c

2

Which of the following is not an agricultural product made by recombinant DNA technology?

1. Frost retardant

2. Pectinase

3. Glyphosate-resistant crops

4. Bacillus thuringiensis insecticide

5. Nitrogenase (nitrogen fixation)

2

Repair of damaged DNA, in some instances and mechanisms, might be viewed as a race between an endonuclease and

1. DNA ligase.

2. primase.

3. methylase.

4. DNA polymerase.

5. helicase.

3

One advantage of a viral vector over a plasmid vector is that the

1. the viral vector can accept larger pieces of DNA and the plasmid vector is circular.

2. viral vector can harbor a selection marker.

3. plasmid vector is circular.

4. viral vector can accept much larger pieces of DNA.

5. viral vector can accept a PCR fragment.

4

A population of bacterial cells carrying a desired plasmid is called a ________.

1. library

2. vector

3. Southern blot

4. PCR

5. clone

5

Which of the following statements is not true regarding a bacterium that is R+?

1. R+ can be transferred to a different species.

2. It is F+.

3. It is resistant to certain drugs and heavy metals.

4. R+ can be transferred to a cell of the same species.

5. It possesses a plasmid.

2

The following data were obtained by incubating gram-positive bacteria in nutrient medium + disinfectant for 24 hours, then transferring one loopful to nutrient medium (subculturing). (+ = growth; - = no growth) (view image)

In the table, which disinfectant was bactericidal?

1. Doom

2. K.O.

3. Mortum

4. Sterl

5. The answer cannot be determined based on the information provided.

3

Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?

1. gamma radiation

2. autoclave

3. ultraviolet radiation

4. microwaves

5. sunlight

1

A source of heat-stable DNA polymerase is

1. Agrobacterium tumefaciens.

2. Saccharomyces cerevisiae.

3. Thermus aquaticus.

4. Pseudomonas.

5. Bacillus thuringiensis.

3

Which of the following does NOT achieve sterilization?

1. autoclave

2. ethylene oxide

3. dry heat

4. supercritical fluids

5. pasteurization

5