Question 1

Which of the following statements best describes the difference between prokaryotic and eukaryotic genomes?

Accepted Answer

Prokaryotic genomes are usually a single circular chromosome without introns, while eukaryotic genomes are multiple linear chromosomes with introns and exons.

Question 2

During DNA replication, what does the term 'semi-conservative' mean?

Accepted Answer

Each new DNA molecule consists of one parental strand and one newly synthesized strand.

Question 3

Which base is present in RNA but not in DNA?

Accepted Answer

Uracil

Question 4

A mutation that changes a codon for an amino acid into a stop codon is called:

Accepted Answer

Nonsense mutation

Question 5

Which of the following best describes the function of tRNA during translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches them to the coded mRNA message using its anticodon.

Question 6

Which of the following is an example of horizontal gene transfer in bacteria?

Accepted Answer

A bacterium acquiring a plasmid from another bacterium through conjugation.

Question 7

Which of the following best describes the operon model of transcriptional control in prokaryotes?

Accepted Answer

A group of genes regulated by a single promoter and operator, allowing coordinated expression.

Question 8

Which of the following best defines 'sterilization'?

Accepted Answer

The destruction of all microorganisms and viruses in or on an object.

Question 9

A hospital is deciding between using autoclaving and dry heat for sterilizing surgical instruments. Which of the following statements is correct regarding these methods?

Accepted Answer

Autoclaving uses moist heat under pressure and is generally more effective and faster than dry heat sterilization.

Question 10

Which of the following chemical disinfectants is most appropriate for sterilizing heat-sensitive medical equipment?

Accepted Answer

Ethylene oxide

Question 11

A laboratory is working with a pathogen that can cause serious or potentially lethal disease through inhalation, but for which treatments exist. Which Biosafety Level (BSL) is required?

Accepted Answer

BSL-3

Question 12

Which of the following best describes the difference between disinfection and antisepsis?

Accepted Answer

Disinfection is used on inanimate objects, while antisepsis is used on living tissue.

Question 13

Which of the following best explains why ionizing radiation is more effective than nonionizing radiation for sterilization?

Accepted Answer

Ionizing radiation causes the formation of highly reactive ions that damage DNA and proteins.

Question 14

A patient is diagnosed with a genetic disorder caused by a single nucleotide substitution that results in a different amino acid being incorporated into a protein. What type of mutation is this?

Accepted Answer

Missense mutation

Question 15

Which of the following best describes the role of the 'triple code' in translation?

Accepted Answer

Each group of three nucleotides in mRNA (codon) specifies a particular amino acid in a protein.

Question 16

Which of the following is a correct sequence of events in the process of bacterial transformation?

Accepted Answer

A bacterium takes up naked DNA from the environment and incorporates it into its genome.

Question 17

Which of the following best describes the function of plasmids in bacteria?

Accepted Answer

Plasmids are small, circular DNA molecules that often carry genes for antibiotic resistance and can be transferred between bacteria.

Question 18

Which of the following best explains why pasteurization is used for milk rather than sterilization?

Accepted Answer

Pasteurization reduces microbial load to safe levels without significantly affecting taste or nutritional value, while sterilization would alter the milk's properties.

Question 19

A researcher exposes bacteria to a chemical that disrupts hydrogen bonding between DNA bases. Which process will be most directly affected?

Accepted Answer

DNA replication

Question 20

Which of the following is a key factor to consider when selecting a microbial control method for a hospital setting?

Accepted Answer

The nature of the item to be disinfected, the type of microbes present, and the potential for damage to the item.

Microbiology Exam 2 Study Guide: Microbial Genetics & Control of Microbial Growth

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