Microbial Genetics: A Comprehensive Guide for Medical Students

Question 1

During DNA replication, the leading strand is synthesized:

Accepted Answer

Continuously in the 5' to 3' direction

Answer

Discontinuously in the 5' to 3' direction

Answer

Continuously in the 3' to 5' direction

Answer

Discontinuously in the 3' to 5' direction

Question 2

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Answer

Polymerase

Answer

Primase

Answer

Ligase

Question 3

The Shine-Dalgarno sequence in prokaryotes is located:

Accepted Answer

Upstream of the start codon

Answer

Downstream of the stop codon

Answer

Within the coding region

Answer

In the 5' untranslated region

Question 4

The process by which bacteria transfer genetic material via a plasmid is called:

Accepted Answer

Conjugation

Answer

Transformation

Answer

Transduction

Answer

Transposition

Question 5

Which genetic code is used by mitochondria?

Accepted Answer

Modified genetic code

Answer

Universal genetic code

Answer

Standard genetic code

Answer

Bacterial genetic code

Question 6

The lac operon in E. coli is a model for:

Accepted Answer

Inducible gene expression

Answer

Repressible gene expression

Answer

Constitutive gene expression

Answer

Negative gene regulation

Question 7

In a laboratory setting, which technique is specifically designed to separate DNA fragments according to their size?

Accepted Answer

Gel electrophoresis

Answer

Polymerase Chain Reaction (PCR)

Answer

DNA sequencing

Answer

Southern blotting

Question 8

How does horizontal gene transfer facilitate the rapid evolution of microbial communities?

Accepted Answer

Introduces new genetic material, enhancing diversity and providing advantageous traits.

Answer

Accelerates mutation rates, increasing genetic variation.

Answer

Reduces competition, promoting resource sharing.

Answer

Stabilizes genetic makeup, minimizing genetic drift.

Question 9

In what ways does microbial genetics contribute to the advancement of antibiotic development?

Accepted Answer

Identification of novel targets for antibiotic action

Accepted Answer

Development of more effective antibiotics against existing pathogens

Answer

Prediction of antibiotic side effects

Question 10

Which of the following nitrogenous bases is NOT found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Guanine

Answer

Thymine

Question 11

Which enzyme unwinds the DNA double helix during replication?

Accepted Answer

Helicase

Answer

Polymerase

Answer

Ligase

Answer

Primase

Question 12

Which of the following mutation types involves the insertion of an extra nucleotide into a gene?

Accepted Answer

Insertion

Answer

Deletion

Answer

Substitution

Answer

Inversion

Question 13

What is the primary function of a promoter in gene expression?

Accepted Answer

To bind RNA polymerase and initiate transcription

Answer

To terminate transcription

Answer

To splice mRNA

Answer

To translate mRNA into protein

Question 14

Which of the following techniques amplifies specific DNA sequences?

Accepted Answer

PCR

Answer

Electrophoresis

Answer

DNA sequencing

Answer

Southern blotting

Question 15

What is the primary function of the CRISPR-Cas system in bacteria?

Accepted Answer

To provide defense against invading viruses and mobile genetic elements

Answer

To regulate gene expression

Answer

To repair DNA damage

Answer

To facilitate horizontal gene transfer

Question 16

How do plasmids differ from chromosomes?

Accepted Answer

Plasmids are extra-chromosomal DNA molecules, while chromosomes are contained within the nucleus

Answer

Plasmids are essential for bacterial survival, while chromosomes are dispensable

Answer

Plasmids are inherited vertically, while chromosomes are inherited horizontally

Answer

Plasmids are found only in prokaryotic cells, while chromosomes are found in both prokaryotic and eukaryotic cells

Question 17

Which type of mutation leads to a premature stop codon?

Accepted Answer

Nonsense mutation

Answer

Frameshift mutation

Answer

Missense mutation

Answer

Silent mutation

Question 18

During DNA replication, which enzyme is responsible for unwinding the DNA double helix?

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

RNA polymerase

Answer

Ligase

Question 19

What is the primary function of sigma factors in bacterial gene expression?

Accepted Answer

Binding to specific DNA sequences to initiate transcription

Answer

Translating mRNA into proteins

Answer

Splicing introns from pre-mRNA

Answer

Modifying newly synthesized proteins

Question 20

Which technique is commonly used to study gene expression by quantifying specific mRNA molecules?

Accepted Answer

Northern blotting

Answer

Southern blotting

Answer

Western blotting

Answer

PCR

Question 21

What is the primary function of the ribosome during protein synthesis?

Accepted Answer

Translating mRNA into proteins

Answer

Synthesizing DNA from RNA

Answer

Degrading proteins

Answer

Transporting molecules across the cell membrane

Question 22

In microbial genetics, which technique is primarily employed to transfer foreign DNA into a recipient cell?

Accepted Answer

Bacterial transformation

Answer

Polymerase Chain Reaction (PCR)

Answer

Gene knockout

Answer

Microinjection

Question 23

Which of the following is NOT a type of genetic mutation that can occur in microbial genomes?

Accepted Answer

Gene inversion

Answer

Point mutation

Answer

Frameshift mutation

Answer

Nonsense mutation

Question 24

Which defining characteristic of microbial genetics is accurately described below?

Accepted Answer

Microbial genetics techniques can be applied to both prokaryotic and eukaryotic microorganisms.

Answer

Microbial genetics is exclusively focused on studying the genetics of bacterial organisms.

Answer

Microbial genetics techniques necessitate specialized equipment and advanced technology.

Answer

Microbial genetics research has no practical applications in medicine or biotechnology.

Question 25

Define a conditional mutation in the context of microbial genetics.

Accepted Answer

A mutation that only expresses itself under specific environmental conditions

Answer

A mutation that always leads to cell death

Answer

A mutation that occurs exclusively in bacterial cells

Question 26

Which enzyme is responsible for unwinding and separating the DNA strands during DNA replication?

Accepted Answer

Helicase

Answer

Primase

Answer

Topoisomerase

Answer

Ligase

Question 27

What is the complementary base-pairing rule that governs DNA replication?

Accepted Answer

A-T/C-G

Answer

G-T/C-A

Answer

A-C/T-G

Answer

C-G/A-T

Question 28

Which of the following is a type of mutation that involves the deletion of a single nucleotide?

Accepted Answer

Frameshift mutation

Answer

Missense mutation

Answer

Silent mutation

Answer

Nonsense mutation

Question 29

Which region of a gene is responsible for controlling its expression?

Accepted Answer

Promoter

Answer

Intron

Answer

Terminator

Answer

Exon

Question 30

Which of the following post-transcriptional modifications can affect protein function?

Accepted Answer

Phosphorylation

Answer

Translation

Answer

Replication

Answer

Transcription

Question 31

What unique characteristic of retroviruses distinguishes them from other viruses?

Accepted Answer

Possession of reverse transcriptase

Answer

Absence of an envelope

Answer

Replication in the nucleus

Answer

Single-stranded RNA genome

Question 32

Which type of gene regulation involves changes in chromatin organization?

Accepted Answer

Epigenetics

Answer

Post-translational modification

Answer

Transcriptional control

Answer

Translational regulation

Question 33

What is the primary purpose of genetic mapping?

Accepted Answer

Determining the locations of genes on chromosomes

Answer

Identifying all the proteins encoded by a genome

Answer

Predicting gene function

Answer

Amplifying specific DNA sequences

Question 34

Which of the following is NOT a nitrogenous base found in DNA?

Accepted Answer

Uracil

Answer

Guanine

Answer

Adenine

Question 35

The biological process by which genetic information is copied from DNA to messenger RNA (mRNA) is termed:

Accepted Answer

Transcription

Answer

Mutation

Answer

Replication

Answer

Translation

Question 36

Identify the enzyme responsible for unwinding the DNA double helix during DNA replication:

Accepted Answer

Helicase

Answer

Primase

Answer

Polymerase

Answer

Ligase

Question 37

The reading of the genetic code occurs during which molecular process?

Accepted Answer

Translation

Answer

Proofreading

Answer

Replication

Answer

Transcription

Question 38

In bacteria, the exchange of genetic material through cell-to-cell contact via a plasmid is known as:

Accepted Answer

Conjugation

Answer

Recombination

Answer

Transduction

Answer

Transformation

Question 39

The gene editing tool that utilizes the Cas9 protein guided by a specific RNA molecule is known as:

Accepted Answer

CRISPR-Cas9

Answer

Gel electrophoresis

Answer

Southern blotting

Answer

Polymerase chain reaction

Question 40

The field of genetics that focuses on the genetic diversity within populations is known as:

Accepted Answer

Population genetics

Answer

Molecular genetics

Answer

Quantitative genetics

Question 41

The term used to describe the process of introducing foreign DNA into a mammalian cell is:

Accepted Answer

Transfection

Answer

Transformation

Answer

Transduction

Answer

Conjugation

Question 42

Which enzyme is responsible for adding nucleotides to the growing DNA strand during DNA replication?

Accepted Answer

DNA polymerase

Answer

RNA polymerase

Answer

Helicase

Answer

Topoisomerase

Question 43

What type of mutation involves the change of a single nucleotide resulting in a codon that encodes a different amino acid?

Accepted Answer

Missense mutation

Answer

Silent mutation

Answer

Nonsense mutation

Answer

Frameshift mutation

Question 44

Which of the following is a post-transcriptional modification that can alter the stability or function of an mRNA molecule?

Accepted Answer

Splicing

Answer

Transcription

Answer

Replication

Answer

Translation

Question 45

Which aspect of a protein determines its specific shape and function?

Accepted Answer

Amino acid sequence

Answer

Shape of the protein

Answer

Function of the protein

Question 46

Which technique is used to separate DNA fragments based on size and charge?

Accepted Answer

Gel electrophoresis

Answer

Southern blotting

Answer

DNA sequencing

Answer

PCR

Question 47

What is the primary function of quorum sensing in microbial communities?

Accepted Answer

Coordinating gene expression and behavior in response to population density

Answer

Biofilm formation

Answer

Virulence regulation

Answer

Nutrient acquisition

Question 48

Which ethical concern is particularly relevant to the use of CRISPR-Cas9 gene editing technology?

Accepted Answer

Potential for unintended consequences and misuse

Answer

Limitations of the technology

Answer

Cost of the technology

Answer

Safety concerns

Question 49

Identify the fundamental unit of inheritance in all living organisms.

Accepted Answer

Gene

Answer

Chromosome

Answer

Nucleotide

Question 50

Which biological process involves the duplication of DNA?

Accepted Answer

DNA replication

Answer

DNA recombination

Answer

DNA translation

Answer

DNA transcription

Question 51

Identify the enzyme responsible for synthesizing new DNA strands during DNA replication.

Accepted Answer

DNA polymerase

Answer

Helicase

Answer

RNA polymerase

Question 52

What is the ultimate outcome of gene expression?

Accepted Answer

Protein

Answer

Carbohydrate

Answer

RNA

Question 53

Which type of mutation does NOT alter the amino acid sequence of the encoded protein?

Accepted Answer

Silent mutation

Answer

Nonsense mutation

Answer

Missense mutation

Question 54

A nucleotide sequence change in a gene that leads to an amino acid change in the encoded protein is known as a:

Accepted Answer

Missense mutation

Answer

Nonsense mutation

Answer

Frameshift mutation

Question 55

Horizontal gene transfer between bacteria can occur through:

Accepted Answer

Conjugation

Answer

Budding

Answer

Binary fission

Question 56

During transduction, genetic material is transferred from one bacterium to another by:

Accepted Answer

Bacteriophage

Answer

Plasmid

Answer

Transposon

Question 57

Identify the type of genetic recombination that occurs specifically during meiosis.

Accepted Answer

Crossing over

Answer

Conjugation

Answer

Transformation

Question 58

The direct transfer of genetic material between cells through physical contact is known as:

Accepted Answer

Conjugation

Answer

Transformation

Answer

Transduction