Molecular Biology Quizzes: Test Your Knowledge in Genetics, DNA, and Proteins

Question 1

Which RNA molecule is not directly involved in protein synthesis?

Accepted Answer

Small nuclear RNA (snRNA)

Answer

Messenger RNA (mRNA)

Answer

Transfer RNA (tRNA)

Answer

Ribosomal RNA (rRNA)

Question 2

How does DNA methylation regulate gene expression? Provide a specific example of how this mechanism is used in cellular processes.

Accepted Answer

DNA methylation inhibits gene expression by blocking transcription factor binding to promoter regions.

Answer

DNA methylation promotes gene expression by recruiting proteins that remodel chromatin into an open and transcriptionally active state.

Answer

DNA methylation enhances gene expression by protecting DNA from degradation by nucleases.

Question 3

Describe the importance of non-coding DNA in cellular processes. Explain its role in epigenetics and gene regulation, providing specific examples to illustrate its impact on gene expression.

Accepted Answer

Non-coding DNA helps package DNA into chromosomes, affecting chromatin structure and gene accessibility, thus regulating gene expression.

Answer

Non-coding DNA is transcribed into RNA but not translated into proteins; it mainly provides structural support to the cell.

Answer

Non-coding DNA is only found in prokaryotes and has no functional significance in eukaryotes.

Question 4

Describe how molecular biology techniques are used in research and biotechnology. Provide specific examples of their impact in fields like medicine, agriculture, and forensics.

Accepted Answer

In medicine, molecular biology techniques have led to advances in personalized medicine and gene therapy.

Accepted Answer

In agriculture, molecular biology techniques have enhanced crop yields and reduced pesticide usage.

Accepted Answer

In forensics, molecular biology techniques have revolutionized identification and DNA fingerprinting methods.

Answer

Molecular biology techniques have limited applications in research and biotechnology.

Question 5

How have molecular biology techniques revolutionized our understanding and treatment of infectious diseases? Provide specific examples of their impact on disease diagnosis and treatment strategies.

Accepted Answer

Molecular biology techniques have enabled rapid and accurate identification of infectious agents, leading to more targeted and effective treatments.

Answer

Molecular biology techniques have had a minimal impact on our understanding of infectious diseases.

Answer

Molecular biology techniques are primarily used for research and have limited practical applications in disease management.

Answer

Molecular biology techniques are only relevant for studying rare and emerging infectious diseases.

Question 6

How do microRNAs (miRNAs) regulate gene expression after transcription? Explain how miRNAs target and control the stability and translation of mRNA molecules.

Accepted Answer

miRNAs bind to the 3' untranslated region (UTR) of mRNA, causing mRNA degradation or blocking translation.

Answer

miRNAs activate gene transcription by binding to the promoter region.

Answer

miRNAs break down mRNA molecules into smaller pieces, preventing translation.

Answer

miRNAs do not play a role in post-transcriptional gene regulation.

Question 7

Where do amino acids form covalent bonds to create proteins?

Accepted Answer

Peptide bond

Answer

Disulfide bond

Answer

Hydrogen bond

Answer

Ionic bond

Question 8

Which of the following describes the primary structure of a protein?

Accepted Answer

Linear sequence of amino acids

Answer

Three-dimensional shape

Answer

Domains and motifs

Answer

Quaternary structure

Question 9

What process involves transcribing and translating a gene to produce a protein?

Accepted Answer

Gene expression

Answer

DNA replication and transcription

Answer

Protein synthesis only

Answer

Transcription only

Question 10

Which enzyme is responsible for unwinding DNA during transcription?

Accepted Answer

Helicase

Answer

RNA polymerase

Answer

Primase

Answer

DNA ligase

Question 11

What is the role of a promoter region in gene regulation?

Accepted Answer

Binding site for regulatory proteins

Answer

Site of transcription termination

Answer

Region containing the gene sequence

Answer

Enhancer sequence that boosts transcription

Question 12

Which of the following is an example of a post-translational protein modification?

Accepted Answer

Glycosylation

Answer

Splicing

Answer

Translation

Answer

Transcription

Question 13

What is the primary function of RNA polymerase?

Accepted Answer

To transcribe DNA into mRNA

Answer

To translate mRNA into proteins

Answer

To replicate DNA

Answer

To regulate gene expression

Question 14

Which of the following is a non-coding region of DNA in eukaryotes?

Accepted Answer

Intron

Answer

Exon

Answer

Promoter

Answer

Terminator

Question 15

Which of the following enzymes unwinds the DNA double helix during replication?

Accepted Answer

Helicase

Answer

Ligase

Answer

Topoisomerase

Answer

Primase

Question 16

Which of the following is a characteristic of eukaryotic DNA?

Accepted Answer

It is organized into chromosomes

Answer

It is circular

Answer

It is not associated with histone proteins

Answer

It is found in the cytoplasm

Question 17

What is the primary function of transcription factors in gene expression?

Accepted Answer

To bind to specific DNA sequences and promote the initiation of transcription

Answer

To terminate transcription

Answer

To splice mRNA

Answer

To translate mRNA into proteins

Question 18

What is the primary function of the cell membrane?

Accepted Answer

To regulate the passage of molecules into and out of the cell

Answer

To store genetic information

Answer

To carry out protein synthesis

Answer

To generate energy

Question 19

Which nitrogenous base is not found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 20

What is the complementary strand to the DNA sequence: 5'-ATGC-3'?

Accepted Answer

5'-TACG-3'

Answer

5'-GCAT-3'

Answer

5'-ATCG-3'

Answer

5'-CGTA-3'

Question 21

Which of the following is a type of gene regulation that occurs post-transcriptionally?

Accepted Answer

mRNA stability

Answer

Promoter binding

Answer

Intron splicing

Answer

Histone modification

Question 22

What is the process by which DNA is copied into an RNA molecule?

Accepted Answer

Transcription

Answer

Replication

Answer

Translation

Answer

Mutation

Question 23

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

Accepted Answer

Uracil

Answer

Adenine

Answer

Thymine

Answer

Cytosine

Question 24

Gene expression occurs in the following sequence:

Accepted Answer

Replication → Transcription → Translation

Answer

Transcription → Translation → Replication

Answer

Translation → Transcription → Replication

Answer

Replication → Translation → Transcription

Question 25

The genetic code is best described as:

Accepted Answer

A set of rules that determines the sequence of amino acids in proteins

Answer

A sequence of nucleotides that make up DNA

Answer

The entire collection of genes in an organism

Answer

A measure of genetic diversity within a population

Question 26

Which type of RNA carries genetic instructions from the nucleus to the ribosomes?

Accepted Answer

mRNA

Answer

tRNA

Answer

rRNA

Answer

snRNA

Question 27

Which of the following factors does NOT influence the rate of mutation?

Accepted Answer

Natural selection

Answer

Exposure to radiation

Answer

Chemical exposure

Answer

Errors in DNA replication

Question 28

Polypeptide chains are formed by:

Accepted Answer

Linking of amino acids

Answer

Linking of nucleotides

Answer

Linking of sugars

Answer

Linking of vitamins

Question 29

Which nitrogenous base is NOT found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 30

Which enzyme initiates unwinding of the DNA double helix during replication?

Accepted Answer

Helicase

Answer

Polymerase

Answer

Ligase

Answer

Primase

Question 31

Which RNA molecule transports genetic information from DNA to the ribosome for protein synthesis?

Accepted Answer

mRNA

Answer

tRNA

Answer

rRNA

Answer

snRNA

Question 32

Which region of a gene encodes a specific protein?

Accepted Answer

Exon

Answer

Intron

Answer

UTR

Answer

Promoter

Question 33

Which enzyme catalyses the breakdown of peptide bonds in proteins?

Accepted Answer

Protease

Answer

Ligase

Answer

Polymerase

Answer

Helicase

Question 34

Which process uses energy to synthesize new proteins in cells?

Accepted Answer

Translation

Answer

Transcription

Answer

Replication

Answer

Metabolism

Question 35

What is the primary function of RNA polymerase?

Accepted Answer

To synthesize new RNA strands

Answer

To synthesize new DNA strands

Answer

To unzip the DNA double helix

Answer

To translate mRNA into proteins

Question 36

Which of the following is NOT a type of RNA molecule?

Accepted Answer

DNA

Answer

mRNA

Answer

tRNA

Answer

rRNA

Question 37

What is the process of copying DNA into mRNA called?

Accepted Answer

Transcription

Answer

Replication

Answer

Translation

Answer

Mutation

Question 38

Define the genetic code:

Accepted Answer

A set of rules that determines the sequence of amino acids in a protein

Answer

A set of rules that determines the sequence of nucleotides in a DNA strand

Answer

A set of rules that determines the sequence of RNA molecules in a cell

Answer

A set of rules that determines the structure of a protein

Question 39

What is the main function of a ribosome?

Accepted Answer

To translate mRNA into proteins

Answer

To synthesize new DNA strands

Answer

To synthesize new RNA strands

Answer

To regulate gene expression

Question 40

What is the name of the process by which cells repair damaged DNA?

Accepted Answer

DNA repair

Answer

Replication

Answer

Transcription

Answer

Translation

Question 41

What region of DNA code for a specific protein?

Accepted Answer

Gene

Answer

Exon

Answer

Intron

Answer

Promoter

Question 42

Adenine, thymine, and guanine are nitrogenous bases found in DNA. Which of the following is NOT a nitrogenous base found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Thymine

Answer

Guanine

Question 43

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

Accepted Answer

Helicase

Answer

RNA polymerase

Answer

DNA polymerase

Answer

Ligase

Question 44

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 pre-mRNA.

Answer

To translate mRNA.

Question 45

What is the process by which proteins acquire their functional shape called?

Accepted Answer

Folding

Answer

Transcription

Answer

Translation

Answer

Denaturation

Question 46

What is the primary role of the ribosome in protein synthesis?

Accepted Answer

To translate mRNA into amino acids.

Answer

To unwind the DNA double helix.

Answer

To synthesize RNA molecules.

Answer

To modify and process proteins.

Question 47

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

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

RNA polymerase

Answer

Ligase

Question 48

What is the primary function of a codon in an mRNA molecule?

Accepted Answer

To specify a specific amino acid

Answer

To start or stop protein synthesis

Answer

To carry genetic information from the nucleus

Answer

To assemble ribosomes

Question 49

Which of the following is a type of mutation that involves the insertion or deletion of nucleotides, causing a shift in the reading frame?

Accepted Answer

Frameshift mutation

Answer

Point mutation

Answer

Nonsense mutation

Answer

Missense mutation

Question 50

What is the name of the regulatory element that controls gene expression by binding to repressor proteins?

Accepted Answer

Operator

Answer

Promoter

Answer

Enhancer

Answer

Terminator

Question 51

Which of the following is a characteristic of eukaryotic DNA?

Accepted Answer

It is linear and double-stranded

Answer

It is circular and double-stranded

Answer

It is circular and single-stranded

Answer

It is linear and single-stranded

Question 52

What is the process by which DNA is transcribed into RNA?

Accepted Answer

Transcription

Answer

Translation

Answer

Replication

Answer

Gene expression

Question 53

What is the name of the chemical bond that holds together consecutive amino acids in a polypeptide chain?

Accepted Answer

Peptide bond

Answer

Glycosidic bond

Answer

Phosphodiester bond

Answer

Hydrogen bond

Question 54

Which of the following is a type of enzyme that catalyzes the addition or removal of chemical groups from DNA?

Accepted Answer

Restriction enzyme

Answer

Polymerase

Answer

Ligase

Answer

Helicase

Question 55

How can genetic engineering be used to improve crop yield, resistance to pests and diseases, and nutritional value?

Accepted Answer

Increase crop yield

Accepted Answer

Enhance resistance to pests and diseases

Accepted Answer

Improve nutritional value

Question 56

Which of the following is NOT a component of a nucleotide?

Accepted Answer

Amino acid

Answer

Nitrogenous base

Answer

Pentose sugar

Answer

Phosphate group

Question 57

The process by which DNA is copied into RNA is known as:

Accepted Answer

Transcription

Answer

Replication

Answer

Translation

Answer

Transcription and Translation

Question 58

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

Accepted Answer

Helicase

Answer

DNA Polymerase

Answer

RNA Polymerase

Answer

Ligase

Question 59

Which type of RNA carries the genetic code from DNA to the ribosome?

Accepted Answer

mRNA

Answer

tRNA

Answer

rRNA

Answer

snRNA

Question 60

The bond formed between a nitrogenous base and a sugar molecule in a nucleotide is called a:

Accepted Answer

Glycosidic bond

Answer

Phosphodiester bond

Answer

Peptide bond

Answer

Hydrogen bond

Question 61

Which of the following is NOT a function of proteins?

Accepted Answer

Duplicating themselves

Answer

Catalyzing reactions

Answer

Transporting molecules

Answer

Storing information

Question 62

The process by which a cell deciphers the message in DNA and synthesizes a protein is known as:

Accepted Answer

Translation

Answer

Transcription

Answer

Replication

Answer

Mutation

Question 63

How does DNA methylation affect gene expression?

Accepted Answer

DNA methylation prevents transcription factors from binding, turning off gene expression.

Answer

DNA methylation changes the DNA structure, making it easier for transcription factors to bind, turning on gene expression.

Question 64

Which of the following statements describes genetic code degeneracy?

Accepted Answer

Multiple codons can code for the same amino acid

Answer

A single codon codes for multiple amino acids

Answer

The genetic code is identical in all living organisms

Answer

Genetic code degeneracy influences protein structure