Molecular Biology Learning Quizzes for Year 12 Biology Students

Question 1

In eukaryotic cells, which of the following correctly describes the sequential molecular events involved in gene expression?

Accepted Answer

RNA transcription, mRNA processing, protein translation

Answer

DNA transcription, RNA translation, protein synthesis

Answer

DNA replication, RNA transcription, protein synthesis

Answer

RNA transcription, protein synthesis, DNA replication

Question 2

In DNA, which base pairs with Adenine?

Accepted Answer

Thymine

Answer

Uracil

Answer

Cytosine

Answer

Guanine

Question 3

Which nitrogenous base is NOT found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 4

Which of the following is **not** a step in protein synthesis?

Accepted Answer

Replication

Answer

Transcription

Answer

Translation

Answer

Splicing

Question 5

Which of the following is not a stage of transcription?

Accepted Answer

Translation

Answer

Initiation

Answer

Elongation

Answer

Termination

Question 6

Identify the nitrogenous base NOT found in DNA:

Accepted Answer

Uracil

Answer

Adenine

Answer

Guanine

Question 7

Question: In molecular biology, which process creates RNA using a DNA template?

Accepted Answer

Transcription

Answer

DNA replication

Answer

Translation

Answer

Meiosis

Question 8

Which component is NOT found in a nucleotide?

Accepted Answer

Amino acid

Answer

Nitrogenous base

Answer

Deoxyribose or ribose sugar

Answer

Phosphate group

Question 9

Which nitrogenous base is exclusive to RNA and absent in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Question 10

Which of these is NOT a nucleotide base found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Guanine

Question 11

In transcription, which enzyme plays the primary role in creating an RNA molecule that complements a DNA template?

Accepted Answer

RNA polymerase

Answer

DNA polymerase

Answer

Reverse transcriptase

Answer

Helicase

Question 12

During DNA replication, which enzyme adds complementary nucleotides to the growing DNA strands?

Accepted Answer

DNA polymerase

Answer

Helicase

Answer

RNA polymerase

Answer

Ligase

Question 13

In metaphase of mitosis, how do the chromosomes align?

Accepted Answer

In a straight line along the equator of the cell

Answer

In pairs at the center of the cell

Answer

Migrating to opposite ends of the cell

Question 14

Which protein is essential for the proper separation of chromosomes during cell division?

Accepted Answer

Cohesin

Answer

Histone

Answer

DNA polymerase

Answer

RNA polymerase

Question 15

In prophase, which cellular structure transforms to prepare for cell division?

Accepted Answer

Chromosomes

Answer

Nuclear envelope

Answer

Spindle fibers

Answer

Centrioles

Question 16

In gene expression, which process utilizes messenger RNA (mRNA)?

Accepted Answer

Translation

Answer

Transcription

Answer

Replication

Answer

Mutation

Question 17

During mitosis, which phase involves the condensation of chromosomes and the formation of the mitotic spindle?

Accepted Answer

Prophase

Answer

Interphase

Answer

Metaphase

Answer

Telophase

Question 18

Which nitrogenous base is exclusive to RNA and absent in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Guanine

Answer

Cytosine

Question 19

Which nitrogenous base is exclusive to DNA and not found in RNA?

Accepted Answer

Thymine

Answer

Adenine

Answer

Guanine

Answer

Cytosine

Question 20

During transcription, an RNA molecule is synthesized using a DNA template. Which of the following processes does NOT occur during transcription?

Accepted Answer

Translation of the RNA molecule into a protein

Answer

Initiation of RNA synthesis at the promoter region

Answer

Elongation of the RNA molecule by adding nucleotides complementary to the DNA template

Answer

Termination of transcription and release of the RNA molecule

Question 21

Which process uses the information in mRNA to make proteins?

Accepted Answer

Translation

Answer

Transcription

Answer

Replication

Answer

Mutation

Question 22

In transcription, the DNA template strand is used to create an RNA molecule. What is the correct sequence of stages in this process?

Accepted Answer

Initiation, Elongation, Termination

Answer

Elongation, Initiation, Termination

Answer

Termination, Elongation, Initiation

Answer

Initiation, Termination, Elongation

Question 23

In DNA replication, which enzyme plays a crucial role in synthesizing new DNA strands?

Accepted Answer

DNA polymerase

Answer

Helicase

Answer

Ligase

Answer

Primase

Question 24

During the cell cycle, which stage involves the separation of replicated chromosomes and their movement to opposite ends of the cell?

Accepted Answer

Anaphase

Answer

Prophase

Answer

Metaphase

Answer

Telophase

Question 25

During DNA replication, which enzyme is responsible for unwinding and separating the DNA double helix, allowing it to be copied?

Accepted Answer

Helicase

Answer

Polymerase

Answer

Ligase

Question 26

Which enzyme elongates the new DNA strand by adding nucleotides to its 3' end during DNA replication?

Accepted Answer

DNA polymerase III

Answer

DNA ligase

Answer

DNA polymerase I

Answer

DNA primase

Question 27

Which component is unique to DNA and contributes to its double-helix structure, distinguishing it from RNA?

Accepted Answer

Thymine

Answer

Adenine

Answer

Ribose

Answer

Guanine

Question 28

In molecular biology, which molecule provides the template for the synthesis of messenger RNA (mRNA)?

Accepted Answer

DNA

Answer

RNA polymerase

Answer

Transfer RNA (tRNA)

Answer

Ribosomes

Question 29

Which force holds the double helix structure of DNA together?

Accepted Answer

Hydrogen bonds

Answer

Covalent bonds

Answer

Ionic bonds

Answer

Hydrophobic interactions

Question 30

Which process leads to the unwinding of the DNA double helix and the separation of its complementary strands?

Accepted Answer

DNA replication

Answer

Transcription

Answer

Translation

Answer

Gene expression

Question 31

In eukaryotes, which enzyme initiates DNA replication?

Accepted Answer

DNA polymerase alpha-primase

Answer

DNA ligase

Answer

DNA polymerase I

Answer

Helicase

Question 32

Which nitrogenous base is found exclusively in RNA and not in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 33

What are the three main components of a nucleotide?

Accepted Answer

Phosphate group, sugar molecule, and nitrogenous base

Answer

Phosphate group, sugar molecule, and amino acid

Answer

Sugar molecule, nitrogenous base, and amino acid

Answer

Phosphate group, nitrogenous base, and fatty acid

Question 34

In mitosis, which phase is defined by the physical separation of identical sister chromatids?

Accepted Answer

Anaphase

Answer

Prophase

Answer

Metaphase

Answer

Telophase

Question 35

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 36

Which of the following accurately describes Chargaff's rules for base pairing in DNA?

Accepted Answer

Adenine pairs with thymine, and cytosine pairs with guanine.

Answer

Adenine pairs with cytosine, and thymine pairs with guanine.

Answer

Guanine pairs with thymine, and adenine pairs with cytosine.

Answer

Cytosine pairs with thymine, and adenine pairs with guanine.

Question 37

In the process of transcription, which of these plays a role?

Accepted Answer

RNA polymerase

Answer

DNA helicase

Answer

Ligase

Answer

Primase

Question 38

Describe the structure and function of the ribosome, emphasizing its role in protein synthesis.

Accepted Answer

The ribosome is a complex molecular machine in the cytoplasm, made of proteins and RNA.

Accepted Answer

The ribosome has a large and small subunit that come together to make it work.

Accepted Answer

The ribosome helps make proteins by joining amino acids with peptide bonds.

Answer

The ribosome is where mRNA is made from DNA.

Question 39

Which nitrogenous base is exclusive to RNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 40

Which of the following are applications of molecular biology in medicine?

Accepted Answer

Gene therapy: modifying genes to treat diseases

Accepted Answer

Genetic testing: identifying individuals at risk of genetic diseases

Accepted Answer

Personalized medicine: tailoring treatments to a patient's genetic profile

Question 41

In a double-stranded DNA molecule, the nitrogenous bases pair in the following manner:

Accepted Answer

A with T, and G with C

Answer

T with A, and C with G

Answer

G with C, and A with T

Answer

C with G, and A with T

Question 42

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

Accepted Answer

Helicase

Answer

Ligase

Answer

Polymerase

Answer

Primase

Question 43

What is the term for the set of rules that specifies the sequence of amino acids in a protein?

Accepted Answer

Genetic code

Answer

Transcription factor

Answer

Central dogma

Answer

Operon

Question 44

Which of the following is not a function of proteins?

Accepted Answer

Storing genetic information

Answer

Catalyzing biochemical reactions

Answer

Providing structural support

Answer

Transporting molecules

Question 45

Which technique allows for the separation of DNA fragments based on their size?

Accepted Answer

Gel electrophoresis

Answer

Polymerase chain reaction (PCR)

Answer

DNA sequencing

Answer

Southern blotting

Question 46

What type of mutation involves a change in a single nucleotide?

Accepted Answer

Substitution

Answer

Deletion

Answer

Insertion

Answer

Inversion

Question 47

In the process of translation, the ribosomal subunit's primary function is to:

Accepted Answer

Hold the mRNA and tRNA molecules in place

Answer

Catalyze the formation of peptide bonds

Answer

Unwind the DNA double helix

Answer

Release the newly synthesized protein

Question 48

The process of synthesizing mRNA from a DNA template is known as:

Accepted Answer

Transcription

Answer

Translation

Answer

Replication

Answer

Mutation

Question 49

What is the correct order in which genetic information is processed through the central dogma of molecular biology?

Accepted Answer

DNA → mRNA → tRNA → Proteins

Answer

Proteins → mRNA → DNA → tRNA

Answer

tRNA → DNA → Proteins → mRNA

Answer

mRNA → tRNA → DNA → Proteins

Question 50

Which of the following is the primary role of RNA polymerase in the process of transcription?

Accepted Answer

To transcribe DNA into mRNA

Answer

To translate mRNA into proteins

Answer

To replicate DNA

Answer

To regulate gene expression

Question 51

Which of the following amino acids contains a sulfur atom in its structure?

Accepted Answer

Methionine

Answer

Glycine

Answer

Leucine

Answer

Asparagine

Question 52

Which of the following is an example of a regulatory protein involved in gene expression?

Accepted Answer

Transcription factor

Answer

Hemoglobin

Answer

Insulin

Answer

Collagen

Question 53

What is the difference between a codon and an anticodon in the context of protein synthesis?

Accepted Answer

Codons are located on mRNA and specify the amino acid sequence, while anticodons are located on tRNA and are complementary to the codon.

Answer

Anticodons are located on mRNA and specify the amino acid sequence, while codons are located on tRNA and are complementary to the anticodon.

Answer

Codons contain three nucleotides, while anticodons contain four nucleotides.

Answer

Anticodons contain three nucleotides, while codons contain four nucleotides.

Question 54

Which of the following techniques is commonly used to amplify DNA in molecular biology?

Accepted Answer

Polymerase chain reaction (PCR)

Answer

Gel electrophoresis

Answer

DNA sequencing

Answer

DNA fingerprinting

Question 55

One of the ethical implications of genetic engineering is:

Accepted Answer

Potential misuse of genetic information

Answer

It has no ethical implications

Answer

It only benefits society by improving healthcare and crop yield

Answer

It should be banned because it goes against the principles of natural selection

Question 56

What is the final product of the protein synthesis process?

Accepted Answer

Polypeptide chain

Answer

mRNA

Answer

tRNA

Answer

DNA molecule

Question 57

In RNA interference (RNAi), what is the primary function of microRNAs?

Accepted Answer

Guide RISC to complementary mRNA, leading to mRNA cleavage

Answer

Inhibit mRNA translation directly, preventing protein synthesis

Answer

Involve in DNA methylation, causing epigenetic changes in gene expression

Question 58

In the development of cancer, which statement accurately describes the roles of oncogenes and tumor suppressor genes?

Accepted Answer

Oncogenes stimulate cell growth, while tumor suppressor genes hinder it.

Answer

Oncogenes hinder cell growth, while tumor suppressor genes stimulate it.

Answer

Both oncogenes and tumor suppressor genes stimulate cell growth.

Question 59

Which of the following is not a core principle of bioinformatics?

Accepted Answer

Drug discovery and development

Answer

Data acquisition and management

Answer

Sequence analysis

Question 60

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

Accepted Answer

Helicase

Answer

Polymerase

Answer

Ligase

Question 61

Describe the primary function of tRNA in protein synthesis.

Accepted Answer

Transporting amino acids to the ribosome

Answer

Identifying the codon on mRNA

Answer

Joining amino acids

Question 62

Describe the primary role of a promoter in gene expression.

Accepted Answer

Initiating transcription by binding RNA polymerase

Answer

Terminating transcription

Answer

Splicing introns out of pre-mRNA

Question 63

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

Accepted Answer

Gel electrophoresis

Answer

Restriction digestion

Answer

DNA sequencing

Question 64

State the central dogma of molecular biology.

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Answer

Protein is transcribed into DNA, which is then translated into RNA.