Master DNA Structure and Replication: Interactive Quizzes for Year 13 Biology

Question 1

Which of the following best describes the process of DNA replication?

Accepted Answer

Helicase is an enzyme that unwinds the DNA double helix, allowing for strand separation.

Accepted Answer

DNA replication is a semi-conservative process, resulting in each new DNA molecule containing one original and one newly synthesized strand.

Answer

DNA replication occurs in the cell's cytoplasm.

Answer

DNA replication is only necessary for cell division.

Question 2

What type of base pairing is observed in DNA?

Accepted Answer

A-T and G-C

Answer

A-C and G-T

Answer

A-G and C-T

Answer

T-T and C-C

Question 3

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

Accepted Answer

Helicase

Answer

Polymerase

Answer

Ligase

Answer

Primase

Question 4

What is the primary function of the hydrogen bonds in the DNA double helix?

Accepted Answer

To hold the base pairs together

Answer

To provide stability to the helix

Answer

To control gene expression

Answer

To catalyze chemical reactions

Question 5

What is the primary significance of DNA replication in cell division?

Accepted Answer

Ensures each new cell receives a complete copy of the genetic material

Answer

Provides a mechanism for DNA repair and maintenance

Answer

Initiates transcription and translation

Answer

Regulates cell growth and development

Question 6

What type of bond connects the two strands of the DNA double helix?

Accepted Answer

Hydrogen bond

Answer

Covalent bond

Answer

Ionic bond

Answer

Van der Waals force

Question 7

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

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

Ligase

Answer

RNA polymerase

Question 8

During DNA replication, which nucleotide is added to the growing strand when the template strand has a cytosine (C) base?

Accepted Answer

Guanine (G)

Answer

Adenine (A)

Answer

Thymine (T)

Answer

Cytosine (C)

Question 9

What is the primary significance of DNA replication in cell division?

Accepted Answer

Ensures that each daughter cell receives an identical copy of the genetic material.

Answer

Prevents mutations from accumulating in the genome.

Answer

Facilitates the repair of damaged DNA.

Answer

Promotes cell growth and development.

Question 10

Which of the following laboratory techniques is commonly used to separate DNA fragments based on their size?

Accepted Answer

Gel electrophoresis

Answer

Polymerase chain reaction (PCR)

Answer

Southern blotting

Answer

DNA sequencing

Question 11

What is the structural difference between a purine and a pyrimidine nitrogenous base?

Accepted Answer

Purines have a double-ring structure, while pyrimidines have a single-ring structure.

Answer

Purines have a single-ring structure, while pyrimidines have a double-ring structure.

Answer

Purines contain nitrogen and carbon atoms, while pyrimidines contain nitrogen and oxygen atoms.

Answer

Pyrimidines contain nitrogen and oxygen atoms, while purines contain nitrogen and carbon atoms.

Question 12

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

Accepted Answer

Uracil

Answer

Adenine

Answer

Guanine

Answer

Cytosine

Question 13

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

Accepted Answer

Helicase

Answer

Polymerase

Answer

Ligase

Answer

Primase

Question 14

During DNA replication, which strand is synthesized continuously in the 5' to 3' direction?

Accepted Answer

Leading strand

Answer

Lagging strand

Answer

Both strands are synthesized continuously.

Answer

Neither strand is synthesized continuously.

Question 15

What is the distinction between the template strand and the coding strand in DNA replication?

Accepted Answer

The template strand is used to synthesize the new complementary strand, while the coding strand serves as the reference for transcription.

Answer

The coding strand is used to synthesize the new complementary strand, while the template strand is the original strand.

Answer

The template strand contains the genetic code, while the coding strand does not.

Answer

The coding strand contains the genetic code, while the template strand does not.

Question 16

Which of the following is NOT a type of DNA damage?

Accepted Answer

RNA crosslinking

Answer

Single-strand breaks

Answer

Double-strand breaks

Answer

Base modifications

Question 17

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

Accepted Answer

Gel electrophoresis

Answer

PCR

Answer

DNA sequencing

Answer

DNA microarrays

Question 18

In DNA, which of the following pairs of nitrogenous bases are complementary?

Accepted Answer

Adenine and thymine, guanine and cytosine

Answer

Adenine and cytosine, guanine and thymine

Answer

Adenine and both thymine and guanine, while cytosine pairs with both uracil and cytosine

Answer

Thymine and both adenine and cytosine, while guanine pairs with both uracil and guanine

Question 19

Which type of bond is primarily responsible for maintaining the double helix structure of DNA?

Accepted Answer

Hydrogen bonds

Answer

Ionic bonds

Answer

Covalent bonds

Answer

Van der Waals forces

Question 20

Which enzyme plays a central role as the catalyst for DNA replication?

Accepted Answer

DNA polymerase

Answer

RNA polymerase

Answer

Ligase

Answer

Helicase

Question 21

Why is the process of DNA replication referred to as semi-conservative?

Accepted Answer

Each newly formed DNA molecule comprises one original strand and one newly synthesized strand

Answer

The replication process is very fast

Answer

It enables DNA to repair damaged sections

Answer

It prevents the occurrence of mutations

Question 22

Which factor does NOT influence the rate of DNA replication?

Accepted Answer

DNA sequence

Answer

Temperature

Answer

pH

Answer

Enzyme concentration

Question 23

What is the purpose of the proofreading step during DNA replication?

Accepted Answer

Correcting errors introduced by DNA polymerase

Answer

Preventing mutations

Answer

Removing RNA primers from newly created DNA strands

Answer

Joining Okazaki fragments on the lagging strand

Question 24

Which type of DNA repair mechanism is used to repair double-strand breaks?

Accepted Answer

Homologous recombination

Answer

Mismatch repair

Answer

Nucleotide excision repair

Answer

Base excision repair

Question 25

Which of the following statements accurately describes the structure of DNA?

Accepted Answer

DNA consists of nucleotides, each composed of a sugar, phosphate, and nitrogenous base.

Answer

DNA is a single-stranded molecule.

Answer

DNA exclusively contains guanine nucleotides.

Answer

The nitrogenous bases of DNA are not involved in hydrogen bonding.

Question 26

Which type of bond primarily maintains the structure of the DNA double helix?

Accepted Answer

Hydrogen bond

Answer

Covalent bond

Answer

Ionic bond

Answer

Disulfide bond

Question 27

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

Accepted Answer

DNA helicase

Answer

DNA ligase

Answer

RNA polymerase

Answer

Primase

Question 28

What is the primary role of RNA primers in DNA replication?

Accepted Answer

To act as templates for DNA polymerase to initiate DNA synthesis

Answer

To prevent DNA strands from breaking down

Answer

To stabilize the DNA double helix

Answer

To terminate DNA synthesis

Question 29

Which of the following is NOT a key step in the DNA replication process?

Accepted Answer

Translation of DNA into proteins

Answer

Unwinding of the DNA double helix

Answer

Formation of new complementary DNA strands

Answer

Proofreading and repair of DNA strands

Question 30

Which of the following is NOT a type of mutation?

Accepted Answer

Epigenetic change

Answer

Silent mutation

Answer

Frameshift mutation

Answer

Chromosomal mutation

Question 31

Telomeres play a crucial role in DNA replication and cellular aging. Explain their function and significance.

Accepted Answer

Telomeres are specialized DNA sequences that protect chromosome ends from damage and fusion.

Accepted Answer

During DNA replication, telomeres shorten due to the inability of DNA polymerase to fully replicate chromosome ends.

Accepted Answer

Telomere shortening triggers cellular senescence or apoptosis, limiting the lifespan of normal human cells.

Answer

Telomeres are absent in prokaryotic cells and have no role in DNA replication or cellular aging.

Question 32

Identify the enzyme that initiates the unwinding of the DNA double helix during replication.

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

RNA polymerase

Answer

Ligase

Question 33

Describe the role of ligase in DNA replication.

Accepted Answer

Joins newly synthesized DNA fragments

Answer

Unzips the DNA double helix

Answer

Adds nucleotides to the growing DNA strand

Answer

Proofreads the newly synthesized DNA strand

Question 34

Which type of mutation allows for the addition of new genetic material to a gene?

Accepted Answer

Insertion

Answer

Substitution

Answer

Deletion

Question 35

What type of chemical bond joins the nitrogenous bases in a DNA molecule?

Accepted Answer

Hydrogen bond

Answer

Van der Waals force

Answer

Ionic bond

Answer

Covalent bond

Question 36

Which of the following accurately describes the shape of a DNA molecule?

Accepted Answer

Double helix

Answer

Single helix

Answer

Linear

Answer

Circular

Question 37

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

Accepted Answer

Helicase

Answer

Ligase

Answer

Polymerase

Question 38

What is the primary function of DNA polymerase in DNA replication?

Accepted Answer

Catalyzes the addition of nucleotides to the growing DNA strand

Answer

Removes RNA primers

Answer

Joins Okazaki fragments

Answer

Unwinds the DNA double helix

Question 39

Which of the following is NOT a recognized mode of DNA replication?

Accepted Answer

RNA replication

Answer

Conservative replication

Answer

Semi-conservative replication

Answer

Dispersive replication

Question 40

What is the fundamental purpose of DNA replication during cell division?

Accepted Answer

Ensures that each new daughter cell receives an identical copy of the genetic material from the parent cell

Answer

Repairs damaged DNA

Answer

Increases cell size

Question 41

What are Okazaki fragments?

Accepted Answer

Short, newly synthesized DNA segments formed on the lagging strand during DNA replication

Answer

Long, newly synthesized DNA segments formed on the leading strand during DNA replication

Answer

Enzymes that join adjacent Okazaki fragments together

Question 42

What is the significance of DNA replication in the context of inheritance?

Accepted Answer

It enables the transmission of genetic information from one generation to the next

Answer

Repairs damaged DNA

Answer

Controls cell growth

Question 43

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

Accepted Answer

Amino acid

Answer

Deoxyribose sugar

Answer

Nitrogenous base

Answer

Phosphate group

Question 44

What type of bond links complementary nitrogenous bases in DNA?

Accepted Answer

Hydrogen bond

Answer

Covalent bond

Answer

Ionic bond

Answer

Van der Waals force

Question 45

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

Accepted Answer

Helicase

Answer

Ligase

Answer

Polymerase

Question 46

What is the role of Okazaki fragments in DNA replication?

Accepted Answer

Short DNA segments synthesized on the lagging strand

Answer

Initiation points for leading strand synthesis

Answer

Gaps in the newly synthesized DNA strand

Question 47

Which of the following is a consequence of DNA replication errors?

Accepted Answer

Mutations

Answer

Increased genetic diversity

Answer

Enhanced cell division

Answer

Improved DNA stability

Question 48

Which of the following is NOT a function of DNA polymerase?

Accepted Answer

Breaking hydrogen bonds between nitrogenous bases

Answer

Proofreading newly synthesized DNA

Answer

Adding nucleotides to the growing DNA strand

Answer

Elongating the DNA strand in the 5' to 3' direction

Question 49

What is the purpose of DNA ligase?

Accepted Answer

To join Okazaki fragments on the lagging strand

Answer

To proofread newly synthesized DNA

Answer

To synthesize RNA primers

Answer

To unwind the DNA double helix

Question 50

Which of the following statements about DNA replication is true?

Accepted Answer

It occurs in the nucleus of eukaryotic cells.

Answer

It is a continuous process on both leading and lagging strands.

Answer

It results in the formation of four identical DNA molecules.

Answer

It is catalyzed by RNA polymerase.