DNA Structure and Replication: Interactive Quizzes for Year 12 Biology

Question 1

Which nitrogenous base is NOT found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Thymine

Answer

Cytosine

Question 2

Which of the following statements about DNA replication is correct?

Accepted Answer

It is a semi-conservative process

Answer

It occurs only in the nucleus.

Answer

It results in the formation of four identical daughter DNA molecules

Answer

It is initiated by the enzyme polymerase

Question 3

What is the role of RNA primers in DNA replication?

Accepted Answer

To provide a starting point for DNA polymerase

Answer

To stabilize the DNA double helix

Answer

To remove RNA nucleotides from the DNA molecule

Answer

To proofread the newly synthesized DNA strand

Question 4

What is the name of the region of DNA where replication is initiated?

Accepted Answer

Origin of replication

Answer

Telomere

Answer

Centromere

Answer

R-loop

Question 5

Which of the following is the correct sequence of events in DNA replication?

Accepted Answer

Unwinding → RNA primer synthesis → DNA synthesis → RNA primer removal → Ligation

Answer

Unwinding → DNA synthesis → RNA primer synthesis → RNA primer removal → Ligation

Answer

DNA synthesis → Unwinding → RNA primer synthesis → RNA primer removal → Ligation

Answer

RNA primer synthesis → Unwinding → DNA synthesis → RNA primer removal → Ligation

Question 6

What is the difference between the leading and lagging strands in DNA replication?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously

Answer

The lagging strand is synthesized continuously, while the leading strand is synthesized discontinuously

Answer

Both strands are synthesized continuously

Answer

Both strands are synthesized discontinuously

Question 7

What is the shape of the DNA molecule?

Accepted Answer

Double helix

Answer

Single helix

Answer

Triple helix

Answer

Quadruple helix

Question 8

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

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

Ligase

Answer

Primase

Question 9

What is the role of Okazaki fragments in DNA replication?

Accepted Answer

Fragments of DNA synthesized on the lagging strand

Answer

Fragments of DNA synthesized on the leading strand

Answer

Fragments of DNA joined together by DNA polymerase

Answer

Fragments of DNA removed by exonuclease

Question 10

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

Accepted Answer

Gel electrophoresis

Answer

PCR

Answer

DNA sequencing

Answer

DNA microarrays

Question 11

According to the double helix model, how are the two strands of DNA held together?

Accepted Answer

Hydrogen bonds

Answer

Ionic bonds

Answer

Covalent bonds

Answer

Phosphodiester bonds

Question 12

Which of the following is NOT a factor that can affect the rate of DNA replication?

Accepted Answer

Number of genes

Answer

Temperature

Answer

pH

Answer

Enzyme concentration

Question 13

What is the role of telomerase in DNA replication?

Accepted Answer

Extends the ends of chromosomes

Answer

Shortens the ends of chromosomes

Answer

Protects chromosomes from damage

Answer

Initiates DNA replication

Question 14

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

Accepted Answer

Gel electrophoresis

Answer

Polymerase chain reaction

Answer

Microarray

Answer

DNA sequencing

Question 15

What is the significance of DNA methylation in gene expression?

Accepted Answer

Represses gene expression

Answer

Activates gene expression

Answer

Has no effect on gene expression

Answer

Causes mutations in DNA

Question 16

Which nitrogenous base is NOT found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Thymine

Answer

Cytosine

Question 17

What is the shape of a DNA molecule?

Accepted Answer

Double helix

Answer

Straight line

Answer

Circular

Answer

Triangular

Question 18

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

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

Ligase

Answer

Primase

Question 19

What is the role of primers in DNA replication?

Accepted Answer

To provide a free 3'-OH group for DNA polymerase to add nucleotides

Answer

To stabilize the newly synthesized DNA strand

Answer

To unwind the DNA strands

Answer

To activate the nucleotides

Question 20

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

Accepted Answer

Gel electrophoresis

Answer

PCR

Answer

DNA sequencing

Answer

DNA hybridization

Question 21

Which nitrogenous base is NOT present in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 22

What type of bonds connect the nitrogenous bases in DNA nucleotides?

Accepted Answer

Hydrogen bonds

Answer

Ionic bonds

Answer

Covalent bonds

Answer

Van der Waals bonds

Question 23

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

Accepted Answer

Double helix

Answer

Straight chain

Answer

Circular

Answer

Linear

Question 24

Who is credited with discovering the double helix structure of DNA?

Accepted Answer

James Watson and Francis Crick

Answer

Charles Darwin

Answer

Rosalind Franklin

Answer

Gregor Mendel

Question 25

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

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

DNA ligase

Answer

RNA polymerase

Question 26

What is the significance of the leading and lagging strands during DNA replication?

Accepted Answer

To allow for continuous replication in both directions

Answer

To ensure accurate copying of the DNA

Answer

To prevent DNA tangling

Answer

To control the speed of replication

Question 27

What is the relevance of the central dogma of molecular biology?

Accepted Answer

It explains the flow of genetic information in cells

Answer

It describes how DNA is utilized to synthesize proteins

Answer

It highlights the genetic basis of inheritance

Answer

It predicts the structures of various biomolecules

Question 28

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

Accepted Answer

Gel electrophoresis

Answer

Polymerase chain reaction (PCR)

Answer

DNA sequencing

Answer

DNA microarrays

Question 29

In DNA replication, what is the main role of DNA helicases?

Accepted Answer

Unwinding the DNA double helix

Answer

Creating new DNA strands

Answer

Correcting errors in DNA replication

Answer

Organizing DNA into nucleosomes

Question 30

Identify the complementary base pair to thymine in DNA.

Accepted Answer

Adenine

Answer

Cytosine

Answer

Guanine

Answer

Uracil

Question 31

During DNA replication, which enzyme plays a crucial role in unwinding and separating the DNA strands?

Accepted Answer

Helicase

Answer

DNA Polymerase

Answer

Primase

Answer

DNA Ligase

Question 32

What is the name given to the short RNA fragments that initiate DNA replication?

Accepted Answer

Primers

Answer

Okazaki fragments

Answer

Telomeres

Answer

Centromeres

Question 33

In eukaryotic cells, what is the primary function of telomeres?

Accepted Answer

Protecting chromosome ends from degradation

Answer

Initiating DNA replication

Answer

Regulating gene expression

Answer

Facilitating chromosome segregation

Question 34

Which technique is commonly used to visualize and analyze DNA fragments?

Accepted Answer

Gel electrophoresis

Answer

PCR (Polymerase Chain Reaction)

Answer

DNA sequencing

Answer

Microarrays

Question 35

State the central dogma of molecular biology.

Accepted Answer

DNA → RNA → Protein

Answer

RNA → DNA → Protein

Answer

Protein → DNA → RNA

Answer

Protein → RNA → DNA

Question 36

Which of the following represents the complementary base pairing rule in DNA?

Accepted Answer

Adenine pairs with thymine, while cytosine pairs with guanine.

Answer

Adenine pairs with cytosine, while guanine pairs with thymine.

Answer

Guanine pairs with cytosine, while adenine pairs with thymine.

Answer

Thymine pairs with cytosine, while adenine pairs with guanine.

Question 37

The outcome of DNA replication is:

Accepted Answer

Two identical daughter molecules with genetic information identical to the parent DNA.

Answer

One daughter molecule identical to the parent DNA and one with a distinct genetic sequence.

Answer

Two daughter molecules that are genetically identical but different from the parent DNA.

Answer

Four daughter molecules, each containing half the genetic information of the parent DNA.

Question 38

During DNA replication, which enzyme unwinds the DNA molecule?

Accepted Answer

DNA helicase

Answer

DNA polymerase

Answer

RNA polymerase

Answer

Primase

Question 39

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

Accepted Answer

Uracil

Answer

Thymine

Answer

Adenine

Answer

Guanine

Question 40

What type of bond links complementary base pairs in DNA?

Accepted Answer

Hydrogen bond

Answer

Glycosidic bond

Answer

Phosphodiester bond

Answer

Covalent bond

Question 41

Which scientists are credited with discovering the double helix structure of DNA?

Accepted Answer

Watson and Crick

Answer

James Watson

Answer

Rosalind Franklin

Answer

Gregor Mendel

Question 42

What is the primary role of helicase in DNA replication?

Accepted Answer

Unwind the double helix

Answer

Separate the leading and lagging strands

Answer

Proofread newly synthesized DNA

Question 43

Which of the following enzymes is responsible for synthesizing new DNA strands during replication?

Accepted Answer

DNA polymerase

Answer

Helicase

Answer

RNA polymerase

Answer

Topoisomerase

Question 44

What is the key difference between the leading and lagging strands during DNA replication?

Accepted Answer

The lagging strand is synthesized discontinuously

Answer

The leading strand is synthesized in the 5' to 3' direction

Answer

The leading strand is longer than the lagging strand

Answer

The leading strand is more accurate than the lagging strand

Question 45

What is the primary function of telomeres in DNA replication?

Accepted Answer

Prevent the loss of genetic information during cell division

Answer

Proofread newly synthesized DNA strands

Answer

Initiate the process of DNA replication

Question 46

What is the significance of DNA replication in living organisms?

Accepted Answer

Ensures the accurate transmission of genetic information to daughter cells

Answer

Repairs damaged DNA

Answer

Provides energy for metabolic processes

Question 47

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

Accepted Answer

Uracil

Answer

Guanine

Answer

Adenine

Answer

Cytosine

Question 48

The shape of the DNA molecule is best described as a:

Accepted Answer

Double helix

Answer

Single helix

Answer

Linear chain

Answer

Triple helix

Question 49

Who are credited with discovering the iconic double helix structure of DNA?

Accepted Answer

James Watson and Francis Crick

Answer

Gregor Mendel

Answer

Charles Darwin

Answer

Rosalind Franklin

Question 50

The biological process responsible for copying DNA is referred to as:

Accepted Answer

Replication

Answer

Mutation

Answer

Transcription

Answer

Translation

Question 51

During DNA replication, the two newly synthesized strands are arranged in an:

Accepted Answer

Antiparallel orientation

Answer

Perpendicular orientation

Answer

Parallel orientation

Answer

Random orientation

Question 52

Which enzyme plays a crucial role in unwinding and separating the DNA double helix during replication?

Accepted Answer

Helicase

Answer

Ligase

Answer

Polymerase

Answer

Topoisomerase

Question 53

The leading strand during DNA replication is synthesized:

Accepted Answer

Continuously in the 5' to 3' direction

Answer

Discontinuously in the 3' to 5' direction

Answer

Discontinuously in the 5' to 3' direction

Answer

Randomly

Question 54

According to the complementary base pairing rules, which base pairs with adenine (A) in DNA?

Accepted Answer

Thymine (T)

Answer

Guanine (G)

Answer

Cytosine (C)

Answer

Uracil (U)