DNA Structure and Gene Expression
Practise Questions
Set 1
1. Question: Explain the importance of the chromosome manipulation that took place in
1908 in the context of molecular biology.
o A) It allowed scientists to understand the structure of DNA
o B) It paved the way for genetic engineering and understanding heredity
o C) It led to the discovery of RNA and its functions
o D) It established the concept of epigenetics
Answer: A) It allowed scientists to understand the structure of DNA
2. Question: Explain the importance of the discovery of meiosis in 1911 in the context of
genetics and reproduction.
o A) It revealed how DNA is replicated
o B) It provided insight into how genetic variation occurs during sexual
reproduction
o C) It demonstrated the process of protein synthesis
o D) It showed how mutations affect gene expression
Answer: B) It provided insight into how genetic variation occurs during sexual
reproduction
3. Question: The discovery of the genetic role of DNA began with research by
_____________ in 1928.
Answer: Frederick Griffith
4. Question: What type of molecule did Oswald Avery and his colleagues identify as the
transforming principle in their experiments with heat-killed pathogenic bacteria?
Answer: DNA
5. Question: Explain Chargaff's rule of base pairing and its significance in the structure of
DNA.
Answer: It asserts that the amount of adenine equals the amount of thymine and the
amount of guanine equals the amount of cytosine, which is essential for the double helix
structure.
6. Question: Who were the scientists credited with the discovery of the double helix
structure of DNA?
Answer: James Watson and Francis Crick
7. Question: What is the primary purpose of using X-ray diffraction in the study of DNA?
Answer: To visualize the three-dimensional structure of DNA
8. Question: "Photo 51" played a pivotal role in the discovery of the DNA double helix
structure. Which statement about "Photo 51" is incorrect?
o A) It was imaged by James Watson and Francis Crick
o B) It was captured by Rosalind Franklin
o C) It provided key information for the structure of DNA
, o D) It showed the helical structure of DNA
Answer: A) It was imaged by James Watson and Francis Crick
9. Question: What is the distance that Watson and Crick's model indicates for one full turn
of the DNA double helix?
Answer: 3.4 nm
10. Question: The fact that within a double-stranded DNA molecule, adenine forms two
hydrogen bonds with thymine and cytosine forms three hydrogen bonds with guanine is
known as ________.
Answer: Chargaff's rule
Set 2
1. Question: Constitutive gene expression means the genes are
o A) Always 'on'
o B) Expressed only when required
o C) Never transcribed
o D) Only active in certain cell types
Answer: A) Always 'on'
2. Question: Genes that are expressed only as needed are called ________________.
Answer: Inducible genes
3. Question: Which of the following correctly describes the composition of a nucleotide?
o A) A nitrogenous base, a pentose sugar, and one or more phosphate groups
o B) Two nitrogenous bases, a ribose, and a phosphate
o C) A nitrogenous base and a ribose
o D) A phosphate and a nitrogenous base only
Answer: A) A nitrogenous base, a pentose sugar, and one or more phosphate
groups
4. Question: What is the function of the 2' carbon in the pentose sugar found in DNA and
RNA?
o A) In DNA, it lacks an oxygen atom, making it deoxyribose; in RNA, it has an
OH group, making it ribose
o B) It helps the nucleotide bind to other nucleotides
o C) It is involved in DNA replication
o D) It determines the base pairing properties
Answer: A) In DNA, it lacks an oxygen atom, making it deoxyribose; in RNA, it
has an OH group, making it ribose
5. Question: The 'code' in DNA is made by varying which part of each nucleotide?
Answer: The nitrogenous base
6. Question: What defines a nucleoside in the context of nucleic acid structure?
Answer: A combination of a nitrogenous base and a sugar linked by a glycosidic bond
7. Question: Which of the following statements accurately describes the role of the
phosphate group in a nucleotide?
Answer: It provides a negative charge and is attached to the 5'-carbon of the sugar
8. Question: Which of the following correctly describes a nucleoside monophosphate
(NMP)?
Practise Questions
Set 1
1. Question: Explain the importance of the chromosome manipulation that took place in
1908 in the context of molecular biology.
o A) It allowed scientists to understand the structure of DNA
o B) It paved the way for genetic engineering and understanding heredity
o C) It led to the discovery of RNA and its functions
o D) It established the concept of epigenetics
Answer: A) It allowed scientists to understand the structure of DNA
2. Question: Explain the importance of the discovery of meiosis in 1911 in the context of
genetics and reproduction.
o A) It revealed how DNA is replicated
o B) It provided insight into how genetic variation occurs during sexual
reproduction
o C) It demonstrated the process of protein synthesis
o D) It showed how mutations affect gene expression
Answer: B) It provided insight into how genetic variation occurs during sexual
reproduction
3. Question: The discovery of the genetic role of DNA began with research by
_____________ in 1928.
Answer: Frederick Griffith
4. Question: What type of molecule did Oswald Avery and his colleagues identify as the
transforming principle in their experiments with heat-killed pathogenic bacteria?
Answer: DNA
5. Question: Explain Chargaff's rule of base pairing and its significance in the structure of
DNA.
Answer: It asserts that the amount of adenine equals the amount of thymine and the
amount of guanine equals the amount of cytosine, which is essential for the double helix
structure.
6. Question: Who were the scientists credited with the discovery of the double helix
structure of DNA?
Answer: James Watson and Francis Crick
7. Question: What is the primary purpose of using X-ray diffraction in the study of DNA?
Answer: To visualize the three-dimensional structure of DNA
8. Question: "Photo 51" played a pivotal role in the discovery of the DNA double helix
structure. Which statement about "Photo 51" is incorrect?
o A) It was imaged by James Watson and Francis Crick
o B) It was captured by Rosalind Franklin
o C) It provided key information for the structure of DNA
, o D) It showed the helical structure of DNA
Answer: A) It was imaged by James Watson and Francis Crick
9. Question: What is the distance that Watson and Crick's model indicates for one full turn
of the DNA double helix?
Answer: 3.4 nm
10. Question: The fact that within a double-stranded DNA molecule, adenine forms two
hydrogen bonds with thymine and cytosine forms three hydrogen bonds with guanine is
known as ________.
Answer: Chargaff's rule
Set 2
1. Question: Constitutive gene expression means the genes are
o A) Always 'on'
o B) Expressed only when required
o C) Never transcribed
o D) Only active in certain cell types
Answer: A) Always 'on'
2. Question: Genes that are expressed only as needed are called ________________.
Answer: Inducible genes
3. Question: Which of the following correctly describes the composition of a nucleotide?
o A) A nitrogenous base, a pentose sugar, and one or more phosphate groups
o B) Two nitrogenous bases, a ribose, and a phosphate
o C) A nitrogenous base and a ribose
o D) A phosphate and a nitrogenous base only
Answer: A) A nitrogenous base, a pentose sugar, and one or more phosphate
groups
4. Question: What is the function of the 2' carbon in the pentose sugar found in DNA and
RNA?
o A) In DNA, it lacks an oxygen atom, making it deoxyribose; in RNA, it has an
OH group, making it ribose
o B) It helps the nucleotide bind to other nucleotides
o C) It is involved in DNA replication
o D) It determines the base pairing properties
Answer: A) In DNA, it lacks an oxygen atom, making it deoxyribose; in RNA, it
has an OH group, making it ribose
5. Question: The 'code' in DNA is made by varying which part of each nucleotide?
Answer: The nitrogenous base
6. Question: What defines a nucleoside in the context of nucleic acid structure?
Answer: A combination of a nitrogenous base and a sugar linked by a glycosidic bond
7. Question: Which of the following statements accurately describes the role of the
phosphate group in a nucleotide?
Answer: It provides a negative charge and is attached to the 5'-carbon of the sugar
8. Question: Which of the following correctly describes a nucleoside monophosphate
(NMP)?
