BIOL 112: Unit 2 Practice Questions & Answers – PART I
This document contains some questions for you to practice. The questions are grouped by topic along with
the learning objectives associated with each of the topics. We encourage you to use the learning objectives to
guide your studying; ask yourself if you could answer each objective if it was in the form of a question. There
are different levels of questions provided:
1. Study questions: these are questions on your direct knowledge of the topics, so essentially ‘drills’ on
the basics – practice to make sure you get the fundamentals. Work with these questions first to build
up your skills.
2. Exam-type questions, of which there are two types:
a. Multiple choice: these are the types of questions you are likely to see on the exam – various
levels of application of the fundamental knowledge and skills for each topic area.
b. Open response questions (ORQs): a few examples to give you an idea of the kinds of short
answer questions you will see on the exams.
Nucleic Acids - Structure, DNA assembly and organization
Nucleic acids are one of the four major macromolecules in cells. This topic focuses on the structure, assembly and
organization of DNA highlighting some key structural comparisons to RNA.
Nucleic Acids – Genomes
This topic deals with all the heritable genetic information of a cell or organism as a whole, and introduces how the
structural sequence of the genome dictates observable characteristics.
Study questions:
1. What interactions serve to stabilize/hold DNA together in its secondary structure? Explain how this
stabilizes DNA in its aqueous environment.
Hydrogen bonds between strands (base pairing), stacking interactions (mostly ID-ID) above and below in the
same strand. The stacking interactions allow for the hydrophobic surfaces to be excluded from water, allowing
water to have more motional freedom and thereby increasing stability.
2. By convention how is the directionality of a DNA molecule written?
5’ to 3’
3. By convention how is the directionality of a protein molecule written?
N to C
4. Which linkage forms the backbone of a nucleic acid?
A. A base-phosphate linkage
B. A Sugar-phosphate linkage
C. A sugar-base-phosphate linkage
D. A sugar-base linkage
5. In describing DNA or RNA, you will see the term 5’ to 3’ (verbally, this is “5-prime to 3-prime”). The
terms 5’ and 3’ apply to which of the statement(s) below? Choose all that apply.
A. One of the two DNA strands.
B. The sequence of the bases in the DNA or RNA.
C. The direction of the strands.
D. Particular carbon atoms on the ribose or deoxyribose ring.
E. The linkage between the ribose ring and the base.
,Exam Type Questions:
6. In a bacterium, 14% of the DNA nucleotides were found to be Thymine. What proportions of the bases
would be Guanine?
A. 28% G
B. 36% G
C. 14% G
D. 58% G
E. Cannot be determined.
7. In normal double-stranded DNA, purines base pair with only certain types of pyrimidines. This is
because…
A. a purine-purine pair would be too small, and a pyrimidine-pyrimidine pair would be too large
B. the number of A must equal the number of T and the number of G must equal the number of C
C. the strongest stacking interactions are found between purines and pyrimidines, making the DNA
more stable
D. purine-pyrimidine pairs maximize the number of hydrogen bonds, making the DNA more stable.
E. all Watson-Crick purine-pyrimidine base pairs have the same geometries
8. You are comparing the genetic material of two species. Species A has 100 million base pairs in one of
its skin cells. Species B has 96 million base pairs in one of its skin cells.
From this data, you can conclude that:
A. The genome of species A is larger than the genome of species B.
B. Species A has more genes than species B.
C. The genome of species B is larger than the genome of species A.
D. Species B has more genes than species A.
E. More than one of the above can be concluded based on this data.
F. None of the above can be concluded based on this information.
9. From a series of experiments, you determine the following information.
Amount of DNA in a cell Number of base-pairs
Species
(base pairs) that code for proteins
A 8,000,000 8,000
B 200,000,000 19,000
C 19,000,000 500,000
Based on the information shown, which statement is true? The genome …
A. of species A is the largest.
B. of species B is the largest.
C. of species C is the largest.
D. of species B contains the most genes.
10. Two strands of a short DNA molecule with 3 base pairs are shown below. The dotted lines indicate
hydrogen bonds. Five atoms are labelled from 1 to 5. Indicate which label correctly points to one of the 5’
ends of one of the DNA strands.
, A. 1
B. 2
C. 3
D. 4
E. 5
11. DNA is double stranded and the two strands are said to run in an antiparallel fashion. The term antiparallel
refers to which observation?
A. One strand of DNA is identical to the other but is simply the mirror image
B. One strand of DNA is complimentary to the other but they both run in the same direction from
5’ to 3’
C. One strand of DNA runs 5’ to 3’ while the other strand runs in the opposite direction from 3’ to
5’
12. Anti-parallel stands of DNA form complementary base pairing by hydrogen bonds. Which of the following
statements is false regarding base pairing?
A. Adenine always base pairs with thymine while guanine forms three hydrogen bonds with cytosine.
B. A purine will always base pair with a pyrimidine to correctly align the bases to maintain a uniform
DNA double helix.
C. One set of the complimentary base pairs has stronger interactions via H bonds.
D. Adenine is always linked to a thymine by a phosphodiester bond.
This document contains some questions for you to practice. The questions are grouped by topic along with
the learning objectives associated with each of the topics. We encourage you to use the learning objectives to
guide your studying; ask yourself if you could answer each objective if it was in the form of a question. There
are different levels of questions provided:
1. Study questions: these are questions on your direct knowledge of the topics, so essentially ‘drills’ on
the basics – practice to make sure you get the fundamentals. Work with these questions first to build
up your skills.
2. Exam-type questions, of which there are two types:
a. Multiple choice: these are the types of questions you are likely to see on the exam – various
levels of application of the fundamental knowledge and skills for each topic area.
b. Open response questions (ORQs): a few examples to give you an idea of the kinds of short
answer questions you will see on the exams.
Nucleic Acids - Structure, DNA assembly and organization
Nucleic acids are one of the four major macromolecules in cells. This topic focuses on the structure, assembly and
organization of DNA highlighting some key structural comparisons to RNA.
Nucleic Acids – Genomes
This topic deals with all the heritable genetic information of a cell or organism as a whole, and introduces how the
structural sequence of the genome dictates observable characteristics.
Study questions:
1. What interactions serve to stabilize/hold DNA together in its secondary structure? Explain how this
stabilizes DNA in its aqueous environment.
Hydrogen bonds between strands (base pairing), stacking interactions (mostly ID-ID) above and below in the
same strand. The stacking interactions allow for the hydrophobic surfaces to be excluded from water, allowing
water to have more motional freedom and thereby increasing stability.
2. By convention how is the directionality of a DNA molecule written?
5’ to 3’
3. By convention how is the directionality of a protein molecule written?
N to C
4. Which linkage forms the backbone of a nucleic acid?
A. A base-phosphate linkage
B. A Sugar-phosphate linkage
C. A sugar-base-phosphate linkage
D. A sugar-base linkage
5. In describing DNA or RNA, you will see the term 5’ to 3’ (verbally, this is “5-prime to 3-prime”). The
terms 5’ and 3’ apply to which of the statement(s) below? Choose all that apply.
A. One of the two DNA strands.
B. The sequence of the bases in the DNA or RNA.
C. The direction of the strands.
D. Particular carbon atoms on the ribose or deoxyribose ring.
E. The linkage between the ribose ring and the base.
,Exam Type Questions:
6. In a bacterium, 14% of the DNA nucleotides were found to be Thymine. What proportions of the bases
would be Guanine?
A. 28% G
B. 36% G
C. 14% G
D. 58% G
E. Cannot be determined.
7. In normal double-stranded DNA, purines base pair with only certain types of pyrimidines. This is
because…
A. a purine-purine pair would be too small, and a pyrimidine-pyrimidine pair would be too large
B. the number of A must equal the number of T and the number of G must equal the number of C
C. the strongest stacking interactions are found between purines and pyrimidines, making the DNA
more stable
D. purine-pyrimidine pairs maximize the number of hydrogen bonds, making the DNA more stable.
E. all Watson-Crick purine-pyrimidine base pairs have the same geometries
8. You are comparing the genetic material of two species. Species A has 100 million base pairs in one of
its skin cells. Species B has 96 million base pairs in one of its skin cells.
From this data, you can conclude that:
A. The genome of species A is larger than the genome of species B.
B. Species A has more genes than species B.
C. The genome of species B is larger than the genome of species A.
D. Species B has more genes than species A.
E. More than one of the above can be concluded based on this data.
F. None of the above can be concluded based on this information.
9. From a series of experiments, you determine the following information.
Amount of DNA in a cell Number of base-pairs
Species
(base pairs) that code for proteins
A 8,000,000 8,000
B 200,000,000 19,000
C 19,000,000 500,000
Based on the information shown, which statement is true? The genome …
A. of species A is the largest.
B. of species B is the largest.
C. of species C is the largest.
D. of species B contains the most genes.
10. Two strands of a short DNA molecule with 3 base pairs are shown below. The dotted lines indicate
hydrogen bonds. Five atoms are labelled from 1 to 5. Indicate which label correctly points to one of the 5’
ends of one of the DNA strands.
, A. 1
B. 2
C. 3
D. 4
E. 5
11. DNA is double stranded and the two strands are said to run in an antiparallel fashion. The term antiparallel
refers to which observation?
A. One strand of DNA is identical to the other but is simply the mirror image
B. One strand of DNA is complimentary to the other but they both run in the same direction from
5’ to 3’
C. One strand of DNA runs 5’ to 3’ while the other strand runs in the opposite direction from 3’ to
5’
12. Anti-parallel stands of DNA form complementary base pairing by hydrogen bonds. Which of the following
statements is false regarding base pairing?
A. Adenine always base pairs with thymine while guanine forms three hydrogen bonds with cytosine.
B. A purine will always base pair with a pyrimidine to correctly align the bases to maintain a uniform
DNA double helix.
C. One set of the complimentary base pairs has stronger interactions via H bonds.
D. Adenine is always linked to a thymine by a phosphodiester bond.
