DNA STRUCTURE AND FUNCTION
1. What is DNA?
a. DNA is the hereditary material in humans and almost all other organisms. The order, or sequence, of these
bases determines the information available for building and maintaining an organism.
2. What is a genome?
a. A genome is the genetic material of an organism.
3. List at least 10 specific features of the structure of DNA that are visible in text figure 10.3D.
a. Two strands, repeating nucleotides, anti-parallel, double-helix, base pairs that link strands to each other,
phosphate groups, sugar, base, hydrogen bonds, A-T and G-C
4. What insights into DNA structure did Watson and Crick derive from the findings of Chargaff?
a. Chargaff found out information about the composition of DNA. There is an equal amount of “A” and “T”,
and an equal amount of “G” and “C”. The percantage of each combination varies by species.
5. What insights into DNA structure did Watson and Crick derive from the findings of Franklin?
a. Franklin foune that sugar-phosphate backbones are on the outside of the helix, which forces the
nucleotides to be on the side. They are 2nm in diameter.
6. What insights did Watson and Crick contribute to their “model” or description of DNA structure?
a. Watson and Crick determined that the basic shape of DNA is a helix with a uniform diameter. They used
a model to find that purine always binds with a pyrimidine on the opposite strand to produce a uniform
thickness.
7. What is the repeating subunit (monomer) of DNA? What is the structure of this subunit?
a. The repeating subunit of DNA are nucleotides. Every nucleotide has three parts, a five-carbon sugar
called deoxyribose, phosphate group and a nitrogenous base. The phosphate group is negative charged.
The nitrogenous base can be either A (adenine), T (thymine), C (cytosine) or G (guanine).
8. How many different kinds of monomers are there in DNA? How do they differ from one another? How are they alike?
a. There are four types of monomers in DNA: adenine, thymine, cytosine and guanine. They are different because
adenine and guanine are purines connected with a double ring, while thymine and cytosine and pyrimidines
connected with a single ring. They are similar because they are both connected with hydrogen bonds.
9. What is complementary base pairing? What are the “rules” of complementary base pairing?
a. Complementary base pairing is the structural pairing of nucleotide bases in DNA. The rules are that “A” pairs
with “T”, connected with 2 hydrogen bonds. Next, “C” pairs with “G” always pair together but with 3 hydrogen
bonds. “A” and “G” are both purine, both consisting of N and C atoms while “T” and “C” are both pyrimidine, that
have a single ring conisting of N and C atoms.
10. Why is complementary base pairing an important feature in the cell?
a. Complementary base pairing is important because it ensures that the cell makes two identical copies of
DNA during replication and ensures that RNA molecules carry accurate instructions for making proteins
during translation and transcription.
11. What was the design of Hersey and Chase’s experiment (question, hypothesis, subjects, groups, and variables)?
a. Question:
b. Hypothesis:
c. Subjects:
d. Groups:
e. Variables:
12. What were the results of Hershey and Chase’s experiment? What did Hershey and Chase conclude from these
results?
a. The results of Hershey and Chase’s experiment were that
13. What are the 2 major functions of DNA in the cell?
a. DNA stores genetic information to make more DNA and genetic information that is passed from the
parent to the offspring. Also, it carries instructions for making RNA, protein/molecules and Central
Dogma.
14. What are the differences between RNA and DNA?
a. DNA: deoxyribose, deoxyribonucleic acid, double stranded, bases are A:T and C:G, and strands are long
b. RNA: ribose, ribonucleic acid, single stranded, bases are A:U and C:G, and strands are short
DNA REPLICATON
14. How is DNA replicated in a cell?
a. Two strands of parental DNA separate and free nucleotides bind to the template strand. Enzymes
generate a new sugar phosphate backbone, and the end result is 2 identical new strands.
15. What enzymes are involved? What is the role/contribution of each?
a. Topoisomerase: Unwinding DNA
b. Helicase: Pry apart helix/double stranded DNA
c. DNA polymerase: Adds nucleotides to 3’ -OH
1. What is DNA?
a. DNA is the hereditary material in humans and almost all other organisms. The order, or sequence, of these
bases determines the information available for building and maintaining an organism.
2. What is a genome?
a. A genome is the genetic material of an organism.
3. List at least 10 specific features of the structure of DNA that are visible in text figure 10.3D.
a. Two strands, repeating nucleotides, anti-parallel, double-helix, base pairs that link strands to each other,
phosphate groups, sugar, base, hydrogen bonds, A-T and G-C
4. What insights into DNA structure did Watson and Crick derive from the findings of Chargaff?
a. Chargaff found out information about the composition of DNA. There is an equal amount of “A” and “T”,
and an equal amount of “G” and “C”. The percantage of each combination varies by species.
5. What insights into DNA structure did Watson and Crick derive from the findings of Franklin?
a. Franklin foune that sugar-phosphate backbones are on the outside of the helix, which forces the
nucleotides to be on the side. They are 2nm in diameter.
6. What insights did Watson and Crick contribute to their “model” or description of DNA structure?
a. Watson and Crick determined that the basic shape of DNA is a helix with a uniform diameter. They used
a model to find that purine always binds with a pyrimidine on the opposite strand to produce a uniform
thickness.
7. What is the repeating subunit (monomer) of DNA? What is the structure of this subunit?
a. The repeating subunit of DNA are nucleotides. Every nucleotide has three parts, a five-carbon sugar
called deoxyribose, phosphate group and a nitrogenous base. The phosphate group is negative charged.
The nitrogenous base can be either A (adenine), T (thymine), C (cytosine) or G (guanine).
8. How many different kinds of monomers are there in DNA? How do they differ from one another? How are they alike?
a. There are four types of monomers in DNA: adenine, thymine, cytosine and guanine. They are different because
adenine and guanine are purines connected with a double ring, while thymine and cytosine and pyrimidines
connected with a single ring. They are similar because they are both connected with hydrogen bonds.
9. What is complementary base pairing? What are the “rules” of complementary base pairing?
a. Complementary base pairing is the structural pairing of nucleotide bases in DNA. The rules are that “A” pairs
with “T”, connected with 2 hydrogen bonds. Next, “C” pairs with “G” always pair together but with 3 hydrogen
bonds. “A” and “G” are both purine, both consisting of N and C atoms while “T” and “C” are both pyrimidine, that
have a single ring conisting of N and C atoms.
10. Why is complementary base pairing an important feature in the cell?
a. Complementary base pairing is important because it ensures that the cell makes two identical copies of
DNA during replication and ensures that RNA molecules carry accurate instructions for making proteins
during translation and transcription.
11. What was the design of Hersey and Chase’s experiment (question, hypothesis, subjects, groups, and variables)?
a. Question:
b. Hypothesis:
c. Subjects:
d. Groups:
e. Variables:
12. What were the results of Hershey and Chase’s experiment? What did Hershey and Chase conclude from these
results?
a. The results of Hershey and Chase’s experiment were that
13. What are the 2 major functions of DNA in the cell?
a. DNA stores genetic information to make more DNA and genetic information that is passed from the
parent to the offspring. Also, it carries instructions for making RNA, protein/molecules and Central
Dogma.
14. What are the differences between RNA and DNA?
a. DNA: deoxyribose, deoxyribonucleic acid, double stranded, bases are A:T and C:G, and strands are long
b. RNA: ribose, ribonucleic acid, single stranded, bases are A:U and C:G, and strands are short
DNA REPLICATON
14. How is DNA replicated in a cell?
a. Two strands of parental DNA separate and free nucleotides bind to the template strand. Enzymes
generate a new sugar phosphate backbone, and the end result is 2 identical new strands.
15. What enzymes are involved? What is the role/contribution of each?
a. Topoisomerase: Unwinding DNA
b. Helicase: Pry apart helix/double stranded DNA
c. DNA polymerase: Adds nucleotides to 3’ -OH
