Name__________________________ Class _______________ Date _____________
Section 12.1 Identifying the
Substance of Genes
s the process by which one strain of bacteria c
- What is
was the conclusion from Avery’s experiments?
- What is a
- Circle the
letter of each part that makes up a bacteriophage.
d. DNA core
- Hershey and
Chase concluded that the genetic material of the bacteriophage was
The Role of DNA
6. List the
three critical things that the DNA that makes up genes are known to do.
c. Genes had to be easily copied.
Section 12.2 The Structure of DNA
The Components of DNA
- What is
- What are
the building blocks of nucleic acids?
the components of a nucleotide in the diagram below as 5 –carbon sugar,
phosphate group or a nitrogen base. Label the bases as either purines
guanine, cytosine, and thymine are four kinds of ___________________
bases in DNA.
- Is the
following sentence true or false? The nucleotides must be joined together in
a specific order. ______
Solving the Structure of DNA
- Use figure
12-5. Is the following sentence true or false? Adenine and guanine are
larger molecules than cytosine and thymine because they have two rings in
their structure. ______
to Chargaff’s rules, the percentages of _____________________are equal to
thymine and the percentages of _______________________are equal to guanine
in the DNA molecule.
Franklin’s work with X-ray diffraction showed that the DNA molecule is
shaped like a(an) ________________________and contains ______________
- How did
Watson and Crick describe the structure of DNA?
The Double –Helix Model
- What does a
double-helix look like?
- What is
meant by “antiparallel” strands?
- What holds
the two strands of DNA together?
- Look at
figure 12-7, how many hydrogen bonds are between C and G? between A and T?
the following sentence true or false? According to the principle of base
hydrogen bonds could form only between adenine
and cytosine. _________
Section 12.3 DNA Replication
Copying the Code
- Why are the strands of a
DNA molecule said to be complementary?
- What is the first step in
eukaryotic DNA replication?
- If the base sequence on a
separated DNA strand is CGTAGG, what will the base sequence on its
complementary strand be?
- What enzyme joins
individual nucleotides to produce the new strand of DNA?
- What enzyme makes it less
likely that DNA will be lost from telomeres during replication?
How does this
replication take place in the same direction along both strands of the DNA
molecule that is being replicated? Explain your answer. (Hint: Look at the
illustration of DNA replication in your textbook.)
fork, DNA polymerase, the original strand, and the new strand.
Replication in Living
Complete the table to compare and contrast DNA replication in prokaryotes and
Location of DNA
Amount of DNA
Starting point(s) for replication