Name:______________________________
Date:_________________________Hr:___
DNA Replication
DNA was proven as the hereditary material and Watson and Crick had discovered its structure
with the help of Wilkins and Franklin’s x-ray photograph. Now that they knew the structure,
what remained was to learn how DNA copied its information and how it was expressed.
It was discovered that DNA goes through a process of replication to produce two DNA molecules,
each of which are composed of one-half original DNA and one half old DNA, which are
complementary of each other.
DNA replication begins when the DNA unwinds and the hydrogen bonds between the bases
are broken by an enzyme. This process is compared to a zipper being unzipped.
Another enzyme comes in and bonds the complementary bases to the open strands on both
sides to create two strands that are now identical.
Cells can not functions without a complete set of DNA, so when the cell divides each
cell must have a complete functioning copy of DNA. This is why DNA replication occurs.
Questions: Answer the following questions in COMPLETE SENTENCES.
1. What is the process DNA goes through when dividing into more cells?
2. How many strands are created after the process and are they identical or different?
3. In your own words, summarize the process of DNA replication. Be sure to include when it happens,
how it occurs and what is produced.
4. Explain why DNA must be replicated.
5. When does DNA replication occur?
Name:______________________________
Date:_________________________Hr:___
The original strand of DNA has been provided. Complete the complementary strand using the original strand. Then complete the
process of DNA replication by filling in the missing complementary bases on the other strands.
Original Strand
Complementary Strand
C
G
Replicate the DNA
DNA Replication:
1. What is step 1 in DNA replication?_______________________________________________________
2. What “unzips” the DNA molecule? ______________________________________
3. After DNA replication, the two DNA strands are said to be: circle one (a.) identical or
(Hint: compare the two strands to the right of the arrow in the diagram above)
4. Where are the hydrogen bonds that are broken during DNA replication located? Circle one
a. Between the complementary bases OR b. between the sugar and phosphates
(b.) different
Name:______________________________
Date:_________________________Hr:___
Structure of Nucleic Acids
1. What kind of molecule is DNA?________________________________________
2. The building blocks of a nucleic acid or the basic unit of DNA is known as a _________________________.
3. Draw and label the three parts of a nucleotide in the box below.
Function of DNA
1. DNA stands for_____________________________
2. DNA is located in the ____________________________
3. What is the function of DNA? Be specific._________________________________________________
Structure of DNA
1. The sugar found in DNA is ____________________________
2. In complimentary base paring ______bonds with______and ______bonds with_______
Diagram of DNA molecule
1. A DNA molecule consists of ____________ strands.
2. DNA is a long chain made of repeating units called__________________________.
3. Nucleotides are attached by bonds between the ______________ and the phosphate.
4. DNA is shaped like a ___________________ helix.