AP Biology
Name/Hr: ____Key___
DNA Structure & Replication
Chapter 16
S tr u c tu r e o f N u c leic A c id s
1. The building blocks of nucleic acids are known as Nucleotide.
2. Draw and Label the 3 parts of the building block and provide detail about each part.
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Phosphate Group
Attaches to 3’ C on next Nucleotide to
form Sugar/Phosphate backbone
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Pentose (5 C) Sugar
Deoxyribose in DNA
Ribose in RNA
Part of Sugar/Phosphate backbone
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Nitrogenous Base
DNA = A, T, C & G
RNA = A, U, C & G
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3. Complete the table about Nitrogenous Bases.
N am e
G eneral Structure
Versions
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Single Ring
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Cytosine & Thymine
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Double Ring
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Adenine & Guanine
Pyrimidine
Purine
F u n c tio n o f D N A
4. DNA stands for Deoxyribonucleic Acid.
5. DNA makes up chromosomes, which are located in the Nucleus.
6. Small sections of DNA molecules that determine genetic traits are called Genes.
S tr u c tu r e o f D N A
7. The sugar found in DNA is Deoxyribose.
8. The pyrimidine bases are Cytosine & Thymine.
9. The purine bases are Adenine & Guanine.
10. In complimentary base pairing, C bonds with G; and A bonds with T.
D ia g r a m o f D N A M o lec u le
11. A DNA molecule consists of 2 strands. Held together by
Hydrogen bonds.
12. DNA is a long chain made up of repeating units called
Nucleotides.
13. These monomers are attached by bonds between the
phosphate & Sugar groups.
14. The common term for the shape of DNA is known as the
Double Helix.
15. The “sides” of the DNA ladder are made up of Sugar &
Phosphate.
16. The “rungs” of the DNA ladder are mad up of Nitrogenous
Bases.
17. Diagram and Label a section of DNA in the box to the
right.
D N A R ep lic a tio n
18. The replication of DNA begins with the Unwinding/Uncoiling of
the double helix.
19. DNA replication is said to be Semi-Conservative because each
strand acts as a template to construct the other half of the molecule.
20. Using what you now know of DNA structure and what you read
about DNA Replication. Complete the diagram to the right.
Provide all missing bases and also label any missing 3’ or 5’ ends
of DNA.
21. DNA Polymerase is the name of the enzyme that reads old DNA
and lays down new DNA.
22. This enzyme reads template DNA from 3’ to 5’.
23. The enzyme then lays down new DNA from 5’ to 3’.
24. The Leading strand can continuously be made as DNA uncoils.
25. The Lagging strand is made in small pieces referred to as Okazaki
fragments.
26. These fragments are then joined together by the enzyme DNA
Ligase.
27. Provide arrows on the new strands in direction they were made.