CHAPTER 12: DNA
Below is a diagram representing the structure of DNA, specifically a nucleotide.
1. A nucleotide is which of the following: monomer or
polymer?
2.What are the 3 basic components of a nucleotide?
3.What are the 4 kinds of nitrogenous bases (letters
and names)?
Below is a diagram representing the structure of DNA.
4. Is the structure to the left a monomer or polymer?
5. What are the 3 structures that each deoxyribose sugar
is bonded to?
6. What is the term given to the combination of all the
sugars and phosphates bonded together?
7. Why are bases called “nitrogen” bases?
7. What is the difference between purines and
pyrimidines?
8. Which 2 nitrogen bases are purines?
9. Which 2 nitrogen bases are pyrimidines?
10. Does it matter which nucleotide (GCAT) is bonded to
one another in the vertical orientation of the DNA
molecule?
Below is a diagram representing the double stranded structure of DNA.
11. What type of bond connects the
left side of a DNA molecule to the
right side?
12. Base Pairing Rules: Adenosine (A)
pairs with ________________ and
Guanine (G) pairs with
________________.
13. What is different about this bond
between an A-T and G-C ?
14. One purine pairs with one
__________________.
15. What is the width of one nucleotide? What is a nanometer equal to?
16. What do you notice about the left half of this DNA molecule and the right half? What is the term
used to describe this phenomenon?
Below is a picture of the two men given credit for discovering the structure of DNA (standing next to
the model they made).
17. Who are these two scientists? Where are they from?
18. What year did they publish a paper revealing their
discovery?
19. Who’s work aided their understanding of the DNA
molecule (unfortunately she died cancer, more than likely
caused by radiation, and was not awarded the Noble Prize
with these two scientist)?
Below is a diagram of the complete structure of DNA.
20. What is the term used to describe the “twisted
ladder” appearance of DNA?
21. What is the specific function of DNA?
Below is a diagram representing bacterial structure, specifically DNA structure.
22. Structurally, what is the difference
between a prokaryotes DNA and a
eukaryotes DNA?
23. Structurally, what is similar between a
prokaryotes DNA and a eukaryotes DNA?
Below is a electron microscope picture of a bacterial cell’s DNA (the E. coli cell has ruptured and the
DNA is outside of the cell).
24. How many base pairs can an E. coli bacterial cell
contain?
25. What is the “challenge” that a cell faces with this
many base pairs in its DNA?
Below is a diagram representing a eukaryotic chromosome.
26. What is the length of DNA found within one human nucleus?
27. You have ~50 trillion cells in your body. If you extracted the DNA from them, lined each strand up
from end-to-end, how long would this connected strand be (meters and miles)?
28. The Moon is ~240,000 miles from Earth. How many times would your DNA, lined up like #27, make
it to the Moon and back? (Crazy, huh?)
29. How is so much DNA folded into each nucleus?
30. Eukaryotic chromosomes contain both _____ and _____________. The combination of these two
items tightly packed together forms a substance called ______________________.
30. Chromatin is composed of ____ that is coiled tightly around proteins called _______________.
31. What is a nucleosome? What is their function?
Below is a set of diagrams illustrating the process of DNA replication.
32. Why does a cell have to “duplicate” its
DNA (also known as “replication”)?
33. What does the term “complementary
strand” mean?
34. What are the final products of this
process?
Below is a detailed diagram of DNA replication. The diagram of the left shows the overall process and
the diagram on the right shows a close-up view of the left ½ of the process.
35. Label the “replication fork” on this diagram (could be more than one).
36. What is the name of the enzyme that aids in replication?
37. Draw an arrow above the top strand to show the direction that replication is occurring. Do the same
for the bottom strand (the original complementary strand).
38. In front of both enzymes, there appears to be small structures in the shape of a “T”. What are these
structures?
39. What is meant by “base pairing” in reference to DNA replication?
40. What enzyme facilitates this “base pairing”?
41. If a DNA strand has the bases AGGTCTCCA, what would be the complementary bases on the
replicated strand?
42. What is meant by “proofreading” and what enzyme is responsible for this process?
43. Humans have 46 strands of DNA (chromosomes) in the nuclei of each cell, except sperm and eggs.
At the conclusion of DNA replication, how many strands of DNA are in the nuclei of each cell?