Chapter 16 – The Molecular Basis of Inheritance

DNA Structure

1. Label the diagram of DNA’s structure 2. Color code the diagram:

Purines = Pyrimidines = Phosphates = Deoxyribose = Hydrogen bonds =

3. Label the 5’ and 3’ ends How can one identify 3’ vs. 5’? Why is this arrangement important to the overall structure of DNA? DNA is read to DNA is built to

4. What are Chargaff’s Rules?

5. Typical Structure question . . . If 20% of the DNA in a guinea pig cell is adenine, what percentage is cytosine? Explain your answer.

6. In the picture to the right, using 2 different colors – one for light (14N) and heavy (15

N) strands of DNA - sketch the results of the replication cycles of heavy DNA when E. coli are moved to a light medium for two generations. Show the resulting density bands that would appear in the centrifuge tubes. a. The result should indicate that DNA replication is? b. What early experimental evidence supported this idea? c. Who presented these findings?

Name Period

DNA Replication Our analysis will focus on the DNA replication process in bacteria, however it is similar in eukaryotic cells, just a little more involved. For example Human replication utilizes 11 different DNA Polymerases vs. 2 in E. coli, higher number of replication bubbles, longer time – you get the idea.

In the diagram below, label the following: leading and lagging strands, Okazaki fragments, DNA polymerase, DNA ligase, helicase, primase, single-stranded binding protein (SSBP), RNA primer, replication fork, 5’ end, 3’ end.

1. Color code the following enzymes and provide their function in relations to DNA replication

Enzyme Function Helicase

Leading Strand Lagging Strand Primase

DNA Polymerase III

DNA Polymerase I

DNA Ligase

2. Explain the following as they relate to DNA Replication a. Replication bubbles b. Telomeres c. Telomerase d. Okazaki fragments

Chapter 17 – From Gene to Protein DNA→pre-mRNA→mRNA processing→translation (initiation, elongation, termination)

Translation Up Close In the diagram below: A. Name the stages 1-4 B. Identify the components (a-l) C. Provide a brief description of what is happening in each stage. D. Color Code the Aminoacyl-tRNA, peptidyl-tRNA and exit sites.

Description of Stages 1.

2.

3.

4.

Say it with DNA Use the handout and follow the directions to decode the DNA messages below.

1. Complete the partially solved message example DNA code mRNA tRNA Amino acid Letter Symbol

2. We have discussed that mRNA provides the code that determines the amino acid tRNA

carries to the ribosome – is this simulation still following that rule? Explain.

3. Choose 2 different messages to decode from the DNA messages. Message # DNA code mRNA tRNA Amino acid Letter Symbol

Message # DNA code mRNA tRNA Amino acid Letter Symbol

4. Design your own DNA message. Exchange it with a friend to see if they can decipher it. Then enter your message into the DNA message contest – Categories will include: Most creative, Make you Laugh, Bio related and Best Advice Winning messages will get a Bonus point on the test!