Lecture 21: Review of chemistry and structure of nucleic acids
(Old Lecture 20)
1. Briefly summarize the flow of information from a gene to a final gene product, including the form that the information takes at each step along the way and the names of the major processes that are involved in achieving the flow of information.
2. Distinguish between prokaryotic and eukaryotic in a manner that makes it clear that you know what each is and how they differ.
3. Summarize two different lines of evidence that have demonstrated that genetic information is carried in nucleic acids.
4. Identify the four nitrogenous bases that are used for the coding of genetic information in DNA. How are they related to the bases used for coding genetic informaiton in RNA?
5. What are the chemical differences between DNA and RNA?
6. What is a phosphodiester link and how does it give polarity to nucleic acids?
7. Identify the base pairs in DNA. Which pairs are more stable and why?
8. What is meant by the term "antiparallel" as it applies to double helical DNA?
9. Distinguish between sense and antisense strands in a manner that makes it clear you know what each is and how they differ.
10. What factors determine how rapidly DNA renatures after being denatured?
11. Distinguish between transcription and translation in a manner that makes it clear that you know what each is and how they differ.
12. Explain how electrophoresis can be used to separate nucleic acid molecules by size. What role does the gel play in the process?
13. The nucleotide sequence of the sense strand of a double helical DNA molecule is ATGCGTAACTAACCG.
a. What nucleotide is at the 5'-end?
b. What nucleotide is at the 3'-end?
c. How would you distinguish the 5'-end from the 3'-end if the bases were the same at both ends?
d. What is the nucleotide sequence of the complementary strand? (You always start at the 5'-end when describing a nucleotide sequence).
e. What will be the nucleotide sequence of the mRNA that is transcribed from this DNA?
14. You collect bacteria that live in very hot water in a geyser basin, and a second sample from a very cold pond formed by melting ice at the foot of a glacier. What differences would you expect in the ratio of AT base pairs to GC base pairs in the DNA from each sample? What is your basis for that expectation?
15. Ribose and deoxyribose are both 5-carbon sugars.
a. What is the difference between ribose and deoxyribose?
b. What is attached to carbon #1 of these sugars when they are in nucleic acids?
c. What is attached to carbon #3 of these sugars when they are in nucleic acids?
d. What is attached to carbon #5 of these sugars when they are in nucleic acids?
e. Ribothymidine is an unusual nucleoside that can be recovered from certain types of transfer RNA (transfer RNAs contain a variety of modified bases). What is unusual about finding ribothymidine in a nucleic acid?
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