Chapter Objectives

1. Explain why researchers originally thought protein was the genetic material
2. Summarize the experiments performed by the following scientists
   1. Frederick Griffith
   2. Alfred Hershey and Martha Chase
   3. Erwin Chargaff
   4. Avery, McCarty, and MacLeod
3. List the 3 components of a nucleotide
4. Distinguish between ribose and deoxyribose
5. List the nitrogen bases found in DNA and distinguish between pryrimidine and purine
6. Explain how Watson and Crick deduced the structure of DNA and describe what evidence they used
7. Explain the base-pairing rule and describe its significance
8. Describe the structure of DNA and explain what kind of chemical bond connects the nucleotides of each strand and what type of bond holds the 2 strands together
9. Explain semisconservative replication and describe the Meselson-Stahl experiment
10. Describe the process of DNA replication and explain the role of helicase, single strand binding protein, DNA polymerase, ligase, and primase.
11. Explain what energy source drives endergonic synthesis of DNA
12. Define antiparallel and explain why continuous synthesis of both DNA strands is not possible
13. Distinguish between the leading strand and the lagging strand
14. Explain how the lagging strand is synthesized when DNA polymerase can add nucleotides only to the 3' end
15. Explain the role of DNA polymerase, ligase, and repair enzymes in DNA proofreading and repair

 

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16. Describe early experimental evidence that implicated proteins as the links between genotype and phenotype
17. Describe Beadle and Tatum's experiments with Neurospora and explain the contribution they made to our understanding of how genets control metabolism
18. Distinguish between the "one gene~~one enzyme" hypothesis and the "one gene~~one polypeptide" hypothesis and explain why the original hypothesis was changed
19. Explain how DNA differs from RNA
20. Explain how information flows from gene to protein
21. Describe where transcription and translation occur in prokaryotes and in eukaryotes and explain why it is significant that in eukaryotes, transcription and translation are separated in space and time
22. Define codon and explain what relationship exists between the linear sequence of codons on mRNA and the linear sequence of codons on mRNA and the linear sequence of amino acids in a polypeptide
23. List the three stop codons and the one start codon
24. Explain in what way the genetic code is redundant and unambiguous
25. Explain the evolutionary significance of a nearly universal code
26. Explain the process of transcription including the 3 major steps of initiation, elongation, and termination
27. Explain the general role of RNA polymerase in transcription
28. Explain how RNA polymerase recognizes where transcription should begin
29. Specifically describe the primary functions of RNA polymerase II
30. Distinguish among mRNA, tRNA, and rRNA
31. Describe the structure of tRNA and explain how the structure is related to function
32. Given a sequence of bases in DNA, predict the corresponding codons transcribed on mRNA and the corresponding anticodons of tRNA
33. Describe the wobble effect
34. Explain how an aminoacyl-tRNA synthetase matches a specific amino acid to its appropriate tRNA and describe the energy source that drives this endergonic process
35. Describe the structure of a ribosome and explain how this structure relates to function
36. Describe the process of translation including initiation, elongation, and termination and explain what enzymes, protein factors, and energy sources are need for each stage
37. Explain what determines the primary structure of a protein and describe how a polypeptide must be modified before it becomes fully functional
38. Describe what determines whether a ribosome will be free in the cytosol or attached to rough ER
39. Explain how proteins can be targeted for specific sites within the cell
40. Describe the difference between prokaryotic and eukaryotic mRNA
41. Explain how eukaryotic mRNA is processed before it leaves the nucleus
42. Describe some biological functions of introns and gene splicing
43. Explain why base-pair insertions or deletions usually have a greater effect than base-pair substitutions
44. Describe how mutagenesis can occur

Chapter Terms:

Chapter Outline Framework

1. DNA as the Genetic Material
1. The search for the genetic material led to DNA
2. Watson and Crick discovered the double helix by building models to conform to X-ray data
2. DNA replication and Repair
   1. During DNA replication, base-pairing enables existing DNA strands to serve as templates for new complementary strands
   2. A large team of enzymes and other proteins carries out DNA replication
   3. Enzymes proofread DNA during replication and repair damage to existing DNA
   4. The ends of DNA molecules pose a special function
3. The Connection between Genes and Proteins
   1. The study of metabolic defects provided evidence that genes specify proteins
   2. Transcription and translation are the 2 main processes linking gene to protein
   3. In the genetic code, nucleotide triplets specify amino acids
   4. The genetic code must have evolved very early in the history of life
4. The Synthesis and Process of RNA
   1. Transcription is the DNA-directed synthesis of RNA
   2. Eukaryotic cells modify RNA after transcription
5. The Synthesis of Proteins
   1. Translation is the RNA-directed synthesis of a polypeptide
   2. Signal peptides target some eukaryotic polypeptides to specific locations in the cell
   3. RNA plays multiple roles in the cell
   4. Comparing protein synthesis in prokaryotes and eukaryotes
   5. Point mutations can affect protein structure
   6. What is a gene?

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