Download Nucleic Acids - U of L Class Index

Chapter 22
22
Nucleic Acids
Study Goals
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Draw the structures of the nitrogen bases, sugars, and nucleotides in DNA and RNA
Describe the structures of DNA and RNA.
Explain the process of DNA replication.
Describe the preparation of recombinant DNA
Describe the transcription process during the synthesis of mRNA.
Use the codons in the genetic code to describe protein synthesis.
Explain how an alteration in the DNA sequence can lead to mutations in proteins.
Describe the regulation of protein synthesis in the cells.
Chapter Outline
22.1
22.2
22.3
22.4
22.5
22.6
22.7
22.8
22.9
Components of Nucleic Acids
Nucleosides and Nucleotides
Primary Structure of Nucleic Acids
DNA Double Helix: A Secondary Structure
DNA Replication
Types of RNA
Transcription: Synthesis of mRNA
The Genetic Code
Protein Synthesis: Translation
Health Note: Many Antibiotics Inhibit Protein Synthesis
22.10 Genetic Mutations
Explore Your World: A Model for DNA Replication and Mutation
22.11 Recombinant DNA
Health Note: Cancer
22.12 Viruses
Health Note: Cancer
Chapter Summary and Demonstrations
1.
DNA and RNA
The components and structures of the nucleic acids, DNA and RNA, are described. The concept of
complementary base pairing is emphasized for an understanding of the process by which DNA is
replicated and its synthesis of mRNA for protein synthesis in the ribosomes. The control of protein
synthesis through induction and repression is discussed. The concept of recombinant DNA is
introduced as a method of placing a foreign DNA into a gene for the production of a particular
protein. The changes in DNA structure as a result of a mutation and the consequent effects upon the
amino acid order and structure of the resulting protein are discussed along with examples of genetic
diseases. Additional topics include the role of DNA in cancer and viruses.
Demonstration Large-scale models of DNA are useful to show the double helix of DNA.
Nucleic Acids
Laboratory Suggestions
Lab 40 DNA Components and Extraction
Students write the structures of the components of DNA. In plant cells, DNA strands are
combined with protein and RNA molecules. Students extract and isolate DNA from a variety of
plant and animal cells. Three processes are required: (1) breaking down the cellular membranes,
(2) heating the mixture and denaturing the proteins, and (3) precipitating the DNA as a white,
stringy, fibrous material.
A. Components of DNA
B. Extraction of DNA
Laboratory Skills to Demonstrate
Preparation of plant or animal cells for extraction of DNA
Removing DNA strands from a solution of DNA