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Section 12-1: DNA
Avery and other scientists discovered that DNA is the nucleic acid that stores and transmits the genetic information from one generation of an organism to the next.
Hershey and Chase concluded that the genetic material of the bacteriophage they used to infect bacteria was DNA, not protein.
Watson and Crick's model of DNA was a double helix, in which two strands were wound around each other.
Section 12-2: Chromosomes and DNA Replication
During DNA replication, the DNA molecule separates into two strands, then produces two new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serves as a template, or model, for the new strand.
Section 12-3: RNA and Protein Synthesis
There are three main types of RNA: messenger RNA, ribosomal RNA, and transfer RNA.
During transcription, RNA polymerase binds to DNA and separates the DNA strands. RNA polymerase then uses one strand of DNA as a template on which nucleotides are assembled into a strand of RNA.
During translation, the cell uses information from messenger RNA to produce proteins.
Section 12-4: Mutations
Gene mutations result from changes in a single gene. Chromosomal mutations involve changes in whole chromosomes.
Section 12-5: Gene Regulation
The lac genes are turned off by repressors and turned on by the presence of lactose.
Most eukaryotic genes are controlled individually and have regulatory sequences that are much more complex than those of the lac operon.