Table 2.
Concepts are organized into a nested hierarchy based on relative importance
| 7. DNA is the source of heritable information in a cell. |
| 7-1. The amino acid sequence of proteins is encoded in DNA. |
| 7-1-1. three letters in the nucleic acid alphabet (sets of four letters) specify one letter in the protein alphabet (sets of 20 letters). |
| 7-1-1-1. 64 triplet codons: ATG initiating methionine, three Stop codons, 60 other codons for the remaining 19 amino acids. |
| 7-2. Information is encoded in DNA, using different languages that are recognized by different machinery. |
| 7-2-1. DNA encodes when a gene will be expressed or not. |
| 7-2-1-1. DNA sequence: promoter, operator, enhancer. |
| 7-2-1-2. Protein machinery: activator, repressor, transcription factors. |
| 7-2-2. DNA encodes the point at which replication begins. |
| 7-2-2-1. DNA sequence: origin of replication (ori). |
| 7-2-2-2. Protein machinery: origin recognition complexes. |
| 7-2-3. t-RNA acts an adaptor to translate the nucleotide sequence into an amino acid sequence. |
| 7-2-3-1. The anticodon of a t-RNA is complementary and antiparallel to the codon it binds. |
| 7-2-3-2. Ribosomes are responsible for bringing the mRNA and t-RNA together and catalyzing the formation of peptide bonds. |
| 7-2-4. DNA encodes the information to properly segregate chromosomes during cell division. |
| 7-2-4-1. DNA sequence: centromere. |
| 7-2-5. DNA encodes the cellular address of each protein. |
| 7-2-5-1. DNA sequence encodes: nuclear localization signal, mitochondrial uptake sequence, signal sequence, and transmembrane domain. |
| 7-2-5-2. Protein machinery: receptors bind these amino acid sequences and localize proteins accordingly. |
| 7-2-6. DNA encodes: restriction endonucleases recognition sites. |
| 7-3. When DNA is mutated, the information it contains may be changed. |
| 7-3-1. Because DNA can encode amino acid sequences, the structure and therefore the function of proteins may be changed. |
| 7-4. Segments of DNA that contain all of the information to encode the sequence of a product and regulate its expression are called genes. |
| 7-4-1. The DNA that comprises an organism's genome is organized into chromosomes. |
Attempts are made to use as little technical terminology and as much natural language as possible in the upper levels of the structure.