1. The genetic material is organized into chromosomes. Chromosomes may be represented differently in males and females. However, the number of chromosomes is constant for a given species.
2. Mitosis is the form of cell division that results in growth and repair processes. It ensures an orderly and accurate distribution of chromosomes during the cell cycle. Cytokinesis results in the division of the cytoplasm.
3. Meiosis is the form of cell division that results in the formation of gametes. It reduces die chromosome number by half and allows for the random distribution of one member of each pair of parental chromosomes to the offspring.
4. Deoxyribonucleic acid (DNA) is the genetic material of the cell. Its double helix structure suggests how it can replicate itself and how it can code for the sequences of amino acids that make proteins.
5. Protein synthesis involves two processes. Transcription is the production of a messenger RNA (mRNA) molecule that is complementary to a gene in DNA. Translation is the assembly of proteins at the ribosomes based on the genetic information in the transcribed mRNA.
6. Changes in DNA and chromosomes increase the variation within a species and account for evolutionary change.
7. Principles of classical genetics explain the inheritance patterns of many animal traits, including dominance, segregation, and independent assortment.
8. Many alternative forms of a gene may exist in a population, and these alternative forms may interact in different ways.
9. Patterns of inheritance observed at an organismal level are explained at a molecular level by the presence or absence of functional enzymes.