Big Idea 3 – Living systems store, retrieve, transmit and respond to information essential to life processes.EU 3A – Heritable information provides for continuity of life. 1. DNA and in some cases RNA, is the primary source of heritable information. 2. In eukaryotes, heritable information is passes to the next generation in processes that include the cell cycle and mitosis or meiosis plus fertilization. 3. The chromosomal basis of inheritance provides an understanding of the pattern of passage (transmission) of genes from parent to offspring. 4. The inheritance pattern of many traits cannot be explained by simple Mendelian genetics.EU 3B – Expression of genetic information involves cellular and molecular mechanisms. 1. Gene regulation results in differential gene expression, leading to cell specialization. 2. A variety of intercellular and intracellular signal transmissions mediate gene expression.EU 3C – The processing of genetic information is imperfect and is a source of genetic variation. 1. Changes in genotype can result in changes in phenotype. 2. Biological systems have multiple processes that increase genetic variation. 3. Viral replication results in genetic variation, and viral infection can introduce genetic variation into the hosts.EU 3D – Cells communicate by generating, transmitting, and receiving chemical signals. 1. Cell communication processes share common features that reflect a shared evolutionary history. 2. Cells communicate with each other through direct contact with other cells or from a distance via chemical signaling. 3. Signal transduction pathways link signal reception with cellular response. 4. Changes in signal transduction pathways can alter cellular response.EU 3E – Transmission of information results in changes within and between biological systems. 1. Individuals can act on information and communicate it to others. 2. Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses.