- Signal transduction pathways begin with the recognition of a signal by a cell and
ends with the cellular response. - A blocked or defective signal transduction pathway can change the cellular
response.
E. Information transmission results in changes in biological systems. - Organisms communicate and exchange information.
- Animal nervous systems perform a key role in the reception, transmittal, and pro-
cessing of information to produce a response.
Big Idea 4: Interactions
A. Biological systems (from cells to ecosystems) contain parts that interact with each other.- The properties of biological molecules are determined by their components
(monomers and polymers). - Organelles are essential to cell processes.
- Interactions between external stimuli and gene expression produce specialized cells,
tissues, and organs. - Complex properties in organisms are the result of interactions among their con-
stituent parts. - Populations of organisms interact in communities.
- The movement of matter and flow of energy are a result of interaction between
communities and their environment.
B. Biological systems are characterized by competition and cooperation. - The structure and function of a molecule are influenced by its interaction with
other molecules. - Cooperative interaction within organisms promotes efficiency.
- Interactions within and between populations affect species distribution and
abundance. - Ecosystem distribution changes over time (human impact accelerates change).
C. Diversity within biological systems influences interactions with the environment. - Variation in molecular units (e.g., different chlorophyll molecules, antibody pro-
teins, or alleles of a gene) provides cells with a broad range of functions. - Gene expression is influenced by environment.
- Variation influences population dynamics.
- Diversity affects ecosystem stability.
The Four “Big Ideas” of AP Biology ❮ xxiiihttp://www.ebook3000.com