AP BiologyAn Introduction Big Idea I Evolution Evolution
AP Biology-An Introduction
Big Idea I. Evolution • Evolution is the core theme in biology • It is defined as descent from a common ancestor with modification • Natural Selection is the main mechanism that drives evolution. The environment is the driving force behind natural selection
Evolution • Darwin’s “finches” were strong evidence for the idea of natural selection
Big Idea II: Energy Transfer • Life does not occur without energy exchanges Photosynthesis and respiration
Big Idea III. Continuity and Change • All species tend to maintain themselves from generation to generation using the same genetic code. • However, there are genetic mechanisms in place that can lead to change over time, or evolution.
A Hierarchy of Organization:
Big Idea IV. Interactions and Feedback • Molecular interactions-Chemical reactions, catalysis, synthesis, breakdown, metabolism • Cellular interactions-intercellular and extracellular communication, feedback, senescence, apoptosis • Organismal interactions-between each other and the environment • Community interactions-man vs. nature, man vs. the environment
Feedback • Feedback mechanisms regulate life processes. • Feedback can be negative or positive in nature
Relationship of Structure to Function • The way that anything works is correlated to its structure. • Mitochondrial Cristae (folds)-increase surface area to allow many chemical reactions to take place • Also a place for enzymes for these reactions
Interdependence in Nature • Includes both biotic and abiotic factors
What You Really Need to Know-Huge Ideas • The shape of a biological molecule is called its conformation • Molecules can only function well if they maintain their conformation • Changes in temperature and p. H cause conformation changes, which in turn cause the molecule to not be able to function. This is termed denaturation.
What You Really Need to Know-Huge Ideas • This is especially important for enzymes. • Change the shape and they lose their conformation, and their ability to catalyze reactions.
What You Really Need to Know-Huge Ideas • The use of energy (ATP) can be used to change the conformation of enzymes and other molecules • This activation is known as phosphorylation, as a phosphate group is used to change the conformation
What You Really Need to Know-Huge Ideas • Cells communicate by phosphorylation and the conformation change of molecules • The cells can communicate without anything crossing the membrane
What You Really Need to Know-Huge Ideas • Your DNA determines your traits by coding for the making of proteins • The strands of DNA that carry the code are genes • Many factors control what genes are expressed when. • Molecules can bind or unbind to DNA, affecting expression • Often the binding or unbinding is due to conformation changes due to phosphorylation
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