The Chemistry of Life

Biosphere Biodivers ity Biology Organism -- includes everything that lives on Earth, and every place where those things live -- the variety, or all the different types, of life on Earth -- the scientific study of all forms of life, or all types of organisms -- any individual living thing Tidepo ol Estuary

1. Cells 2. Need for Energy -- all organisms are made up of one or more cells -- a cell is the basic unit of life -- all organisms need a source of energy for their life processes -- all the chemical reactions that build up or break down materials in an organism is metabolism

3. Respond to Environment 4. Reproduce & Develop -- all organisms react to the environment to survive -- physical factors such as temperature, light and touch are called stimuli -- member of a species have the ability to produce new individuals, reproduce -- organisms pass their genetic material through DNA

Systems -- all levels of life have systems of related parts a cell has chemicals and processes a body system has interacting organs an ecosystem has living and nonliving things that interact

Structure & Function -- structure determines function proteins with different structures perform different functions heart muscle cells have different structure and function than stomach muscle cells different species have different anatomical structures

Homeostasi s -- organisms must maintain homeostasis to survive in diverse environments -- homeostasis allows organisms to maintain constant internal conditions

Unity & Diversity -- evolution is the change in living things over time -- an inherited trait that gives an advantage to future generations is adaptation -- evolution can occur through natural selection of adaptations

Scientifc Method -- scientists make careful & systematic observations -- observations are recorded as data -- they form a hypothesis as a possible answer to a question -- scientists test their hypotheses

Problem Hypothesis Test Analysis Conclusion -- make observations --- identify the problem -- form a testable explanation -- typically an “ if…then ” statement -- test the hypothesis -- perform an experiment -- analyze data -- calculations, graphs & charts -- evaluate the results -- peer review, publication

Experimenta l Design I.V.I.V. D.V.D.V. Constants Control -- carefully planned components of an experiment -- independent variable -- manipulated by scientist -- dependent variable -- measured in response to I. V. -- variables that are kept constant -- same for all groups -- set aside for comparison -- doesn ’ t get the I. V.

Laws vs. Theories -- a law is a statement based on repeated observations -- doesn ’ t attempt to explain, simply describes -- ex ) law of gravitation -- a theory is a proposed explanation supported by much evidence -- can change with new evidence -- explains why -- ex ) the universal particle theory

Microscope s -- provides an enlarged image of an object light microscopes scanning electron microscopes transmission electron microscopes stoma

Imaging in Medicine -- imaging technology is vital in medicine X - ray imaging magnetic resonance imaging ( MRI ) computed tomography ( CT )

Computers & DNA -- computer models are useful when experimental procedures are not safe or ethical -- DNA & molecular genetics give rise to new studies

Why study biology ? -- help you better understand… your health environmental issues issues with biotechnology unanswered questions

Atoms -- All living things consist of atoms. smallest unit of matter that retains its chemical properties an element consist of one type of atom every atom has a nucleus and electrons protons and neutrons are found in the nucleus electrons are outside the nucleus in the electron cloud Oxygen (O) 8 protons 8 neutrons 8 electrons

Compounds -- two or more elements chemically bonded together ex ) H 2 O, CO 2 smallest unit of a compound is a molecule most compounds in living things contain carbon Water (H 2 O) O H H Carbon Dioxide (CO 2 )

Ions -- ions form when an atom or group of atoms gain or lose electrons positive ions ( lose negative e -) negative ions ( gain negative e -) ionic bonds form between oppositely charged ions

Molecules -- atoms share electron pairs in covalent bonds most common bonding in living things molecules can have multiple covalent bonds Methane (CH 4 )