Chapter 1 Review  Key Concepts we have covered so far

Themes of Biology  Living organisms are diverse but share certain characteristics

Themes of Biology  All living organisms ○ Are composed of cells ○ Grow and develop ○ Are able to maintain homeostasis

Themes of Biology  Living organisms reproduce producing offspring similar to themselves

Themes of Biology  Living Organisms obtain and use energy to stay alive  Living organisms respond to their environment

Themes of Biology  Seven themes unify the science of biology 1. Cellular structure and function 2. Reproduction 3. Metabolism 4. Homeostasis 5. Heredity 6. Evolution 7. Interdependence

Biology in Your World  Pollution of the atmosphere, extinction of plants and animals and a growing demand for food are current environmental problems caused by the growing human population

Biology in Your World  Biologists are using genetic engineering to develop crops that require fewer fertilizers and pesticides and to develop new crops

Biology in Your World  Biological research and new technologies will help scientists battle diseases such as AIDS, cancer and cystic fibrosis

Scientific Processes  Scientists add to scientific knowledge by sharing observations and posing questions about those observations

Scientific Processes  Although there is no single method; observing, asking questions, forming and testing hypothesis are important in planning a scientific investigation.

Scientific Processes  In a controlled experiment, the independent variable is varied between the experimental and control groups. The measured variable is the dependent variable.

Scientific Processes  A collection of hypothesis that have been repeatedly tested and are supported by a great deal of evidence forms a theory

Chapter 2 Review  Key concepts of Chapter 2 we have covered so far

Nature of Matter  All matter is made of atoms  Atoms consist of Electrons (negative charge) Protons (positive charge) Neutrons (no charge - neutral)

Nature of Matter  Molecules are groups of atoms linked by covalent bonds  Covalent bonds form when two or more atoms share electrons

Nature of Matter  Hydrogen bonding occurs between polar molecules  Molecules with an unequal distribution of electrical charge are called polar molecules

Nature of Matter  An ion is an atom or molecule that has a charge because it has gained or lost an electron  Ions of opposite charges attract each other and may form an ionic bond

Water and Solutions  Water, which is essential for life, stores heat efficiently and binds to itself and other molecules

Water and Solutions  When the bonds between water molecules break, hydrogen ions form  Acids increase the hydrogen ion concentration of a solution  Bases decrease the hydrogen ion concentration of a solution

Water and Solutions  The pH scale measures the strength of acids and bases, how much they increase or reduce the number of hydrogen ions

Chemistry of Cells  Organic compounds are found in living things

Chemistry of Cells  Carbohydrates, such as glucose, are a source of energy and are used as structural materials in organisms

Chemistry of Cells  Lipids are nonpolar molecules that store energy and are important part of cell membranes

Chemistry of Cells  Proteins are chains of amino acids. The sequence of amino acids determines a protein’s shape and specific function

Chemistry of Cells  Nucleic acids (DNA and RNA) store and transmit hereditary information

Chemistry of Cells  ATP is the main energy currency of cells temporarily storing energy for a cell’s use after food is broken down

Energy and Chemical Reactions  Chemical reactions absorb or release energy

Energy and Chemical Reactions  Starting a chemical reaction requires activation energy

Energy and Chemical Reactions  Enzymes speed up chemical reactions by decreasing the activation energy of the reactions

Energy and Chemical Reactions  Enzymes bind to only certain substances

Energy and Chemical Reactions  Factors such as temperature and pH affect enzyme activity