1. 1 Levels of Organization Subatomic Particles – electrons, protons, neutrons Molecule – Atoms bound together Macromolecule – Molecules bound together Atom – Basic unit of matter

2. 2 Organelle – Carry out specific activities in the cell Cell – basic unit of life Tissue – group of cells that work together to perform a similar function Organ – group of different types of tissues that work together to perform a specific function Organ System – two or more organs that work together Organism – any individual living thing

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4. 4 Levels of Organization

5. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Human Atom Protons, Neutrons, Electrons Molecule Macromolecule Mitochondria Animal Cell Stomach Tissue Stomach Digestive System Make your own Level of Organization Model on pg. 12 DRAW PICTURES and LABEL Cells/Organelles pg 73-79 Systems/Organs pg 872-1011

6. 6 Sponge: anywhere on pg. 12-13 What do we mean by the statement “Structure is always related to function”? The structures are developed to perform a specific job or function

7. 7 Clinical Application Medical Imaging Noninvasive procedures Provide images of soft internal structures Magnetic Resonance Imaging Requires injection of dye Produces computerized images from different angles Ultrasonography Use of high- frequency sound waves Relatively quick and inexpensive

8. 8 Characteristics of Life Movement – change in position; motion Responsiveness – reaction to a change Growth – increase in body size; no change in shape Respiration – obtaining oxygen; removing carbon dioxide; releasing energy from foods Reproduction – production of new organisms and new cells

9. 9 Characteristics of Life Absorption – passage of substances through membranes and into body fluids Circulation – movement of substances in body fluids Assimilation – changing of absorbed substances into chemically different forms Excretion – removal of wastes produced by metabolic reactions Digestion – breakdown of food substances into simpler forms

10. 10 Requirements of Organisms Life depends on five environmental factors water food oxygen heat pressure

11. 11 Requirements of Organisms Water - most abundant substance in body - required for metabolic processes - required for transport of substances - regulates body temperature Food - provides necessary nutrients - supplies energy - supplies raw materials

12. 12 Requirements of Organisms Oxygen (Gas) - one-fifth of air - used to release energy from nutrients Heat - form of energy - partly controls rate of metabolic reactions Pressure - application of force on an object - atmospheric pressure – important for breathing - hydrostatic pressure – keeps blood flowing