Diffusion by reflection from a rough surface is described in this chapter. Light can also be diffused by refraction. Describe how this occurs in a specific situation, such as light interacting with crushed ice.
. Cell theory: Cell: the structural and functional unit of life How well the entire organism functions depends on individual and combined activities of all of its cells Biochemical functions of cells are directed by shape of cell and specific subcellular structures Continuity of life has cellular basis Cells differ in shape, size, and subcellular components which lead to different functions (Fig. 3.1) Erythrocytes (RBCs), epithelial, and fibroblasts connect body parts or transport gases Macrophages fight disease and skeletal muscle cells and smooth muscle cells move organs All cells have some common structures and functions . Human cells have 3 basic parts: 1. Plasma membrane: flexible outer boundary 2. Nucleus: contains DNA 3. Cytoplasm: intracellular fluid containing organelles . Extracellular materials: substances found outside cells 1. Extracellular fluids: Interstitial fluid: cells are bathed in this fluid Blood plasma: fluid of the blood Cerebrospinal fluid: fluid surrounding nervous system organs 2. Cellular secretions such as mucus and saliva 3. Extracellular matrix: substance that acts as a glue to hold cells together in tissues . Plasma membrane (cell membrane): (Fig. 3.3) Acts as an active barrier separating intracellular fluid (ICF) from extracellular fluid (ECF) Controls what enters and what leaves the cell Consists of a flexible lipid bilayer that have membrane pro