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Unformatted text preview: Chapter 2 The Cell I. Introduction: foundation of microscopy and cell theory A. Concept of a cell - the smallest living unit in the human body 1. structural building blocks of all plants and animals 2. produced by division of preexisting cells 3. smallest structural units that perform vital functions B. two types of cells 1. sex cells- germ cells (sperm and ovum) 2. somatic cells- all other cells II. Cellular anatomy A. general information 1. cells float in watery medium - extracellular fluid- high in sodium ions 2. exterior of cell is surrounded by cell membrane a. separates extracellular fluid from cell contents - cytoplasm 3. cytoplasm - a. cytosol- internal fluid - intracellular fluid b. organelles- structures B. Cell membrane - plasma membrane - plasmalemma 1. thin and delicate 2. composed of phospholids, proteins, glycolipids and cholesterol 3. phospholipid bilayer 4. functions a. separates intracellular fluid from extracellular fluid b. controls entry and exit of substances - permeability- ease with which dissolved materials can cross a membrane 1) passive process a) diffusion- movement from high concentration to low concentration b) osmosis - diffusion of water c) filtration- solutes/dissolved nutrients by hydrostatic force cross the membrane with water d) facilitated diffusion- special carrier proteins transport large m o l e c u l e s 2) active transport...
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- Spring '12
- B. Cell membrane, cell membrane a., cell membrane ii.