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Chapter 3 Structure and Function of Cells Metabolism Anabolism Catabolism Cell respiration Aerobic Anaerobic Copyright © 2009 Pearson Education, Inc. Cells Are Classified by Internal Organization Eukaryotes have Plasma membrane Nucleus: information center Cytoplasm: fluid within membrane Organelles: structures with specialized functions Prokaryotes have No nucleus No true organelles Copyright © 2009 Pearson Education, Inc. Cell Structure Reflects Cell Function Muscle cells Contain numerous organelles providing energy needed for muscle contraction Nerve cells Long and thin to carry impulses over distance Copyright © 2009 Pearson Education, Inc. The Plasma Membrane Extracellular environment Receptor protein Channel protein (always open) Gated channel protein (closed position) Cytoskeleton Phospholipid filaments Cytoplasm Copyright © 2009 Pearson Education, Inc. Carbohydrate groups Lipid Transport Glycoprotein bilayer protein Cholesterol Figure 3.5 Structural Features of the Plasma Membrane Lipid bilayer Phospholipids: polar head and nonpolar tail Cholesterol: makes membrane a bit more rigid Proteins: provide means of transportation through membrane Carbohydrates: recognition patterns for cells and organisms Copyright © 2009 Pearson Education, Inc. Diffusion: Passive Transport Through Membrane Passive transport No energy required Diffusion Movement from area of high concentration to low Copyright © 2009 Pearson Education, Inc. Figure 3.6 Osmosis: Diffusion of Water Osmosis: net diffusion of water across a semipermeable membrane Copyright © 2009 Pearson Education, Inc. Figure 3.7 Variations in Tonicity Isotonic Extracellular and intracellular ionic concentration equal Hypotonic Extracellular ionic concentration less than intracellular Hypertonic Extracellular ionic concentration more than intracellular Copyright © 2009 Pearson Education, Inc. Tonicity Copyright © 2009 Pearson Education, Inc. Figure 3.13a Internal Structures of an Animal Cell Cytosol Semifluid gel material inside the cell Peroxisome Destroys cellular toxic waste Centrioles Microtubular structures involved in cell division Cytoskeleton Structural framework of the cell Nucleus Information center for the cell. Contains DNA Smooth endoplasmic reticulum Primary site of macromolecule synthesis other than proteins Rough endoplasmic reticulum Primary site of protein synthesis by ribosomes Golgi apparatus Refines, packages, and ships macromolecular products Secretory vesicle Membrane-bound shipping container Ribosomes Site of protein synthesis Plasma membrane Controls movement of materials into and out of cell Mitochondrion Produces energy for the cell Lysosome Digests damaged organelles and cellular debris Copyright © 2009 Pearson Education, Inc. Figure 3.14 Endoplasmic Reticulum (ER) and Ribosomes Copyright © 2009 Pearson Education, Inc. Figure 3.16 Golgi Apparatus Receives substances from ER, refines and packages them Smooth ER Golgi apparatus Vesicle Lysosome Secretory vesicle Plasma membrane Copyright © 2009 Pearson Education, Inc. Figure 3.17 (1 of 2) Vesicles Ship and Store Cellular Products Harmless waste Alcohol Vesicles Ship and store cellular products Secretory membranebound spheres Examples: secretory, endocytic, peroxisomes, lysosomes Copyright © 2009 Pearson Education, Inc. Peroxisome Golgi apparatus Cell toxic waste Lysosome Residual body Bacterium Plasma membrane Figure 3.18 Mitochondria: Provide Energy to the Cell Double membrane Inner membrane contains enzymes that break down foods Liberated energy is used to create ATP Copyright © 2009 Pearson Education, Inc. Figure 3.19a Energy Storage Fat Triglycerides Long-term energy storage in animals Glycogen Carbohydrate storage Short-term energy storage in animals Copyright © 2009 Pearson Education, Inc. Cytoskeleton Supports the Cell Microtubules Microfilaments Copyright © 2009 Pearson Education, Inc. Figure 3.20 Cell Structures for Support and Movement: Cilia, Flagella, Centrioles Cilia and flagella Used in movement 9 + 2 microtubule arrangement Centrioles Used in cell division Copyright © 2009 Pearson Education, Inc. Figure 3.20 Cells Use and Transform Matter and Energy: Two Basic Metabolic Pathways Anabolism Requires enzymes Making/assembling large molecules May require energy (ATP) Copyright © 2009 Pearson Education, Inc. Cells Use and Transform Matter and Energy: Two Basic Metabolic Pathways Catabolism Requires enzymes Breakdown of molecules May release energy Used in breaking down nutrients and recycling cell components Copyright © 2009 Pearson Education, Inc. Cellular Respiration: Cells Use Glucose and Oxygen to Supply ATP Glucose provides energy for the cell Copyright © 2009 Pearson Education, Inc. Figure 3.23 Stages of Cellular Respiration Glycolysis: in cytoplasm Splits glucose Produces two ATP and two pyruvate molecules Citric acid cycle: in mitochondria Also called the Krebs cycle Extracts high-energy electrons Produces two ATP and carbon dioxide Electron transport system: in mitochondria Energy from electrons is used to produce ATP Produces water and carbon dioxide Copyright © 2009 Pearson Education, Inc. Cellular Respiration: Overview Copyright © 2009 Pearson Education, Inc. Figure 3.29a The Preparatory Step Copyright © 2009 Pearson Education, Inc. Figure 3.26 Fats and Proteins: Additional Energy Sources Copyright © 2009 Pearson Education, Inc. Figure 3.30 Fats and Proteins: Additional Energy Sources Fats Triglycerides have twice the energy of carbohydrates Proteins Same energy as carbohydrates Copyright © 2009 Pearson Education, Inc. Anaerobic Pathways: Energy Extraction Without Oxygen Glucose (Glycolysis) (2) ATP Lactic acid buildup Pyruvate Mitochondrial metabolism blocked without oxygen Mitochondrion Copyright © 2009 Pearson Education, Inc. Figure 3.31