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Explore the internal organization of cells, metabolic pathways, and essential cellular structures for support and energy production in this informative guide. Understand the processes of anabolism, catabolism, and cellular respiration, detailing the role of organelles and metabolic networks within cells. Discover the significance of structures like the plasma membrane, nucleus, and mitochondria in maintaining cell function and survival. Dive into topics such as diffusion, osmosis, and variations in tonicity to grasp the fundamentals of cell biology and metabolism.
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Chapter 3 • Structure and Function of Cells • Metabolism • Anabolism • Catabolism • Cell respiration • Aerobic • Anaerobic
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
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
The Plasma Membrane Extracellular environment Receptor protein Channel protein (always open) Gated channel protein (closed position) Carbohydrate groups Cytoskeleton filaments Phospholipid Lipid bilayer Transport protein Glycoprotein Cholesterol Cytoplasm 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
Diffusion: Passive Transport Through Membrane • Passive transport • No energy required • Diffusion • Movement from area of high concentration to low Figure 3.6
Osmosis: Diffusion of Water • Osmosis: net diffusion of water across a semipermeable membrane 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
Tonicity Figure 3.13a
Internal Structures of an Animal Cell Cytosol Semifluid gel material inside the cell Peroxisome Destroys cellular toxic waste Nucleus Information center for the cell. Contains DNA Centrioles Microtubular structures involved in cell division Cytoskeleton Structural framework of the cell Smooth endoplas- mic reticulum Primary site of macromolecule synthesis other than proteins Rough endoplas- mic 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 Mitochondrion Produces energy for the cell Plasma membrane Controls movement of materials into and out of cell Lysosome Digests damaged organelles and cellular debris Figure 3.14
Endoplasmic Reticulum (ER) and Ribosomes Figure 3.16
Golgi Apparatus • Receives substances from ER, refines and packages them Smooth ER Golgi apparatus Vesicle Lysosome Secretory vesicle Plasma membrane Figure 3.17 (1 of 2)
Vesicles Ship and Store Cellular Products Harmless waste Alcohol • Vesicles • Ship and store cellular products • Secretory membrane-bound spheres • Examples: secretory, endocytic, peroxisomes, lysosomes 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 Figure 3.19a
Energy Storage • Fat • Triglycerides • Long-term energy storage in animals • Glycogen • Carbohydrate storage • Short-term energy storage in animals
Cytoskeleton Supports the Cell • Microtubules • Microfilaments 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 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)
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
Cellular Respiration: Cells Use Glucose and Oxygen to Supply ATP • Glucose provides energy for the cell 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
Cellular Respiration: Overview Figure 3.29a
The Preparatory Step Figure 3.26
Fats and Proteins: Additional Energy Sources Figure 3.30
Fats and Proteins: Additional Energy Sources • Fats • Triglycerides have twice the energy of carbohydrates • Proteins • Same energy as carbohydrates
Anaerobic Pathways: Energy Extraction Without Oxygen Glucose (Glycolysis) (2) ATP Lactic acid buildup Pyruvate Mitochondrial metabolism blocked without oxygen Mitochondrion Figure 3.31