copyright © 2010 pearson education, inc. the organelles membranous organelles –five types of...
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Copyright © 2010 Pearson Education, Inc.
The Organelles
• Membranous Organelles
– Five types of membranous organelles:
• Endoplasmic reticulum (ER)
• Golgi apparatus
• Lysosomes
• Peroxisomes
• Mitochondria
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The Organelles
• Endoplasmic Reticulum (ER)
– Functions:
• Synthesis of proteins, carbohydrates, and lipids
• Storage of synthesized molecules and materials
• Transport of materials within the ER
• Detoxification of drugs or toxins
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The Organelles
• Endoplasmic Reticulum (ER)
– Smooth endoplasmic reticulum (SER):
• No ribosomes attached
• Synthesizes lipids and carbohydrates:
– phospholipids and cholesterol (membranes)
– steroid hormones (reproductive system)
– glycerides (storage in liver and fat cells)
– glycogen (storage in muscles)
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The Organelles
• Endoplasmic Reticulum (ER)
– Rough endoplasmic reticulum (RER):
• Surface covered with ribosomes:
– active in protein and glycoprotein synthesis
– folds polypeptide protein structures
– encloses products in transport vesicles
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The Endoplasmic Reticulum
Figure 3-13
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Organelles and the Cytoplasm
• Golgi Apparatus– Vesicles enter forming face and exit maturing face:
• Secretory vesicles:
– modify and package products for exocytosis
• Membrane renewal vesicles:
– add or remove membrane components
• Lysosomes:
– carry enzymes to cytosol
Functions of the Golgi Apparatus
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The Golgi Apparatus
Figure 3-14
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The Organelles
• Lysosomes– Powerful enzyme-containing vesicles
• Functions of Lysosomes– Clean up inside cells:
• Break down large molecules• Attack bacteria• Recycle damaged organelles• Eject wastes by exocytosis
– Autolysis• Auto- = self, lysis = break• Self-destruction of damaged cells:
– lysosome membranes break down– digestive enzymes are released– cell decomposes– cellular materials recycle
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The Organelles
• Peroxisomes
– Are enzyme-containing vesicles:
• Break down fatty acids, organic compounds
• Produce hydrogen peroxide (H2O2)
• Replicate by division
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The Organelles
• Mitochondria– Have smooth outer membrane and inner membrane
with numerous folds (cristae)
– Matrix: • Fluid around cristae
– Mitochondrion takes chemical energy from food
(glucose):• Produces energy molecule ATP
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The Organelles
• Mitochondria– Aerobic metabolism (cellular respiration)
• Mitochondria use oxygen to break down food and produce ATP
glucose + oxygen + ADP carbon dioxide + water + ATP
• Glycolysis: – glucose to pyruvic acid (in cytosol)
• Tricarboxylic acid cycle (TCA cycle):– pyruvic acid to CO2 (in matrix)
• Electron transport chain– inner mitochondrial membrane
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Mitochondria
Figure 3-15
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Nuclear Structure and Contents
• Nucleus– Largest organelle
– The cell’s control center
• Nuclear Envelope– Double membrane around the nucleus
• Perinuclear Space– Between the two layers of the nuclear envelope
• Nuclear Pores– Communication passages
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The Nucleus
Figure 3-16
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Nuclear Structure and Contents• DNA
– All information to build and run organisms
• Nucleoplasm– Fluid containing ions, enzymes, nucleotides, and some RNA
• Nucleoli– Are related to protein production
– Are made of RNA, enzymes, and histones
– Synthesize rRNA and ribosomal subunits
• Chromatin
– Loosely coiled DNA (cells not dividing)
• Chromosomes
– Tightly coiled DNA (cells dividing)
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Information Storage in the Nucleus
• DNA– Instructions for every protein in the body
• Gene– DNA instructions for one protein
• Genetic Code– The chemical language of DNA instructions:
• Sequence of bases (A, T, C, G)
– Triplet code:• 3 bases = 1 amino acid