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PowerPoint Presentation to Accompany © 2010 Delmar, Cengage Learning 1 Chapter 4 Cellular Metabolism and Reproduction: Mitosis and Meiosis © 2010 Delmar, Cengage Learning 2 Introduction to Cellular Metabolism • Metabolism: total cellular chemical changes – Anabolism: process of building up – Catabolism: process of breaking down • Calorie: measure of energy contained in food • ATP: energy source available to the cell © 2010 Delmar, Cengage Learning 3 Anabolism Anabolism provides the materials needed for cellular growth and repair Dehydration synthesis • type of anabolic process • used to make polysaccharides, triglycerides, and proteins • produces water © 2010 Delmar, Cengage Learning 4 4 Anabolism 5 Catabolism Catabolism breaks down larger molecules into smaller ones Hydrolysis • a catabolic process • used to decompose carbohydrates, lipids, and proteins • water is used to split the substances • reverse of dehydration synthesis 6 Catabolism 7 Control of Metabolic Reactions Metabolic pathways • series of enzyme-controlled reactions leading to formation of a product • each new substrate is the product of the previous reaction Enzyme names commonly • reflect the substrate • have the suffix – ase • sucrase, lactase, protease, lipase 8 Control of Metabolic Reactions Cofactors • make some enzymes active • non protein component • ions or coenzymes Coenzymes • organic molecules that act as cofactors • vitamins Factors that alter enzymes • heat • radiation • electricity • chemicals • changes in pH 9 Energy for Metabolic Reactions Energy • ability to do work or change something • heat, light, sound, electricity, mechanical energy, chemical energy • changed from one form to another • involved in all metabolic reactions Release of chemical energy • most metabolic processes depend on chemical energy • oxidation of glucose generates chemical energy to promote cellular metabolism • cellular respiration releases chemical energy from molecules 10 and makes it available for cellular use Cellular Metabolism or Biochemical Respiration © 2010 Delmar, Cengage Learning 11 ATP Molecules • each ATP molecule has three parts: • an adenine molecule • a ribose molecule • three phosphate molecules in a chain • third phosphate attached by high-energy bond • when the bond is broken, energy is transferred • when the bond is broken, ATP becomes ADP • ADP becomes ATP through phosphorylation • phosphorylation requires energy released from cellular respiration 12 Glycolysis • Breakdown of glucose • Anaerobic or aerobic process • Final outcome – 2 pyruvic acid molecules, 2 ATP molecules (anaerobic), 8 ATP molecules (aerobic) © 2010 Delmar, Cengage Learning 13 © 2010 Delmar, Cengage Learning 14 The Krebs Citric Acid Cycle • Pyruvic Acid > Acetic Acid > Acetyl-CoA • Acetyl-CoA enters Krebs cycle in mitochondria • Final outcome – 6 CO2, 8 NADH2, 2 FADH2, 2 ATP (GTP) © 2010 Delmar, Cengage Learning 15 © 2010 Delmar, Cengage Learning 16 The Electron Transport (Transfer) System • • • • Series of reduction/oxidation reactions Requires O2 Electron carriers Number of ATP molecules dependent on electron carrier • Water is a waste product © 2010 Delmar, Cengage Learning 17 Summary of ATP Production • During glycolysis, the citric acid cycle, and electron transport • Glycolysis: 8 ATP (aerobic) • Krebs cycle and electron transport – 28 ATP + 2 GTP or – 30 ATP • 1 glucose molecule yields 38 ATP © 2010 Delmar, Cengage Learning 18 Anaerobic Respiration © 2010 Delmar, Cengage Learning 19 Fermentation • Yeast breaks down glucose anaerobically • Pyruvic acid broken down by decarboxylase – Forms carbon dioxide and acetaldehyde • Final products: 2 ATP, CO2, ethyl alcohol © 2010 Delmar, Cengage Learning 20 Anaerobic Production of ATP by Muscles • Pyruvic acid converted to lactic acid – Accumulation of lactic acid causes fatigue in muscles – When oxygen supplied, lactic acid turns back into pyruvic acid • 2 ATP produced per glucose molecule © 2010 Delmar, Cengage Learning 21 Production of ATP from General Food Compounds © 2010 Delmar, Cengage Learning 22 Production of ATP from General Food Compounds (cont’d.) • Carbohydrates fit into cellular furnace at same level as glucose – Can be stored in liver or as fat • Fats digested into fatty acids and glycerol – Glycerol enters at PGA stage of glycolysis – Fatty acids enter Krebs citric acid cycle © 2010 Delmar, Cengage Learning 23 Production of ATP from General Food Compounds (cont’d.) • Proteins digested into amino acids – Enter into Krebs cycle at different stages • Dependent on chemical structure © 2010 Delmar, Cengage Learning 24 Introduction to Cellular Reproduction © 2010 Delmar, Cengage Learning 25 Introduction to Cellular Reproduction (cont’d.) • • • • Process of cell duplication Mitosis: duplication of genetic material Cytokinesis: duplication of organelles Meiosis: reduction division only in gonads © 2010 Delmar, Cengage Learning 26 The Structure of the DNA Molecule © 2010 Delmar, Cengage Learning 27 The History of the Discovery of DNA • • • • Friedrich Miescher, 1869: first discovery P.A. Levine, 1920s: composition Rosalind Franklin: helical structure Watson and Crick: three-dimensional structure © 2010 Delmar, Cengage Learning 28 The Anatomy of the DNA Molecule • Double helical chain of nucleotides – Phosphate group – Five-carbon sugars (deoxyribose) – Nitrogen-containing base • Pyrimidines (thymine and cytosine) • Purines (adenine and guanine) – Pyrimidines pair with purines – Chains held together by hydrogen bonds © 2010 Delmar, Cengage Learning 29 The Anatomy of the DNA Molecule (cont’d.) • Gene: sequence of base pairs that codes for polypeptide or protein • Human Genome Project – 3 billion base pairs that code for 30,000 genes • Duplication of DNA molecule – Helicase separates at hydrogen bonds – DNA polymerase adds new nucleotides © 2010 Delmar, Cengage Learning 30 The Cell Cycle © 2010 Delmar, Cengage Learning 31 Introduction • All reproduction begins at cellular level • Interphase – Previously called resting stage • Mitosis • Cytokinesis © 2010 Delmar, Cengage Learning 32 Interphase • Time between divisions – G1: Primary growth phase – S: DNA duplication – G2: Centrioles complete duplication, mitochondria replicate, chromosomes condense and coil © 2010 Delmar, Cengage Learning 33 Mitosis • Prophase – Chromosomes become visible as chromatids joined by centromere – Two kinetochores at the centromere – Centrioles move to opposite poles – Nuclear membrane breaks down – Microtubules attach kinetochores to spindle © 2010 Delmar, Cengage Learning 34 Mitosis (cont’d.) • Metaphase – Chromatids align at equator of cell – Centromere divides © 2010 Delmar, Cengage Learning 35 Mitosis (cont’d.) • Anaphase – Divided centromere pulls chromatids to opposite pole – Cytokinesis begins © 2010 Delmar, Cengage Learning 36 Mitosis (cont’d.) • Telophase – Chromosomes uncoil and decondense – Spindle apparatus breaks down – New nuclear membrane forms – Cytokinesis nearly complete © 2010 Delmar, Cengage Learning 37 Animation - Mitosis • Stop and watch a 3-D presentation of mitosis. [Insert mitosis.swf] © 2010 Delmar, Cengage Learning 38 Cytokinesis • Animal cells – Cleavage furrow forms – Cell is pinched into daughter cells • Plant cells – Cell plate forms at equator – Cell plate becomes new cell wall © 2010 Delmar, Cengage Learning 39 Meiosis: A Reduction Division © 2010 Delmar, Cengage Learning 40 Introduction • Occurs only in the gonads • Reduces genetic material from diploid to haploid • Two divisions resulting in four cells © 2010 Delmar, Cengage Learning 41 Stages of Meiosis • Prophase I: homologous chromosomes pair and cross over • Metaphase I: chromosomes align along equator • Anaphase I: centromeres pulled to poles – One member to each pole • Telophase I: one of each pair is at each pole © 2010 Delmar, Cengage Learning 42 Stages of Meiosis (cont’d.) • Prophase II: spindle forms; centrioles move to poles • Metaphase II: chromosomes line up at equator • Anaphase II: centromeres divide • Telophase II: chromatids at each pole; new nuclear membrane forms © 2010 Delmar, Cengage Learning 43 Animation - Meiosis • Now that you have learned about the stages of meiosis, watch the meiosis animation for a visual of this process. • [Insert meiosis.swf] © 2010 Delmar, Cengage Learning 44 Gametogenesis: The Formation of the Sex Cells © 2010 Delmar, Cengage Learning 45 Gametogenesis: The Formation of the Sex Cells (cont’d.) • Spermatogenesis – Four cells produced – Develop into sperm • Oogenesis – Four cells produced – Only one becomes functional egg © 2010 Delmar, Cengage Learning 46 Animation – Cancer Metastasizing • Refer to the Common Disease, Disorder or Condition box on Cancer in your textbook and read about the growth of cancer cells. Now watch the 3-D Cancer Metastasizing animation. • [Insert cancer metastasizing.swf] © 2010 Delmar, Cengage Learning 47 Summary • Discussed how glucose is converted into ATP in the presence of oxygen • Discussed how glucose is converted into ATP in the absence of oxygen • Described how fats and proteins are converted into ATP • Discussed the cell cycle © 2010 Delmar, Cengage Learning 48