Human Anatomy & Physiology I Chapter 4 Cell Metabolism 4-1

Chapter 4 Cellular Metabolism ________________ – all chemical reactions that occur in the body Two types of metabolic reactions Anabolism _______ molecules are made ________________ _____________ larger molecules are broken down _____________ 4-2

Anabolism Anabolism provides the substances needed for cellular growth and repair ____________________ type of anabolic process used to make polysaccharides, triglycerides, and proteins _________________ 4-3

Anabolism 4-4

Catabolism Catabolism breaks down larger molecules into smaller ones Hydrolysis ___________________ used to decompose ____________, lipids, and proteins water is used reverse of dehydration synthesis 4-5

Catabolism 4-6

Control of Metabolic Reactions ____________ control rates of metabolic reactions lower activation energy needed to start reactions globular proteins with specific shapes not consumed in chemical reactions _____________ shape of _________ determines substrate 4-7

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 – _____ ________e, lactase, protease, ________ 4-8

Control of Metabolic Reactions Cofactors make some enzymes active _________________ Coenzymes organic molecules that act as cofactors ____________ Factors that alter enzymes ________ ___________ _________ chemicals changes in ____ 4-9

Energy for Metabolic Reactions Energy ____________________________________ heat, light, sound, electricity, mechanical energy, chemical energy ________________________________ involved in all metabolic reactions Release of chemical energy most metabolic processes depend on chemical energy ___________ of glucose generates chemical energy ________________ releases chemical energy from molecules and makes it available for cellular use 4-10

Cellular Respiration Occurs in three series of reactions 1.___________ 2.______________ 3.Electron transport chain Produces ______________ ________ ATP (chemical energy) heat Includes anaerobic reactions (without O 2 ) - produce little ATP aerobic reactions (requires O 2 ) - produce most ATP 4-11

ATP Molecules each ATP molecule has three parts: ____________________ a ________________ 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 _____________________________________ phosphorylation requires energy released from cellular respiration 4-12

Glycolysis series of ten reactions breaks down glucose into ________________ occurs in cytosol ________________________ respiration yields two ATP molecules per glucose Summarized by three main events 1. _________________ 2. ______________ 3. production of NADH and ATP 4-13

Glycolysis Event 1 - ______________ two phosphates added to glucose requires ATP Event 2 – _______(cleavage) _-carbon glucose split into ______________ molecules 4-14

Glycolysis Event 3 – ________________ and ______ hydrogen atoms are released hydrogen atoms bind to _____ to produce _______ NADH delivers hydrogen atoms to electron transport chain if oxygen is available ____ is phosphorylated to become _______ two molecules of _________ are produced 4-15

Anaerobic Reactions If oxygen is not available - electron transport chain cannot accept _______ _________ is converted to lactic acid glycolysis is inhibited ATP production declines 4-16

Aerobic Reactions If oxygen is available – pyruvic acid is used to produce _________ citric acid cycle begins electron transport chain functions carbon dioxide and water are formed __ molecules of ATP produced per glucose molecule 4-17

Citric Acid Cycle begins when acetyl CoA combines with _________ acid to produce citric acid citric acid is changed into oxaloacetic acid through a series of reactions cycle repeats as long as pyruvic acid and oxygen are available for each citric acid molecule: one ATP is produced eight hydrogen atoms are transferred to NAD + and FAD two CO 2 produced 4-18

Electron Transport Chain NADH and FADH2 carry electrons to the ETC ETC series of electron carriers located in cristae of mitochondria energy from electrons transferred to ________________ ATP synthase catalyzes the phosphorylation of ADP to ATP water is formed 4-19

Summary of Cellular Respiration 4-20

Summary of Catabolism of Proteins, Carbohydrates, and Fats 4-21

Carbohydrate Storage Excess glucose stored as _________ (primarily by liver and muscle cells) fat converted to amino acids 4-22

Regulation of Metabolic Pathways limited number of regulatory enzymes _________________ 4-23

Nucleic Acids and Protein Synthesis Gene – segment of DNA that codes for one protein _______________ – instructs cells how to construct proteins; stored in DNA Genome – ________________ _________ – method used to translate a sequence of nucleotides of DNA into a sequence of amino acids 4-24

Structure of DNA two polynucleotide chains hydrogen bonds hold nitrogenous bases together bases pair specifically (____________) forms a helix DNA wrapped about histones forms chromosomes 4-25

RNA Molecules Messenger RNA (mRNA) - delivers genetic information from nucleus to the cytoplasm single polynucleotide chain formed beside a strand of DNA ______________ are complementary to DNA nucleotides (exception – no thymine in RNA; replaced with uracil) making of mRNA is transcription 4-26

RNA Molecules _______________________ - carries amino acids to mRNA carries anticodon to mRNA _________ a codon of mRNA into an amino acid Ribosomal RNA (rRNA) – provides structure and enzyme activity for ribosomes 4-27

Protein Synthesis 4-28

Protein Synthesis 4-29

DNA Replication hydrogen bonds break between bases double strands unwind and pull apart new nucleotides pair with exposed bases controlled by _____ polymerase 4-30

Mutations Mutations – _________________ information Result when __________________ deleted bases are changed May or may not change the protein Repair enzymes correct mutations 4-31

Clinical Application ________________ PKU enzyme that breaks down the _____________________ is missing build up of phenylalanine causes mental retardation treated by diets very low in phenylalanine 4-32