Metabolism Chapter 4 ivyanatomy.com Anatomy & Physiology

Metabolism is the sum of all reactions in the body Anabolism Synthesize larger molecules from smaller ones. Cells use energy Decomposes larger molecules into smaller ones. Releases energy for cellular use Catabolism Cellular Metabolism

Glucose molecules are joined by dehydration synthesis Most polymers are synthesized through dehydration synthesis. Anabolic Reactions Dehydration Synthesis A water molecule is released to join molecules together. + + H2OH2O

Dehydration synthesis synthesizes polysaccharides, fats, proteins, and nucleic acids from their monomers. Several Monomers Polymer + H2OH2O Dehydration Synthesis

Dehydration synthesis of a polysaccharide. Amylose is a polysaccharide composed of several thousand glucose monosaccharides. + H2OH2O glucose

Dehydration Synthesis Dehydration synthesis of a triglyceride. + H2OH2O

Dehydration Synthesis Dehydration synthesis of a polypeptide. + H2OH2O

S CH 2 B P O O OH O Dehydration Synthesis Dehydration synthesis of a polynucleotide. S CH 2 B P O O OH O S CH 2 B P O O O O OH S CH 2 B P O O OH O + H2OH2O

Water is consumed to break apart the molecules hydrolysis is the reverse of dehydration synthesis hydrolysis releases energy from chemical bonds Hydrolysis + + H2OH2O

Hydrolysis is used to decompose polysaccharides, fats, proteins, and nucleic acids into their monomers. Several Monomers Polymer + H2OH2O Hydrolysis

Hydrolysis of a polysaccharide. Water is added to amylose, which decomposes into glucose molecules + H2OH2O glucose

++ H2OH2O Hydrolysis Hydrolysis of a triglyceride (fat).

Hydrolysis Hydrolysis of a dipeptide. + H2OH2O +

S CH 2 B P O O OH O Hydrolysis Hydrolysis of a dinucleotide. S CH 2 B P O O O O OH S CH 2 B P O O OH O + H2OH2O S CH 2 B P O O OH O

+ Monomers linked by covalent bond Dehydration Synthesis Hydrolysis + Monomers linked by covalent bond

Activation energy Activation Energy – Amount of energy required to initiate a reaction

Activation energy A catalyst – increases the rate of the reaction without being consumed by the reaction Activation energy without catalyst Activation energy with a catalyst Catalysts lower the activation energy required to initiate a reaction Lower energy state

*A substrate is the target molecule of an enzyme Characteristics of enzymes Enzymes lower the activation energy of a reaction Most enzymes are proteins Enzymes catalyze reactions (they increase the rate of reactions, but are not consumed by the reaction) Enzymes are specific to one substrate*. Most enzymes end in ____ase. (lipase, protease, nuclease, ATPase, etc.) Enzymes

Synthesis reaction involving an enzyme Enzymes catalyze reactions (increases rate), but are not consumed by the reaction (reusable). Proteins Substrates A B Active Site A B Enzyme A Enzyme-Substrate Complex B Product Active Site A B Enzyme is unchanged

The rate of an enzyme-catalyzed reaction is limited by: 1. The concentration of substrate 2. The concentration of enzyme 3. Enzyme efficiency Measures how efficiently the enzyme converts substrates into produces Enzymes

A metabolic pathway is a complex series of reactions leading to a product Metabolic Pathways are controlled by several enzymes Metabolic Pathways

The product of each reaction becomes the substrate of next reaction. Each step requires its own enzyme The least efficient enzyme is the “Rate-Limiting Enzyme” Rate-limiting enzyme is usually first in sequence Enzyme A = Rate-limiting Enzyme Metabolic Pathways Substrate 1 Substrate 2 Enzyme B Enzyme A Substrate 3 Enzyme C Substrate 4 Enzyme D Product

Negative feedback prevents too much product from being produced. The product of the metabolic pathway often inhibits the rate-limiting enzyme. Negative Feedback in Metabolic Pathway Substrate 2 Enzyme B Enzyme A Substrate 3 Enzyme C Substrate 4 Enzyme D Product Rate-limiting

Cofactor substance that increases the efficiency of an enzyme Cofactors include ions (zinc, iron, copper) and coenzymes Coenzymes are organic cofactors Coenzymes include Vitamins (Vitamin A, B, D) Reusable – required in small amounts Enzymes

Vitamins are essential organic molecules that humans cannot synthesize, so they must come from diet Many vitamins are coenzymes Vitamins can function repeatedly, so can be used in small amounts. Example: Coenzyme A Enzymes

Energy: is the capacity to change something, or ability to do work. Common forms of energy : Heat Radiant (light) Sound Chemical Mechanical Electrical Energy

Conservation of Energy: Energy can be converted from one form to another, but it cannot be created or destroyed. Energy

Examples of transferring energy: Automobile energy converts chemical energy into mechanical and heat energy Lightbulb converts electrical energy into radiant (light) energy and heat energy Tree converts radiant (light) energy from the sun into chemical energy.

Energy from foods such as glucose is used to make ATP for the cell. Initial fuel or energy source ATP = Energy currency for cells Cellular Respiration Cell Respiration is the transfer of energy from food molecules into a form the cells can use

adenine ribose P P P P P P Adenosine Triphosphate ATP ATP (Adenosine Triphosphate) carries energy in a form the cell can use Main energy-carrying molecule in the cell; energy from ATP breakdown is used for cellular work ATP Molecules

Hydrolysis of ATP

+ Energy released for metabolism Energy invested from respiration

Many metabolic processes require chemical energy, which is stored in ATP Energy is held in chemical bonds, and released when bonds are broken Oxidation releases energy from glucose Energy is then used to power cellular metabolism In cells, enzymes initiate oxidation by lowering activation energy Energy is transferred to ATP: 40% is released as chemical energy 60% is released as heat; maintains body temperature 34 Release of Chemical Energy

+ + Oxidation releases energy from glucose Overview of Cell Respiration Oxidation – transfer of electrons to a final electron acceptor. Glucose (C 6 H 12 O 6 ) 6 O CO 2 6 H 2 O +

Release of Chemical Energy Oxidation of glucose releases energy that is use to produce new ATP Energy is transferred to ATP: 40% is captured to produce ATP 60% is released as heat C 6 H 12 O 6 (Glucose) 6 O CO 2 6 H 2 O + + Energy

Overview of Cell Respiration 1. Glycolysis 2. Citric Acid Cycle 3. Electron Transport Chain Lactic Acid oxygen present (aerobic respiration) oxygen not present (anaerobic respiration) Glucose (C 6 H 12 O 6 )

Electron Carriers (NADH & FADH 2 ) NAD NAD H -e H FAD H -e H2H2 + FAD (each hydrogen has an electron) H -e

Electron Carriers (NADH & FADH 2 ) NADH is worth 3 ATP FADH 2 is worth 2 ATP Electron Transport Chain To extract ATP from NADH and FADH2, the electron carriers must first be transferred to the ETC

Glycolysis Occurs in cytosol Anaerobic (no oxygen required) Yields 2 ATP per glucose

Glycolysis CCCCCC CCC CCC 1. Phosphorylation 2. Cleavage 3. Oxidation (next slide) CCC P CCC P CCCCCC P P Glucose (C 6 H 12 O 6 ) ATP ADP 2ATP 2ADP NAD + NADH pyruvate

Glycolysis CCCCCC CCCCCC 1. Phosphorylation 2. Cleavage 3. Oxidation ATP ADP pyruvate CCC P CCC P CCCCCC P P 2ATP 2ADP NAD + NADH Oxygen Available No Oxygen 2. CAC 3. ETC Lactic Acid anaerobic respiration aerobic respiration

Anaerobic Respiration CCC Pyruvate NAD H -e NAD + H -e CCC + Lactic Acid

Anaerobic Respiration H -e CCC O O Oxygen debt is the amount of O2 required to convert the lactic acid back to glucose after exercise. CCCCCC Glucose (C 6 H 12 O 6 ) Lactic Acid oxygen

Citric Acid Cycle & Electron Transport Chain

Glycolysis CCCCCC CCC CCC 1. Phosphorylation 2. Cleavage 3. Oxidation CCC P CCC P CCCCCC P P Glucose (C 6 H 12 O 6 ) ATP ADP 2ATP 2ADP NAD + NADH pyruvate

Glycolysis CCCCCC CCCCCC 1. Phosphorylation 2. Cleavage 3. Oxidation ATP ADP pyruvate CCC P CCC P CCCCCC P P 2ATP 2ADP NAD + NADH Oxygen Available No Oxygen 2. CAC 3. ETC Lactic Acid anaerobic respiration aerobic respiration

mitochondria Mitochondria are the powerhouse of cell. Most ATP are synthesized within mitochondria

Priming Pyruvic Acid for the Citric Acid Cycle Before pyruvic acid can enter the CAC it must first be converted into acetyl CoA Acetyl CoA is the substrate for the citric acid cycle. For each pyruvic acid, this reaction produces 1 CO 2 molecule 1 NADH molecule 1 Acetyl CoA 1 molecule of CO 2 is released NAD + NADH acetyl CoA Coenzyme A CCC pyruvate CC acetic acid CC

Citric Acid Cycle The citric acid cycle occurs in the matrix of the mitochondrion.

CCCC CC CCCCCC citric acid 3 NAD+ 3 NADH ADP + P ATP Citric Acid Cycle FAD FADH 2 2CO 2 acetyl CoA CCCCCC oxaloacetic acid Co-Enzyme A is released CCCC

1 ATP 3 NADH 1 FADH 2 2 CO 2 Products of the citric acid cycle:

Each Glucose = 2 turns of the CAC glucose CAC CCCCCC CCC pyruvate CCC CC acetyl CoA CC

electron transport chain (ETC) The ETC is located on the inner membrane of mitochondria An enzyme called ATP synthase forms ATP by attaching a phosphate to ADP ATP synthase is powered by the transfer of e- along a chain protein complexes that form the ETC. ETC

The ETC produces ATP per glucose Oxygen removes electrons from the final complex protein, so it is the final e- acceptor electron transport chain (ETC)

57 Carbohydrate molecules from foods can: Enter catabolic pathways for energy production Enter anabolic pathways for energy storage React to form some of the amino acids Excess glucose can be converted into and stored as: Glycogen: Most cells, but liver and muscle cells store the most Fat to store in adipose tissue Carbohydrate Metabolism

Carbohydrates, Lipids & Proteins can be broken down and used for ATP synthesis Most organic molecules enter the citric acid cycle as acetyl coA catabolism of proteins, fats, & carbohydrates

DNA Replication & Protein Synthesis Chapter 4.6

nucleus cytoplasm

nucleus cytoplasm

Definitions Gene: portion of DNA that encodes one protein Genome: complete set of genetic instructions for an organism Human genome = 20,000 genes on 46 chromosomes

Genetic (triplet) code: 3 letter DNA sequence that encodes for 1 amino acid

Double-stranded helix

Anti-parallel The sugar in DNA is deoxyribose Sugar-phosphate backbone 4 Nitrogenous Bases Deoxyribonucleic Acid (RNA) Hydrogen bonds

Purines Adenine & Guanine Pyrimidines Thymine & Cytosine DNA contains 4 nitrogenous bases Adenine (A) Thymine (T) Guanine (G)Cytosine (C) Properties of DNA

Complimentary Base Pairs

Example of complimentary base pairs.

S Phase DNA Replication

DNA replication is catalyzed by the enzyme DNA Polymerase DNA Replication

Replication Fork

DNA replication is Semi-Conservative – One strand of the replicated DNA is new, the other is the original molecule. DNA Replication

The two DNA molecules separate during mitosis

Chapter 4.7 Transcription & Translation

81 There are several kinds of RNA Transfer RNA (tRNA): Transfers amino acids to the ribosomes during translation. Ribosomal RNA (rRNA): Provides structure and enzyme activity for ribosomes Messenger RNA (mRNA): Conveys genetic information from DNA to the ribosomes

mRNA undergoes further processing & leaves the nucleus

Codon: 3 letter mRNA sequence that encodes for 1 amino acid. start codon: Initiates protein synthesis (AUG = start codon) stop codon: terminates translation (doesn’t code for an amino acid)

1.transfer RNA (tRNA) transports amino acid to mRNA 2.anticodon on tRNA aligns with codon on mRNA tRNA 1 Amino acid

Ribosomes 1 Amino acid anticodon codon

A P A U G ribosome U A C 123 tRNA Amino acid

A P A U G 23 U A C 1 tRNA

A P A U G U A C 1 23

A P A U G U A C 1 23 peptide bond

A P A U G U A C

A P A U G U A C

A P A U G U A C

A P A U G

A P A U G

A P A U G

A P A U G

A P A U G

A P 8 STOP CODON A G U

A P 8 STOP CODON A G U Polypeptide chain

Once translation is complete chaperone proteins fold the protein into its configuration enzymes may further modify proteins after translation phosphorylation – adding a phosphate to the protein glycosylation – adding a sugar to the protein post-translational modification End of Chapter 4

Attribution Protein By Emw (Own work) [CC BY-SA 3.0 ( or GFDL ( via Wikimedia Commons. Triglyceride By Wolfgang Schaefer (author) [Public domain], via Wikimedia Commons. "Amylose 3Dprojection.corrected" by glycoform - Own work. Licensed under Public Domain via Commons - ected.png ected.png "Beta-D-Glucose" by Yikrazuul - Own work. Licensed under Public Domain via Commons "Isomers of oleic acid" by Edgar181 - Own work. Licensed under Public Domain via Commons By Fir0002 [GFDL ( or CC-BY-SA-3.0 ( sa/3.0/)], via Wikimedia Commons. "Molecular-collisions" by Sadi_Carnot - Licensed under Public Domain via Commons - collisions.jpghttps://commons.wikimedia.org/wiki/File:Molecular-collisions.jpg#/media/File:Molecular- collisions.jpg Metabolic Pathways Metabolism_pathways_(partly_labeled).svg.png Metabolism_pathways_(partly_labeled).svg.png Genetic Code By Madprime (Own work) [CC0, GFDL ( CC-BY-SA-3.0 ( or CC BY-SA ( sa/ )], via Wikimedia Commons G-C Base Paring By Jypx3 (Own work) [Public domain], via Wikimedia Commons A-T Base Paring By Jypx3 (Own work) [Public domain], via Wikimedia Commons Citation: Sha, K. and Boyer, L. A. The chromatin signature of pluripotent cells (May 31, 2009), StemBook, ed. The Stem Cell Research Community, StemBook, doi/ /stembook By No machine readable author provided. Masur assumed (based on copyright claims). [GFDL ( CC-BY-SA-3.0 ( or CC BY 2.5 ( via Wikimedia Commons DNA Replication Split Horizontal I, Madprime [GFDL ( CC-BY-SA-3.0 ( or CC BY-SA ( sa/ )], via Wikimedia Commons By OpenStax College [CC BY 3.0 ( via Wikimedia Commons By OpenStax College [CC BY 3.0 ( via Wikimedia Commons By Yikrazuul (Own work) [CC BY-SA 3.0 ( via Wikimedia Commons