Chapter 4

Hole’s Essentials of HumanAnatomy & Physiology

David ShierJackie ButlerRicki Lewis

Created by Dr. Melissa Eisenhauer Head Athletic Trainer/Assistant Professor

Trevecca Nazarene UniversityAmended by John Crocker

Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chapter 4Chapter 4Cellular Cellular

MetabolismMetabolism

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IntroductionIntroductionA living cell is the site of A living cell is the site of enzymeenzyme--catalyzed catalyzed metabolic reactions that maintain life.metabolic reactions that maintain life.

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Metabolic ProcessesMetabolic ProcessesMetabolic reactions are of two types:Metabolic reactions are of two types:A.A. anabolicanabolic reactionsreactions

1.1. larger molecules constructedlarger molecules constructed from smaller from smaller onesones

2.2. requires energyrequires energyB.B. cataboliccatabolic reactionsreactions

1.1. larger molecules are broken downlarger molecules are broken down2.2. releases energyreleases energy

C.C. Metabolic reactions are often reversible.Metabolic reactions are often reversible.

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Anabolism Anabolism 1.1. via via dehydration synthesisdehydration synthesis, the removal , the removal

of a water molecule to join two smaller of a water molecule to join two smaller molecules.molecules.

2.2. provides the substances needed for provides the substances needed for growth and repair.growth and repair.

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3.3. Polysaccharides, lipids, and proteins are Polysaccharides, lipids, and proteins are constructed via dehydration synthesis.constructed via dehydration synthesis.

A.A. To form fats, glycerol and fatty acids To form fats, glycerol and fatty acids bond.bond.

B.B. Peptide bond = two amino acidsPeptide bond = two amino acids1)1) Two bound Two bound aminosaminos = = dipeptidedipeptide2)2) Three or more = polypeptideThree or more = polypeptide

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CatabolismCatabolism1.1. breaks apart larger molecules into their breaks apart larger molecules into their

building blocks.building blocks.2.2. via via hydrolysishydrolysis, , the insertion of water the insertion of water

molecule into a polymer which splits it into molecule into a polymer which splits it into two smaller molecules.two smaller molecules.

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Control of Metabolic Reactions:Control of Metabolic Reactions:Enzymes control the rates of all the Enzymes control the rates of all the metabolic reactions of the cell.metabolic reactions of the cell.

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Enzyme ActionEnzyme Action1.1. EnzymesEnzymes are complex proteins that function as are complex proteins that function as catalystscatalysts2.2. Catalysts lower the activation energy of a reaction Catalysts lower the activation energy of a reaction

allowing it to begin and/or to proceed more rapidly. allowing it to begin and/or to proceed more rapidly. 3.3. Each enzyme acts on only one kind of substrate.Each enzyme acts on only one kind of substrate.4.4. Active sites on the enzyme combine with the substrate Active sites on the enzyme combine with the substrate

and a reaction occurs.and a reaction occurs.

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5.5. Enzymes work in small quantities and are recycled Enzymes work in small quantities and are recycled by the cell.by the cell.

6.6. The speed of enzymatic reactions depends on the The speed of enzymatic reactions depends on the number of enzyme and substrate molecules.number of enzyme and substrate molecules.

7.7. Enzymes can be denatured like other proteins.Enzymes can be denatured like other proteins.

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Energy for Metabolic Reactions:Energy for Metabolic Reactions:A.A. EnergyEnergy is the capacity to do work.is the capacity to do work.

B.B. Common forms include:Common forms include:1.1. HeatHeat2.2. LightLight3.3. SoundSound4.4. Electrical energyElectrical energy5.5. Mechanical energyMechanical energy6.6. Chemical energy.Chemical energy.

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C.C. Release of Chemical Energy Release of Chemical Energy ––Cellular Respiration Cellular Respiration

1.1. OxidationOxidation of glucose is the primary of glucose is the primary source of chemical energy in the cell.source of chemical energy in the cell.

2.2. Energy is required to initiate burning of Energy is required to initiate burning of glucose.glucose.

3.3. Enzyme catalyzed reactions occur in the Enzyme catalyzed reactions occur in the cytosolcytosol and mitochondria. and mitochondria.

4.4. EndEnd--products = heat + stored energy.products = heat + stored energy.5.5. Energy is stored asEnergy is stored as ATPATP

(Adenosine Tri(Adenosine Tri--Phosphate).Phosphate).

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D.D. ATP MoleculesATP Molecules1.1. Up to Up to 3838 molecules of ATP are produced molecules of ATP are produced

for each molecule of glucose oxidized.for each molecule of glucose oxidized.2.2. ATP molecules contain three phosphates ATP molecules contain three phosphates

in a chain.in a chain.

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3.3. Energy is stored in the last phosphate Energy is stored in the last phosphate bond when ADP is converted to ATP.bond when ADP is converted to ATP.

4.4. WWhen energy is released ATP becomes hen energy is released ATP becomes ADP which can then be regenerated into ADP which can then be regenerated into ATP.ATP.

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E.E. Anaerobic RespirationAnaerobic Respiration1.1. GlycolysisGlycolysis is the initial step of cellular is the initial step of cellular

respirationrespiration2.2. GlycolysisGlycolysis occurs in the occurs in the cytosolcytosol and is and is

anaerobicanaerobic (does not use O(does not use O22).).3.3. 66--C glucose is split through a series of C glucose is split through a series of

enzymeenzyme--catalyzed steps resulting in catalyzed steps resulting in two two 33--C molecules of C molecules of pyruvatepyruvate..

4.4. Energy from ATP is used to start the Energy from ATP is used to start the process but there is a net gain of energy process but there is a net gain of energy as a result.as a result.

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F.F. Aerobic RespirationAerobic Respiration1.1. Respiration within the mitochondria is Respiration within the mitochondria is

aerobic (with Oaerobic (with O22).).2.2. Aerobic respirationAerobic respiration results in a much results in a much

greater gain of ATP molecules.greater gain of ATP molecules.3.3. Final products of glucose oxidation are Final products of glucose oxidation are

carbon dioxide, water, and energycarbon dioxide, water, and energy

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Metabolic Pathways:Metabolic Pathways:A.A. The enzymes controlling either an The enzymes controlling either an

anabolic or catabolic sequence of anabolic or catabolic sequence of reactions must act in a specific order.reactions must act in a specific order.

B.B. A sequence of enzymeA sequence of enzyme--controlled controlled reactions is called a reactions is called a metabolic pathwaymetabolic pathway..

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C.C. Regulation of Metabolic PathwaysRegulation of Metabolic Pathways1.1. The rate of a metabolic pathway is The rate of a metabolic pathway is

determined by a regulatory enzyme determined by a regulatory enzyme responsible for one of its steps.responsible for one of its steps.

2.2. A A raterate--limiting enzymelimiting enzyme is the first step is the first step in a series. in a series.

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Nucleic Acids and Protein Nucleic Acids and Protein Synthesis: Synthesis:

A.A. Deoxyribonucleic acid (DNA)Deoxyribonucleic acid (DNA) contains the contains the genetic code needed for the synthesis of all genetic code needed for the synthesis of all cellular proteins.cellular proteins.

B.B. A A genegene is a portion of a DNA molecule that is a portion of a DNA molecule that contains the genetic information for making a contains the genetic information for making a single protein.single protein.

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C.C. DNA Molecules DNA Molecules 1.1. The nucleotides of DNA form a sugarThe nucleotides of DNA form a sugar--

phosphate backbone with bases extending phosphate backbone with bases extending into the interior of the DNA molecule.into the interior of the DNA molecule.

2.2. The nucleotides of DNA exhibit The nucleotides of DNA exhibit complementary base pairingcomplementary base pairingA.A. adenine pairs with thymine adenine pairs with thymine B.B. cytosine with guaninecytosine with guanine

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3.3. The DNA molecule twists to form a The DNA molecule twists to form a double helix and may be millions of base double helix and may be millions of base pairs long.pairs long.

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DNA ReplicationDNA Replication

1.1. Each new cell must be provided with an exact Each new cell must be provided with an exact replica of the parent cell's DNA.replica of the parent cell's DNA.

2.2. DNA replication occurs during DNA replication occurs during interphaseinterphase. . A.A. The DNA molecule splits.The DNA molecule splits.B.B. Nucleotides form complementary pairs with Nucleotides form complementary pairs with

the original strands.the original strands.3.3. Each new DNA molecule consists of one Each new DNA molecule consists of one

parental strand and one newlyparental strand and one newly--synthesized synthesized strand of DNA.strand of DNA.

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Genetic CodeGenetic Code1.1. The sequence of nucleotides in a DNA The sequence of nucleotides in a DNA

molecule gives the sequence of amino acids molecule gives the sequence of amino acids for a given protein.for a given protein.

2.2. This method of storing information for This method of storing information for protein synthesis is the protein synthesis is the genetic codegenetic code..

3.3. RNA molecules copy and transfer this RNA molecules copy and transfer this information to the cytoplasm where proteins information to the cytoplasm where proteins are manufactured.are manufactured.

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4.4. Transcription Transcription A.A. RNA moleculesRNA molecules

1)1) SingleSingle--stranded stranded 2)2) Contain ribose rather than Contain ribose rather than deoxyribosedeoxyribose3)3) Use Use uraciluracil rather than thymine.rather than thymine.

B.B. Messenger RNA (mRNA)Messenger RNA (mRNA)1)1) molecules are synthesized in the nucleus molecules are synthesized in the nucleus

in a process in a process called transcriptioncalled transcription..2)2) sequence is complementary to the DNA sequence is complementary to the DNA

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5.5. TranslationTranslationA.A. Each amino acid corresponds to a Each amino acid corresponds to a triplet triplet

of DNA nucleotides called a of DNA nucleotides called a codoncodonB.B. Messenger RNAMessenger RNA (mRNA) can move out of (mRNA) can move out of

the nucleus and associate with the nucleus and associate with ribosomesribosomesin the cytoplasm where the protein will in the cytoplasm where the protein will be constructed viabe constructed via translationtranslation..

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C.C. In the cytoplasm In the cytoplasm transfer RNAtransfer RNA ((tRNAtRNA) has ) has a triplet of nucleotides called the a triplet of nucleotides called the anticodonanticodon, which is complementary to , which is complementary to nucleotides of the messenger RNA nucleotides of the messenger RNA codoncodon..

D.D. The ribosome holds the messenger RNA The ribosome holds the messenger RNA in position while the transfer RNA carries in position while the transfer RNA carries in the correct amino acid in sequence, in the correct amino acid in sequence, with anticodons matching up to codons.with anticodons matching up to codons.

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E.E. The ribosome contains enzymes needed The ribosome contains enzymes needed to join the amino acids together.to join the amino acids together.

F.F. As the amino acids are joined, the new As the amino acids are joined, the new protein molecule folds into its unique protein molecule folds into its unique shape.shape.

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LaboratoryLaboratoryWeek 2Week 2

Chapters 3 & 4Chapters 3 & 4

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Chapter 3 Chapter 3 –– Chemistry of LifeChemistry of LifeColorimetric test for pHColorimetric test for pHBiuretBiuret test for proteintest for proteinBenedictBenedict’’s test for simple sugars test for simple sugarIodine test for starchIodine test for starchSudan IV test for lipidsSudan IV test for lipids

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Chapter 4 Chapter 4 –– Basic MicroscopyBasic MicroscopyRules for useRules for useElements of a light microscopeElements of a light microscopeSlide preparationSlide preparation

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Bring text, lab manual, and supplementBring text, lab manual, and supplement

Be prepared to stay for the full periodBe prepared to stay for the full period

Take care with equipment and make sure that Take care with equipment and make sure that everything is cleaned and returned to its everything is cleaned and returned to its proper placeproper place