1. Chapter 15 Biochemistry: A Molecular View of Life
Chemistry for Changing Times 10th edition
Hill/Kolb
Chapter 15 Biochemistry: A Molecular View of Life
Daniel Fraser
University of Toledo, Toledo OH
©2004 Prentice Hall

2. Biochemistry Chemistry of living things and life processes
Cell: structural unit for all living things
Cell membrane defines cell and lets material flow into and out of cell
Plant cells: also have walls made of cellulose
Animal cells: do not have cell walls
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3. Plant Cells vs. Animal Cells
Contain cell wall
Contain chloroplast
Large central vacuole
Generally much larger in size
Lack cell wall
No chloroplasts
Small vacuoles
Tend to be smaller than plant cells
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4. Plant Cells
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5. Animal Cells
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6. Major Internal Structures
Cell nucleus: contains material that controls heredity
Ribosomes: carry out protein synthesis
Mitochondria: produce energy
Chloroplasts: only in plant cells
Convert solar energy into chemical energy
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7. Metabolism Series of coordinated reactions that keeps cells alive
Catabolism: reactions that break down molecules for energy
Anabolism: synthesize molecules of living systems
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8. Building Blocks of Organisms
Carbohydrates
Lipids
Proteins
Nucleic Acids
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9. Carbohydrates Sugars, starches, and cellulose
General formula: Cx(H2O)y
Sugars: sweet tasting carbohydates
Aldoses: aldehyde functional group
Ketoses: ketone functional group
Monosaccharides: simplest sugars
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11. Polysaccharides Contain two or more monosaccharides
Main energy storage system: starch
Plants use them for cell walls: cellulose
Both are polymers of glucose
Difference in way they are linked together
Determines chemistry
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12. Polysaccharides
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13. Starch Two kinds in plants Amylose: straight chain
Both made of glucose
Amylose: straight chain
Amylopectin: branched chain
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14. Lipids Defined by solubility Fats are largest subgroup of lipids
Insoluble in water
Fats are largest subgroup of lipids
Made up of fatty acids and glycerol
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15. Some Naturally Occurring Fatty Acids
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16. Saturated vs. Unsaturated Fats
Saturated fats have no C=C bonds
Saturated with hydrogen
Unsaturated fats have C=C bonds
May have more than one double bond
Can add more hydrogen to fats
React readily with iodine, bromine, and chlorine
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17. Iodine Number
Iodine Number: number of grams of iodine consumed by 100 g of fat
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18. Proteins Serve as structural material for animals
Required in all living cells
Composed of carbon, hydrogen, oxygen, and usually sulfur
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19. Amino Acids Building blocks for polymers called proteins
Contain an amino group, –NH2, and a carboxylic acid, –COOH
Can form zwitterions: have both positively charged and negatively charged groups on same molecule
20 required for humans
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22. Peptide Bond Connect amino acids from carboxylic acid to amino group
Produce amide linkage: -CONH-
Holds all proteins together
Indicate proteins by 3-letter abbreviation
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23. Sequence of Amino Acids
Amino acids need to be in correct order for protein to function correctly
Similar to forming sentences out of words
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24. Structure of Proteins Four organizational levels
Primary structure: amino acid sequence
Secondary structure: arrangement of chains around an axis
Pleated sheet
Alpha helix: right-handed helix
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25. Pleated Sheets
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26. Alpha Helix
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27. Tertiary Structure
Spatial relationships of amino acids relatively far apart in protein chain
Globular proteins: compact spherical shape
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28. Quaternary Structure
Structure when two or more amino acid sequences are brought together
Hemoglobin has four units arranged in a specific pattern
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29. Intermolecular Forces in Proteins
Hydrogen bonding
Ionic bonds
Disulfide linkages
Dispersion forces
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30. Enzymes Biological catalysts produced by cells Nearly all are proteins
Enormous catalytic power
Reactions occur at lower temperatures and at higher rates
Ordinarily highly specific
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31. Induced-Fit Model of Enzymes
Explains how enzyme works
Substrate: reacting substance
Active site: where chemical reaction takes place and where substrate fits
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32. Cofactors Something other than polypeptide chain required by enzyme
May be metal
Iron in hemoglobin
May be organic cofactor
Coenzyme
Apoenzyme: does not have cofactor
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33. Inhibition of Enzymes Lets cell control when an enzyme works
Inhibitor binds to allosteric site
Prevents substrate from binding
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34. Nucleic Acids Serve as information and control center of the cell
Deoxyribonucleic acid (DNA)
Carries blueprint for proteins
Found in cell nucleus
Ribonucleic acid (RNA)
Carries out protein assembly
Found in all parts of the cell
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35. Nucleotides Three components Sugar Phosphate unit Nucleic acid
Either ribose or deoxyribose
Phosphate unit
Nucleic acid
Purines: two fused rings
Pyrimidines: one ring
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36. Nucleotides
Four bases in DNA
Pair up in a specific pattern
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37. DNA
When all base pairs are paired up with second strand – form double helix
Held together by hydrogen bonding
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38. RNA
Tends to form single strand
May pair up with itself
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39. Genetic Information
Chromosomes: hereditary material, concentrated in long threadlike bodies
46 in humans
Made of protein and DNA
Gene: basic unit of heredity
Section of DNA
Genome is complete set of genes for an organism
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40. Information Pathway
DNA
mRNA
tRNA
ribosome
protein
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41. Self-Replication
Occurs every time a cell divides
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42. Transcription Converts DNA code to RNA
Must occur before protein synthesis
Can make multiple copies to make multiple copies of the protein
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43. Translation Converts code on RNA into protein Read using base triplet
Code for amino acids
Some redundancy
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44. Polymerase Chain Reaction (PCR)
Method to rapidly amplify any DNA present in sample
Can use very small amounts of DNA
Allows for genetic testing
Cut DNA into relatively small sizes
Amplify it to see any pattern
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45. Recombinant DNA Allows for addition of genes to organisms
Make microorganisms produce useful drugs
All insulin is made this way
Rapidly change genetics of plants
Treat genetic disorders in humans
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46. Gene and plasmid are fused together with DNA ligase
Plasmid and gene of interest are both treated with the same restriction enzyme to create “sticky ends”
Gene and plasmid are fused together with DNA ligase
Newly formed plasmid is put into a new bacterium by heat shock or electroporation
Bacterium reproduces, each new clone carries a copy of the gene
Purify protein encoded by the gene
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