Bio 100 Chapter 3


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Bio 100 Chapter 3

  1. 1. Chapter 3Organic Molecules and Cells
  2. 2. The Variety of Organic Molecules Makes Life DiverseThe chemistry of carbon makes diverse molecules possible• Organic Chemistry – the chemistry of carbon• Carbon has 6 electrons so it needs to bond with other elements (CHNOPS) to fill its outer shell• Hydrocarbons – chains of carbons bonded to hydrogen• Carbon can have single, double, or triple bonds
  3. 3. • Biomolecules are made of 4 classes – Carbohydrates – Lipids – Proteins – Nucleic acids• Carbon is the essential ingredient to biomolecules• Functional groups add to the variety of biomolecules – Carbon chain – backbone of a biomolecule – Functional group – specific combination of bonded atoms that always react in the same way, regardless of the particular carbon backbone – R – rest of the molecule
  4. 4. -OH (hydroxyl) turns amolecule into alcohol-COOH (carboxyl) when itionizes, releases hydrogenions making a solution moreacidic
  5. 5. Isomers – organic molecules that have identical molecular formulas but a different arrangement of atoms
  6. 6. Molecular subunits can be linked to form varied large biomolecules• Polymer – Largest of the biomolecules – Made of many monomers – Glucose is a monomer of starch, a polymer – Proteins are made up of many amino acids – Nucleic acids contain many nucleotides
  7. 7. To create a polymer, a dehydration reaction occurs• A water molecule (-OH and –H) is removed• A bond between two monomers results
  8. 8. Degredation of a biomolecule requires a hydrolysis (“water” “breaking apart”) reaction• -OH attaches to one subunit• -H attaches to the other subunitEnzyme – molecule that speeds a reaction by bringing reactants together
  9. 9. Carbohydrates are energy sources and structural componentsSimple carbohydrates provide quick energy• Monosaccharide – Single sugar molecule – Carbon backbone of 3-7 carbons• Glucose (C6H12O6) – Monosaccharide with 6 carbons – Glucose has isomers such as fructose and galactose• Ribose and deoxyribose – Monosaccarides with 5 carbon atoms – Found in RNA and DNA respectively
  10. 10. • Disaccharide – Contains two monosaccharides joined during a dehydration reaction – Maltose, sucrose (table sugar), and lactose are disaccharides – People with lactose intolerance cannot break down the disaccharide into monosaccharides – When disaccharides come into the body, a hydrolysis reaction occurs
  11. 11. Complex carbohydrates store energy and provide structural supportComplex carbohydrates are polysaccharides (polymers of monosaccharides)• Some polysaccharides (glycogen and starch) are storage molecules – Potatoes contain starch during the winter until it is needed for growth in the spring• Structural polysaccharides – Cellulose in plants – Chitin in animals – Peptidoglycan in bacteria
  12. 12. Lipids store energy and have other functionsFats and oils are rich energy-storage molecules• Fats and oils consist of – Glycerol – a compound with 3 –OH groups – Fatty acids – a compound with a long hydrocarbon chain with a –COOH group at one end• Fat or oil formation – 3 fatty acids (-COOH portion) react with –OH of glycerol during a dehydration reaction
  13. 13. • Saturated fatty acid – No double bonded carbons – No kinks – Tightly packed solid• Unsaturated fatty acids – Double bonded carbons – Kinks – Liquid• Trans fats – Double bonds – Hydrogens are on different sides of the chain (trans means across)Saturated and trans fat cause plaque buildup in blood vesselsUnsaturated protects against plaque buildup
  14. 14. Other lipids have structural, hormonal, or protective functionsPhospholipids, steroids, and waxes• Phospholipids – Glycerol, 2 fatty acids, phosphate – Fatty acids are hydrophobic – Head is hydrophilic – In water a phospholipid bilayer naturally occurs • Cell membrane is a phospholipid bilayer• Steroids – 4 fused carbon rings – Cholesterol – participates in plaque formation – Estrogen and testosterone – sex hormones• Waxes – Combines fatty acids and alcohols – Hydrophobic so waterproof and resistant to degredation – Plant leaves, animal skin and fun, ear canal, honey storage
  15. 15. Proteins have many vital functionsProteins are the most versatile of life’s molecules• Proteins – polymers of amino acids – Support • Structure • Silk, hair, fingernails – Metabolism • Enzymes – bring reactants together – Transport • Allow substances to enter and exit cells – Defense • Antibodies – Regulation • Hormones • Intercellular messengers – Motion • Contractile proteins allow parts of the cell to move and cause muscles to contract
  16. 16. Each protein is a sequence of particular amino acids• A monomer of a protein is an amino acid• Amino acids have – Central carbon – Hydrogen atom – -NH2 (amino group) – -COOH (acid group) – R groupThe R group differs in amino acids and make them different
  17. 17. • Amino acids bond via a dehydration reaction• Peptide – two or more amino acids bonded together• Polypeptide – chain of many amino acids joined by peptide bonds• Peptide bond – covalent bond between two amino acids – Oxygen attracts electrons more than nitrogen – Oxygen is slightly negative – Hydrogen is slightly positive – Polarity allows hydrogen bonds between –CO of one amino acid and –NH of another amino acid
  18. 18. The shape of a protein is necessary to its function• Collagen – Provides strength and support – Super-coiled• Hemoglobin – Globular – Allows it to travel in blood vesselsExtreme temperatures and pH can denature (alter shape) so it can no longer perform its usual functionAlcohol and salts of heavy metals also denature proteins
  19. 19. Levels of Protein Organization• Primary structure – Linear – Sequence of amino acids joined by peptide bonds• Secondary structure – Peptide bond is polar – Hydrogen bonds form alpha helix (spiral) or pleated sheet
  20. 20. • Tertiary structure – Final shape for globular proteins – Hydrophobic portions are packed on the inside – Hydrophilic portions are on the outside – Covalent, ionic, and hydrogen bonds between R groups are present• Quaternary structure – More than one polypeptide coming together
  21. 21. Nucleic acids are information moleculesDNA stores coded information• Genes – Hereditary units composed of DNA (deoxyribonucleic acid) – Control structure and function of cells and organisms by coding for proteins• Nucleotide contains – Phosphate – Pentose (5 carbon) sugar – Nitrogen containing base• Nucleic acid – Polymer of nucleotides
  22. 22. • DNA and RNA (ribonucleic acid) are nucleic acids• DNA structure contains complementary paired bases that are held together by hydrogen bonds – Thymine (T) always pairs with Adenine (A) – Guanine (G) always pairs with Cytosine (C)• Genome – DNA base sequence of all genes of an organism
  23. 23. Genetic information flows from DNA to RNA to proteins• RNA bases include adenine, guinine, uracil, and cytosine• RNA is synthesized next to a segment of DNA• Messenger RNA (mRNA) is a copy of a gene that codes for proteins• DNA to mRNA to protein
  24. 24. Genetic mutations can result in altered proteins• Genetic mutation – Change in the sequence of bases, can result in an altered amino acid sequence in a protein• Sickle-cell – Amino acid valine (Val) appears instead of glutomate (Glu) resulting in sickle shaped red blood cells – Double mutation inheritance • Hard and jagged cells • Can clog vessels • Pain, organ damage, low red blood cell count – Single mutation inheritance • Occasionally sickle shaped such as when invaded with malarial parasite • Shape causes parasite to die • Individual has advantage • More common in Africa where malaria is prevalent
  25. 25. The nucleotide ATP is the cell’s energy carrierAdenosine triphosphate (ATP)• Adenine base and ribose – Form adenosine• 3 phosphate groups• High energy molecule because last two phosphates are unstable• ADP (adenosine diphosphate) and phosphate molecule – Created when the last phosphate bond is hydrolyzed
  26. 26. • ATP breaks down, releases energy, which is used by cells to create biomolecules• Muscle cells use it for muscle contractions• Nerve cells use it for nerve impulses