1 / 34

The Structure and Function of Macromolecules

The Structure and Function of Macromolecules. Chapter 5 AP Biology. Polymer Principles. Very large molecules = macromolecules Most macromolecules are polymers chains of identical or similar building blocks—monomers. Polymer Principles, continued. Formation: Condensation Reactions

leopold
Download Presentation

The Structure and Function of Macromolecules

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Structure and Function of Macromolecules Chapter 5 AP Biology

  2. Polymer Principles • Very large molecules = macromolecules • Most macromolecules are polymers • chains of identical or similar building blocks—monomers

  3. Polymer Principles, continued • Formation: Condensation Reactions • monomers to polymers • water is released—dehydration • Disassembly: Hydrolysis—requires H2O

  4. Example of Condensation Reaction

  5. Hydrolysis of Sucrose

  6. Polymer Principles, continued • Various polymers are built from a small set of monomers • Each class of polymer: • formed from a specific set of monomers • Limited monomer types • Unique arrangements possible • Due to specific arrangement of monomers into polymers.

  7. Monomer Characteristics • Very small • Mostly soluble in water • Pass in/out of cells easily • some organisms (autotrophs) synthesize monomers • other organisms get monomers from "food" (heterotrophs)

  8. Monomer-Polymer Characteristics • Monomer-polymer pattern • extremely efficient and flexible • Few monomers needed • less than 30 common monomers in cells • Thousands of kinds of polymers made

  9. Polymer Characteristics • Polymer diversity results from: • Different monomer used • Different sequence of monomers • e.g English alphabet and different words possible • Different patterns of branching: • glycogen is more branched than starch • Polymers can be broken down into monomers and re-used to make different polymers—cellular recycling.

  10. Polymer Characteristics Summary • Extremely largedo not enter or leave cells except by special mechanisms. • Synthesized by condensation reactions (dehydration synthesis) • Broken down by hydrolysis (digestion) • Great diversity possible from only a few kinds of monomers • Cellular recycling—monomer subunits reused to make different polymers

  11. Organic Compounds • Four major classes in cells (Note: cells are the basic unit of life): • Carbohydrates • Lipids • Proteins • Nucleic Acids

  12. Carbohydrate Protein Lipid Examples of Organic Molecules

  13. Examples of Organic Molecules, continued • Nucleic Acid (building block: nucleotide—nitrogen base, phosphate group, and sugar)

  14. Functional Groups contribute to diversity of molecules

  15. Formation of Polymers • Joining monomers to each other • Series of chemical reactions • To form long chain molecules • Formation reaction: • condensation reaction or • dehydration synthesis reaction

  16. Formation of Polysaccharides

  17. Formation of Polypeptides(and Proteins)

  18. CARBOHYDRATES--FUEL AND BUILDING MATERIAL • Sugars: smallest carbohydrates • “Fuel” and carbon sources • Monosaccharides—simplest carbohydrates • Used directly for fuel • Converted to other types of organic molecules • Used as monomers for polymers. • Disaccharides: • Two monosaccharides • Connected by a glycosidic linkage

  19. Polysaccharides • Polysaccharides • Polymers of sugars • Have storage and structural roles • Monosaccharide monomers of polysaccharides connected by glycosidic linkages • Starch (plants) and glycogen (animals): • storage polymers of glucose. • Cellulose: • important structural polymer of glucose • in plant cell walls. • Starch, glycogen, and cellulose differ in the positions and orientations of their glycosidic linkages.

  20. LIPIDS--DIVERSE HYDROPHOBIC MOLECULES • Fats store large amounts of energy • Fats (triacylglycerols) • Glycerol molecule joined to three fatty acids • Dehydration reactions • Saturated Fatty Acids: • Have maximum number of hydrogen atoms • Unsaturated Fatty Acids (in oils) • Have one+ double bonds in hydrocarbon chains.

  21. Lipids, continued • Phospholipids • Major components of cell membranes • Contrast with fats--no third fatty acid linked to glycerol • Have a negatively charged phosphate group • may be joined to another small hydrophilic molecule • “Head" of phospholipid is hydrophilic.

  22. Lipids, continued • Steroids • Cholesterol • Certain hormones—progesterone, testosterone, estradiol • Steroids have basic four fused rings of carbon atoms structure.

  23. PROTEINS--MANY STRUCTURES, MANY FUNCTIONS • Protein • One or more polypeptide chains • Folded into a specific three-dimensional conformation

  24. Polypeptides • Polymer of amino acids • Connected in a specific sequence • Constructed from 20 different amino acids (aa) • Each aa has characteristic side chain (R group). • Carboxyl and amino groups of adjacent aa link together (peptide bonds)

  25. Protein Function and Structure • Function linked to conformation • Primary Structure = unique sequence of aa • Secondary Structure = folding or coiling into repeating configurations • Mainly helix and b pleated sheet • Due to hydrogen bonding of parts of polypeptide backbone.

  26. Protein Structure, continued • Tertiary Structure = overall three-dimensional shape of polypeptide • Due to aa side chain interactions • Proteins of more than one polypeptide chain (subunits) have a quaternary level of structure. • Structure and function of protein are sensitive to physical and chemical conditions. • Protein shape: ultimately determined by primary structure, but in the cell, proteins called chaperonins may help the folding process.

  27. NUCLEIC ACIDS--INFORMATIONAL POLYMERS • Nucleic acids: store and transmit hereditary information • DNA stores info for protein synthesis • RNA (specifically, mRNA) carries genetic info to protein-synthesizing machinery.

  28. Nucleic Acid Strands • Polymer of nucleotides • Each nucleotide monomer = pentose covalently bonded to a phosphate group and to one of four different nitrogenous bases (Adenine, Guanine, Cytosine, and Thymine or Uracil). • RNA has ribose as its pentose; • DNA has deoxyribose. • RNA has U and DNA has T

  29. Nucleic Acid Strand Formation • Nucleotides join and form a sugar-phosphate backbone • Nitrogenous bases project from backbone • Sequence of bases along a gene specifies aa sequence of a particular protein

  30. Nucleic Acids and Inheritance • Inheritance: based on replication of the DNA double helix • DNA: helical, double-stranded macromolecule with bases projecting into the interior of the molecule. • A always hydrogen-bonds to T • C always hydrogen-bonds to G • Nucleotide sequences of the two strands are complementary.

  31. DNA and Evolution • DNA and proteins useful for evolution measures. • Molecular comparisons help biologists sort out the evolutionary connections among species.

  32. Quiz • What kind of chemical reaction is needed to form a polymer from individual monomers? __________________ • What kind of reaction is needed to break a polymer into its constituent monomers? ______________ • What are the monomers needed to build sucrose? _____________

  33. 4. What is starch? _______________ 5. What is glycogen? _____________ 6. What kind of chemical bond is responsible for the secondary structure of proteins? ___________ 7. What determines the primary structure of proteins? ___________ 8. All proteins contain carbon, hydrogen, oxygen and what other element? ______

More Related