Building Blocks; Macromolecules

Macromolecule

• A large, complex molecule created from the linkage of smaller subunits.

  • Carbohydrates, lipids, proteins, and nucleic acids

    • Carbon backbones “decorated” with different chemical groups

Polymer

• A large molecule consisting of repeating structural units of monomers linked together by covalent bonds.

Monomer / Subunit

• The smallest structural unit that acts as a building block for larger molecules.

Polysaccharide

• A large, complex carbohydrate molecule created through the linkage of monosaccharides by GLYCOSIDIC bonds.

Membrane Lipids

• Protective layer surrounding cells created by phospholipids (and sometimes cholesterol) that bond together.

Proteins (C.H.O.N.)

• One of the 4 macromolecules

• Monomer: amino acid

• Polymer: Polypeptide (chains of amino acids)

  • Linked together through PEPTIDE BONDS

• Consist of (1) R group, (2) amino group, (3) carbon, (4) hydrogen, (5) carboxyl group

• R group: Gives each amino acid its identity

  • Flexible, allowing the polypeptide chains to twist

• Distinct ends that allow for structural and directional polarity (folding, functions, interactions)

  • “N”-terminus: Start of protein

  • “C”-terminus: End of protein (synthesis)

• Function: enzyme (catalyst) reactions, building/repairing tissues, regulating hormones, supporting immune function (antibodies)

Carbohydrates (C.H.O)

• One of the 4 macromolecules

• Monomer: Monosaccharide (simple sugar)

  • Smallest monomer has 3 carbons

• Intermediate Chain: Oligosaccharide (usually refers to ~10 monomers linked)

• Polymer: Polysaccharide

  • linkage of monosaccharides through GLYCOSIDIC BONDING

  • Condensation (linking molecules through the removal of H2O)

  • Smallest polymer has 6 carbons (linkage of 2 monomers w/ 3 carbons each)

• Chemical Equation Template: (C1H2O1)n, where n can be 3, 4, 5, 6

• In aqueous solutions, takes on ring-like structure

• Carbon skeletons for many other molecules

• A source of stored energy

• Can transport chemical energy (meaning molecules can store energy in covalent bonds, that upon breakage, can be transported by cells)

  • Glucose

    • In animals, as glycogen

    • In plants, as starch

Lipids (C.H.O)

• One of 4 macromolecules

• Make up membranes of the cells (phospholipid bilayers)

• Can be stored in the cytosol in droplets (triaclyglycerols) as an energy reserve

• Fatty Acid Structure

  • Hydrophilic (“water-loving”) head

    • carboxylic

  • Hydrophobic (“water-fearing”) tail

    • hydrocarbon

    • covalently attached to the head

• Amphipathic nature of lipids promotes formation of membranes in aqueous solutions

• No “traditional polymers” through covalent bonds

  • Rather, holding them together is accomplished through van der Waal forces

Nucleic Acids (C.H.O.N.P.)

• One of 4 macromolecules

• Help carry genetic information in the sequence of nucleotides

• Monomer: Nucleotide (subunits of DNA & RNA)

• Intermediate molecule: Oligonucleotide

• Polymer: Nucleic acids

• Structure of nucleotides

  • phosphate group, pentose (5-carbon) sugar, nitrogenous base

  • location of carbon 1: attached to nitrogenous base

• Pyrimidines

  • Cytosine (C), Thymine (T), and Uracil (U) (found only in RNA)

  • represented by only one nitrogen-containing ring

• Purines

  • Adenosine (A), Guanine (G)

  • represented by two connected nitrogen-containing rings

• Ribonucleotides

  • Nucleotides that contain the ribose sugar (meaning carbon 2 has hydroxide group)

• Deoxyribonucleotides

  • Nucleotides that contain the deoxyribose sugar (meaning carbon 2 has a lone H attached to it)

• Polymerization of Nucleotides

  • Phosphodiester bonds

  • Hydroxide group of one nucleotide joins with phosphate group of another nucleotide

• Strands of DNA and RNA have polarity

  • 5’ and 3’ ends

Condensation Reaction

• Building up of polymers by expelling a H2O molecules for each bond that is created

• Energetically unfavorable (meaning nonspontaneous)

  • Requires an input of energy

• 3 macromolecules affected

  • Proteins, nucleic acids, carbohydrates

Hydrolysis Reaction

• Breaking down of polymers by inputs of H2O

• Energetically favorable (meaning spontaneous)

  • Releases energy

• 3 macromolecules affected

  • Proteins, nucleic acids, carbohydrates