Functional Groups and Macromolecules Biochemistry Functional Groups and Macromolecules

Biochemistry Part 2: Macromolecules

Polymers are MADE/BROKEN a lot in biology Macromolecule = biomolecule Molecule of life Most macromolecules are polymers, built from monomers Polymer = “chain” Monomer = single “link” in polymer chain Polymers are MADE/BROKEN a lot in biology

Putting Polymers Together Covalent monomers Formed by condensation reaction aka- dehydration reaction One monomer provides a -OH group while the other provides a –H to form a H2O Ex: making proteins, DNA, etc.  BIOSYNTHESIS

Breaking Apart Polymers Hydrolysis: bonds between monomers are broken by adding H2O Ex: breaking apart DNA, protein  digestion

There are 4 macromolecules needed for life

1. Carbohydrates LOTS of: Has one carbonyl group a. Monosaccharides LOTS of: -OH’s Has one carbonyl group Needed in cellular respiration raw material for amino acids and fatty acids

2 FORMS of Glucose α Glucose β Glucose Structural iosmers!!!

Carbohydrates cont’d b. Disaccharides glycosidic linkage covalent bond between 2 monosaccharides covalent bond by dehydration reaction Ex: Sucrose (table sugar) most common disaccharide 1-2 link 1-4 link

Plus 1 water molecule b/c DEHYDRATION RXN Common Disaccharides Glucose + Glucose = Maltose (found in beer) USES a 1-4 Carbon glycosidic linkage **Glucose + Fructose = Sucrose (table sugar…YUM!) USES a 1-2 Carbon glycosidic linkage Glucose + Galactose = Lactose (milk sugar) Plus 1 water molecule b/c DEHYDRATION RXN

Carbohydrates cont’d still!! c. Polysaccharides Function #1 SHORT TERM Energy Storage!!!! Starch (PLANTS) Chains of glucose Glycogen (ANIMALS) Stored in liver

Carbohydrates cont’d still!! c. Polysaccharides (con’t) Function #2 Structural/Support!!!! Cellulose (aka –Fiber… to humans) most abundant compound in world Wood and cell walls Chitin Insect exoskeletons Cell walls of fungi Surgical thread

2. Lipids Not polymers Instead glycerol + fatty acid Includes fats, phospholipids, steroids Hydrophobic (NON-POLAR) Non-polar C-H bonds in fatty acid ‘tails’ Ester linkage: covalent bonds in lipids

Function of Lipids Main Function Lipids= long term energy storage like carbs but carbs = short-term usage Other functions: Insulation Protection (membranes) Chemical signals

3 different types of Lipids a. Fats Triacyglycerol (triglyceride) Saturated vs. unsaturated fats single vs. double bonds

unsaturated Saturated

Lipids cont’d

b. Phospholipids 2 fatty acids instead of 3 1 phosphate group ‘Tails’ hydrophobic NON-POLAR ‘Heads’ hydrophilic POLAR

b. Phospholipids Bilayer double layer in cell membranes

c. Steroids Lipids with 4 or 5 fused carbon rings Helps make animal membranes cell signaling/messaging Ex: cholesterol, cell membranes, precursor for other steroids, sex hormones

Waxes – 1 fatty acid chain; very hydrophobic Another Type of Lipid Waxes – 1 fatty acid chain; very hydrophobic

#3. Proteins Monomer = Amino Acids Center carbon, carboxyl group, amino group Some amino acids are polar or charged, some nonpolar 20 amino acids = many combo’s; R group makes them different

R group characteristics Proteins (con’t) R group characteristics Some are: polar (hydrophilic) nonpolar (hydrophobic) Acidic Basic ALL proteins have a 3D shape (called its conformation) Form polypeptides peptide bonds (covalent bond) are created

Peptide Bonds Amino acids connected by peptide bond (covalent) bonds via dehydration

Proteins have 3 (and sometimes 4) for LEVELS of conformation Proteins (con’t) Proteins have 3 (and sometimes 4) for LEVELS of conformation

i. Primary Structure **Uses peptide bonds Conformation: Linear structure of linked together amino acids each type of protein has unique primary structure of amino acids **Uses peptide bonds

ii. Secondary Structure Conformation: coils & folds Uses hydrogen bonds Alpha Helix: coiling Pleated Sheet: parallel

iii. Tertiary Structure Conformation: The 3D structure Involves R groups bonding together R group = specific to EACH amino acid hydrophobic disulfide bridges hydrogen bonds ionic bonds Van der Waals

iv. Quaternary Structure Conformation: When 2 or more polypeptides chains combine into 1 macromolecule SAME bonds used as 3° structures Examples: Collagen (connective tissue) Hemoglobin (blood protein)

DNA  RNA  protein  trait 4. Nucleic Acids a. Deoxyribonucleic acid (DNA) Holds genetics information B. Ribonucleic acid (RNA) Carries genetics information DNA  RNA  protein  trait (called Central Dogma of Biology) Made of polymers of nucleotides Nucleotide nitrogen base, pentose sugar & PO43- Nitrogenous bases: pyrimidines (small)= cytosine thymine, uracil Purines (big)= adenine, guanine

SMALL BASES LARGE BASES

SMALL BASES U instead of T RNA LARGE BASES

**Monomer of a nucleic acid (DNA or RNA) Nucleotide **Monomer of a nucleic acid (DNA or RNA) HAS 3 PARTS: Pentose Sugar (5 carbons) **ribose (RNA) **deoxyribose (DNA) 2. Nitrogen base 3. Phosphate group (PO4-3)

Nucleic Acids (con’t) Polynucleotide Hooks together phosphate + sugar Uses Phosphodiester linkages Covalent bonds in DNA and RNA Hooks together phosphate + sugar

AATCGAT TTAGCTA Nucleic Acids Inheritance based on DNA replication Double helix Watson & Crick – 1953 H bonds between paired bases Also uses van der Waals forces A to T & C to G pairing Complementary AATCGAT TTAGCTA