NOTES FOR BIOLOGY 1201

Section 001

Spring 2005

DR. STEVEN POMARICO

Carbohydrates: Monosaccharides - 2.5.1

>>>>Carbohydrates are used as fuels and building material

---Carbohydrates

-Monomers of simple sugars are called monosaccharides.

---Monosaccharide

General structure of carbohydrates

1) Each carbon has a hydroxyl group (-OH) and at least one hydrogen (-H) attached to it for except one carbon, which has a carbonyl group instead of the hydroxyl.

aldose or ketose.

2) The size of the carbon skeleton

Some examples of common sugars:

3) Enantiomers exist for each asymmetric carbon

4) In aqueous solutions, monosaccharides with 5 or more carbons in the skeleton form ring structures.

Dehydration Synthesis and Hydrolysis: Disaccharides - 2.5.2

>>>>>Macromolecules and polymers.

---Macromolecules

---Polymer

---Monomer

>>>>>The reaction that forms a polymer from monomers is a polymerization reaction.

Most biological polymerization reactions are condensation reactions also called a dehydration synthesis reaction.

---Condensation reactions (a.k.a. dehydration synthesis reaction)

---Hydrolysis

>>>>Disaccharides

---Disaccharides

---Glycosidic linkage

α (alpha)-linkage and β (beta)-linkage

Examples of disaccharides:

Polysaccharides: Energy Storage Molecules - 2.5.3

>>>>>Polysaccharide

---Polysaccharide

Storage polysaccharide

---Starches - Amylose and Amylopectin

---Glycogen

Polysaccharides: Structural Molecules - 2.5.4

Structural polysaccharide

---Cellulose

Found in plant cell walls

---Chitin

Lipids: An Introduction - 2.6.1

>>>>>Lipids are mostly hydrophobic molecules with diverse functions

---Lipids

Important lipid types are: fats, phospholipids, and steroids.

>>>>Fats and Oils

---Fats

---Oils

---Fatty acids (FA)

---Glycerol

---Ester linkage

---Triglyceride

Saturated vs. Unsaturated Fats - 2.6.2

Features of saturated and unsaturated fats:

Phospholipids, Waxes, and Steroids - 2.6.3

>>>>>Phospholipids

---Phospholipids

Hydrophillic heads and hydrophobic tails

Micelles and Bilayers

>>>>>Steroids

---Steroids

Nucleic Acids: An Introduction to Genetic Material - 2.6.4

---nucleic acids

deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)

---nucleotide

Composed of sugar, phosphate group, and a nitrogenous base.

The sugar is a pentose (5 carbon) in a ring conformation.

In RNA the pentose is ribose, whereas in DNA the pentose is a derivative of ribose called, deoxyribose.

The sugar and phosphate group make up the nucleic acid backbone.

---Phosphodiester linkage

There are two families of nitrogenous bases:

          Pyrimidines and Purines

---Pyrimidines

          Cytosine

          Thymine (only in DNA)

          Uracil (only in RNA)

---Purines

          Guanine

          Adenine

Proteins: Amino Acids and the Peptide Bond - 2.7.1

>>>>A protein is a polymer of amino acids connected in a specific sequence

---Protein

---Amino acids

α (alpha)-carbon

---Peptide bond

---Polypeptide bond

Amino Acids: The R Groups - 2.7.2

Classes of amino acids:

          Nonpolar

          Polar

          Charged

                     Acidic

                     Basic

Primary and Secondary Structure - 2.7.3

>>>>>Proteins are the molecular tools for most cellular functions.

Protein functions

          Structural support

          Storage (of amino acids)

          Transport (e.g. hemoglobin)

          Signaling (chemical messengers)

          Cellular response to chemical proteins (receptors)

Movement (contractile proteins)

          Immuno-defense (antibodies)

          Catalysts (enzymes)

A protein function is dependant on the protein conformation

The protein structure leads to its final conformation and also its function

1) Primary structure

---Primary structure

N-terminus versus C-terminus

Changes in the primary structure can result in changes in all the remaining levels of structure.

2) Secondary structure

---Secondary structure

Polypeptide backbone

a (alpha)-helix and b (beta)-pleated-sheet

---a (alpha)-helix

---b (beta)-pleated-sheet

Tertiary Structure - 2.7.4

3) Tertiary structure

---Tertiary structure

Amino acid side chains

Interactions of amino acid side chains:

          -Covalent linkage

                     Disulfide bridges

          -Weak interaction

                     Van der Waals interactions

                     Ionic bonds

                     Hydrophobic interactions 

                     Hydrogen bonding

Quaternary Structure - 2.7.5

4) Quaternary structure (when a protein has more than one polypeptide chains)

---Quaternary structure

>>>>>What determines protein conformation?

A proteins native conformation is dictated by the primary structure and the subsequent secondary, tertiary and quaternary structures that result.

Protein Structure: A Summary - 2.7.6

>>>>>Four levels of protein structure

Conformation changes

---Denaturation

>>>>>Protein folding

Chaperone proteins aid the folding of many proteins

>>>>>Diversity in polymers comes from the variation in the arrangement of the monomers.

FOUR CLASSES OF MACROMOLECULES