Ch 3: Biomolecules

Ch 3: Biomolecules

• Organic compounds ? contain– Carbon Based

• Very Diverse Group ? 4 major– H,O,N,C….leads to millions of types of molecules

• Carbon has 4 Valence electrons– So can covalently bond to? – Up to 4 elements, including itself– When with H…

Reasons For Diversity:

1. Can Bond with other Carbons to form….– Chains

– Branched Chains

– Rings

Ring Structure

• Aromatic Compounds= Double bond somewhereEx: Benzene C6H6

Ring Structure

• Aliphatic Compounds= Only Single Bonds

Ex: Cyclohexane C6H12

Reasons For Diversity:

2. Varied Bonding Patterns(Single, double, triple)

Hydrocarbons• Alkane Single• Alkene Double• Alkyne Triple

Reasons For Diversity:

3. Biomolecules exist as isomers.

Same molecular formula, different structural formulaImportance in Biology?

FORM DRIVES FUNCTION!!

Reasons For Diversity:

3. Biomolecules exist as isomers. C5H12

Same molecular formula, different structurally = different properties

P/S: 4 main macromolecules, and their monomers?

• Proteins– Amino Acids (20)

• Nucleic Acids– Nucleotides– DNA/RNA

• Carbohydrates– Monosaccharides– Sugars

• Lipids– Fatty Acids

Reasons For Diversity:

4. Functional Groups– Adds to the diversity of biomolecules by replacing

an H atom or a methyl group (-CH3)– Ex: Hydrocarbon vs alcohol

Reasons For Diversity:

4. Functional Groups Provides a “Fingerprint” which classifies a compound Helps to “Predict” how compounds will act in a

chemical reaction Makes molecules more reactive Where new bonds are formed and broken

WHERE THE ACTION IS!

Carbonyl C=O

Carbohydrates• C,H,O 2:1• Energy!• Sugars ‘___ose’‘simple’ = MonosaccharidesDisaccharides (sucrose)

Polysaccharides – Storage: Starch, glycogen, Structure: cellulose

chitin- exoskeleton

Carbohydrate Functional Groups?

Hydroxyl (-OH) Carbonyl (-C=O) Hexose, Pentose, Triose

Glycosidic Linkages:

http:http://Formation of a disaccharide

Dehydration Synthesis

Dehydration synthesis vs. hydrolysis

Alpha vs Beta Glucose

• 1-4 linkage

animation

Lipids

• Composition? • Functional Group?

• C,H,O *No Ratio H:O • Carboxyl -COOH

• Long term storage of energy• Component of cell membrane structure• Protective surface coating (plant cuticle)• Insulation; nerve function (Animals)• Basis for many hormones

Waxes Phospholipids Steroids Fats and Oils (triglycerides)

• Natural…fyi• Anabolic..fyi

Steroids

4 interconnected rings

*MAJOR component of all cell membranes “phopholipid bilayer”

HydrophobicHydrophilic

Amphipathic "amphi" = "both“ - dual nature -polar/non-polar)

Phospholipid vsTriglycerideStructure

Ester Linkages Hydroxyl-carboxyl connection

Formation of a triglyceride

H2O

(All single)

• Solid at room temp (Animal fats) tightly packed

• Liquid at room temp (Plant, fish fats- aka oils) ‘kinks’ in the structure

• Most complex• Primary elements?• C, H, O, ****N

• Functional groups? • Carboxyl –COOH• Amine -NH2

• *Functions*• *Forms*• Building Blocks: Amino Acids- 20 common amino acids

Proteins

• http://www.biotopics.co.uk/as/aminocon.html

Peptide Linkages

LEVELS of PROTEIN STRUCTURE

1 2 3 4

Peptide bonds Alpha,Beta Di-sulfide Bridges 4+ Tertiary Forms H-bonds R-group Interaction

Protein Structure and Function

• Structural framework• Storage• Movement: cellular

and body• Metabolism/

Catalysis(Enzymes-Hormones)

• Transport• Body Defense

Beta

Globular and Fibrous Proteins Fibrous ProteinsLittle or no tertiary structure.Long parallel polypeptide chains.Cross linkages at intervals forming long fibres or sheets.Usually insoluble.Many have structural roles.E.x- keratin in hair and the outer layer of skin, collagen (a connective tissue). -Actin/Myosin- movement

Globular ProteinsHave complex tertiary and sometimes quaternary structures.Folded into spherical (globular) shapes.Roles in metabolic reactions.E.g.- enzymes, hemoglobin, insulin. -antibodies/defense

Denatured Protein

The Amino Acids

• R-group- changes the shape and the function

Nucleic Acids

Phosphodiester Linkage