Chp. 5 - Organic Chemistry

Structure and Function of Macromolecules

AP Biology

Vocabulary Check

SIZE prefixes• Mono

– One

• Poly– Many

• Di– Two

Miscellaneous• Lysis = to break

BIOMOLECULE roots• Sacchar-

– Sugar– End in -ose

• Peptide– Protein– Enzymes: end in -ase

• Lipid– Fat

The synthesis and breakdown of polymers

Dehydration Synthesis & Hydrolysis

• Building bigger molecules– Dehydration synthesis– Removing water to create a

bigger molecule

• Breaking up big molecules– Hydrolysis– Uses water to break apart a

big molecule into subunits

Building and Breaking MoleculesDehydration Synthesis vs. Hydrolysis

OH OH OH

+ +

H H H

OH

H

2H2O

Explanation: 3 Glucose molecules (monomers)bind to create a Starch molecule (polymer).

DehydrationSynthesis

OH OH OH

+ +

H H H

OH

H2H2O

Hydrolysis

Explanation: A starch molecule (polymer) becomes the glucose (monomers)that make it up.

What does this look like in sugars?

• Dehydration Synthesis Reaction– Carbons are numbered (for ease)– Links can be made between different carbons– Glycosidic linkage is a covalent bond between 2

monosaccharides

Carbohydrates

• Energy Source– Cell processes require energy– Mono/disaccharides– Polysaccharides – stored energy (starch for plants,

glycogen for animals)

• Carbon Source– Structure; building material (cellulose for plants)– Can be used to construct amino acids and fatty

acids

Monosaccharide Characteristics

• Ring structure

• Formula = C6H12O6

• Generally sweet• Examples: glucose, fructose, galactose, ribose,

deoxyribose• Function = Source of quick energy or raw

material for creating other molecules

Disaccharide Characteristics

• 2 ring structure with a glycosidic linkage

• Formula = C12H22O11

• Generally semi-sweet• Examples: sucrose, maltose, lactose• Function = Source of fairly quick energy or

raw material for creating other molecules

Polysaccharides: Starch vs. Cellulose

• Both are chains of glucose

• Cellulose does not dissolve in water (cotton does not dissolve when you wash it)

• You use starch as an energy source via respiration

• You do not have the enzyme to digest cellulose

What are Lipids?

• Hydrophobic molecules (have a “fear” of water)

• Most diverse biomolecule category. Examples:– Fats– Phospholipids– Steroids– Waxes & Pigments

Lipids • Fats (triglycerols)

• Energy storage in animals. • Fat cells are designed for continuous

synthesis and breakdown of triglycerols, controlled mainly by the activation of hormone-sensitive enzyme lipase.

• Provides high caloric content, about 9 kcal/g, compared with 4 kcal/g for the breakdown of carbohydrates and proteins.

• Migratory birds that must fly long distances without eating use stored energy of triglycerols to fuel their flights.

Saturated vs. Unsaturated

• Saturated• As many hydrogen as

possible are bonded to the carbon chain.

• Solid at room temp.• Unsaturated• One or more double

bonds forms a kink.• Liquid at room temp.

Saturated vs. Unsaturated Fats

SATURATED• All single bonds• Straight shape, compact• Solid at room temp.

– Ex. Butter, lard

UNSATURATED• Include 1+ double bond• Kinked shape, not

compact• Liquid at room temp.

– Ex. Vegetable oil

Phospholipids (cell membranes)• Carbon chain is non-polar (doesn’t dissolve in water)• Phosphate is polar (dissolves in water)

Phospholipids

• Major part of cell membranes• Structure:

– 2 Hydrophobic tails – Hydrophilic head – In a bilayer

Steroids• Carbon rings are non-polar• Non-polar means hydrophobic

Steroids• Regulate organism functioning• Structure: 4 fused rings with different side groups• Note: change in side groups = change in function

What’s Up with Proteins?

• Amino Acid/peptide = the monomer of proteins

• Amino acids join by peptide bonds into a polypeptide

• A protein is more than just a chain of polypeptides– Shape is essential!!

COMPONENTS:

• Amine group (NH2)

• Carboxyl group (COOH)

• R group (different for each of 20 amino acids)

Protein (amino acid + amino acid + amino acid, etc.)

Are proteins diverse?

• A 20 letter “alphabet”

• Proteins can be 100s or 1000s of “letters” long– Imagine the

diversity!

Protein Functions• Structure – support (connective tissue, webs)• Storage – store amino acids; egg white, milk, seeds• Transport – hemoglobin (carries oxygen), channels

(H+ through ATP synthase)• Hormonal – regulation; insulin• Receptor – Na+ and K+ receptors in nervous system• Contractile – movement (actin/myosin in muscle)• Defense – antibodies fight bacteria/viruses• Enzymes – speed up chemical reactions

4 levels of Protein Structure

• Primary– Unique sequence of amino acids

• Secondary– Hydrogen bonds create coils and folds– Alpha helix– Beta pleated sheets

• Tertiary– Irregular contortions do to side chain (disulfide bridges)

• Quaternary – Two or more polypeptides joined together

Levels of Protein Structure

• Primary (1°)—amino acid sequence• Secondary (2°)—folds/coils of amino acid

change caused by hydrogen bonds• Tertiary (3°)—interactions between R groups• Quaternary (4°)—2+ polypeptides that form

one functional protein

Primary Structure

Secondary Structure

Tertiary Structure

Quaternary Structure

What are Nucleic Acids?

• Information Storage Molecules– Consist of other molecules

• Deoxyribose or Ribose sugars• Phosphate groups (also in some lipids)• Nitrogenous bases

– Store the blueprints that make the proteins that create your traits!