I. The Structure and Function of Macromolecules

A. Macromolecule- Large molecules, some with

molecular weights exceeding 100,000 Daltons 1. Macromolecules are composed of polymers.

Chains of similar subunits

2. Monomers- individual subunits that make up polymers

3. Polymers and molecular Diversitya) All macromolecules are composed of 40-50 of the

same monomers

b) All proteins in all organisms are made of the same 20 amino acids. Just as 26 letters make all words

4. Making a Breaking Polymers

a) Condensation Reaction- usually occurs between –OH groups of two monomers. H2O is removed linking the monomers with an oxygen bridge

b) Hydrolysis- breaking apart polymers at their oxygen bridge by adding H2O which results in two monomers

B. Carbohydrates- sugars and starches that serve as important sources of fuel and structural components

Carbohydrates1. Monosaccharides- single

sugars with 3-6 carbons. (Glucose, Fructose, Galactose)

2. Disaccharides- two monosaccharides joined in a condensation reaction

3. Polysaccharides- many single sugars joined together

Types of Polysaccharides

a) Starch- storage form of carbohydrate in plants. (Spiraling 1-4α glycosidic bonds)

b) Glycogen- Storage form of carbohydrates in animals. (Spiraling, highly branched, 1-4α glycosidic bonds)

c) Cellulose- Structural polysaccharide in plants. (Straight polysaccharide with 1-4β glycosidic bonds)

4. Modified CarbohydratesA) Chitin- main

component of the exoskeletons of arthropods. Contains a monosaccharide derivative glucosamine

Lipids

Animal Fat Plant Oils Waxes

C. Lipids- molecules used to store energy in organisms as well as structural materials. Made of C, H, O. Less oxygen than in carbohydrates. Twice the amount of energy. Soluble in

non-polar solvents

1. Neutral Fats- 1 glycerol with fatty acid chains

Types of Lipids

a) Saturated fat- Solid at room temperature. Many hydrogen. No double bonds between carbons. Animal fats. Cause arteriosclerosis.

b) Unsaturated and Polyunsaturated Fat- Oils. Liquid at room temperature. Double bond between some of the carbons. 2 essential fats are oleic and linoleic acid. These cannot be synthesize by the body but must be in the diet

2. Phospholipid- important constituents of the cell membrane made of a glycerol and 1-2 fatty acid chain with the glycerol bonded to a phosphate group. Contains a hydrophilic and hydrophobic

end

Other Lipids

3.Carotenoids- red and yellow plant pigments that play a role in photosynthesis

A) splitting the orange plant pigment carotene yeilds a retinol molecule

B) Retinol molecules play an important role as photoreceptors in eyes

4. Steroids- class of compounds with four interlocking rings to form many biologically important molecules (Cholesterol, bile salts, hormones etc….)

D. Proteins- all enzymes, some hormones and many structural components of the cell are proteins.

1. Subunit Structure (Protein monomer = Amino Acid)

a) Amino acids are composed of an amino group (-NH2) and an acidic carboxyl group but different r groups

Amino group

Carboxyl group

R group

b) The “R” group determines the identity of the amino acid

Amino Acids with Hydrophobic Side Groups

Note the methyl groups at the bottom of the chains

Amino Acids with Hydrophilic Side Groups

Note the charged or polar groups at the bottom of the chains

And Some Amino Acids are in Between

Hydrophobic and Hydrophilic regions influence protein shape.

C) Amino acids can serve as acids or bases and are therefore considered buffers

D) Amino acids are linked by a condensation reaction and form peptide bonds

E) When many amino acids are joined, a polypeptide is formed

2. Levels of Protein Structure

A) Primary- Linear sequence of amino acids joined by peptide bonds in a condensation reaction

B) Secondary- coiling and pleating of amino acid chains (α helixes or β pleats) stabilized by hydrogen bonds

C) Tertiary- overall shape caused by the folding or twisting of the secondary structure

D) Quaternary Intertwining of multiple polypeptides to produce a highly specific 3D shape

3. Importance of Proteins

Class Function ExampleA) Enzymes. Control Chemical Reactions. MaltaseB) Structure. Building material of cells. CollegenC) Contractile. Movement. Actin and myosin D) Hormones. Regulatory chemicals. Insulin E) Transport. Ship important substances hemoglobinF) Defense Fight Disease antibodies

a) Proteins are the most abundant molecule in living cells. Functionally diverse, They control all life functions

c) Proteins are sensitive and may denature (change shape) and become non functional. Heat, pH and metals all can cause denaturation

E. Nucleic Acids- large complex molecules formed

of smaller smaller units called nucleotides 1. Nucleic Acid structure (monomer = nucleotide)

a) Nucleotide consists of a sugar a phosphate group and a nitrogen base

b) Sugars:1) Ribose in RNA

2) Deoxyribose in DNA

c) Bases:1) Purines (2 rings) Adenine and Guanine

2) Pyrimidines (1 ring) cytosine and Thymine

Nucleic Acids

2. DNA structure is a double helix with the base pairing of Thymine & Adenine and Cytosine & Guanine.

3. RNA structure is a single spiral with Uracil replacing thymine.

4. Nucleic Acid Function

a) DNA carries the genetic code. The information for constructing proteins

b) RNA Carries the genetic code to the ribosome. c) Adenosine Triphosphate (ATP) supplies

energy to the celld) Other Nucleotides and dinucleotides are electron

transport molecules and energy carriers– GTP, UTP, CTP– dGTP, dATP, dCTP, dTTP– AMP, NAD+, NADP, FAD