Just Enough Chemistry for Genetics

Cell Bio/Genetics

Mr. Foster

Types of Bonds

• Ionic Bond-–Ion - atom that has gained or lost

electrons (e-’s)–Transfer of e-’s b/t 2 atoms–Metals and nonmetals (ex. NaCl)

• Covalent Bond-–Share e-’s equally–Nonmetal and nonmetal (ex. H2O)

Covalent Bond

Types of Bonds (cont.)• Polar Covalent Bond-

– e-’s are shared unevenly– One atom holds e-’s closer (electronegativity)– H2O

• Hydrogen Bond-– A slightly +H of a polar cov. bond in one

molecule is attracted to a slightly neg. atom of another molecule (WEAK)

– Ex. H with O, F, N

H H

O

Compounds of Life

• Organic- contain carbon

VERY IMPORTANT

• Inorganic- usually do not contain carbon

Organic

• Form chains or rings

• Form strong stable bonds

• Form 4 bondsMethane

Benzene

Compounds of Life (cont.)

1. Water– Most abundant compound in

living organisms

– Uneven distribution of electrons• Polar molecule• Give water unique characteristics

– Wide range of temp. is liquid– Good solvent- dissolves many substances

H H

O

-

+

2. Carbohydrates– C, H and O

– Sugar & Starches

(Glucose) (Glycogen)

– Functions• Provide energy• Contribute to cellular structure

– Hydroxyl functional group (R-OH)

Compounds of Life (cont.)

3. Lipids– C, H, O

– Fats, oils, Waxes

– Carboxyl group

– (COOH)

Compounds of Life (cont.)

R

OH

?

Compounds of Life (cont.)4. Proteins

– C,H,O and N

– Amino acids- building blocks

– Functional group – amine group

– Functions• Structure• Enzymes-

biological catalysts

EnzymesSubstrate- (X) reactants effected by enzyme

Active Site

EnzymeEnzymes are very specific

Enzymes are sensitive to temperature and pH

5. Nucleic Acids (DNA, RNA)–C, H, O, N, P

–Building blocks Nucleotide

–Functional Group- phosphate group

–Functions• Store genetic info.• Transmit genetic info.

Compounds of Life (cont.)