CHEMISTRY OF LIFE

BIOLOGY-THE STUDY OF LIFE

The Chemistry of Life

I. Organization of Atoms

II. Bonds

III. Water Molecules

IV. Classification of Compounds

V. Compounds found in living things.

I. Organization of Atoms

A. Atom- the smallest unit of matter that cannot be broken down by chemical means.

1. Protons- positive charge, located in the nucleus.

2. Neutrons- no charge, located in the nucleus.

3. Electrons- negative charge surrounding the nucleus in a cloud.

I. Organization of Atoms

B. Element- a pure substance made of only one kind of atom. C. Compound- a substance made of the joined atoms of two or

more different elements. Ex. NaCl (Sodium Chloride)D. Molecule- a group of atoms held together by covalent bonds.

I. Organization of Atoms

E. Ion- an atom or molecule that has gained or lost one or more electron. Ions have an electric charge because they contain an unequal number of electrons and protons.

1. Positive charge- atom that has lost an electron.

2. Negative charge- atom that has gained electrons.

II. Bonds

A. Ionic Bonds- when ions of opposite charges interact. Ex. Sodium chloride—an atom of sodium is unstable—only 1 electron in the outer shell (valence electron). An atom of chlorine is unstable because it has 7 valence electrons. The atoms are readily attracted to each other.

II. Bonds

B. Covalent bonds – form when two or more atoms share electrons. (very strong bonds --“super glue”)

C. Hydrogen bonds – a weak chemical attraction between polar molecules. Ex. A water molecule—H2O.

III. Water Molecules

A. The electrons in a water molecule are shared by oxygen and hydrogen atoms.

B. A water molecule has positive and negative ends, thus polar.

III. Water Molecules

C. Particles are able to dissolve readily in water due to its polarity. Thus, the “universal solvent”.

III. Water Molecules

D. Cohesion – an attraction between substances of the same kind. The hydrogen bonds between water molecules cause the cohesion of liquid water molecules at the surface of water (like holding hands).—this attractions is “surface tension”

III. Water Molecules

E. Adhesion – attraction between different substances. Ex. Water molecules moving upward through the stem of a plant.

III. Water Molecules

F. Evaporative cooling – Water heats more slowly and retains heat longer. Organisms release heat through water evaporative cooling (sweat).

IV. Classification of Compounds

A. Organic- compounds containing carbon (with hydrogen). Ex. Plants, animals

B. Inorganic- compounds that do not contain carbon. Ex. Air, water, minerals

V. Compounds Found in Living Things

Compound Atoms involved

Function Examples

Carbohydrates CHO

1:2:1

(fill in from next slides)

List examples

Lipids CHO (fill in from next slides)

List examples

Proteins CHON (fill in from next slides)

List examples

Nucleic Acids CHONP (fill in from next slides)

List examples

CHO

CHO

CHON

CHON

P

CHO

CHO

CHON

CHON

P

CHOCHOCHONCHONP

CHOCHOCHONCHONP

CHOCHOCHONCHONP

Carbohydrates

• A key source of energy• Building blocks are simple sugars-

monosaccharides (glucose & fructose)

• Disaccharides• Polysaccharides

Lipids

• Stored energy (mostly in animal-some plant seeds)

• Nonpolar molecules• Fats, oils, steroids,

and waxes• Phospholipids—

make up the lipid bilayer of cell membranes

Proteins

• Important for structural functions– Skin, ligaments, tendons, muscles, hair

• Anitibodies, hemoglobin, hormones, enzymes• Building blocks are amino acids

– 20 different amino acids are found in living things

Nucleic Acids

• Contain all genetic, hereditary information

• DNA, RNA

• Building blocks are nucleotides

Biomolecules of Life: Foldable

Carbohydrates

C H O

Lipids

________

Proteins

________

Nucleic Acids

________

Bio

mole

cule

s of L

ife

FRONT

Picture of chemical structure

Common compounds

Uses

Key terms associated with biomolecule

Any other important information

Make sure you include the monomers that make up proteins

Make sure you include the monomers that make up nucleic acids

INSIDE

Terms that must be defined on your foldable…

• Saturated, unsaturated

• Monosaccharide, polysaccharide

• Nucleic acids

• Amino acids

• Monomer, polymer