The Chemistry of Life

Organic Chemistry

Organic Chemistry is the chemistry of Carbon!

Organic Chemistry vs. Inorganic Chemistry

C, H, N, O, P, S All Elements

Large # of Atoms Small # of Atoms

Associated with Life Associated with Environment

NaCl

Organic Chemistry

Carbon can form many bonds! Valence=4

Can store/release lots of energy

Carbon can build large and diverse molecules

Carbon

Functional GroupsGroups of atoms that bond to the “carbon skeleton”

Determine the properties of organic molecules

Behave consistently from one carbon-based molecule to another

Functional Groups

Hydroxyl

-OH

Alcohols, carbohydrates

Polar

Hydrophilic

Carbonyl (Aldehyde)

-C=O

At the end of the carbon skeleton

Carbohydrates (Aldose sugars)

Polar

Hydrophilic

Carbonyl (Ketone)

-C=O

On an inside carbon of the carbon skeleton

Carbohydrates (Ketose sugars)

Polar

Hydrophilic

Carboxyl-COOH

Carbon double bonded to oxygen and also attached to a hydroxyl

Lipids and Proteins

Polar

Hydrophilic

Called carboxylic acid because they tend to dissociate to release H+

Phosphate-OPO3

2-

Phosphorus atom surrounded by O

Lipids and Nucleic Acids, ATP

Polar

Hydrophilic

Amino

-NH2

Amino acids/proteins

Polar

Hydrophilic

Can act as a base by accepting a H+ to form –NH3

+

Most organic molecules are macromolecules (Really Big!)

Macromolecules are formed by a process called polymerization

Biological Macromolecules

Large compounds are constructed by joining together many smaller units….

Small Units: Monomers (Basic Unit)

Polymerization

Large Units: Polymers (Many Units)

Polymerization

Monomers Polymers

Process called Dehydration SynthesisMany bonds formed by removing water

Energy Stored

Animation

Dehydration Synthesis

Polymers Monomers

Process called HydrolysisBonds broken by adding water

Energy is released!

Animation

Hydrolysis

The compounds of life are all carbon based organic compounds!

There are 4 groups of organic biomolecules found in all living things:

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

Organic Biomolecules

Carbohydrates

Contain Carbon, Hydrogen, and Oxygen in a 1:2:1 ratio

Building blocks (monomers) are Monosaccharides

MonosaccharidesCommonly called “sugars”

General formula is (CH2O)n

Contain 2 or more Hydroxyl groups, and a Carbonyl groupAldehyde = aldose sugarsKetone = ketose sugars

Very polar, hydrophilic

Straight chains or rings

Examples:

GlucoseFructoseGalactoseMannose

All C6H12O6

Monosaccharides

Isomers

Molecules that have the same chemical formula but different structure

Disaccharides

Two monosaccharides joined by dehydration synthesis

Strong covalent bond called Glycosidic Linkage

Example:

Sucrose C12H22O11

PolysaccharidesLarge complex carbohydrates

Made up of many repeating monosaccharides

Functions:

Energy storage

Structural molecules used to build cells/tissues

Energy Storage Polysaccharides

Plant Cells Animal Cells

Starch Glycogen

Structural Polysaccharides

Plant Cells Animal Cells

Cellulose Chitin

Lipids

Contain many Carbon and Hydrogen atoms and few Oxygen

Commonly called “fats”, “oils”, or “waxes”

All lipids are nonpolar and hydrophobic

Lipids

Lipids: Triglycerides (fat)

Building blocks include:

1 Glycerol a 3 carbon molecule

3 Fatty Acids long chains of Carbon with a single carboxyl group

Lipids: Triglycerides (fat)

Fatty Acids:

Saturated fatty acids contain carbon to carbon single bonds and the maximum number of H atoms

Unsaturated fatty acids contain 1 or more carbon to carbon double bonds and fewer than the maximum number of H atoms

Lipids: Triglycerides (fat)

Lipids: Triglycerides (fat)

3 fatty acids are joined to glycerol by dehydration synthesis

Strong covalent bond called ester linkage

Fats store concentrated energy in the many C-H bonds

Also provide insulation against cold, protect internal organs, provide waterproofing

Lipids: PhospholipidsGlycerol

2 Fatty acids

Phosphate group

Nonpolar tails, polar head (amphipathic)

Form bilayers that make cell membranes

Lipids: Phospholipids

Lipids: Steroids

Hormones that regulate cellular activities

Ring-shaped, not like triglycerides

ProteinMost abundant and diverse molecules in living cells

Contains C, H, O, and N

Carboxyl group

Amino group

Building blocks are called amino acidsPolymers of amino acids are called Polypeptides

Protein: Amino Acids

Amino Acids:

• Building blocks of proteins

• Central carbon atom

• Hydrogen atom

• Amino group

• Carboxyl group

• R group (variable structure)

There are 20 different amino acids

Diversity of R groups

Varied chemical properties and interactions

Protein: Peptide Bonds

Two amino acids joined together by dehydration synthesis

Strong covalent bond called peptide bond

Bond forms between C of carboxyl group and N of the amino group

Two amino acids joined together are called a dipeptide

Formation of a Polypeptide

Protein: Polypeptide

Many amino acids joined by peptide bonds

Primary structure (sequence of amino acids) is determined by genetic code

Tertiary structure results from amino acid chain folding back on itself. Results in globular, 3 dimensional molecule

Protein function is determined by its molecular shape (tertiary structure)

Structure in organisms: collagen, connective tissue, keratin

Hormones: regulate body functions

Movement: major role in muscle contraction

Transport: through cell membrane, and O2 in blood

Enzymes: catalysts that speed up chemical reactions

Protein: Functions

All complex proteins can be denatured!

Change in pH or temperature

Shape is lost

Function is lost

Function can be restored if conditions are restored!

Protein: Denaturing

Contain C, H, O, N and P atoms

The primary function of nucleic acids is to store and transmit genetic information!

Found in the nucleus of eukaryotic cells and in the nucleoid region of prokaryotic cells

Nucleic Acids

The building blocks of nucleic acids are called nucleotides

Nucleotides contain 3 parts:

1. 5 carbon sugar (pentose)2. Phosphate group3. Nitrogenous base

Nucleic Acids: Nucleotides

Two nucleotides are joined together by dehydration synthesis

Strong covalent bond called phosphodiester linkages link the phosphate of one nucleotide to the sugar of the next nucleotide.

This polynucleotide creates the “sugar-phosphate backbone”

Nucleic Acids: Nitrogenous BasesRing-shaped carbon and nitrogen molecules

Purines are double rings: Adenine and Guanine

Pyrimidines are single rings: Thymine, Cytosine, and Uracil (RNA)

DNA

Deoxyribonucleic Acid

Deoxyribose sugar

Bases: (A and T) (C and G)

Double Stranded

Stores genetic information in nucleus

Nucleic Acids: Polymers

RNARibonucleic Acid

Ribose Sugar

Bases: (A and U) (C and G)

Single stranded

Carries genetic code to ribosomes for protein synthesis

The Special Chemicals of Life