Carbon ChemistryIB Biology

Why Study Carbon?

Life is built of carbon •Cells –~72% H2O –~25% carbon compounds

•carbohydrates •lipids •proteins •nucleic acids

–~3% salts •Na, Cl, K…

Chemistry of Life

• Carbon atoms are versatile building blocks –Can form 4 stable covalent bonds

Why is Carbon so Important?

• Organic vs. Inorganic in Chemistry –Organic refers to molecules containing a carbon skeleton –Inorganic refers to carbon dioxide and all molecules without carbon

Complex models assembled like tinkertoys

Hydrocarbons

• Combinations of C & H –Non-polar covalent bond between the C and the H –Non-polar, so…

•not soluble in H2O •hydrophobic

–stable –very little attraction between molecules

Functional Groups

•Parts of organic molecules that are involved in chemical reactions –give organic molecules distinctive properties hydroxyl amino carbonyl carboxyl phosphate

•Affect reactivity –makes hydrocarbons hydrophilic –increase solubility in water

Viva la difference!

•Basic structure of male & female hormones is identical –identical carbon skeleton –attachment of different functional groups –interact with different targets in the body

Functional Groups

• Hydroxyl

• Carbonyl

• Carboxyl

• Amino

• Phosphate

Found in• Alcohols, all

macromolecules• Lipids

• Lipids, Amino acids

• Amino acids

• ATP, DNA, RNA

Organic Molecule Synthesis

• Biomolecules are polymers (chains) of subunits called monomers

Organic Molecule Synthesis

• Monomers are joined together through condensation reactions –Also called dehydration synthesis

Organic Molecule Synthesis

• Polymers are broken apart through hydrolysis (“water cutting”) –Water is broken into H and OH and used to break the bond between monomers

Organic Molecules

• All biological molecules fall into one of four categories –Carbohydrates –Lipids –Proteins –Nucleic Acids

Estimated Molecule Percentage in the Human Body Water 65% Proteins 20% Lipids 12% Inorganic 1.5% RNA 1.0% DNA 0.1% Other organic 0.4%

Organic chemistry is a science based on the study of

A) water and its interaction with other kinds of molecules. B) functional groups. C) carbon compounds. D) the properties of oxygen. E) vital forces interacting with matter.

Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by

A) the addition of water to each monomer. B) the formation of disulfide bridges between monomers. C) ionic bonding of the monomers. D) connecting monosaccharides together. E) the removal of water (condensation reactions).

Which of the following best summarizes the relationship between condensation reactions and hydrolysis?

A) Condensation reactions occur in plants, and hydrolysis happens in animals. B) Condensation reactions assemble polymers, and hydrolysis breaks them down. C) Hydrolysis occurs during the day, and condensation reactions happen at night. D) Hydrolysis creates monomers, and condensation reactions destroy them. E) Condensation reactions can occur only after hydrolysis.