Biochemistry

An Introduction to the Chemistry of Life for Biology Students

Composition of living matter “Living things are composed of

lifeless molecules” (Albert Lehninger)

“Chemistry is the logic of biological phenomena” (Garrett and Grisham)

Organisms are complicated and highly organized

Biological structures serve functional purposes

Living systems are actively engaged in energy transformations

Living systems have a remarkable capacity for self-replication

Biomolecules: The Molecules of Life

H, O, C and N make up 99% of atoms in the human body

ELEMENT PERCENTAGEOxygen 63Hydrogen 25.2Carbon 9.5Nitrogen 1.4

Common in biosystemsCarbon (C)Oxygen (O)Hydrogen (H)

What property unites H, O, C and N and renders these atoms so appropriate to the chemistry of life?

Answer: Their ability to form covalent bonds by electron-pair sharing.

Types of chemical bonds

Covalent bonds• Common in biosystems• Share a pair of electrons

Ionic Bonds• Transfer an electron• Opposite charges attract

Types of Chemical Bonds

Hydrogen bonds• Weak partial bonds• Water surface tension

Van der Waals forcesWeak

Functional groups

Simple Molecules are the Units for Building Complex Structures

Metabolites and Macromolecules Organelles Membranes The Unit of Life is the Cell

Primary Organic Compounds (macromolecules)

1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acids

You are expected to learn the structure and functions of these organic compounds:

Polymers ands Monomers

Each of these types of molecules are polymers that are assembled from single units called monomers.

Each type of macromolecule is an assemblage of a different type of monomer.

Monomers

MacromoleculeCarbohydrates

Lipids

Proteins

Nucleic acids

Monomer ( biomolecule)

Monosaccharide

Not always polymers; Hydrocarbon chains

Amino acids

Nucleotides

How do monomers form polymers? In condensation reactions (also

called dehydration synthesis), a molecule of water is removed from two monomers as they are connected together.

Hydrolysis

In a reaction opposite to condensation, a water molecule can be added (along with the use of an enzyme) to split a polymer in two.

Properties of Biomolecules Macromolecules and Their Building

Blocks Have a “Sense” or Directionality

Macromolecules are Informational Biomolecules Have Characteristic

Three-Dimensional Architecture Weak Forces Maintain Biological

Structure and Determine Biomolecular Interactions

Cell hierarchy

Biomolecules combine to form macromolecules.

And macromolecules combine non covalently to form supramolecules, such as:Supramolecule

Biomolecules Biomolecule

Lipo proteins lipids proteins

Ribosomes Nucleic acids proteins

Glycolipids Sugar lipids

Cell hierarchy

Finally, at the higher level of organization of the cell structure, supramolecules are further assembled into call organelles. ( Nuclei, mitochondria, chloroplasts, etc..)

Macromolecules:a) Carbohydrates Carbohydrates are made of carbon,

hydrogen, and oxygen atoms, always in a ratio of 1:2:1.

Carbohydrates are the key source of energy used by living things.

The building blocks of carbohydrates are sugars, such as glucose and fructose.

Carbohydrates

What do the roots mono-, di-, oligo-, and poly mean?

Each of these roots can be added to the word saccharide to describe the type of carbohydrate you have.

How do two monosaccharides combine to make a polysaccharide?

Polysaccharides

Lipids

Lipids are molecules that consist of long hydrocarbon chains. Attaching the three chains together is usually a glycerol molecule. Lipids are NONpolar.

Saturated vs. Unsaturated Fat

Proteins

Proteins are building blocks of structures called amino acids. Proteins are what your DNA codes to make .

A peptide bond forms between amino acids by dehydration synthesis.

Protein Structure

LevelPrimary

Secondary

Tertiary

Quaternary

DescriptionThe amino acid

sequenceHelices and Sheets

Disulfide bridges

Multiple polypeptides connect