What is Biochemistry? Biochemistry is the study of the chemical interactions of living things. Biochemists study the structures and physical properties of biological molecules. Often are involved in the manufacture of new drugs and medical treatments

Elements in Living Organisms The most common elements found in living organisms include: Carbon (C) Oxygen (O) Nitrogen (N) Hydrogen (H) Phosphorus (P) Sulfur (S)

Periodic Table of the Elements (excerpt)

Macromolecules of Cells Macro = large 4 types of macromolecules in cellular biology 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids

Macromolecule #1: Carbohydrates Sugars and groups of sugars Purposes: energy and structure Includes three types: Monosaccharide (1 sugar – quick energy) Disaccharide (2 sugars – short storage) Polysaccharide (many sugars – energy long storage & form structures)

Macromolecule #1: Carbohydrates Polysaccharide Examples: Glycogen—glucose polymer stored for future energy needs. Found in liver, muscle and sperm, etc. Cellulose—glucose polymer used to form fibers for plant structures. Humans can’t digest (fiber). Most abundant organic molecule. Chitin—glucose polymer for exoskeletons of some crustaceans & insects.

Polysaccharides

Polysaccharides

Macromolecule #2: Lipids Insoluble in water (think oil & water) 4 types: 1-triglycerides (fats & oils) (long-term energy storage, insulation) 2-phospholipids (primary component of cell membrane) 3-steroids (cell signaling) cholesterol molecules modified to form sex hormones. (e.g. testosterone, estrogen, etc.) 4-waxes (protection, prevents water loss) Used mainly by plants, but also bees, some furry animals and humans.

Triglycerides

Phospholipids

Steroids

Waxes

Macromolecule #3: Proteins Probably the most complicated of all biological molecules. Serve the most varied purposes, including: Support structural proteins (e.g., keratin, collagen) Enzymes speed up chemical reactions Transport cell membranes channels, transporters in blood (e.g., Hemoglobin) Defense antibodies of the immune system Hormones cell signaling (e.g., insulin) Motion contractile proteins (e.g., actin, myosin)

Collagen

Antibodies

Cellular Transport

actin & myosin fibers in muscles Motion actin & myosin fibers in muscles

Macromolecule #3: Proteins The building blocks of proteins are AMINO ACIDS. There are only 20 types of Amino Acids. There are millions of different proteins, and they are all built from different combinations of the 20 amino acids. Amino acids join together to form peptides, polypeptides, and polypeptide chains.

Macromolecule #4: Nucleic Acids Nucleotides: building blocks of nucleic acids. Each nucleotide contains (a) phosphate molecule, (b) nitrogenous base, and (c) 5-carbon sugar Several types of nucleic acids, including: DNA: deoxyribonucleic acid Genetic material, double stranded helix RNA: ribonucleic acid Genetic material, single stranded ATP: adenosine triphosphate High energy compound

DNA

Nucleotide Structure

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 Macromolecule Carbohydrates Lipids Proteins Nucleic acids 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.