The+Chemistry+of+Life

"The Chemistry of Life"

What is matter? //**Matter**// is anything that takes up space! It can be a human, and it can be an ant, and it can be a atom.

An //**atom**// is the basic unit of matter. The concept of the atom was first named by the Greek philosopher Democritus, nearly 2,500 years ago! Democritus figured this out by asking a simple question: If you take an object like chalk and break it in half, would both pieces still be chalk? Of course

[|Atom Pic]

A //**chemical element**// is a pure substance that consists entirely of one type of atom. There more than 100 know elements. They are represented by one or two letter symbols. For example: "C" stands for Carbon, "H" stands for Hydrogen, and "Na" stands for Sodium.

[|Periodic Table Element Pic]

A //**chemical compound**//, however, is a substance formed by the chemical combination of two or more elements in definite proportions. Scientists show the composition of compounds through chemical formulas. For example: Water is a compound based off of Hydrogen and Oxygen. H2O is the chemical formula for water. There are two hydrogen's and one oxygens in each molecule of water. A //**molecule**// is the smallest unit of most compounds. In water, each hydrogen atom is joined to water's one oxygen atom by a single covalent bond.

[|Diagram]

//**The Water Molecule:**//

Water is one of the few compounds found in the liquid state over most of the Earth's surface.

Water molecules are neutral. However... - With 8 protons, water's oxygen nucleus attracts electrons more strongly than the single protons of water's two hydrogen's nuclei. - Water's molecule is based off of two atoms. Oxygen which is the negative side of the molecule, and hydrogen which is the positive side of the molecule as shown in the diagram above. - Because of partial positive and partial negative charges, polar molecules such as water can attract to each other. The attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge is know as a //**hydrogen bond**//. The most common partially negative atoms involved in hydrogen bonding are oxygen, nitrogen, and fluorine. - //**Cohesion**// is an attraction between molecules of the same substance. Because a water molecule can be involved in as many as four hydrogen bonds at a time, it is extremely cohesive. - //**Adhesion**// is an attraction between molecules of different substances. Adhesion between water and glass also causes water to rise in a narrow tube against the force of gravity. This effect is called capillary action. - A //**solution**// is when ions evenly disperse throughout the water they are put in. A **solute** is the substance that is dissolved, while the //**solvent**// is the substances that the solute is placed in to dissolve. Water is the number one solute in the world. Water easily dissolves salts, sugars, minerals, gases, and even other kinds of solvents such as alcohol.

An //**Ionic bond**// is formed when one or more electrons are transferred from one atom to another, while a //**covalent bond**// is formed when atoms share electrons. Ionic bonding takes place in molecules such as sodium chloride (NaCl), or salt as we know it. Covalent bonding takes place in molecules such as Chlorine (Cl2).

[|Covalent Bond] [|Ionic Bond]

//**Carbohydrates**// are the main source of energy for plants and animals, basically all organisms. Simple sugars are also known as //**monosaccharides**//. Examples are glucose, galactose which comes from milk, and fructose. When two simple sugars combine they create a //**disaccharide**//. An example of a disaccharide is sucrose. Complex carbohydrates are //**polysaccharides**//. Animals store excess sugars in polysaccharides called glycogen.

//**Lipids**// are a large varied group of biological molecules that are generally not soluble in water. They are made of carbon and hydrogen. Examples of lipids are fats, oils, and waxes. They can also be used to store energy, and some lipids are used to create a waterproof covering for biological membranes.

//**Proteins**// are macromolecules that contain nitrogen, as well as carbon, hydrogen, and oxygen. They are polymers of molecules called amino acids. Amino Acids are compounds with an amino group (-NH2) on one end and a carboxyl group (-COOH) on the other end.Covalent bonds called peptide bonds link amino acids together to form a polypeptides.

//**Nucleic Acids**// are macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus. Nucleic Acids are polymers assembled from individual monomers know as nucleotides. Nucleotides consist of three parts: A 5 carbon sugar, a phosphorus group (-PO4), and a nitrogen base.

//**Monomers**// are molecules that make up polymers. Monomers are able to bond in long chains. //**Polymers**// are sometimes known as macromolecules. Usually polymers are organic.

//**Enzymes**// are proteins that act as biological catalysts. Enzymes speed up chemical reactions that take place in cells. They act like by lowering the activation energies.

[|Enzyme]