Chapter 2

From Atoms to Molecules

All mater is composed of elements, and an element is the basic building block. The fundamental part of an element is an atom. An atom is comprised of neutrons, protons (which determines the atomic weight), and electrons (which determine the chemical properties of an element by the number of electrons in the outer shell). All atoms combine together chemically, to make molecules, by using ionic bonds, the exchange of one or more electrons, or covalent bonds, the sharing of electrons.

Carbon 12 Atom

http://content.answers.com/main/content/img/ahd4/A4atom.jpg

Water and Living things

Water has many unique qualities that make it very suitable for living organisms. Water is a liquid at room temperature, and heats and cools slowly, which allows for good temperature regulation. Water is also considered to be the universal solvent, is ph+ neutral, and cohesive. Not to mention we are comprised of 60-90% by weight of water.

Molecules of Life

Human Biology Power Point Presentation, Human Biology 156 by Larry M. Frolich, Phd.

Carbohydrates function is for the short-term storage of energy in everything organic. There are two types: simple carbohydrates or monosaccharides and complex carbohydrates or polysaccharides. When plants and animals break carbohydrates down to glucose, plants store it as starch and animals store it as glycogen.

Lipids are simply fats. Which all cells need to form the cell membrane and allows a cell to maintain homeostasis.

Proteins have multiple roles depending on the shape and chains that are formed. Amino acids and the peptide bonds that they form are the building blocks of proteins. Proteins form: support cells, such as hair, nails, and collagen; enzymes, that speed chemical reactions; transport cells, allowing substances to enter and leave through the cell membranes; defense cells, or antibodies; hormones, such as insulin; motion cells, that allow muscles to contract. The shapes that proteins can take are: primary structure (linear), secondary structure, a right-handed spiral, tertiary structure, a pleated sheet, and quaternary structure, or combination of the three pervious shapes (hemoglobin is an example of a quaternary structure).

Nucleic Acids

There are two types of nucleic acids, Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA), both are polymers of nucleotides. A nucleotide is a combination of a phosphate, a pentose sugar and a nitrogen-containing base. In DNA the bases are: adenine (A), thymine (T), guanine (G), and cytosine (C). In RNA the bases are the same except for the base uracil (U) takes the place of thymine (T). DNA has a double stranded helix shape with base pairings (shown below) whereas RNA does not.

Deoxyribonucleic Acid

http://en.wikipedia.org/wiki/DNA

ATP: An Energy Carrier

Nucleotides have an additional function of breaking down glucose into packets of energy that can be used by the cells. In the form of ATP inside the cell the easily combine with water and release energy, ADP and inorganic phosphate.

Sources:

Human Biology 10^th Edition by Sylvia S. Mader

http://content.answers.com/main/content/img/ahd4/A4atom.jpg

Human Biology Power Point Presentation, Human Biology 156 by Larry M. Frolich, Phd.

http://en.wikipedia.org/wiki/DNA