Chemistry of Living Things Course Study Guide

Chemistry of Living Things Chemistry: ● The study of the structure of matter and composition of substances, their properties, and their chemical reactions. ○ Biochemistry ■ The study of the chemical reactions of living things. ● Matter and Energy: ○ Matter ■ Anything that has weight (mass) and occupies space. ■ Exists in solid, liquid, and gas forms. ○ Energy ■ The ability to do work or to put matter into motion. ■ Exists in our bodies ● Potential energy ○ Stored in cells waiting to be released. ○ Ex. laying in bed. ● Kinetic energy ○ Work resulting in motion. ○ Ex. getting out of bed. ○ Atoms ■ The smallest piece of an element. ■ Invisible to the human eye. ■ The normal atoms are made up of subatomic particles: ● Protons ○ Has a positive electrical charge. ● Neutrons ○ Have no electrical charge. ● Electrons ○ Has a negative charge. ■ Isotopes ● Have the same number of protons but a different number of neutrons. ● Radioactive ○ Some isotopes are unstable and decay. ○ Elements ■ Substances that can neither be created nor destroyed by ordinary chemical means. ○ Compounds ■ Elements combined in definite proportion by weight to form a new substance. ■ Unicellular ● One-celled microbe ■ Multicellular ● Many-celled animal or plants ■ Organic compounds ● Compounds that contain the element carbon ○ Molecules ■ The smallest unit of a compound that still has the properties of the compound and the ability to lead its own stable and independent existence. ○ Chemical bonds ■ Bonds formed when atoms share or combine their electrons with atoms of other elements. ■ Ionic bond ● Bond in which one atom gives up an electron to another atom. ■ Covalent bond ● Atoms share electrons to fill their outermost levels/shells. ■ Hydrogen bond ● Bond that holds water molecules by forming a bridge between the negative oxygen atom of one water molecule and the positive hydrogen atom of another molecule. ● Types of Compounds: ○ Inorganic ■ Made of molecules that do not contain the element carbon (C). ○ Organic ■ Always contain the element carbon, combined with hydrogen and other elements. ○ Carbohydrates ■ Compounds of the elements carbon, hydrogen, and oxygen. ■ Have twice as many hydrogen atoms as oxygen and carbon. ■ Divided into 3 groups: ● Monosaccharides ○ Sugars that cannot be broken down further. ○ Also called single or simple sugars. ○ Ex. glucose, fructose, galactose… ● Disaccharides ○ Known as a double sugars because it is formed from 2 monosaccharide molecules by a chemical reaction called dehydration synthesis. ● Polysaccharides ○ Large, complex molecules of hundreds to thousands of monosaccharides bonded together in one long, chain-like molecule. ○ Ex. starch, cellulose, glycogen ○ Lipids ■ Molecules containing the elements carbon, hydrogen, and oxygen. ■ Different from carbohydrates because they have much less oxygen in relation to hydrogen ■ Ex. fats, phospholipids, and steroids. ● Fats (triglycerides) ○ Consists of glycerol and fatty acids and make up 95% of fats in the human body. ● Phospholipids ○ Contain carbon, hydrogen, oxygen, and phosphorus. ○ This type of lipid may be found in the cell membranes, the brain and nervous tissue. ● Steroids ○ Lipids that contain cholesterol. ■ Cholesterol is essential in the structure of the semipermeable membrane of the cell. ○ Proteins ■ Organic compounds containing the elements carbon, hydrogen, oxygen, nitrogen, and normally phosphorus and sulfur. ■ Found in every part of a living cell. ■ Amino acids ● Small molecular units that work together to build proteins in the body. ■ Enzymes ● Specialized protein molecules found in all living things. ● They help control the various chemical reactions occurring in a cell, so each reaction occurs just at the right moment and time. ○ Nucleic acids ■ Important organic compounds containing the elements carbon, oxygen, hydrogen, nitrogen, and phosphorus. ■ There are 2 groups of nitrogenous bases ● Pyrimidines ○ Either cytosine or thymine ● Purines ○ Either adenine or guanine