Created by: J. Quigley September 2013 Chemistry of Life Created by: J. Quigley September 2013

Matter and Substances Every living and nonliving thing is made up of matter. Matter is anything that has a mass and takes up space To understand how living things work and interact, you must understand the structure of matter

Atoms All matter is made of atoms An atom is the smallest unit of matter that cannot be broken down by physical means An atom has a positively charged core surrounded by a negatively charged region

Atomic Structure Atoms are made of three types of particles Protons: have a positive charge Electrons: have a negative charge Neutrons: Have no charge

Elements An element is a substance made up of atoms that all have the same number of protons… For example, each atom of carbon has 6 protons.

Chemical Bonds Valence electrons- electrons in the outermost level/shell of the atom Chemical bonds form between groups of atoms because most atoms become stable when they have eight electrons in the valence shell… therefore they like to give, take electrons or share electrons

Compound A compound forms when atoms of different elements bond, it is a substance made of the bonded atoms of two or more different elements Sodium (Na) has an extra electron. Chlorine (Cl) is missing one electron. When Sodium gives its electron to Chlorine they become a compound and have a chemical bond between them… Na + Cl = NaCl

Covalent Bonds A covalent bond is when atoms SHARE electrons Water is a covalent bond. Remember atoms want 8 electrons in their outer shell. Oxygen has 6, and each hydrogen has 1. H2O has two hydrogen and one oxygen 6+1+1 = 8 Electrons A molecule is a group of atoms held together by covalent bonds.

Ionic Bonds Atoms can also achieve a stable valence level (8 electrons) by losing or gaining electrons. When an atom loses an electron it becomes positively charged When an atom gains an electron it becomes negatively charged When an atom has either a positive or negative charge, it is called an ION. The attractive force between oppositely charged ions is called an IONIC BOND. The salt example is Ionic Na+ + Cl- = NaCl

Polarity In some covalent bonds, the shared electrons are attracted more strongly to one atom than another. As a result, one end, or pole, of the molecule has a partial negative charge while the other end has a partial positive charge

Polarity When a molecule, like water, has a partial negative and partial positive side, it is said to be POLAR When a molecule, like CH4, is totally balanced and does NOT have any partial positive or negative sides (oil, grease, fat, wax)… it is said to be NONPOLAR

Solubility Because of the charges involved, water can dissolve POLAR molecules Nonpolar substances do NOT dissolve in water.

Hydrogen Bonds When bonded to oxygen, nitrogen or fluorine atoms, a hydrogen atom has a partial charge nearly as great as a proton’s charge. It attracts the negative pole of other nearby molecules This attraction is called a hydrogen bond Hydrogen bonding plays an important role in many of the molecules that make up living things.

Water and Solutions A human can survive for a few weeks without food, but only a few days without water. In fact, all of the Earth depends on this simple substance Most of the unique properties of water result because water molecules form hydrogen bonds with each other

Properties of water ICE FLOATS- when water freezes, hydrogen bonds lock water molecules into crystal structure with empty spaces. This makes frozen water less dense than liquid water… allowing it to float

Properties of Water WATER ABSORBS AND RETAINS HEAT: Hydrogen bonds are constantly forming and breaking between water molecules, because of this, water can absorb a large amount of heat without changing temperature… it is also why water takes a longtime to cool.

Properties of Water WATER MOLECULES STICK TO EACH OTHER: hydrogen bonds hold water molecules together much the same way hold hands keeps a crown of people together. This is why small drops of water make a ball. Cohesion- attraction of particles of the same substance. Water is cohesive

Properties of Water WATER MOLECULES STICK TO OTHER POLAR SUBSTANCES: attraction between particles of different substances is called adhesion. Adhesion is the attractive force between two bodies of different substances that are in contact with each other.

Solutions A solution is a mixture in which two or more substances are uniformly dispersed Dissolving salt into water creates the solution: salt water Dissolved substances can move more easily within and between cells

Acids and Bases Some water molecules break apart to form ions. In pure water hydronium ions (H+) & hydroxide ions (OH-) are present in equal numbers In solution, some substances change the balance of these ions.

ACIDS Acids: any compound that increases the number of hydronium (H+) ions when dissolved in water Lemons HCl (Hydrochloric acid) Vinegar

BASES Base: any compound that increases the number of hydroxide (OH-) ions when dissolved in water Ammonia Antacid (tums) Hand soap

pH pH is a measure of how acidic or basic a solution is. The pH scale goes from 0 to 14. 0 is the most acidic possible 14 is the most basic possible 7 is neutral (neither acidic or basic)

Buffers The pH of the solutions in living things must be stable. The pH of human blood is about 7.4. If the pH goes down to 7.0 or up to 7.8, the person will die within minutes! A buffer is a substance that reacts to prevent pH changes in solutions. It helps to maintain the pH of a solution.

Carbon Compounds The parts of a cell are made up of large, carbon based, complex molecules, often called biomolecules. Lipids Proteins Carbohydrates Nucleic acids

Biomolecules A biomolecule is a large, complex molecule built from a few smaller, simpler substances, repeating units arranged in an extremely precise way. They are the molecules of LIFE!

Carbohydrates A carbohydrate is a biomolecule that includes sugars, starches and fiber It is made of carbon, hydrogen and oxygen in predictable rations (CH2O) Sugars are the building blocks of carbohydrates

Carbohydrates A single sugar molecule is called a monosaccharide Glucose Two sugars can be linked to make a disaccharide Sucrose and lactose Many sugars can be lined to make polysacchrides Starch, cellulose and glycogen

Carbohydrates They are a major source for quick energy Cellulose (a type of carbohydrate) is important in providing structural support in shells and cell walls The basic unit of a carbohydrate is a SUGAR!

Lipids Lipids are biomolecules that are made of fat (waxes and steroids) The main function of lipids are to store energy, control water movement and insulation/protective coatings. Lipids also include steroid hormones, used in signaling molecules.

Lipids Lipids consist of chains of carbon atoms bonded to each other and hydrogen atoms, they also have oxygen There are much fewer oxygen atoms in lipids than in carbohydrates Beef Fat (C57H110O6)

Lipids Lipids are insoluble (do not dissolve) in water They are made of a fatty acid and a glycerol

Proteins A protein is made of one or more chains of amino acids that twist and fold into certain shapes that determine what the proteins do. It is an important part of every single cell Proteins: provide structure and support, enable movement, aid in communication and help carry out chemical reactions

Proteins A protein molecule is made of amino acids Every amino acid has an amino group (NH2), a carboxyl group (-COOH) and a variable side group (can be many different things) The carboxyl group of an amino acid can link with the amino group of another amino acid and form a PEPTIDE BOND

Nucleic Acids All of your cells contain nucleic acids Nucleic acid is a long chain of nucleotide units A nucleotide is a molecule made up of three parts: A Sugar A base Phosphate group

Nucleic Acid Nucleotides of deoxyribonucleic acid, or DNA contain the sugar deoxyribose Nucleotides of ribonucleic acid or RNA, contain the sugar ribose

Nucleic Acid DNA molecules act as “instructions” for the processes of an organism’s life. These instructions called the genetic code, depend on the order of the bases in the nucleotides that spiral around each other. Nucleic acids store and transmit hereditary information

Nucleic Acid Some single nucleotides have important roles. Cells need a steady supply of adenosine triphosphate (ATP) to function. ATP is a nucleotide that has three phosphate groups ATP releases energy when it breaks apart

Biological Reactions Living things carry out many chemical reactions that help maintain a stable internal environment. Many of these reactions require large amounts of energy to get started. Many of these reactions would not occur without the help of enzymes

Enzymes An enzyme is a molecule that increases the speed of a biochemical reaction Enzymes hold molecules close together and in the correct orientation By assisting in necessary biochemical reactions, enzymes help organism maintain homeostasis, without enzymes, chemical reactions would not occur quickly enough for life to exist!

Enzymes

Metabolism Your cells get most of the energy needed for metabolism from the food you eat. When food is digested, it is broken down into small molecules that enter the blood, which delivers them to the cells. In the cells, chemical reactions release energy by breaking down the food molecules so that cells can use it