Chemistry of Life

Part 1: Inorganic Chemistry

Matter Anything that has mass and takes up space. Matter exists in 3 states or phases: Solid - has definite shape and volume Liquid - has definite volume but shape depends on the container Gas - both the shape and volume are determined by the container

Energy Definition: Ability to do work. Two types: Potential energy: energy stored in a system Kinetic energy: energy in motion Which type of energy determines the state of matter?

The Atom The atom is the building block of matter. Atoms are made of three particles (subatomic): Protons have a “+” charge and a mass of 1 AMU (atomic mass unit). Protons are located in the nucleus of an atom. Neutrons have no charge and a mass of 1 AMU. Neutrons are located in the nucleus of an atom. Electrons have a “-” charge and no mass. Electrons move around the nucleus of an atom.

The Atom DRAW

Atomic Structure

Hydrogen = ? Helium = ? Carbon = ? Elements Specific type of atom is an element Can’t be broken down further Everything is made of elements Every element has a chemical symbol Hydrogen = ? Helium = ? Carbon = ? C H He How do we organize all the known elements in the universe?

C Periodic Table 6 Carbon 12.011 Displays all known chemical elements Atomic number = the # of protons Each element has a specific number of protons called its atomic number. If you add or remove protons you will have a different element. 6 Atomic Number C Carbon 12.011

C Atomic Mass = # of Protons + # of neutrons 6 Carbon 12.011

What is the atomic mass of Magnesium (Mg)? How many protons does Calcium (Ca) have? How many neutrons are in an atom of zinc (Zn)? #P + #N = Mass so 30 + #N = 65 #N = 35

Ions When atoms gain or lose electrons they are called ions. If an atom… Gains an electron, its charge becomes negative (-) Loses an electron, its charge become positive (+) What forms when a chlorine atom gains one electron? A chlorine ion (Cl-) Oxygen gains two electrons? Oxygen ion O-2 Magnesium (Mg) loses two electrons? Magnesium ion Mg+2

Chemical Bonds Molecules are formed by combining 2 or more atoms, e.g. O2, or H2O Chemical bonds are forces that hold two or more atoms together by sharing or transferring electrons.

Types of Chemical bonds: Ionic – 2 or more atoms transfer one or more electrons. Sodium loses an electron to become Na+ Chlorine gains an electron to become Cl- Sodium chloride (NaCl) forms

Ionic Bonding Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1

2. Covalent Bond – 2 or more atoms share electrons. covalent bonds are the most common in living systems.

Hydrogen Bonding - a weak force of attraction between H and O, F or N.

Chemical Bonding Movie

Chemical Reactions Chemical reactions occur when chemical bonds are being broken and reformed. All reactions either produce or use energy. Reactants are on the left; products are on the right. An arrow represents the progress of the reaction. 2 H2 + O2 -----> 2 H2O

Water and its properties Polarity Water is polar because it has an uneven distribution of charge Slight (+) charge on hydrogen atoms and a slight (-) charge on oxygen; this causes hydrogen bonding

Hydrogen bonding is responsible for the following properties… High surface tension Cohesion – attraction between molecules of the same substance

High heat capacity (its temperature is hard to change) and therefore: It’s a good coolant It’s a good antifreeze How much does the ocean temperature change in a day? during the year?

Water shows capillary action (drinking straw) 4. Water has a high heat of fusion (freezing occurs at a low temperature) and vaporization (it takes a lot of heat to boil)

5. Most dense at 4°C. How does this property affect life in a lake in the winter? Water is a universal solvent (dissolves things) Water is a good lubricant

pH - “Potential of Hydrogen” pH scale (0-14) Lower the number the more acidic (0-7) Higher numbers are more basic or alkaline (7-14). Neutral is 7. Oven cleaner Bleach Ammonia solution Increasingly Basic Soap Sea water Human blood Neutral Pure water Normal rainfall Tomato juice Increasingly Acidic Lemon juice Stomach acid

Acid Base (alkali) Buffer Wants to donate (H+), which lowers pH of a solution and tastes sour. Base (alkali) Wants to donate (OH-), which raises pH of a solution, feels slippery, and tastes bitter. Buffer Weak acids or bases that can react with strong acids or bases to prevent sharp pH changes Buffers keep the human body between 6.5 and 7.5 in order to maintain homeostasis

Part 2: Organic Chemistry

Organic compounds Contain carbon atom(s) and usually come from living things. Exception - CO2 and CO Organic compounds are basic to life function and include carbohydrates, lipids, proteins and nucleic acids.

Carbohydrates Glucose Made of carbon, hydrogen and oxygen. Structure: DRAW IN GRAPHIC ORGANIZER Glucose

Functions Food sources Primary/fastest energy source (4 Kcals/gram) Roughage or fiber (so you can poop!) Cell wall of plant cells Food sources Sweets, bread, pasta, fruit, cereals

Types of Carbohydrates Monosaccharide Disaccharide

Lipids (fats and oils) Made of carbon, hydrogen and oxygen. Structure: Functions: padding and insulation. a long-term energy storage (9 Kcal/gram). building blocks for some hormones. some vitamins are stored in fats.

Food sources: Saturated fats: come from animals, are solid at room temperature, and clog your arteries (butter, bacon grease, cheese)

Unsaturated fats: come from fish and plants, are liquid at room temperature and don’t clog your arteries (nuts, seeds, olive oil, sunflower oil)

Proteins Made of amino acids Structure:

Function: Growth and repair of cells in our bodies Form enzymes (speed up chemical reactions) Form antibodies (fight disease) Make up some hormones (testosterone) Form toxins (bee sting) Food examples: Dairy, meat, poultry, fish, plants (especially nuts, beans and peas) Which is the healthiest source of protein?

E. Enzymes 1. Control nearly all chemical reactions in cells. 2. End in “ase” (Ex: amylase, polymerase) 3. Properties of Enzymes a. Made of proteins b. Speed up chemical reactions c . Enzymes are not used up in reactions, so they can be used over and over d. Specific for certain molecules e. Sensitive to temperature and pH

4. Enzyme Action a. Enzymes provide a place where certain molecules can react more quickly

Nucleic Acids Made of large chains of nucleotides Function: Store information to make proteins Direct cellular activities Examples: DNA and RNA Structure: