Biochemistry A little chemistry in Biology

Atoms are the ________________: ______________ are found ______________ ______________ ___________________ in ____________________ PROTONS (+) NEUTRONS ELECTRONS ( - ) Animation from: basic unit of MATTER in NUCLEUS orbit outside nucleus energy levels

Created by G.Baker What are elements?  Each element represents a specific type of atom.  Elements combine to make molecules  While the atoms may have different weights and organization, they are all built in the same way. Information & picture from Chem4kids at

Created by G.Baker More about Elements..  Elements are the building blocks of all matter.  The periodic table is a list of all of the elements that can build matter. It’s a little like the alphabet of chemistry.

Elements differ in __________ of _______, ________,& _______ Image from: NUMBERS PROTONS NEUTRONSELECTRONS Element Song

Atoms that have _________________ have an _____________ and are called __________ They are written with a + or – next to their symbol IONS Na + Cl - gained or lost electrons electric charge

Atoms/ions important for living things Carbon - C 1.____________ 2.____________ 3.____________ 4.____________ 5.____________ 6.____________ Used to make bigger molecules Ions = electrically charged atoms 1.____________ 2.____________ 3.____________ 4.____________ 5.____________ Oxygen - O Hydrogen - H Nitrogen - N Sulfur - S Sodium – Na + Chloride – Cl - Potassium – K + Calcium – Ca +2 Phosphorus - P Hydrogen – H +

ATOMS CAN ______TOGETHER TO _____________________ Ex: Joining 2 HYDROGEN atoms with 1 OXYGEN atom makes one ______ molecule. WATER A _______________ tells _________ of and __________ atoms are in a molecule EX: ________ H2OH2OH2OH2O MAKE MOLECULES JOIN chemical formula what kind how many

Chemical Bonds  Compounds such as water, salt, and carbon dioxide are formed when two or more substances combine.  The force that holds the substances together is called a chemical bond.  Two main types of chemical bonds –  Covalent bonds  Ionic bonds

VERY, VERY LARGE MOLECULES = ____________________ MACROMOLECULES EXAMPLE: Insulin = C 254 H 377 N 65 O 76 S 6 Image from: http ://

A chemical equation tells what happens in a chemical reaction when molecules interact. NaOH + HCl → NaCl + H 2 0 _______________ ________________ Molecules that react Molecules that are produced REACTANTS Image by RIedell PRODUCTS →

Properties of Water Water video Properties of water

Water  A water molecule (H 2 O), is made up of atoms --- one and two. H H O three oxygenhydrogen

Polar/Nonpolar  Polar- a molecule having electrical poles (Positive and negative ends)  Nonpolar- molecule that does not have negative and positive ends

Water is Polar Water is Polar oxygen atom attracts more "fair share" electrons  In each water molecule, the oxygen atom attracts more than its "fair share" of electrons POLAR  The end “acts” The end “acts” Causes the water to be POLAR oxygennegative hydrogen positive

Hydrogen Bonds Exist Between Water Molecules  Formed between a highly of a polar molecule and a  One hydrogen bond is, but many hydrogen bonds are Electronegative atom Hydrogen weak strong

Interaction Between Water Molecules Negative Oxygen end of one water molecule is attracted to the Positive Hydrogen end of another water molecule to form a HYDROGEN BOND

What are the Properties of Water?

Properties of Water  At sea level, pure water and.  At sea level, pure water and.  The boiling temperature of water decreases at higher elevations (lower atmospheric pressure).  For this reason, an egg will take longer to boil at higher altitudes boils at 100 °C freezes at 0 °C

Properties of Water 1.Cohesion 2.Adhesion 3.High Specific Heat 4.High Heat of Vaporization 5.Less Dense as a Solid

1. Cohesion  Attraction between particles (why water is attracted to itself)  Attraction between particles ( why water is attracted to itself)  Occurs because of water molecules forming hydrogen bonds with nearby water molecules o Results in (a measure of the strength of water’s surface)  Produces a on water that allows insects to walk on the surface of water of the same substance Surface tension Surface film

Cohesion … Helps insects walk across water

2. Adhesion Attraction between substances. Attraction between substances. Water will make hydrogen bonds with other polar molecules (sugar) as well as with ions (salt) Water will make hydrogen bonds with other polar molecules (sugar) as well as with ions (salt)  -water molecules will “tow” each other along when in a thin glass tube.  Example: process which plants and trees remove water from the soil, and paper towels soak up water. two different Capillary action transpiration

Adhesion Causes Capillary Action Which gives water the ability to “climb” structures

Adhesion Also Causes Water to … Form spheres & hold onto plant leaves Attach to a silken spider web

3. High Specific Heat - Amount of heat needed to raise or lower of a substance. - Amount of heat needed to raise or lower of a substance.  Water, both for heating and cooling.  Water can absorb or release large amounts of heat energy with little change in actual temperature. Specific Heat 1 gram 1° C resists temperature change

Who Cares about Specific Heat? cooling  It’s the reason water is used in cooling (car radiators, cooling nuclear cores, etc) water temperatures  It’s also the reason why water temperatures don’t fluctuate as much as air temperatures (benefits aquatic life)

4. High Heat of Vaporization  - Amount of energy to convert 1g of a substance from a liquid to a gas  In order for water to evaporate, must be broken (takes a lot of heat to do this)  As water, it removes a lot of heat with it. Heat of vaporization hydrogen bonds evaporates

Who Cares about Vaporization?  Why do we sweat?

5. Water is Less Dense as a Solid Ice is Ice is as a solid than as a liquid (ice floats) hydrogen bonds constantly being broken and reformed. Liquid water has hydrogen bonds that are constantly being broken and reformed. Frozen water lattice Frozen water forms a lattice whereby molecules are set at fixed distances. less dense crystal-like

Water is Less Dense as a Solid Which is ice and which is water?Which is ice and which is water?

Water is Less Dense as a Solid WaterIce

Homeostasis  Ability to maintain a despite changing conditions  Water is important to this process because: a. Makes a b. Resists temperature change c. d. Coolant e. Ice protects against temperature extremes (insulates frozen lakes) steady state good insulator Universal solvent

WATER is important for all living things Image from: Average person ~~ 60-70% water Babies ~~ 78% Human brain ~~ 90%

WHY Water is important to cells: 1. It’s __________ so it can ____________ lots of different substances. 2. It can _________ lots of ______ _______________________________ very much. (That helps with _________________) 3. ____________________ form between water molecules so they stick together. 4.Water is an important ___________________ in many CHEMICAL REACTIONS. POLAR DISSOLVE HOMEOSTASIS HYDROGEN BONDS REACTANT/PRODUCT absorbHEAT WITHOUT changing temperature

The pH Scale  Indicates the  Ranges from (equal amounts  pH of (equal amounts H + and OH -) 0 up to 7 is acid  pH 0 up to 7 is acid … H + above 7 – 14 is b  pH above 7 – 14 is basic… OH - 10X  Each pH unit represents a factor of 10X change in concentration  pH 3 is 10 x 10 x 10 (1000) stronger than a pH of 6 concentration of H + ions 0 – 14 7 is neutral

Acids  Strong Acids have a pH of 1-3  Produce lots of H + ions

Bases  Strong Bases 11 to 14  Strong Bases have a pH of 11 to 14 lots of OH - ions  Contain lots of OH - ions and fewer H+ ions

Acids and Bases  The H+ ions formed in acids (and the OH- ions formed by bases) can cause certain chemical reactions that may interfere with a cell’s normal functioning (can lead to cell death)  Our stomachs contain hydrochloric acid (pH of 1-2) that causes chemical reactions with bacteria in food to kill them (our stomach is protected by a layer of mucus)

Buffers  Weak acids or bases that react with strong acids or bases to prevent sharp, sudden changes in pH  Produced naturally by the body to maintain homeostasis Weak Acid Weak Base