The Chemistry of LifeBiochemistry

=Branch of science that deals with the chemical composition (makeup) and processes of living things

I. AtomsA. The basic unit of matter

(Matter = anything that has mass and takes up space)

B. There are three subatomic particles that are combined to make each atom.

* Proton (+)

* Neutron (o)

* Electron (-)

move around nucleus in electron cloud

Nucleus (+)

Energy Levels1st = 22nd = 83rd = 18

C. Isotopes – Atoms of the same element with different number of neutrons1. Identified by mass number (atomic mass)2. Ex.: Carbon-12; Carbon-13; Carbon-14

II. ElementsA. An element is a substance that

contains one type of atom

B. We can find information about all known elements in the Periodic Table of Elements

C. Element Key Atomic Number (+), (-)

Chemical Symbol Element Name Atomic Mass/ Mass Number (+ ; o) (protons plus neutrons)

1. Atomic Number = number of protons in nucleusa. All atoms of the same element have same atomic numberb. This number also equals number of electrons in electron

cloud

2. Atomic Mass = average of all the isotopes of that element

3. Mass Number = number of protons and neutrons that make up atom nucleus

1H

Hydrogen1.0079

• Equations to know:– At. Mass = p + n p = protons– At. No. = p = e n = neutrons– e = p e = electrons

D. All substances are made up of elements1. On Earth 90 elements occur naturally2. 25 elements are essential to living things

* Carbon ( C)* Hydrogen (H)* Oxygen (O)* Nitrogen (N)

96 % of human body

III. Combining AtomsA. When two or more atoms are combined a

molecule is formed (O₂)

B. When two or more atoms of different elements combine a compound is formed (CO₂)

ALL COMPOUNDS ARE MOLECULES, BUT NOT ALL MOLECULES ARE COMPOUNDS!!!!!!

Be able to explain this statement.

C. We can describe the composition of compounds by using a chemical formula

Ex: H₂O (2 atoms of hydrogen, 1 atom of oxygen)

C₆H₁₂O₆ (6 carbon, 12 hydrogen, 6 oxygen)

• The chemical properties of each compound are different from each of the elements that form it.

• Chemical properties = characteristics– Ex: Sodium (Na) – silver metal, soft, reacts violently

with water• Chlorine (Cl) – poisonous, green gas ---------------------------------------------------------------------• Sodium Chloride (NaCl) or table salt–White solid, dissolves easily in water, essential for

survival of living things

IV. Chemical BondsA. Bonds : a force that holds atoms together

1. Covalent Bondsa. Forms when atoms share electrons

• Share 2 = single bond• Share 4 = double bond• Share 6 = triple bond

b. Ex: water

2. Ionic Bonds

a. Formed when atoms lose or gain electronsb. Creates electrically charged atoms called

ions (different number of protons/electrons)

* if atom loses electron = + ion* if atom gains electron = - ion

c. Ions with opposite charges are attracted to each other.

d. Ex: NaCl

3. Hydrogen Bonds

a. Form when the positive end of one molecules is attracted to the negative end of another moleculesb. Form without the interaction of electronsc. Responsible for the cohesion of water

*allows raindrops to form or water to beadd. Easily broken

V. Mixtures and CompoundsA. Mixture: two or more substances that are not chemically

combined

1. Heterogeneous: components not evenly mixed; all components keep their own identity

Example: sand, salad, soup

2. Homogeneous: components are evenly mixed; cannot see each component; also called solutionExample: kool-aid, air

3. Components of a mixture can be separated by physical means, while components of a compound must be separated by chemical means.

B. Parts of a Solution1. Solute: substance being dissolved2. Solvent: substance doing the dissolving

C. Suspensions1. form when some materials do not dissolve2. ex: blood – mostly H₂O, dissolved compounds,

cells, and misc. particles

VI. Acids/Bases/pHA. Acids – a solution with a high concentration

of Hydrogen ions (H+)

B. Bases – a solution with a high concentration of hydroxide ions (OH-)

C. pH – means potential for hydrogen

1. pH Scale: a measurement system used to indicate the concentration of H+ ions

ranges from 0 - 14– 0.1 – 6.9 = acid (pop, juice, coffee)– 7. 0 = neutral (pure water)– 7.1 – 14 = base (blood, soap, some cleaning products)

pH can determine what type of organisms can live in an environment or what types of chemical reactions can take place

7.0 pure water

Balancing Equations

Steps to Solve Equation1. write down elements on reactants side2. write down elements on product side3. write number of atoms for each element on each side4. Begin adding coefficients to balance equation

2 H₂ + O₂ → 2 H₂O

Practice Problems

1. ____ N₂ + ____ H₂ → ____ NH₃

2. ____ Cu₂O + ____ C → ____ Cu + ____CO₂

3. ____ Mg + ____ O₂ → ____MgO

4. ____CH₄ + ____ O₂ → ____CO₂ + ____ H₂O

5. ___ Zn + ____ CrCl₃ → ____CrCl₂ + ____ZnCl₂

6. ___ CO₂ + ___ H₂O → ____C₆H₁₂O₆ + ____ O₂

7. ____C₂ + ____H₂ + ____OH → ____C₃H₇OH

8. ____C₃ + ____H₂O → ____C₉H₈O₄

9. ____O₂ + ____Cl₂S₃ → ____Cl₂O₄ + ____ SO₂

10. ____N₂ + ____H₂ + ____Cl₃ → ____NH₄Cl

ORGANIC CHEMISTRYI. Organic chemistry is the study of compounds

that contain bonds between carbon atoms

A. Carbon atoms have 4 valence electrons; therefore, each electron can join with electrons from another atom to form strong covalent bonds

B. Carbon can bond with:* Hydrogen (H) * Phosphorus (P) * Oxygen (O) * Carbon (C)* Nitrogen (N) * Sulfur (S)

C. Carbon can form chains of unlimited lengths

II. Organic Compounds Found in All Living Things

A. Carbohydrates

B. Lipids

C. Proteins

D. Nucleic acids

A. Carbohydrates

1. Made up of C, H, and O in a 1 : 2 : 1 ratio2. Uses

a. Energy (quick)b. Structural building blocks (cellulose – plant cell walls)

3. Sugars and Starchesa. Monosaccharides (one)b. Disaccharides (two)c. Polysaccharides (many)

Monosaccharidesi. Simple sugarii. Chemical formula: C₆H₁₂O₆iii. Ex: Glucose, Fructose, and Galactose are 3

isomers of a monosaccharide= molecules with same chemical formula but different structure

Disaccharidesi. A two-sugar moleculeii. When 2 carbohydrate monomers are joined, a

dehydration synthesis(removal of H₂O) takes place to form a disaccharide.

iii. Chemical formula: C₁₂H₂₂O₁₁iv. Ex: glucose + galactose → Lactosev. When disaccharides are used for energy, they are

digested by enzymes that break them up into monosaccharides which are metabolized in the process of cellular respiration

• Hydrolysis Reaction

glucose + galactose → Lactose (C₆H₁₂O₆) + (C₆H₁₂O₆) - (H₂O) = C₁₂H₂₂O₁₁

• Monomer = a single unit/molecule• To digest lactose (sugar in dairy), you need

lactase enzyme• Lactose intolerant people can’t produce lactase

Polysaccharidesi. Large macromolecules or polymers that can

consist of hundreds or thousands of monomers (C₆H₁₀O₅)n

1. Starches (plant: corn & wheat)a. Amylase (enzyme) breaks it down into monomers which are absorbed into the bloodstream to be used by the cells.

2. Glycogen (animal starches)a. Stored in the liver and muscles when there is excess

monosaccharides

3. Cellulosea. Can not be digested = roughage

B. Lipids

1. Made up mostly of C and H with some O2. Uses:

a. Energy – 2x the amount of chemical energy per gram compared to carbohydrates

b. Making biological membranes Ex: plasma membrane in cells

c. Water proof coverings in plantsd. Physical & thermal insulation to animals

3. Lipids are generally insoluable in water4. Formed when a glycerol molecule (C₃H₅O₃)

joins a fatty acid

a. Saturated fats form when each carbon atom in the fatty acid chain is joined to another carbon atom by a single covalent bond • Solid at room temperature• Ex: butter

b. Unsaturated fats form when there is a least one carbon-carbon double bond• liquid at room temperature• Olive oil

c. Polyunsaturated fats form when there are two or more carbon-carbon double bonds• liquid at room temperature• Corn, sesame & peanut oil

d. Steroids are lipids whose C, H, and O atoms are arranged in rings• Estrogen, Androgen, Cholesterol

C. Proteins1. Made up of C, H, O, and N 2. Uses:

a. Regulate cell processes and control reaction ratesb. Make up bulk of all solid material in the body (muscle, bone, skin, hair)c. Transport substances in and out of cell

3. Proteins are polymers of amino acidsa. Amino acids are compounds

with an amino group (NH₂) at one end and a carboxyl group (COOH) at the other.

b. There are 20 different amino acidesc. Amino acids are joined together by peptides bonds to form a dipeptide or a polypeptide molecule

4. Enzymes are proteins that are formed during the process of protein synthesis

a. Enzymes are biological catalysts that control the rate of chemical reactions.

b. Each type of enzyme catalyzes only one type of reaction.

c. Names of enzymes usually end in –ase and are named for the reaction they catalyze.

Example: lactase → lactose protease → protein

D. Nucleic Acids1. Made up of C, H, O, N, and P2. Uses:

a. Store and transmit genetic informationb. Make proteins

3. Made up of nucleotidesa. 5 – Carbon sugarb. Phosphate groupc. Nitrogenous base

4. Example: DNA and RNA