Ch 2: The Chemistry of Life
I. The Nature of Matter
A. _________________ : the basic unit of matter made up of protons, neutrons and electrons.
1. p + (________________) & n 0 (____________________) are approximately the same mass a) bond together to form nucleus
2. e- has ____________________ the mass of a p + a) orbits the nucleus b) attracted to the nucleus but remains outside due to the energy of motion
B. Elements and Isotopes
1. Elements : _________________________________________________ a) over 100 identified but only about _____________________ are common in living organisms b) represented by a 1 or 2 letter symbol c) number of p + = ________________________ d) typically the number of p + =number of e = number of n 0
1) unless an ________________ or an ion
2. Isotopes : atoms of an element with different numbers of n 0 a) sum of p + and n 0 = ________________ b) Isotopes are identified by their mass number c) all isotopes of an element have the same ________________________ because they have the same number of e -
3. Radioactive Isotopes : isotopes whose nuclei are unstable and break down at a constant rate a) _____________________can be dangerous but often has scientific and practical uses
1) used to ________________, _________________, __________________, and trace movements of substances
C. Chemical Compounds : substance formed from the chemical combination of 2 or more elements in definite proportions
1. Composition shown in the chemical formula
2. Physical and chemical properties are usually very different from the elements in it
D. _________________________ : holds atoms together in compounds using valance e -
1. _____________ bonds : forms when e are transferred a) atom that loses becomes a ____________________, atom that gains becomes a ________________ b) the oppositely charged ions have a strong attraction
2. _______________ bonds : electrons are shared between atoms a) can share up to 6 e b) ________________ : the structure that results from covalent bonds; smallest unit of most compounds
3. Van der Waal's Forces; a force of attraction that results from charged regions of covalently bonded molecules a) not as strong as ionic or covalent b) a gecko’s foot has a large surface area to increase Van der Waal's forces
II. Properties of Water
A. Water Molecule: charge of H
2
O is __________________ (10 p + = 10 e )
1. Polarity a) 8 p + in O has a stronger pull on shared e than the 1 p + in H b) results in O having a slight negative charge & H having a slight positive charge
2. ___________________ bonds a) results from attraction between polar molecules
1) not as strong as covalent or ionic bonds, but are the strongest bonds that can form between molecules
2) a water molecule may have up to 4 bonds at one time b) ___________________ : attraction between molecules of the same substance
1) causes water molecules to be drawn inward

2) explain why water “beads” and the ability of insects to walk on water c) ___________________ : attraction between molecules of different substances
1) allows water to hold onto the sides of a glass container i) causes the meniscus in a graduated cylinder because adhesion is greater than cohesion ii) causes ________________ (upward movement of water in a narrow tube against the force of gravity)
B. Solutions Suspensions
1.
________________ : material composed of 2 or more elements or compounds that are physically mixed together but not chemically combined
2.
________________ : type of mixture where all of the components are evenly distributed a) ________________ : substances dissolved b) ________________ : substance in which solute is dissolved c) polarity of water enables it to dissolve ionic compounds and other polar molecules (“greatest solvent on Earth”)
1) water molecules will surround and separate the ionic compounds into + & - ions
3. ________________ : mixture of water and no dissolved material that is suspended by the movement of water molecules a) blood is a suspension
C. Acids, Bases, & pH
1. Water molecules can form ions (H + & OH ) a) because number of H + and OH are equal, water is neutral
2. ________________ : indicates concentration of H + ions in solution a) ranges from 0 to 14 with 7 being neutral
1) each step up is a factor of 10 b) solutions below 7 are acidic because they have more H + than OH c) solutions above 7 are basic because they have fewer H + than OH -
3. ________________ : any compound that forms H + ions in solution a) strong acids range from 1 to 3
4. ________________ : any compound that produces OH ions in solution a) strong bases range from 11 to 14
5. ________________ : weak acid or base that reacts with strong acids or bases to prevent sudden changes in pH a) cells in the human body generally require a pH of 6.5 to 7.5, any variation affects the internal chemical reactions
III Carbon Compounds
A. Chemistry of Carbon
1. C has 4 valance e-, allowing it to covalently bond with many elements
2. a C atom can bond to other C atoms to form chains or rings with single, double or triple covalent bonds
B. ________________ : molecules made from thousands or hundreds of thousands of smaller molecules
1. Formed by polymerization (monomers join to form polymers)
C. ________________ : compounds made up of C, H and O atoms usually in a 1:2:1 ratio
1. Used for energy source and structural purpose a) _____________________ : simple sugar molecules (e.g.: glucose, fructose) b) _____________________ : macromolecules formed from monosaccharides (e.g.: starch, glycogen, cellulose)
D. ________________ : can be used to store energy, membranes and waterproof coverings
1. Made mostly from C & H atoms and generally are insoluble
2. Examples include fats, oils, waxes and steroids a) ________________ : a fatty acid that contains the maximum number of H atoms b) ________________ : a fatty acid that has at least 1 C-C double bond c) ________________ : a fatty acid that has more than 1 C-C double bond
E. ________________ : macromolecules containing H, O, N, C and P
1. Polymers assembled from nucleotide monomers a) Nucleotides consist of 3 parts: a 5 C sugar, phosphate group and a nitrogenous base

2. Stores and transmits genetic information a) RNA: ribonucleic acid (with the sugar ribose) b) DNA: deoxyribonucleic acid (with the sugar deoxyribose)
F. ________________ : macromolecules that contain N, C, H & O; are polymers of amino acids
1. Amino acids have an amino group (NH
2
-) on one end and a carboxyl group (-COOH) on the other end
2. More than 20 different amino acids are found in nature a) all may be covalently joined by bonding an amino group to a carboxyl group b) differences are in a side chain called an R-group
3. Controls the rates of reactions and regulates cell processes, forms bone & muscle, transport substances, & fights disease
4. Has 4 levels of organization: sequence, chains, folded chains, multiple chains a) Van der Waal’s forces and H bonds maintain shape
IV. Chemical Reactions and Enzymes
A. _______________________ : a process that changes one set of chemicals into another through changes in chemical bonds
1. ________________ : elements or compounds that enter a chemical reaction
2. ________________ : elements are compounds that result from a chemical reaction
B. Energy in Reactions
1. Energy changes a) exothermic reactions (releases energy) often occurs spontaneously b) endothermic reactions (absorbs energy) will not occur without a source of energy
1) organisms must have an energy source
2. _______________________ : energy needed to start a reaction a) prevents spontaneous reactions of exothermic reactions
C. ________________ : proteins that act as a catalyst to increase reaction speed in cells
1. ________________ : substance that increases rate of a chemical reaction
2. Lowers the activation energy
3. Enzymes are specific for 1 reaction
D. Enzyme Action
1. Enzyme-Substrate Complex a) enzymes provide a site where reactants are brought together to and decreases the energy needed for reaction
1) reactants of enzyme-catalyzed reactions are known as ________________
2) enzyme and substrate are bound together during reactions and at the end, the enzyme is freed to repeat the process
2. Regulation of Enzyme Activity a) can be affected by _____________________ that influences a _____________________
1) e.g.: _________ and ______________________
2) enzymes can be regulated by ________________ that turn them “on” or “off”

Chemistry of Life
Analysis Questions
Nature of Matter
1. Compare and contrast C-12 and C-14.
2. Why would the physical and chemical properties of a compound be different from the elements/molecules that formed it?
3. What similarities exist between ionic and covalent bonds?
4. Why is a large surface area be helpful for Van der Waal’s forces?
5. Why couldn’t humans walk up walls using a similar technique to a gecko’s?
Properties of Water
6. Why are water molecules polar?
7. Defend the following statement: “The most important characteristic of water is its polarity.”
8. Since blood contains dissolved compounds, why is it considered a suspension rather than a solution?
9. Why doesn’t normal water have a pH of 7?
Carbon Compounds
10. Justify the following statement: “Carbon is the most versatile element.”
11. What is the main use of carbohydrates?
12. Differentiate between saturated and unsaturated lipids.
13. Which part of the nucleotide contains the genetic information? How did you deduce this?
14. Compare proteins and carbohydrates.
15. Why is it important that amino acids have the ability to bond together?
Chemical Reactions and Enzymes
16. How and why do chemical reactions affect chemical bonds?
17. Which type of naturally occurring chemical reaction do you think is more dangerous - endothermic or exothermic? Justify your answer.
18. Describe the relationship between enzymes and activation energy.
19. Explain why enzymes are important to living organisms.
20. Describe how enzymes function.