The Chemistry of Life Chapter 2

I. Nature of Matter A. Atoms- basic unit of an element Made of 3 subatomic particles: 1. Protons- positive charge, in the nucleus 2. Neutrons- no charge, in the nucleus 3. Electrons- negative charge, circling the nucleus

B. Elements and Isotopes 1. Element-one kind of an atom Periodic table-chart showing all the known and unknown elements 3. Mass number = # protons + # of neutrons 4. Atomic Number = # protons *in a neutral atom the # of protons, neutrons, and electrons is the same no CHARGE

5. Isotope- atoms of same element, but have different # of neutrons Examples: Carbon 12, Carbon 13, Carbon 14 Radioactive isotopes-have unstable nuclei that break down ate steady rate over time Uses? See page 35

C. Chemical Compound- 2 or more atoms in a set proportion 1. Represented by a chemical formula Examples: H2O, CO2, NaCl, O2 *Note: the properties of a compound are very different from the elements they are formed from 2. C6H12O6 means there are 6 Carbon, 12 Hydrogen, and 6 Oxygen atoms

D. Chemical Bond- involves the exchange or sharing of valence electrons between atoms 2 main types of bonds 1. Ionic bond- an atom looses or gains an electron, resulting in a positive or negative charge (see pg. 37) 2. Covalent Bond- electrons are shared between 2 atoms

There are 2 types of covalent bonds a. Single bond shares 2 electrons b. Double bonds share 4 electrons 3. van der Waals forces- slight attraction between opposite charged regions of a molecule *not as strong as an ionic or covalent bond

Properties of Water What do you know about water?

A.The Water Molecule Composed of 2 hydrogen atoms and 1 oxygen atom Polar- an unequal distribution of electrons https://www.google.com/search?um=1&biw=1024&bih=644&hl=en&tbm=isch&sa= 1&ei=R4VBUsuVN4WY2gW954BI&q=water+molecules+and+polarity&oq=water+molecules+and+polarity&gs_l=img.3...157282.161832.0.162237.24.23.0 .1.1.0.122.2026.16j7.23.0....0...1c.1.27.img..8.16.1395.DaVljVYBXGA#biv=i%7C13%3Bd%7CrYNbNY0XOG1CzM%3A Hydrogen bond- weak bonds between valence electrons so the bonds can easily be broken *unique qualities of water: expands when it freezes, makes a good solvent, is adhesive & cohesive

b. cohesion- attraction of molecules of the same substance. example? c. adhesion- attraction of molecules of different substances d. heat capacity- the amount of energy it takes to raise the temperature *water has a high heat capacity. Why is is a good thing?

Which is which?

B. Solutions and Suspensions 1. mixture-material of 2 or more substances that are mixed but not chemically combined a. solution= solute + solvent, where components are evenly distributed, example? What is the best solvent? Why? b. suspension- water molecules and undis- solved materials, example?

C. Acids, Bases, and pH H2O can separate and become H+ and OH- ions pH scale- scale from 0 to 14 and measures the concentration ( []) of H+ ions 1. 0 most acidic, 7 is neutral, 14 is most basic 2. Acids have high [] of H+ ions and pH below 7; examples?

3. Bases have low [] of H+ ions and pH above 7; examples? 4. Buffers- weak acids or bases that react with strong acids or bases; prevent sudden changes in pH levels

Carbon Compounds A. The Chemistry of Carbon- has 4 valence electrons to bond with 1. Carbon bonds with Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, & Sulfur 2. Carbon bonds with other carbons, making it possible to make large chains- macromolecules

B. Macromolecules- large molecules a. monomers- simple molecules b. polymers- chains of monomers C. polymerization-formation of macromolecules & polymers 4 groups of macromolecules: carbohydrates, lipids, nucleic acids, and proteins

Carbohydrates 1C: 2H:1O a. Main source of E (energy) for living 1. Simple sugars= monosaccharides example: glucose, fructose, galactose 2. Complex sugars= polysaccharides example: starch, cellulose, glycogen

Lipids: Carbon & Hydrogen Also known as??? a. Main function- E storage & Structure 1. Saturated-full of H atoms, "bad" fats 2. Unsaturated- not full of H bonds, "good" fats HDL vs. LDL

3. Nucleic Acids made of: H, O, N, C, P a. Main function- store and transmit genetic information b. nucleotides-monomers that make up nucleic acids consist of a 5 Carbon sugar, Phosphate group and a Nitrogenous base

DNA vs. RNA DNA= deoxyribonucleic acid Made w/ sugar called deoxyribose RNA= ribonucleic acid Made with ribose sugar

*proteins are chains of amino acids Proteins: C, N, H, O Main functions-control rates of reactions,regulate cell processes, transports materials, forms muscles & bones Amino acids-make up proteins (pg. 49), have a n amino group and carboxyl group *proteins are chains of amino acids

Chemical Reactions & Enzymes A. chemical reaction- process that changes one set of chemicals to another 1. reactants-chemicals that enter the reaction 2. products-chemicals that result from a reaction

B. Energy (E) in reactions 1. different types of reactions either release or absorb energy a.types of reactions that release E: b. sources of E for reactions: 2. activation E- the amount of E it takes to start a reaction (pg. 51)

C. Enzymes -function in controlling chemical reactions, making things for cells, releasing E, & transferring information -are biological catalysts that speed up chemical reactions by lowering activation E 1. catalyst-speed up reactions

Enzyme-Substrate Complex a. substrate- the reactant or what is broken down, ends in - "ose" b. active site- on the enzyme, ends in. - "ase" c. products- the resulting product

2. Regulation of Enzymes a.Things that affect enzyme activity: temperature, digestion of food, other chemical reactions in the body, pH levels