Chemistry of LifeChemistry of Life

Chapter 2Chapter 2

I. Matter and SubstancesI. Matter and Substances

A.A. What makes up matter?What makes up matter?A.A. Atoms- smallest unit of matter that cannot Atoms- smallest unit of matter that cannot

be broken down by chemical meansbe broken down by chemical means

B.B. Structure of atoms- nucleus contains Structure of atoms- nucleus contains protons and neutrons, surrounded by protons and neutrons, surrounded by electron cloudselectron clouds

C.C. Nucleus is positive because of protons and Nucleus is positive because of protons and electrons are negative- most atoms are electrons are negative- most atoms are neutralneutral

B. An element is a substanceB. An element is a substance

made up of atoms that have the made up of atoms that have the same same number of protonsnumber of protons

1. Atoms of an element may have a 1. Atoms of an element may have a different number of neutrons- isotopesdifferent number of neutrons- isotopes

II. Why Do Atoms Form Bonds?II. Why Do Atoms Form Bonds?

A.A. Atoms have different levels of electrons Atoms have different levels of electrons and the outermost level is the valence and the outermost level is the valence levellevel

B.B. Atoms form bonds to fill the valence shellAtoms form bonds to fill the valence shell

C.C. A compound is a substance made of the A compound is a substance made of the bonded atoms of 2 or more elementsbonded atoms of 2 or more elements

Ionic BondIonic Bond Covalent BondCovalent Bond

D. Polarity occurs when one atom of a D. Polarity occurs when one atom of a covalent bond pulls harder on the shared covalent bond pulls harder on the shared electrons, leaving a slightly positive region electrons, leaving a slightly positive region and a slightly negative regionand a slightly negative region

1. The partially charged ends attract 1. The partially charged ends attract opposite charges!opposite charges!

a. Water can dissolve sugar and salta. Water can dissolve sugar and salt

E. Hydrogen atoms bonded to O, N, or F E. Hydrogen atoms bonded to O, N, or F have a + charge almost as great as a have a + charge almost as great as a proton and can attract other negatively proton and can attract other negatively charged atomscharged atoms

1. Strong bond1. Strong bond

2. Essential in holding DNA together 2. Essential in holding DNA together

Energy Energy F. The ability to do work F. The ability to do work

1.1. Comes in many formsComes in many formsa. Light, chemical, a. Light, chemical,

mechanicalmechanical

G. The transfer of energy G. The transfer of energy causes changes in causes changes in statestate

1. Solid, liquid, gas1. Solid, liquid, gas

H. Chemical reactions involve the absorption H. Chemical reactions involve the absorption or release of energyor release of energy

1. Energy your body needs is provided by 1. Energy your body needs is provided by the breakdown of food, which is the breakdown of food, which is accompanied by a release of energyaccompanied by a release of energy

a. Metabolism refers to chemical a. Metabolism refers to chemical reactions in an organismreactions in an organism

2. Activation energy is the amount of energy 2. Activation energy is the amount of energy needed to start a reactionneeded to start a reaction

a. Catalysts lower the amount of activation a. Catalysts lower the amount of activation energy needed and allow reactions to occur in energy needed and allow reactions to occur in conditions where they normally would notconditions where they normally would not

b. Enzymes are biological catalystsb. Enzymes are biological catalysts

3. Oxidation Reduction reactions occur together 3. Oxidation Reduction reactions occur together and are the result of the transfer of electrons and are the result of the transfer of electrons between atomsbetween atoms

III. What Makes Water Unique?III. What Makes Water Unique?

A. Water has unique properties because A. Water has unique properties because water molecules form hydrogen bonds water molecules form hydrogen bonds with each otherwith each other

1. Ice Floats- frozen water has air 1. Ice Floats- frozen water has air spaces, making it less dense. Ice floating spaces, making it less dense. Ice floating on rivers and lakes prevents the water on rivers and lakes prevents the water from totally freezing, so life can exist from totally freezing, so life can exist beneath beneath

2. Water absorbs and retains heat- large 2. Water absorbs and retains heat- large bodies of water help keep the earth’s bodies of water help keep the earth’s temperature from changing too quicklytemperature from changing too quickly

3. Water molecules stick to each other3. Water molecules stick to each other

Cohesion is attraction of particles of Cohesion is attraction of particles of same substancesame substance

4. Water molecules stick to other polar 4. Water molecules stick to other polar molecules. Adhesion is the attraction of molecules. Adhesion is the attraction of different substancesdifferent substances

a. Cohesion and Adhesion allow water to a. Cohesion and Adhesion allow water to move through the stems of plantsmove through the stems of plants

B. Solutions are mixtures in B. Solutions are mixtures in which ions or molecules are which ions or molecules are evenly distributed in another evenly distributed in another substancesubstance1. Substances are 1. Substances are transported in living things transported in living things by being dissolved in water by being dissolved in water and can move easily within and can move easily within and between cellsand between cells

C. Some water molecules break apart to C. Some water molecules break apart to form ions H+ and OH-form ions H+ and OH-1. In pure water there is an equal amount 1. In pure water there is an equal amount of these ionsof these ions2. Acids are compounds that form extra 2. Acids are compounds that form extra H+ ions when dissolved in water- stomach H+ ions when dissolved in water- stomach acidacid3. Bases form extra OH- ions when 3. Bases form extra OH- ions when dissolved in waterdissolved in water4. Acids and Bases mixed together will 4. Acids and Bases mixed together will neutralize each otherneutralize each other

D. pH is a measure of how acidic or basic D. pH is a measure of how acidic or basic something issomething is

E. pH of living things must be stable- buffers E. pH of living things must be stable- buffers maintain a stable pHmaintain a stable pH

IV. What Are Biomolecules?IV. What Are Biomolecules?

A. The parts of a cell are made up of large, A. The parts of a cell are made up of large, complex molecules called biomoleculescomplex molecules called biomolecules

1. The basic units contain carbon atoms1. The basic units contain carbon atoms

a. C has 4 valence electrons a. C has 4 valence electrons and and covalently bonds to up to 4 covalently bonds to up to 4 atomsatoms

b. Can form rings or chainsb. Can form rings or chains

B. Cells use carbohydrates for sources of B. Cells use carbohydrates for sources of energy, structural material, and cellular energy, structural material, and cellular identificationidentification

1. Made of sugars that contain carbon, 1. Made of sugars that contain carbon, hydrogen, and oxygenhydrogen, and oxygen

2. Glucose, found in animals, is a simple 2. Glucose, found in animals, is a simple sugar, a monosaccharidesugar, a monosaccharide

3. Starches are polysaccharides, they are 3. Starches are polysaccharides, they are complex sugarscomplex sugars

C. The main functions of lipids include C. The main functions of lipids include storing energy and controlling water storing energy and controlling water movement, include fats, steroids, and movement, include fats, steroids, and waxeswaxes

1. Chains of carbons bonded to hydrogen 1. Chains of carbons bonded to hydrogen atoms; structure repels wateratoms; structure repels water

2. Very efficient long term energy storage2. Very efficient long term energy storage

D. Proteins perform many functions: D. Proteins perform many functions: structure, enable movement, transport, structure, enable movement, transport, chemical reactionschemical reactions1. Chains of amino acids that twist and 1. Chains of amino acids that twist and fold into certain shapes that determines fold into certain shapes that determines functionfunction2. Amino Acids are the building blocks of 2. Amino Acids are the building blocks of proteins- link together with peptide bondsproteins- link together with peptide bonds

a. Made of an amino group, carboxyl a. Made of an amino group, carboxyl group, and a side group that group, and a side group that

determines function (20 amino acids)determines function (20 amino acids)

3. 3. http://campusapps.fullerton.edu/news/arts/http://campusapps.fullerton.edu/news/arts/2003/photos/protein-art.jpg2003/photos/protein-art.jpg

E. All cells contain nucleic acids, which are E. All cells contain nucleic acids, which are long chains of nucleotide unitslong chains of nucleotide units

1. Nucleotides have 3 parts: sugar, 1. Nucleotides have 3 parts: sugar, nitrogenous base, phosphate groupnitrogenous base, phosphate group

a. DNA has sugar deoxyribose, RNA a. DNA has sugar deoxyribose, RNA has sugar ribosehas sugar ribose

2. Nucleic Acids store and transmit 2. Nucleic Acids store and transmit hereditary informationhereditary information

3. Transports energy in form of ATP3. Transports energy in form of ATP

MacromoleculesMacromolecules

MonomerMonomer PolymerPolymer

Chemical ReactionChemical Reaction

Law of conservation of matterLaw of conservation of matter

2H2H22+ O+ O22 -> 2H -> 2H22OO