Chemistry & lifeBiology, 21-25 January 2011

Donald Winslow

Readings: Sylvia S. Mader 2011 Inquiry into Life, 13th ed., McGraw-Hill, NY.

Ch. 1 pp 1-9; Ch. 2 pp 20-35, 37-41

Objectives for basic chemistry• Define “atom” & “element” & give examples.

• Define “subatomic particle” & give examples.

• Describe different types of chemical bonds.

• Describe & give examples of acids & bases.

• Describe & give examples of important buffers.

Objective for biochemistry

• Define organic molecules & explain the importance of carbon.

• Describe the structure & function of carbohydrates, lipids, proteins, and nucleic acids.

• Give examples of carbohydrates, lipids, proteins, and nucleic acids.

• Describe dehydration synthesis & hydrolysis.

Matter & energy

• Matter– Composed of particles, has mass

• Energy– The ability to do work, involves forces that

affect position & movement of particles.– Kinetic energy, potential energy, heat, light,

electromagnetic radiation.

Subatomic particles• Atomic nucleus composed of protons &

neutrons; electrons orbit nucleus.• Protons

– Positive (+) charge, ~1 atomic mass unit

• Electrons– Electric (-) charge, ~0 atomic mass units– Potential energy of electron increases with increasing

distance from nucleus.

• Neutrons– No charge, ~1 atomic mass unit

Elements & atoms

• Atomic symbols– C, H, N, O, P, S, etc.

• Atomic numbers– Number of protons in nucleus

• Periodic table of the elements

• Isotopes– 12C & 14C, radiation

Atoms can be combined to form molecules.

Chemical reactions result in exchange of atoms between molecules, synthesis of large

molecules from small molecules, or division of large molecules into

small molecules.

Elements & compounds

• An element contains only one kind of atom.– Examples: Au, O2

• A compound contains multiple kinds of atoms.– Examples: H2O, CO2

Chemical bonds

• Ionic bonds– Relation to salts

• Covalent bonds

• Polar covalent bonds– Hydrogen bonds

Properties of water

• High heat capacity, high heat of vaporization

• Solvent

• Cohesion & adhesion

• Ice is less dense than water

• Hydrogen ion concentration is measured by pH

Acids, bases, & buffers

• An acidic solution has a high H+ concentration & therefore a low pH.– vinegar, citric acid, ascorbic acid, HCl, H2SO4

• A basic (alkaline) solution has a low H+ concentration & therefore a high pH.– sodium bicarbonate (NaHCO3), antacid, NaOH

• A buffer solution contains a compound that maintains the pH within a narrow range by binding excess H+ and OH- ions.– Examples: carbonic acid (H2CO3), NaHCO3

Organic molecules

• Lipids

• Carbohydrates

• Amino acids & proteins

• Nucleic acids

Lipids

• Variable structure– Lots of H & C; not much O or N– Not water soluble

• Functions in energy storage, membranes, chemical messengers, etc.

• Fatty acids, phospholipids, steroids, cholesterol, waxes, oils

Carbohydrates

• Polysaccharides are polymers of monosaccharides (monomeric sugars).

• Function in energy storage & transfer, structural features such as plant cell walls

• Examples: glucose, fructose, sucrose (table sugar), lactose, starch, glycogen

Proteins

• Proteins are polypeptides, often modified to form complex shapes.– A polypeptide is a polymer of amino acids,

connected by peptide bonds.

• Function as enzymes (catalyzing chemical reactions), structural proteins, hormones, antibodies, etc.

• Examples: amylase, keratin, insulin

Nucleic acids

• Nucleic acids are polymers of nucleotides.

• Function in heredity; direct cellular metabolism, development, etc.

• Examples: deoxyribonucleic acid (DNA), ribonucleic acid (RNA)

Molecular shape is important to biological function

Hydrolysis & dehydration synthesis

• Hydrolysis– Splits polymer into smaller molecules, using a

water molecule.

• Dehydration synthesis– Builds polymer from two smaller molecules,

releasing water.

Properties of living things

• Growth, development, reproduction

• Need energy & materials for metabolism

• Composed of cells

• Organized

• Communication of information

• Adaptation

• Genes direct development, etc.

Biological hierarchy

• Cell

• Tissue

• Organ

• Organ system

• Organism

• Population

• Community

Nine-banded armadillo

Ecological hierarchy

• Organism

• Population

• Community

• Ecosystem

• Landscape

• Biome

• Biosphere Agricultural corridor within forested landscape in southern Indiana.

Taxonomic hierarchy

• Domain– Kingdom

• Phylum– Class

» Order» Family» Genus» Species