General Chemistry Review for the biological sciences
Why Chemistry??????? Hey…this is Biology! Why do we need to know about chemistry?? All living things are made up of Atoms Molecules Chemicals We need to know how chemicals interact to be able to understand biology!
Chemical Elements Each element consists of unique atoms Represented by symbols—H, Na, Au, etc. A total of 118 named elements (what are they?) 1-92 are naturally-occurring 93+ are synthetic
Chemical Elements 92 naturally occurring elements About 25 are considered essential to life 4 make up > 95% of living matter Carbon Hydrogen Oxygen Nitrogen
Chemical Elements Other significant elements Ca—nerve impulse transmission, muscle action, blood clotting and cell permeability P—in DNA & RNA, building bones & teeth, energy transfer & storage K—fluid & electrolyte balance, normalizes heartbeat S—a key component in most proteins
Chemical Elements Other significant elements Na—flow of water in cells, blood, nerves Cl—electrolytes, nerves, digestion Mg—breakage of glucose and fat molecules, production of enzymes, proteins and regulation of cholesterol
Chemical Elements Trace elements Fe—blood & oxygen transfer, protein metabolism, and energy production I—thyroid hormones, growth/development Cu—maintaining the strength of the skin, blood vessels, epithelial and connective tissue Zn—absorption of Ca, growth, immune system Co—function of red blood cells and nervous system
Atoms The smallest particle of an element that has the qualities of that element Made up of smaller sub-atomic particles Cannot be broken down into simpler substances by ordinary means
Sub-atomic particles Neutrons nucleus Electrons Protons + + neutral (no) charge symbol n0 mass = 1+ amu + + nucleus Electrons negative charge symbol e- located in electron cloud Mass = 1/1840th amu Protons positive charge symbol p+ mass = 1 amu
The atom (He) The attractions between the positive charges in the nucleus and the negative charges of the electrons keep the electrons in the vicinity of the nucleus.
molecules Atoms of two or more different types chemically combined Chemically different than the atoms that make them up Molecules combine to form compounds
a water molecule H2O Hydrogen: a colorless, odorless gas; explosive! water: a colorless, odorless liquid (at ordinary temps); necessary for life H2O Hydrogen: a colorless, odorless gas; explosive! oxygen: a colorless, odorless gas; supports combustion
So…how are atoms held together in a molecule? CHEMICAL BONDS! Ionic: the giving and taking of electrons Covalent: the sharing of electrons Hydrogen: the attraction of + and -
Ionic Bonds Exchange of electrons Forms charged particles called ions One atom takes electrons & the other donates them Forms charged particles called ions ex—sodium chloride
Covalent Bonds Sharing of electrons Between nonmetals Cl + Cl CH4 Non-polar Polar
Covalent Bonds non-polar polar Equal sharing of electrons between two or more atoms Carbon, Hydrogen CH4 C2H6 Unequal sharing of electrons between atoms Forms polar molecules Water, sugar, alcohol
Hydrogen bonds The attraction between the +charged portion of one polar molecule and the –charged portion of another molecule Found in water, proteins, DNA
Carbon and Macromolecules Moving on to the chemistry of living things… Carbon and Macromolecules
Carbon is the backbone Carbon has 4 valence electrons =Versatility Chains (straight or branched) Rings Single, double and triple bonds Isomers
Functional Groups Certain groups of atoms that may be attached to a carbon skeleton and give organic compounds distinctive features. Attachments that replace one or more of the hydrogens bonded to the carbon skeleton
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Biomolecules or Macromolecules Polymers produced by living things Polymers are Large molecules made up of smaller, repeating units called monomers
Monomer + monomer + monomer + ….. creates the polymer Condensation reaction/dehydration synthesis/ polymerization
Reverse reaction is hydrolysis
Polymer Carbohydrates Lipids Proteins Nucleic acids monomers examples Starches, cellulose, Pasta, potatoes, etc. Fats, oils, waxes Meat, muscle tissue, enzymes, hair, etc. DNA & RNA Simple sugars Glycerol & fatty acids Amino acids nucleotides Carbohydrates Lipids Proteins Nucleic acids
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