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Chemistry of Life
Chapter 2.1
C6H12O6 + 6O2 CO2 + H2O
What elements are represented?
What compounds are represented?
How many atoms of each element are represented?
Is it balanced?Which scientific law do balanced chemical equations enforce?
Atoms – The basic unit of matter. Composed of:Protons – positively charged particles in the nucleus of the atom
Neutrons – particles with mass that have no charge; found in the nucleus of the atom
Electrons – negatively charged particles moving around the nucleus in orbits.
Atoms with equal numbers of protons and electrons are “neutral”
Atoms with uneven numbers of electrons and protons = ion
Atoms with more protons than electrons = cation (positive charge)
Atoms with more electrons than protons = anion (negative charge)
Elements – What is an Element?
One or more atoms Cannot be broken down or split
Represented by a one or two letter symbol
ex. Na (sodium)
C (carbon)
Atomic number = number of protons of an element.
Atomic weight = number of protons plus number of neutrons. Ex: Carbon has 6 protons and 6 neutrons; atomic weight is 12
Look at Carbon – CWhat is its atomic mass?
Can we tell how many electrons it has?
How? (hint – look at its atomic number)
Isotope – Atoms of the same element that have different numbers of neutrons. Ex: Carbon can have 6, 7, or 8 neutrons
Radioactive isotope – isotopes with unstable nuclei. Give off radiation
Valence electronsThose electrons that orbit the outer energy level of an atom.
1st energy 2 electrons
2nd energy level 8 electrons
Filled make the element more stable
Unfilled energy levels make the element more reactive with other elements.
Compound – substance formed by the chemical combination of 2 or more elements. Ex: H2O, NaCl, HCl.
Compound usually has different properties than the elements it is composed of
Ex: H2O is a liquid composed of gaseous hydrogen and gaseous oxygen.
Chemical bonds – forces that hold elements of a compound together.
Forces are created by the interaction of each of the element’s valence electrons
Ionic Bond – formed when one or more electrons are transferred from one atom to another.
Ex: Sodium (Na) donates one electron to Chlorine (Cl) to form an ionic bond and make sodium chloride (NaCl – table salt)
Covalent Bond – formed when one or more electrons are shared between elements. This type of bond between elements creates a molecule. Ex: H2O
OH H
Properties of Water
A common molecule with unique characteristics:
Polar – due to the way the hydrogen atoms are arranged around the oxygen atom, water molecules have a (+) end and a (-) end = polar.
OH H
This electrical orientation causes water to be attracted to other charged elements and form hydration spheres around them. This keeps the elements from combining with other charged elements.
Ex: salt placed in water dissolves. In other words, the sodium separates from chlorine & water molecules keep them apart. Water helps keep things dissolved = universal solvent
Has a high heat capacity and heat of vaporization – water absorbs, transports, and releases a great deal of heat without changing its state (ice to water to vapor).
That’s why, on a hot day, you just perspire and not evaporate. The water in your body stays liquid (and not turn into a vapor) while it is carrying the heat to the surface of your skin.
Cohesive - sticks to itself; ex: beading water
Adhesive - sticks to other things
Highly reactive – virtually no chemical reactions occur in living systems without the presence of water
It’s the major component of body lubricants (mucus), protective cushions (amniotic fluid and cerebrospinal fluid), and transport mediums (blood)
SaltsIn living systems, salts are
compounds that dissolve in water and become electrolytes. Electrolytes conduct electricity in the body. Ex: Na, Ca, K, Cl are the major electrolytes. Gatorade has a concentration of these in it.
ACIDSCompounds that give off
hydrogen ions (H+)in solution. Acids read below 7 on the pH scale. The more H+ given off, the lower the number on the pH scale.
BasesCompounds that give
off hydroxide ions (OH-) in solution. Bases read above 7 on the pH scale. The more OH- given off, the higher the pH.
BiochemistryThe Macromolecules of
Life
Chapter 2.3
Organic ChemistryThe study of all compounds that
have bonds between carbon
atoms.
Importance of Carbon
Carbon has 4 valence electrons
It tends to form covalent bonds with other carbon atoms
In doing so, In doing so, carbon can carbon can form a variety form a variety of shapes…of shapes…
…chains…
…rings…
…branches…
…or combinations of chains, rings, and branches.
Macromolecules
Carbon is able to form large and complex molecules called “macromolecules”
Macromolecules are
made by “polymerization”
in which small compounds
(“monomers”) are put
together to make larger
compounds (called
“polymers”)
There are 4 types of organic macro-molecules (organic polymers):
CarbohydratesLipidsProteinsNucleic Acids
Carbohydrates “sugars”
Made of C, H, O in a 1:2:1 ratio; Ex: C6H12O6
Monomer is monosaccharide
ExamplesGlucose-quick energyStarch-plant storageGlycogen- animal storageCellulose-structure in
plantsChitin-exoskeleton
crayfish
Used as the main source of fuel and/or structural purposes
Found in breads, Found in breads, cereals, pasta, potatoes, cereals, pasta, potatoes, corncorn
Lipids: “fats”Made of mostly of C and H
Monomer is glycerol attached to fatty acids
OR
Used to store energy, make cell membranes, waterproof coverings, chemical messengers
Examples: saturated fats, unsaturated fats, polyunsaturated fats, oils, waxes, cholesterol, steroids
Contained in dairy Contained in dairy products, meats, some products, meats, some vegetablesvegetables
Nucleic AcidsMade of C, H, O, N, PMonomers are nucleotides
Used to store and transmit genetic information
Examples include DNA and RNA
Found in anything that contains cells
ProteinsContains C, H, O, N, S, P
Monomers are amino acids
Used to regulate chemical reactions and cell processes, form body structures, transport materials, or fight disease
Examples include enzymes, antibodies, muscle tissue
Contained in meats, legumes, dairy products
Enzymes – special types of proteins
Enzymes are proteins capable of increasing the rate of a reaction without being consumed in the process
Types of reactions enzymes are involved in include:DigestionSynthesis of moleculesStorage and release of energy
Enzymes have the ability to carry out reactions at lower temperatures that would normally require extremely high temperatures
Activation Energy – the energy required to attach enzymes to substrates and cause a change
Substrate – the molecule undergoing a change; also called the reactant.
Activation site – place on the enzyme where a specific substrate attaches
Reactant – in a chemical equation, it is on the left side; what is added together to form products
Product – the end result of the enzyme-substrate reaction; found on the right side of a chemical equation
Optimum – the best conditions for a reaction to occur. In your body, optimum conditions are a pH of 7 and a temperature of 37oC
Denature – to permanently change the shape of an enzyme due to pH or temperature extremes; can prevent the enzyme from functioning properly.
Coenzyme – needs to be present in some enzymes to aid in the reaction. If it is missing the enzyme may not work; vitamins act as coenzymes.
Inhibitors – things that prevent enzymes from working properlyCompetitive inhibitors – compete with the substrate for binding sites on the enzyme; slows down the reaction; ex: ethanol and isopropanol
Noncompetitive inhibitors – irreversible binding to enzymes; stop the reaction permanently Ex: some heavy metals.
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