chapter 2
DESCRIPTION
Chapter 2. Chemistry of Life. Chemistry Video. http://www.youtube.com/watch?v=m55kgyApYrY. Vocabulary List:. Atom Nucleus Electron Element Isotope Compound Ionic bond Ion Covalent bond Molecule. Q: If you take a stick of chalk and break it in half, are both halves still chalk?. YES. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 2
Chemistry of Life
Chemistry Video• http://www.youtube.com/watch?v=m55kgyApYrY
Vocabulary List:
• Atom• Nucleus• Electron• Element• Isotope• Compound• Ionic bond• Ion• Covalent bond• Molecule
Q: If you take a stick of chalk and break it in half, are both halves still chalk?
YES NO
atomos-unable to cut
ATOM
Protons Neutrons Electrons
+ charge neutral - charge
mass mass 1/1840 mass
nucleus nucleus space
Element = one type of atom
Isotope = atoms of the same element that contain different numbers of neutrons
(# of electrons and protons remain constant)
If the atomic mass is the sum of protons + neutrons atomic number = the # of protons
which number changes in an isotope?
**Marbles or colored blocks
Compound-
substance formed by the chemical combination of 2 or more elements in definite proportions
Atomic Bombs
• Nuclear Fission (splitting) of Uranium or Plutonium• Uranium (U) or Plutonium (Pu) = large & unstable
(radioactive)• Rapid decay rate --> Release energy needed to
hold atom together• Energy release = radiation
• Little Boy: 4 tons of fuel = 15 kilotons of TNT
Nuclear Fission Video: http://www.youtube.com/watch?v=N7C14UIKuv8
Atomic Bombs continued
• Steps:• 1. Explosion from TNT condenses all Pu atoms to “critical mass”• 2. Neutron escapes (energy release) from decaying nuclei and
hits another Pu atom• 3. Pu atom that was hit subsequently decays (more energy
release)• 4. All the Pu atoms start decaying within seconds
CHEMICAL COMPOUNDS
H (gas) + O (gas)
H2O (liquid)
Sodium + Chlorine
NaCl (table salt)
Molecule –the smallest unit of compounds whose atoms are joined by covalent bonds
Chemical bonding-involves the electrons surrounding the nucleus of each atom
Ionic Bond vs. Covalent Bond
Transferring vs. Sharing
To do: 2 circles with 8 chairs apiece
Q: How can this problem be resolved?Science question: What kind of bond is being modeled?
H20
Dehydration• Water = 50-60% of your body weight
• Higher if you have more muscle• Function:
• Transport of nutrients and oxygen via bloodstream• Transport white blood cells to fight infection via
lymphatics• Rid body of waste
• Normal level of H2O loss = 2.5L• 350mL through lungs• 100mL through sweating• 350mL through skin• 1000-2000mL through kidneys
Symptoms of Dehydration:
• Headache• Muscle Cramp, Patesthesia (tingling) • Visual Snow• Decreased Blood Pressure (hypotension)• Dizziness/ Fainting upon standing (orthostatic
hypotension)• Swelling of Tongue • Sunken eyes• Low urine output• Decreased Heart & Respiratory Rate• Tired• Dry skin• Decreased Metabolism
H2O
An oxygen atom has 8 protonsEach hydrogen atom has 1 proton
Polar molecules have an uneven distribution of electrons
10 protons = 10 shared electrons
But will one part of the compound have a greater pull on those electrons?
Yes/No…..why?
Slight Negative Charge
Slight Positive Charge
Water’s Polarity
• 2 polar ends attract each other
• A weak bond between the H of one atom and the O of another in water (or any electroneg…)
• H20 can hydrogen bond with 4 other H20 molecules
hydrogen bonding-the attraction between water molecules
Properties of WaterUniversal Solvent-due to its polarity
-Salts, sugars, acids, bases-Hydrophobic vs hydrophilic
Liquid WaterSolid Water (Ice)
http://expertvoices.nsdl.org/polar/2009/02/03/teaching-about-snowflakes-a-flurry-of-ideas-for-science-and-math-integration/
http://cc.oulu.fi/~nmrwww/comp_res4.html
Water Expands When It Freezes
Water becomes less dense due to hydrogen bonds forming between the water molecules, which line up molecules less efficiently (in terms of volume) when water is frozen.
Structure of Ice
COHESIVE and ADHESIVE
Cohesion-attraction to H20 molecules
Adhesion-attraction of H20 molecules to other surfaces
Cohesion Causes Surface Tension
Adhesion
Adhesion (Capillary Action)
http://discovermagazine.com/2003/mar/featscienceofhttp://www.sciencebuddies.org/science-fair-projects/project_ideas/PlantBio_p033.shtml
DRILL-need to have read
1) Draw a molecule of water, indicating its polarity.
2) Explain the truth of the statement: Water can be considered the
universal solvent due to its polarity
WE NEED A BREAK! Outside…
Dehydration synthesis- build up by removing water
Hydrolysis-break down by adding water
Mixture – composed of 2 or more elements/compounds that are mixed physically but not chemically combined
1) Solution – the components are evenly distributed with the solute dissolved in the solvent
ex: salt water
2) Suspension – mixture of water and nondissolved material
ex: blood is both a suspension (cells) and solution
Acids, Bases and pH
pH scale – a measure of the H+ concentration in solution
Lower ph = more H+
Higher ph = fewer H+
Acid-any compound that forms H+ in solution (HCl in the stomach = pH 2.5)
Base-any compound that produces OH- in solution (bleach = pH 12.5)
***Pure water is always neutralH2O H+ + OH- in equal amounts
LAB- are foods acidic or basic?
FOOD pH (A/B)
Organic Molecules-study of all compounds that contain bonds between CARBON atoms
methane
isooctane
**C-C bonds allow for long chains…Large and complex structures!**4 valence electrons…binds with many other elements
MACROmolecules- giant moleculespolymerizationpolymersmonomers-may be identical/repeating or different
RECALL………
Dehydration Synthesis vs Hydrolysis
Dehydration synthesis- build up by removing water
Hydrolysis-break down by adding water
• Monosaccharide
• Polysaccharide
• Amino acid• Polypeptide
• Nucleotides• Nucleic acid
• Triglyceride• Fat/Wax/
Steroids
Carbs Protein
Nucleic Acid
Lipid
4 ORGANIC MOLECULES
CARBOHYDRATES• Ends in –ose• General formula C1:H2:O1
• Carbohydrate – “carbon hydrate” when CO2 reacts with water to form glucose• major source of ENERGY for all living organisms • source of structural support (plants)
Monosaccharide ex. glucose, fructose and galactoseDisaccharide ex. Lactose, sucrosePolysaccharide ex. Gycogen, starch and cellulose
Simple vs. Complex Carbohydrates
Simple vs. Complex Carbohydrates
A. Starch1. stored energy for the plant2. starch in potatoes, refined wheat and white products
are quickly converted into glucose in the bodyB. Cellulose
1. major component of plant cell walls2. does NOT provide energy nor is it digested by our bodies3. called fiber in our diets & is critical for a healthy digestive system
C. Glycogen1. animal starch2. stored form of glucose in our bodies3. stored in liver to remove glucose from the blood
And your resident dietician says…………why?
LIPIDS
• Not a polymer- all lipids are grouped together because
hydrophobic-“scared of water”/ little or no affinitiy for water ex. You will see oil separate from vinegar in salad dressing
A. Fats1. Greasy, oily or waxy to the touch2. Can be solid or liquid at room temperature3. If excess calories are consumed, excess stored as fat4. Stores vitamins and other chemicals5. Form of insulation for the organism
B. Phospholipids-membranes in & around the cells
C. Waxes1. Keep oganism or parts or organisms waterproof & protected2. Ear was, wax on duck feather
D. Steroids1. Cholesterol
a. important component of cell membranesb. harmful if too much in the diet or bloodstream
2. Hormonesa. estrogen, progesterone and testosterone control reproductive functionb. Anabolic steroids – illegally used to build up muscles
- cause serious damage to hear, liver and kidneys
And your resident dietician says…………
EXTRA CREDIT:
Describe these terms in detail & provide examples:saturated fatunsaturated fat
Due: next class
PROTEINS• Amino acid – monomer• Made up different combinations of 20 amino acids
a. 12 nonessential amino acidsb. 8 essential amino acids
• Complete proteins-contain all 8 essential amino acidsex. Meat, eggs, dairy products, fish and tofu
• Vegetables have some but not alla. must be eaten in combination b. complementary foods (rice and beans) –
together provide a complete protein• Cells recombine aa to build the proteins necessary for function
Protein Function
Movement
Growth and
Repair
NOT for energy
Structure
Biochemical
Control
Defense
Protein = “first or primary”
-some are acidic/basic-polar/nonpolar
LAB: FOOD ANALYSIS
BOGGLEWhen the timer begins, try to construct as many words
as possible using the given letters. You may go in any direction, but not diagonally.
Think & write quickly!!!
NUCLEIC ACIDS• Nucleotide - monomer;
- phosphate group, 5 carbon sugar and nitrogenous base• Nucleotides covalently bind to form a nucleic acid• Nucleic acids store and transmit genetic information
4 Types of nucleotides (A-T/U-C-G) = endless # of different molecules2 Types of Nucleic Acids = DNA and RNA
What do baking soda, vinegar and water have to do with Biology?
Beaker 1
• 5 mL baking soda
• 120 mL water
Beaker 2
• 5 mL vinegar• 120 mL water
Beaker 3
• 5 mL baking soda
• 5 mL vinegar
Chemical reaction – a process that changes or transforms one set of chemicals into another
Reactant Products
Activation Energy – the necessary energy input to jumpstart a reaction
but…..the formation of carbonic acid is slow and the CO2 would build up too quickly in the bloodstream……
CO2 + H2O H2CO3 (carbonic acid)
DRILL
1) Define activation energy?
2) How is an enzyme a catalyst i.e. how does it relate to activation energy?
3) What are the substances that are transformed in a chemical reaction called?
HW: Read Section 2-4 in your textbook and answer questions 9, 10, 22-25, 27, 28 and 33 on pages 57-58 (end of chapter assessment)
Enzymes – catalysts or “biological wedges”
Energy of Reactions
Energy-Absorbing Reaction Energy-Releasing Reaction
Products
Products
Activation energy
Activation energy
Reactants
Reactants
Endothermic Exothermic
Activity Break
• Keys• Shapes• Puzzles
ENZYMES• Usually ends in –ase (with 1st derived from the reaction it catalyzes)
• Works as a 1 enzyme:1 reaction-VERY specific (shape?)
• Enzymes provide a site where reactants can be brought togetherSubstrates- reactants in an enyzme-catalyzed reactionActive site- site of substrate binding on the enzyme
-complementary in “lock & key” style
How Enzymes Work
1. Reactants, called substrates, bind to specific enzymes; the site where enzymes bind is called the active site
2. Once the substrate binds to the active site, it changes shape and forms the enzyme-substrate complex
3. The substrates react to form new products; the enzyme-substrate complex helps to break and form bonds
Enzymes:-Regulate chemical pathways-Make materials that cells need-Release energy
Example of Enzyme Reaction
http://blog.poolcenter.com/print.asp?articleid=6072
Enzyme Video
• http://www.youtube.com/watch?v=CZD5xsOKres&feature=related