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