View
222
Download
3
Category
Tags:
Preview:
Citation preview
Chapter 2
Chemistry of Life
A water molecule is polar b/c there is an uneven distribution of electrons between oxygen and hydrogen atoms
POLARITY: Oxygen end - slightly negative Hydrogen end - slightly positive
The Amazing Properties of Water
Polar Molecule One region more negative and other
more positive Water molecule is bent oxygen is at
one end and hydrogen is at other
+
+
-
Hydrogen Bonds
Water molecules attract each other b/c of their charges
This bond is called a hydrogen bond.
Not very strong, but responsible for unique properties of water.
One water molecule can have up to 4 hydrogen bonds at the same time
Cohesion
An attraction between molecules of the same substanceWater is very cohesive because it sticks to itself
Why? – The pull of hydrogen bonds causes the water molecules to be drawn inward.
AdhesionThe attraction between molecules of different substances.Water is very adhesive because it sticks to other substances
Example:Meniscus in a graduated cylinder. The adhesion between water molecules glass
molecules.
Solutions
Components are evenly mixed throughout the solution.The solution looks uniform throughout. Example: table salt and water
2 parts: solute and solvent
Cl-
Water
Cl-
Na+
Water
Na+
Figure 2-9 NaCI Solution
Figure 2-9 NaCI Solution
Cl-
Water
Cl-
Na+
Water
Na+
Solute vs. Solvent
Solute is dissolved by the solvent.Solute-substance that is dissolvedSolvent-substance that does the actual dissolvingWhat is the universal solvent???
Suspensions
Materials do not dissolve but they are so small they do not settle; they remain suspended.Mixtures of water and non-dissolved material
Example: cloudy river water
What is Blood?
Solution and a suspension
Solution - dissolved sugars, sodium, potassium, Oxygen, Carbon Dioxide
Suspension - white blood cells, red blood cells
Acids, Bases, and pH
Acids
Any compound that produces H+ (hydrogen ions) in solutionpH < 7 (less than 7)Also called acidic
Bases
Any compound that produces OH- (hydroxide ions) in solution
pH > 7 (greater than 7)
Also called alkaline
pH Scale
Measures the H+ concentration0 – 147 is a neutral solution = pure water
Oven cleaner
Bleach
Ammonia solution
Soap
Sea water
Human bloodPure water
MilkNormalrainfall
Acid rainTomatojuice
Lemon juice
Stomach acid
NeutralIn
crea
sing
ly B
asic
Incr
easi
ngly
Aci
dic
pH Scale
Buffers
pH in most human cells must be between 6.5 and 7.5If higher or lower affects chemical reactions in human cellsTherefore, controlling pH is very important for maintaining internal balance (homeostasis). This is done through buffers.Buffers: Weak acids and bases that react with strong acids and bases to prevent sharp changes in pH. Example: Tums (stomach antacid)
2-3
Organic (Carbon) Compounds
Organic Chemistry
Study of compounds with bonds between carbon atomsCarbon – 4 outer electrons can form 4 strong covalent bonds (sharing electrons)
Macromolecules/Polymers
Giant moleculesFormed by bonding smaller moleculesMonomers- smaller units Join to form Polymers process
called polymerization
Organic Compounds
1. Carbohydrates = sugars2. Lipids3. Nucleic Acids4. Proteins
Carbohydrates
C, H, ORatio of 1:2:1 – C6H12O6
Main source energyStructural purposes3 groups…
Monosaccharides – simple sugars
Used for quick energyMonomers
Examples:
Glucose – blood sugar
Fructose – fruit sugar
Galactose – milk sugar
Disaccharides – 2 sugars
Quick energy
Examples:
Sucrose – sugar cane
Lactose – milk sugar
Maltose – important for fermentation
Polysaccharides – many sugars (complex)
Long chains of simple sugars PolymersStored energy – released slowly
Examples:Starch – stored in plants
ex. Grains, pastas
Glycogen – stored in animal muscle
Cellulose – used for structural purposes (cell walls)
Starch
Glucose
Figure 2-13 A Starch
Lipids - FatsConsist mainly of C and Hfat, oil, wax
**Saturatedheart diseaseUses
Structural Purposes – cell membranes/water proof coveringsEnergy StorageChemical Messengers – component of steroids
Nucleic Acids – DNA/RNA
Consist of H, C, O, N and PStore and transmit genetic (hereditary) informationMade of nucleotides (monomers)
Proteins
Made of amino acids (monomers)Consist of C, H, N, and O
Used for:Control and regulate chemical reactions (enzymes)Structural purposes (muscle and bone)Transportation in and out of cells Fighting Disease
General structure Alanine Serine
Figure 2-16 Amino Acids
Amino group Carboxyl group
Aminoacids
Figure 2-17 A Protein
• Proteins can have up to 4 levels of organization1. Sequence of amino acids in chain2. Amino acids within chain twist/fold3. Chain itself is folded4. If more than one chain, each chain has specific
arrangement
http://www.dnatube.com/video/235/How-bunch-of-aminoacids-organise-to-form-functional-protein
EXAMPLE
WHICH ARE CHAINSOF
NUCLEOTIDES
ORGANICCOMPOUNDS
MADE OF 1 SUGAR
MADE OF 2SUGARS
MADE OFMANY SUGARS
WHICH ARE CHAINS OF
SOME ARE BIOLOGICALCATALYSTS CALLED
WHICH ARE ALSO KNOWN AS
CAN BE
FOUND INBUTTER
FOUND INOILS
EXAMPLE
EXAMPLE
EXAMPLE EXAMPLE
WHICH HAS THECHEMICAL FORMULA
C6H12O6
WHICH IS A MAJORCOMPONENT OF
MILK
FOUND IN FOUND IN
PLANTS
WHICH LOWERACTIVATION ENERGYFOR CHEMICAL REACTIONS
Buy SmartDraw!- purchased copies print this document without a watermark .
Visit www.smartdraw.com or call 1-800-768-3729.
2-4
Chemical Reactions and Enzymes
Chemical Reactions
Process that changes one set of chemicals into another set of chemicals (slow=rust, fast=H gas ignited with O)Reactants- elements/compounds that enter into reaction (left side)Products- elements/compounds produced by reaction (right side)
CO2 + H2O H2CO3
Which are the reactants???
Which are the products???
Energy in Chemical Reactions
Exothermic- reaction that releases energy Usually spontaneous Energy released in form of heat/light/sound Reactants have more energy than products Ex. Thunder & Lightning
Endothermic- reaction that absorbs energy Products have more energy than reactants Ex. Digesting food
All of this energy is required for life processes
Activation Energy- amount of energy needed to start reaction
Energy-Absorbing Reaction Energy-Releasing Reaction
Products
Products
Activation energy
Activation energy
Reactants
Reactants
Figure 2-19 Chemical Reactions
Energy-Absorbing Reaction Energy-Releasing Reaction
Products
Products
Activation energy
Activation energy
Reactants
Reactants
Figure 2-19 Chemical Reactions
Enzymes
Proteins that act as biological catalystsCatalyst- substance that speeds up rate of chemical reaction by lowering activation energyCells use enzymes to speed up reactions that take place inside cells
Reaction pathwaywithout enzyme Activation energy
without enzyme
Activationenergywith enzymeReaction pathway
with enzyme
Reactants
Products
Effect of Enzymes
Reactants are called SUBSTRATES if enzymes are involved in the chemical reaction
Enzymes provide a site where SUBSTRATES (reactants) can be brought together activation siteThis site reduces amount of energy needed for reaction lowers activation energy
Glucose
Substrates
ATP
Substratesbind toenzyme
Substratesare convertedinto products
Enzyme-substratecomplex
Enzyme(hexokinase)
ADPProducts
Glucose-6-phosphate
Productsare released
Figure 2-21 Enzyme Action
Active site
Glucose
Substrates!
ATP
Substratesbind toenzyme
Substratesare convertedinto products
Enzyme-substratecomplex
Enzyme(hexokinase)
ADPProducts
Glucose-6-phosphate
Productsare released
Figure 2-21 Enzyme Action
Active site
Glucose
Substrates!
ATP
Substratesbind toenzyme
Substratesare convertedinto products
Enzyme-substratecomplex
Enzyme(hexokinase)
ADPProducts
Glucose-6-phosphate
Productsare released
Figure 2-21 Enzyme Action
Active site
Glucose
Substrates!
ATP
Substratesbind toenzyme
Substratesare convertedinto products
Enzyme-substratecomplex
Enzyme(hexokinase)
ADPProducts!Glucose-6-phosphate
Productsare released
Figure 2-21 Enzyme Action
Active site
Suffixes to note…
- OSE = SUGAR - ASE = ENZYME
Example: Lactase breaks down Lactose
enzyme activity animation!
Recommended