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Chapter 2: The Chemistry of Life
2.1 Nature of Matter:
____: smallest part/basic unit of matter
3 sub-atomic particles:
____________________________
_________: pure substance …all the
same type of atoms
(about 26 elements compose all living
things..most abundant are: _________ )
_____________ : # of __________
_______________________
_______________ (ie..mass of nucleus)
What are the element symbols for…
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Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Phosphorus
Sodium
Chlorine
Potassium
Calcium
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Manganese
Flourine
Helium
Magnesium
Aluminum
Iodine
Lead
Silver
Lithium
Mercury
2.1 Nature of Matter continued
____________: elements with different neutron # than a stable atom
ex: 14C, 3H, 32P, 34S
_______________: have unstable nuclei – break down at a known rate,
give off radioactive particles (gamma rays, etc)
* Dangerous AND useful, too
* ex: fossil dating, bone scans, GI series, chemotherapy
__________: substance formed by 2 or more elements in a fixed ratio
• Physical and chemical properties of compound are different
than atoms composing the compound
• _________: smallest unit of most compounds
Sodium
Chlorine
Sodium
Chloride
BONDING PATTERNS:
1. ______________: attractions between ions of opposite charge
– when atoms gain or lose electrons, ions are created
+
Na
–
Cl
2. _____________: join atoms into molecules through electron sharing
• when two atoms share one or more pairs of outer shell electrons
CH4 = ?
Polar Covalent/Non-polar Covalent/ H Bonds
_______________: When covalently
bonded atoms share electrons ________
Ex: CO2
___________: Electrons are shared
__________ between atoms, creating a
_______ molecule
Ex: H20
___________: weak bonds important in
the chemistry of life
– charged regions on water
molecules are attracted to the
oppositely charged regions on
nearby molecules
– Ex: water to water (cohesion)
Why Water Supports All Life:
1. ________ (w+w) and _________ (w+other)
– allows water to move from rootsleaves
– some insects can walk on water due to
cohesive surface tension
– universal solvent – can dissolve more
solutes than any other solvent
2. Moderates temperature (___________):
– takes a lot of energy to disrupt hydrogen
bonds water can absorb lots of heat
without a large rise in temp
– As water cools a slight drop in temp
releases a large amount of heat
– water molecules take energy with it when
it evaporates evaporative cooling
Mixtures: Solutions and Suspensions:
__________: composed of 2 or more elements or
compounds physically mixed, not chemically combined
(ex: salt and sugar together)
2 types of Mixtures:
a) __________: where components are evenly
distributed (ex: salt water)
* water = solvent NaCl = solute
* polarity of water allows it to dissolve ionic
compounds and polar molecules (ex: salts, sugars,
minerals, gases, other solvents like alcohol)
b) __________: when materials don’t dissolve in
water, but break up into tiny pieces which do not
settle out (they are suspended by the moving water)
* ex: blood (water has dissolved compounds, blood
cells and other components (lipids) which remain
suspended in mixture)
The chemistry of life is sensitive to acidic and basic conditions
________: a compound that forms ___
ions in solution
________: a compound that produces ___
(hydroxide) ions in solution
______ or ______ (____) is measured on
the pH scale:
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From 0 (most acidic) to 14 (most basic)
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The pH of most cells is kept close to 7
(neutral) by buffers (substances that
resist pH change)
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Each step on pH scale is a factor of __.
(ex: pH 5 is 10x more acidic than?)
_______: weak acid or weak base which
can keep a pH stable
ex: _______: most important buffer
in body- maintains homeostasis in blood
When the number of H+ is equal to
the number of OH- water
H+ + OH- H20
2.3 Organic Chemistry: The Chemistry of Carbon
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“_______”: must contain at least one carbon. CH4 = simplest organic molecule
Carbon has _ valence electrons
Therefore, carbon will ______ make 4 bonds with other atoms
Carbon can bond with other carbons, form chains, rings
Ability to form millions of different compounds with other elements
The Four Macromolecules of Life
__________ (polymer) made by joining many monomers (single unit)
__________: chemical rxn which joins monomers to make polymers
The four main classes of biological
molecules:
1. ___________ (sugar, starches, cellulose)
2. ___________ (wax, fats, oils, steroids)
3. _______ (muscle, hair, hormones, enzymes)
4. ___________ (DNA and RNA)
1. CARBOHYDRATES: Monomer = Monosaccharide
•Contain C, H, and O in a 1:2:1 ratio
•Most end with “ose”
•An animal’s main energy source
•______ are burned first in the body
•________________: (C6H12O6):
glucose, fructose, galactose
•________________:
sucrose, lactose, maltose
•_______________: (complex carbohydrates)
– A) glycogen (carb storage animal liver)
– B) starch (carb storage in plants)
– C) cellulose (cell walls, cotton) “roughage”
– D) chitin (exoskeletons of arthropods)
2. LIPIDS: Monomer = Fatty Acids
* Mostly _______ atoms linked by
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nonpolar covalent bonds
_________ - storage molecules
(burned after carbs are gone)
________in water (polar)
Soluble in nonpolar solvents (ether)
More energy in lipids than in carbs
- 9 cal/g Lipid vs. 4 cal/g Carb
Examples: triglycerides, phospholipids,
steroids (cholesterol), waxes, oils, fats
____________= 3 fatty acids + 1 glycerol
____________: all single bonds in chain
- solid at room temp (ex: butter, lard)
____________: one or more C=C bond in chain
- liquid at room temp (ex: all oils)
3. NUCLEIC ACIDS: Monomer = Nucleotide
• Nucleic acids (___________) store and transmit genetic information
• DNA = ______________
• RNA = ______________
• Large macromolecules containing _____________
• One nucleotide = 5-carbon sugar, phosphate (PO4-), nitrogenous base
The sugars and phosphates are the
backbone for the nucleic acid
DNA’s sugar = deoxyribose
RNA’s sugar = ribose
4. PROTEINS: Monomer = Amino Acid
• Essential to the structures and
activities of life
• Contain ________________
• 50% of your dry weight
• examples of groups of proteins:
1. enzymes (amylase, sucrase, maltase,
lactase) –______________
2. structural (collagen, elastin)
3. contractile (actin, myosin)
4. transport (hemoglobin, protein
channels)
5. hormones (insulin)
AMINO ACID: Structure
Each amino acid has:
•An ________________
•A _________________
•An __ group, which
distinguishes each of the __
different amino acids
* Each amino acid has
specific properties
based on the R-group
* ________ link
amino acids together
polypeptide
(protein)
PROTEINS: 4 Levels of Organization
Amino acids are assembled into polypeptide chains according to
instructions coded in the DNA.
_____________: the sequence of
amino acids in its polypeptide chain
___________________:
the coiling
or folding of the chain
_____________: the overall
three-dimensional shape of a
polypeptide – created when Rgroups bond
_____________: the
association of two or more
polypeptide chains
2.4 Chemical Reactions and Enzymes
•__________: process that changes or transforms one set of
chemicals into another
•Those chemicals that enter into a reaction are the “________”,
those that are made are the “_________”
•Chemical reactions change the bonding patterns in the reactants
•Energy is released or absorbed when chemical bonds are formed
or broken during a reaction
•Rxns releasing energy generally happen spontaneously
•Rxns which absorb energy need energy to start them
•Some energy releasing rxns need activation (input of )energy
to get started
Enzymes are vital proteins that run biochemical rxns
• Lower the ________________ of
chemical reactions (they are ______)
• The reactants they “work” on are
called “______________”
• Most enzymes are named for their
substrates with an “-ase” ending
Ex: sucrase digests sucrose
lactase digests lactose
• VERY shape specific (“lock and key”)
reaction with active site on enzyme
(where substrate and enzyme join)
One Enzyme : One Substrate
•Enzymes have unique three-dimensional shapes
so they can fit onto their specific substrate
•Shapes determine function and which chemical
reactions they can perform
•All related to their 3-D folding pattern born
from?
Factors Which Affect Enzyme Activity:
• ___________________________________
• Enzyme inhibitors can alter enzyme function:
– _____________ inhibitor: blocks active site, substrate can’t attach and
remains unchanged
– _____________ inhibitor: alters enzyme’s function by changing its shape
– Many poisons, pesticides, and drugs are enzyme inhibitors
Some food for thought:
1.Why do we put lemon juice on apples?
2.What is the purpose of a fever?
3.What happens when a raw egg hits a hot fry pan?
4.Why do we put produce/perishables in the fridge?
5.How does a Siamese cat get it’s color pattern?
GENES = Sequences of DNA
– DNA sequences spell out the amino acid sequences
of proteins
– _______ in the ___sequence wrong ________
sequence wrong ________ shape no function
– Ex: Lactose Intolerance :
Mutations in lactase gene
mutations in lactase amino acid chain sequence defective lactase shape
enzyme can’t fit onto lactose substrate lactose does not get digested.
Q:
Why is it a big deal?
A:
If YOU don’t digest the lactose in your
digestive tract, all the E.coli will…all of
their waste made from eating all this
food will leave you with cramps, bloating,
and diarrhea…not fun!
Lactase enzyme