Download II. Lipids

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NAME____________________________
PER ______
CHAPTER 2 - THE CHEMISTRY OF LIFE
2.1 - THE NATURE OF MATTER
Atom – the basic unit of matter, made up of protons, neutrons, & electrons
Subatomic Particles:
Subatomic Particle
Charge
Location
Relative Size
Proton
(+)
Nucleus
Same as neutron
Neutron
No charge
Nucleus
Same as proton
Electron
(-)
Space surrounding
nucleus
1/1840th of proton
Element – a pure substance consisting entirely of one type of atom
Isotopes – atoms of same element with different number of neutrons (same numbers of protons &
electrons)
EX/ Carbon 14 (C-14) has ___6___ protons and ____8____ neutrons, while C-12 (the normal
carbon) has __6____ protons and ____6____ neutrons.



Benefits of radioactive isotopes:
Help determine ages of rocks and fossils
Detection and treatment of cancers
Kill bacteria that spoil food
Compound – substance formed by chemical combination of two or more elements in definite proportions
Chemical properties of a compound are unique because: the physical and chemical properties of
the compound are usually very different from those of the elements from which they are formed.
Chemical Bonds
Unite compounds and always involves ___electrons___________ surrounding the nucleus
Types of Bonds:
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1) Ionic – one or more electrons are transferred from one atom to another- after being transferred, the
atoms become ions – charges will attract the two atoms together.
Ions – atoms that have gained electrons(becoming negative ions) or lost electrons (becoming
positive ions). EX/ Formation of NaCl:
2) Covalent – electrons are shared between two atoms (sharing of two electrons = single bond; four
electrons = double bond)
Molecule – structure resulting when atoms are
joined together by covalent bonds
3) Van der Waals Forces – slight attraction that develops
between oppositely charged regions of nearby
molecules
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2.2 - PROPERTIES OF WATER
• Oxygen has a much __stronger___ attraction for electrons than
hydrogen, and the result is that the oxygen side of the water
molecule has a slight __negative__ charge, while the hydrogen side
has a slight ___positive_______ charge.
• This uneven distribution of charge creates a _POLAR__ molecule.
4) Hydrogen Bond – the attraction between the slightly negatively
charged oxygen of one water molecule to slightly negatively charged
hydrogen of another water molecule
Water can form ___multiple__ hydrogen bonds
which lead to many unique properties of water:
a) _COHESION _ - Attraction of water to water (any molecules of same substance). beading of water on
surfaces & surface tension EX/ Water striders walking on water.
b) _ADHESION____ - Attraction of water to other substances (molecules of different substances). EX/
Capillary action in a graduated cylinder or moving water up a plant.
c) __HEAT CAPACTITY____ - The amount of energy needed to heat water is relatively high, which allows
large bodies of water like oceans to absorb large amounts of heat with only small changes in temperature.
Benefit: organisms in these bodies of water are not subjected to drastic temperature changes
& water in cells able to absorb heat produced by chemical reactions, maintaining stable
cellular temperature.
d) Water is the Universal Solvent: Water’s __POLARITY____ gives it ability to dissolve both ionic
compounds & other polar molecules.
Mixture – material composed of two or more elements or compounds that are physically mixed together
but not chemically combined. EX/ Cinnamon & sugar
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Solutions & suspensions are two types of mixtures that can be made with water
Solution – a mixture where all the components are evenly
distributed
EX/ Saltwater
Solute – the substance that gets dissolved in a solution
EX/Salt in saltwater
Solvent – the substance that dissolves the solute
EX/Water in saltwater
Suspension – mixture of water and nondissolved material
EX/ Blood
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NAME____________________________
PER ______
Acids, Bases & pH
About 1 H2O in 550 million splits to form two ions: Hydroxide (OH-) and Hydrogen (H+):
pH scale: indicates concentration of _hydrogen ions (H+) _
in solution - ranges from 0-14.
At a pH of _____7______ (ex/pure water) the
concentration of H+ ions equals concentration of OH- ions.
Notice - each step on the pH scale represents a factor of 10.
Grapefruit is _100 (102)_ times more acidic than black
coffee.
Soapy water is _10,000 (104)_ times more alkaline (basic)
than sea water.
Acid – any compound that forms hydrogen ions (H+) in
solution, have pH values below 7
Base – any compound that produces hydroxide ions (OH-)
in solution, have pH values above 7
Buffers - weak acids or bases that can react with strong acids or bases to prevent sharp, sudden
changes in pH
Ex/ Bicarbonate and phosphate ions are naturally occurring chemical buffers that help to maintain stable
pH (homeostasis) of cells.
2.3 - CARBON COMPOUNDS
What does it mean to be ORGANIC?
Organic compounds are ___CARBON______ based molecules
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Carbon atoms are the most versatile building blocks of molecules.
 TETRAVALENCE – carbon can form _4__bonds with other atoms:
Single bond : one pair of electrons is shared
Double bond : two pairs of electrons are shared
Triple bond : three pairs of electrons are shared
 Variation in CARBON SKELETON contributes to DIVERSITY of
organic molecules (see diagrams)
 Variation leads to ISOMERS – compounds with the same
__molecular formulas____ but different __structural
formulas________; will behave differently in chemical
reactions
Molecular Formula:
C6H12 O6
C6H12 O6
Both Glucose and Fructose have same molecular formulas, but HOW those atoms are arranged are
different.
Making and Breaking of Carbon Compounds
1. Macromolecule -
large biological molecule
(4 Types : __CARBOHYDRATES__, __LIPIDS___, _NUCLEIC ACIDS__, _PROTEINS____)
2. Polymer – chain of smaller molecules linked together
3. Monomer – unit that serves as a building block of larger molecules
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NAME____________________________
PER ______
4. To Build Polymers - reaction called: ____DEHYDRATION SYNTHESIS_________
Monomer + Monomer 
EX/ glucose +
glucose 
Polymer + Water
maltose +
water
5. To Break Polymers reaction called: __HYDROLYSIS__(Hydro = __WATER__Lysis = _BREAK___)
Polymer + Water 
EX/
Monomer + Monomer
sucrose + water  glucose + fructose
Types of Large Carbon Compounds (Macromolecules)
I Carbohydrates: ____CARBON____ + ___WATER__ Are our ___primary____ source of energy.
Monomer : ___monosaccharide___
Generalized Formula : ______C(H2O)n_________
Contain C, H, O ALWAYS with ratio of 2 Hydrogen:1 Oxygen
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A. Types
monosaccharides EX/ glucose (blood sugar), fructose, (fruit sugar), galactose (milk)
_disaccharides EX/ sucrose (glucose + fructose), maltose (glucose +glucose), lactose (glucose +galactose)
_polysaccharides EX/ 1. Glycogen : E storage in animals; polymer of glucose; stored in liver
2. Starch : E storage in plants; polymer of glucose; stored in roots
Most abundant organic 3. Cellulose :structural carbohydrate in plants; found in cell walls
compound on earth!
4. Chitin : exoskeletons of arthropods
II. Lipids
Monomer : Fatty Acids Are our __secondary __ source of energy.
Are insoluble in _water _____ because they are _non-polar __.
___Twice ___ the amount of energy in lipids than in same mass of __carbohydrates___, because
stored in concentrated amounts.
__9__ cal/g for lipids VS __4___ cal/g for carbs
Used as food reserves by animals for __migration______ and _____hibernation____
Types
A. Fats and Oils – formed by __3 fatty acids____ and _____one glycerol (an alcohol)______
___SATURATED ___ fats are solid at room temperature (butter, lard)
because there are no double bonds between any of the carbons in the fatty
acid chains, therefore have the maximum
amount of ___hydrogen atoms____ attached
to the chain
____UNSATURATED_____ fats are liquid at
room temperature (oils) because there are
some double bonds between some of the
carbons in the fatty acid chains, DO NOT have
the maximum number of __hydrogen atoms___ attached to the chain.
B. Phospholipids – One fatty acid is replaced by a __phosphate___ group. Are the primary
building blocks of ____cell membranes_____.
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C. Steroids – different structure than other lipids but are grouped with them b/c they are
_____________insoluble in water_________________
EX/ 1. sex hormones: testosterone, estrogen, progesterone_
2. __cholesterol_____ : the most abundant steroid in the body (most
comes from your liver, not your diet)
III. Nucleic Acids – the genetic material of cells (Contain C, H, O, N, P)
Monomer: __nucleotide_____Which is made of three parts
1) _sugar_(deoxyribose - DNA; ribose - RNA)
2) _phosphate group____
3) _nitrogenous base_(5 possible – A,T,C,G,U)
Types: __DNA__ and ___RNA____
IV. Proteins

Monomer: ____amino acids_____ Contain __C, H, O, N, S____

50% of your __dry weight___; Perform many important functions in living things

Generalized structure of an amino acid:

_20_ naturally occurring amino acids, named by the R group that they contain.

__dipeptide__= two amino acids joined

_polypeptide_= long strings of amino acids
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
_protein_ = functional unit made up of one or more polypeptides.

Amino acids are joined by a ___peptide__ bond, when the
__carboxyl__carbon of one amino acid bonds to the __amino__ nitrogen of
another amino acid. Water is
removed (a dehydration synthesis
reaction)
Water
removed
A. Levels of Protein Structure
1) Primary structure – sequence of __amino acids___
in its polypeptide chain.
2) Secondary structure – the _localized_ folding
patterns of regions of the polypeptide chain
3) Tertiary structure – the _3-dimensional_ folding
pattern of the whole polypeptide chain. (Determined
by interactions of R groups in different parts of the
chain that are relatively far apart from each other)
4) Quaternary structure – overall protein structure
created when _2__ or more polypeptide chains
interact. This will determine the ___function____ of
the protein b.c.
PROTEIN _shape__ = PROTEIN
_function_
When the 3D shape of a protein has been changed it is said to
be _DENATURED_(WON’T FUNCTION PROPERLY).
B. Types & Examples:
Structural: ___collagen & keratin_____: found in hair & nails; give physical support
Contractile: ____actin & myosin______: found in muscle cells; are able to shorten
Transport: __hemoglobin_: carries oxygen in blood; __myoglobin__: carries oxygen in muscles
Storage: __ferritin__: stores iron (Fe)
Note – some hormones are proteins & some are lipids (sex
hormones)
Hormones (not all are proteins): _insulin__: regulates glucose levels in blood stream
Enzymes: _amylase, catalase, maltase__:biological catalysts, increase rates of reactions
“ase” = enzyme = protein
Wolfe H Bio
NAME____________________________
PER ______
2.4 - CHEMICAL REACTIONS AND ENZYMES
Enzymes are proteins that __speed up (catalyze) reactions_____

Reactants are called ___SUBSTRATES_______

Mostly named for the substrate they work on with suffix “ase”
Ex/SUCRASE breaks down sucrose (a disaccharide) into glucose + fructose

__ACTIVE SITE_ on enzyme is where the Enzyme and Substrate(s) join temporarily

“Induced Fit” model – active site changes shape slightly when S binds to E

Enzyme not changed by the reaction, can be reused over and over.

Enzymatic cycle:
Active site empty
Substrate
(sucrose)
Active site
Substrate binds to
enzyme
Enzyme (sucrase)
substrate
enzyme
G
Products
F
Bond
intact
H2O
Products released
Substrate
converted to
products
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Enzymes work by lowering the energy needed to activate a reaction:
EA = __ACTIVATION ENERGY___; E needed to get reaction moving from reactants  products
Reaction path
without
enzyme
EA without enzyme
Reaction path
with enzyme
Energy
EA with enzyme
Change in energy of
reactants to products
Progress of reaction

Factors that affect enzyme activity
Concentration of substrate: _Increase__ concentration of substrate _ Increases rate of
reaction, which therefore _ Increases _ amount of products
Inhibitors: Interfere w/ability of enzyme to bind to substrate; _decreases rate of reaction,
therefore _decreases amount of products
Temperature: _ Increase _ in temp _ Increases rate of reaction
to a point; above this point the heat __denatures___ the enzyme.
pH: Most enzymes have specific ranges w/in they function best.