Transcript File
Biochemistry
Intro to Macro molecules
Molecular Biology
The study of the structure and functioning of biological molecules
Closely linked with biochemistry
Structures of molecules closely linked with function of the molecule
Metabolism
The sum of all the biochemical reactions that happen in the body
The breaking down of molecules in order to obtain ATP that will then be
used to build other molecules needed for life
What were the first molecules?
Chemical evolution occurred billions of years ago
Thousands of carbon based molecules emerged from the more
simple molecules that existed on early Earth
Raw ingredients on earth that were used to create life:
Carbon dioxide (CO2)
Hydrogen gas (H2)
Water (H2O)
Nitrogen gas (N2)
Ammonia (NH3)
Hydrogen sulfide (sulphide) (H2S)
Energy source (electrical discharge lightning)
All these led to the first Amino acids…what is the structure of AA?
AA led to first proteins=LIFE
4 most abundant elements in living
organisms
Hydrogen
Carbon
Oxygen
Nitrogen
They account for 99% of all atoms found in living things
Carbon however, is the most important…why do you think
so?
Carbon
The element of LIFE!
Found in all living organisms!
We are always looking for carbon based life forms
Organic molecules: molecules that contain carbon
C6H12O6, CO2, CH4
Some molecules are made of just CARBON and HYDROGEN…we
call these HYDROCARBONS
These are important in FUEL (aka GASOLINE!!)
Many organic molecules, such as fats, have hydrocarbon components
Hydrocarbons can undergo reactions that release a large amount of energy
Inorganic molecules: molecules that do not contain carbon
H2O, NH3, O2
LE 4-4
Hydrogen
(valence = 1)
Oxygen
(valence = 2)
Nitrogen
(valence = 3)
Carbon
(valence = 4)
Structure of Carbon
Structure
Valence electrons: 4
How many bonds can carbon make with other atoms?
4: single, double, or triple…as long as it has 4 lines touching it
This makes carbon a versatile atom…it can make long chains of
carbons, branched carbon structures, even ring structures with
itself
Drawing and numbering carbon structures
Start with the carbon that is in a carboxyl functional group…that is #1
and then follow sequentially
In ring structures, the C for carbon may be omitted…it is understood that
where ever there are vertices, there is a carbon atom
H’s for hydrogen are also left off for simplicity
LE 4-5
Ethane
Propane
Butane
2-methylpropane
(commonly called isobutane)
Length
Branching
1-Butene
Double bonds
Cyclohexane
Rings
2-Butene
Benzene
Some important words to know
Molecule
Group of covalently bonded atoms
Macromolecule
large molecules composed of thousands of covalently connected atoms
Functional Groups
Group of atoms within a molecule that interact in PREDICTABLE ways
Polar, non-polar, acidic, basic, charged (+/-)
Hydroxyl group
Carbonyl group
Carboxyl group
Amino group
Sulfhydryl group
Phosphate group
LE 4-10aa
STRUCTURE
(may be written HO—)
Ethanol, the alcohol present in
alcoholic beverages
NAME OF COMPOUNDS
Alcohols (their specific names
usually end in -ol)
FUNCTIONAL PROPERTIES
Is polar as a result of the
electronegative oxygen atom
drawing electrons toward itself.
Attracts water molecules, helping
dissolve organic compounds such
as sugars (see Figure 5.3).
LE 4-10ac
STRUCTURE
EXAMPLE
Acetic acid, which gives vinegar
its sour taste
NAME OF COMPOUNDS
Carboxylic acids, or organic acids
FUNCTIONAL PROPERTIES
Has acidic properties because it is
a source of hydrogen ions.
The covalent bond between
oxygen and hydrogen is so polar
that hydrogen ions (H+) tend to
dissociate reversibly; for example,
Acetic acid
Acetate ion
In cells, found in the ionic form,
which is called a carboxylate group.
LE 4-10ba
STRUCTURE
EXAMPLE
Glycine
Because it also has a carboxyl
group, glycine is both an amine and
a carboxylic acid; compounds with
both groups are called amino acids.
NAME OF COMPOUNDS
Amine
FUNCTIONAL PROPERTIES
Acts as a base; can pick up a
proton from the surrounding
solution:
(nonionized) (ionized)
Ionized, with a charge of 1+,
under cellular conditions
LE 4-10bc
STRUCTURE
EXAMPLE
Glycerol phosphate
NAME OF COMPOUNDS
Organic phosphates
FUNCTIONAL PROPERTIES
Makes the molecule of which it
is a part an anion (negatively
charged ion).
Can transfer energy between
organic molecules.
What are macromolecules made of?
• A polymer is a long molecule consisting of many similar building blocks
called monomers
Poly=many
Mono=one
Think of a beaded bracelet….
Large variety of polymers but there are less than 50 like the alphabet…lots of
words, only 26 letters
• Polymerization: THE PROCESS OF MAKING A LARGER MOLECULE BY
PUTTING TOGETHER SMALLER MOLECULES
•
•
•
•
• Three of the four classes of life’s organic molecules are polymers:
Carbohydrates
Proteins
Nucleic acids
***Lipids/fats are not polymers but they are still macromolecules
Brief Overview of 4 Macromolecules
Carbohydrates
Monomer: monosaccharaides and disaccharides
Polymer: polysaccharides aka complex carbohydrates (Starches, cellulose)
Proteins
Monomer: Amino acids
Polymer: Polypeptide Chain (PROTEINS)
Nucleic Acids
Monomer: Nucleotide
Polymer: Nucleic Acids (DNA and RNA)
Lipids, fats, oils and steroids
Monomer: NONE
Polymer: NONE
Making and Breaking Polymers
Polymerization: making polymers
Dehydration/condensation Reaction
Dehydrate means water loss
When a water molecule (H-OH) is released to join a monomer to another monomer
Hydrolysis
Hydro- water
Lysis- to break down
Def: to break apart or disassemble a polymer by adding water (H-OH)
LE 5-2
Short polymer
Unlinked monomer
Dehydration removes a water
molecule, forming a new bond
Longer polymer
Dehydration reaction in the synthesis of a polymer
Hydrolysis adds a water
molecule, breaking a bond
Hydrolysis of a polymer
Polymerization (polymerisation)
Process of putting together many monomers to make a larger
polymer
Examples of common polymers:
Natural:
Rubber
cellulose
Industrially produced:
Polyester
Polythene
Polyvinyl chloride (PVC)
Nylon
All of the above are carbon based subunits containing thousands of
carbon atoms joined end to end
Carbohydrates
Divided into 3 main groups:
Monomer: Monosaccharide or Disaccharide
Polymer: Polysaccharide
Link between monomers is called: Glycosidic Linkage
Formed by a dehydration/condensation reaction
Always have Carbon, Hydrogen, and Oxygen
Cx(H2O)y
Common name: sugar
End with suffix “-ose”
Function: Energy/fuel, structure, storage
GLUCOSE!!!!
What all cells need for energy
Monosaccharides
Sugars
Dissolve easily in water to form sweet solutions
Large carbs (starches and cellulose) do not dissolve
Think about your towels and clothes, duh!
General formula: (CH2O)n
Consist of single sugar molecule (hence mono)
Classified according to # of carbon atoms in each molecule
Trioses (3C)
Pentoses (5C)
Ribose & deoxyribose
Hexoses (6C)
Glucose, fructose, galactose
Ex: Glucose, Fructose, Galactose
2 major Functions:
1. Energy source in respiration (b/c of large # of C-H bonds that can be broken to
release ATP)
2. Important building blocks for larger molecules
Molecular and structural formulas
Molecular formulas show the # of each atom in a molecule
but not how they are arranged
Molecular Formula for hexoses: C6H12O6
Both glucose and fructose have the same molecular
formula… C6H12O6
Structural formulas are used to show the arrangements of
the atoms
Ring structures
Pentoses and hexoses are a chain of carbon atoms that are long
enough to close up on each other and form rings (occurs
in AQUEOUS environment)
This ring structure is more stable than a chain, therefore atoms in
these molecules stay inn rings not chains
Glucose: carbon #1 joins the oxygen attached to carbon
#5…carbon #6 is not part of the ring
C6H12O6
Glucose
Hydroxyl groups on carbon #1 can either
be above the plane or below the plane
Different spatial arrangement of atoms in the
same molecule are called ISOMERS
These isomers of glucose are important in
the formation of polysaccharides: starch,
cellulose and glycogen
Hydroxyl group on C-2 is always below
the plane, and the following carbon atoms
alternate
Alpha Glucose
hydroxyl group is BELOW the ring plane
Beta Glucose
Hydroxyl group is ABOVE the ring plane
Alpha vs
Beta
glucose
Dissaccharides
formed by glycosidic linkage
join together two hydroxyl groups by a process called
CONDENSATION (dehydration)
literally lose a water molecule
HYDROLYSIS is the opposite of condensation rxn…it
causes the breaking of a glycosidic linkage…occurs during
the digestion of disaccharides and polysaccharides
Both reactions controlled by enzymes
Common disaccharides: Maltose and Sucrose
Lactose, Maltose and Sucrose
Functions of Monosaccharides &
Disaccharides
Good sources of energy for living things
1.
Used in respiration ATP
Due to solubility, this is the form carbohydrates are
transported through an organisms body
2.
Animals glucose is dissolved in blood plasma for transport
Plants sucrose is transported in phloem sap
Reducing vs.Non-reducing Sugars
Reducing sugars
Non-reducing sugars
All monosaccharides
Disaccharide SUCROSE
(glucose)
Some disaccharides
(maltose)
Carry our reduction
reaction (donates
electrons) and thus become
oxidised
Do NOT carry our
reduction reactions
Reducing Sugar Test
Benedicts Solution/Reagent
Blue colored solution
Copper (II) sulfate in an alkaline solution
In the presence of reducing sugars, copper (II) sulfate (contains
copper II ions…Cu2+ ) becomes reduced to insoluble redbrown copper-oxide (contains copper I…Cu1+ )
it loses 1+ charge because it has gained an electron from the reducing
sugar
Red-brown copper oxide is visible as a brick red precipitate
Reducing sugar + Cu2+ oxidized sugar + Cu1+
BLUE
RED/BROWN
Reducing Sugar Test Continued
Reducing sugar + Cu2+ oxidized sugar + Cu1+
BLUE
RED/BROWN
Intensity of red color is related to concentration of reducing sugar
Benedicts solution is added to solution being tested
Mixture is heated in warm water bath
In presence of reducing sugar, gradual color change occurs…
Green yellow orange red/brown
Must use EXCESS of benedicts solution to ensure relationship between color
intensity on concentration of reducing sugar
2 ways to measure concentrations:
Compare to set of colour standards previously made with known reducing sugar concentrations
Use a colorimeter to measure concentrations more precisely
Test for non-reducing sugar (sucrose)
Benedicts test would yield NEGATIVE result (no color change, solution
remains blue)
Testing a non-reducing sugar
First break disaccharide a into monosaccharides using ACID HYDROLYSIS
(use hydrochloric acid and a warm water bath)
Benedicts requires ALKALINE environment, so after heating sugar/HCL
mixture, add sodium hydroxide in excess to NEUTRALIZE
THEN, add Benedicts reagent to neutralized solution and heat
Results:
Blue to brick red precipitate = non-reducing sugar present
No color change for either test = no sugars present at all
Mixture of reducing and non-reducing sugars will yield a heavier
precipitate in the non-reducing sugar test than in the reducing sugar test
previously described
Reducing Sugar Test
Safety
Equipment
How to read syringe
Range of Solutions
of different
concentrations
0% water
20%solution
50% solution
100% solution
Practice Question Set 2 (6 questions)