Download Biochemistry PPT - Effingham County Schools

Water, pH and Biological Molecules
What’s so special about water?
It is a great solvent.
It holds heat very well.
It is the most important
inorganic molecule.
It is a polar compound
Water as a Solvent
Dissolving table salt (sodium chloride)
Water Is Lighter as Solid than as a Liquid
This means that ice forms
an insulating blanket over
water.
Water Has High
Surface Tension
The attraction of one
water molecule for
another also accounts
for its ability to hold
huge amounts of heat.
Water is a Polar Compound
• Hydrogen ends holds slightly positive
charges
• Oxygen end holds a slightly negative charge
(+)
1H
p+
p+
(--)
1H
(+)
pH is a Big Deal
pH is a measure of
proton (hydrogen
ion or H+)
concentration.
Low pH (acid) =
lots of H+ ions
High pH (base) =
few H+ ions ; more
OH- ions
Acids and Bases
Acid = H+ Donors
Base = H+ Acceptors
ORGANIC COMPOUNDS
Organic compounds are carbon compounds,
made by living things
Making Molecules
Because carbon contains
4 electrons in its outer
shell, it can share
electrons with many
different atoms in an
“attempt” to fill its outer
shell.
Carbon is the Central Atom of Life.
glucose
amino acids
fat
Some
Useful
Nomenclature
In Biology, Shape Matters
Its not just chemical formula, it’s the shape of the molecule
that lets it do its “job”.
Never forget the axiom – structure dictates function.
Some biological molecules.
Ah, That Smell!
Once again, shape matters. It’s the good fit between odorant
and receptor molecule that lets us detect aromas.
Molecules of Life
How do you build a cell?
Start with water, add lots of small carboncontaining molecules and …….
Four Major Classes of Biological Molecules
Rules of the Game
Macromolecules are built by linking a set of building
blocks (monomers) together into long chains (a
polymer).
Monomers – basic units that
repeats over and over in organic
compounds
Each hexagon is this figure is a
monomer, building blocks linked
together to form a polymer.
Macromolecules Are Built By Linking a Set Of
Building Blocks (Monomers) Together Into Long
Chains (A Polymer).
FOUR TYPES OF ORGANIC
COMPOUNDS
• CARBOHYDRATES
– SUGARS AND STARCHES
• LIPIDS
– FATS
• PROTEINS
– HAIR, FINGERNAILS, MUSCLES
• NUCLEIC ACIDS
– DNA AND RNA (GENETIC MATERIAL)
CARBOHYDRATES
•
•
•
•
ELEMENTS – C, H AND O
RATIO H:O = 2:1
MONOMER = MONOSACCHARIDE
EXAMPLES
– SUGARS & STARCH
• MAIN FUNCTION
– QUICK ENERGY
Glucose: A Simple Carbohydrate Used For
Energy Production and as a Building Block
For Complex Carbohydrates
Linking Simple Sugars – the First Step to a Polymer
and the Last Step to Some Familiar Compounds
MONOSACCHARIDES
DISACCHARIDES
Some Familiar and Important Complex Carbohydrates
3 OR MORE REPEATING UNITS = POLYSACCHARIDE
Carbohydrates
are Central
Players in
Energy
Production
and Storage
LIPIDS
•
•
•
•
ELEMENTS: C, H and O
RATIO OF H:O = More H than O
MONOMER = Glycerol and 3 Fatty Acids
EXAMPLES
– Fats, Oils and Waxes
• MAIN FUNCTION
– Storage
– Energy reserves
– Cell membranes
FA
G
l
y
c
e
r
o
l
FA
FA
Lipids are Hydrophobic Molecules That
Exist In Three Primary Forms
Sterol
Phospholipid
Fat
Fats Are Made By Linking Fatty
Acid Chains to Glycerol, a Three
Carbon Molecule
Space-filling model
of a fat
A fatty acid
Fats are
Used in
Energy
Storage and
Production
The
Degree Of
Saturation
In A Fat
Affects Its
Physical
And
Nutritional
Properties
Where are the
double bonds?
The Degree Of
Saturation In A
Fat Affects Its
Physical And
Nutritional
Properties
saturated
monounsaturated
Where are the
double bonds?
polyunsaturated
Sterols Are Part of Cellular Membranes and Act
as Hormones
Note the four ring structure
common to all sterols.
Sterols As
Hormones
Estrogen,
testosterone,
progesterone,
and
corticosteriods
(cortisol) are all
steroid
hormones.
Sterols As
Hormones
“Designer steroids”
are major sporting
news where they
have been used
illegally in track
and field, baseball,
football and
countless other
sports.
A heavily muscled Linford
Christie who was disqualified
from international
competition after testing
positive for a banned steroid.
Phospholipids are Building Blocks of Cellular Membranes
The hydrophilic head group and hydrophobic tails are the keys to
phospholipid function.
Hydrophilic Head Group And Hydrophobic Tails Are
The Keys To Phospholipid Function
Phospholipids have a Jekyll and Hyde personality.
Phospholipids Form Biological Membranes
THE CELL MEMBRANE
PROTEINS
• Basic building blocks of living material
• ELEMENTS: C, H, O and N
• MONOMER: Amino Acids
– 20 different amino acids
• USES
– Hair, Muscles, Fingernails
– Enzymes – carry out chemical reactions
– Transport in cells
• FORMS PEPTIDE BONDS BETWEEN A.A.
Protein
Proteins are THE key elements of
life. Forget DNA, proteins rule.
Remember the principle - Structure determines Function.
Since proteins are the key players of the cell, it
follows that protein structure determines cell
function.
Some of the Diverse Functions of Proteins
Strands of the Protein Keratin Create Hair
Proteins are Linear Chains of Linked
Amino Acids
A
Common
Thread
and a
Unique
Identity
R – Residual Group
*side chain changes
Amino Group – NH2
Single Hydrogen - H
Acid or Carboxyl Group –
C=O, OH
(Side chain)
PEPTIDE BONDS
• 1 amino acid
• 2 amino acids linked
together – dipeptide
• 3 or more amino
acids linked together
- polypeptide
Peptide bonds
Amino Acids, Peptide Bonds, Polypeptides, Protein
Proteins are linear chains of 20 different building blocks called amino acids.
Peptide bonds
Amino acids are linked by peptide bonds – a form of
covalent bond.
Proteins are
Folded
Structures
Whose Shape
(and therefore
function)
Depends on
Amino Acid
Sequence
Nucleic Acids
There are two kinds
of nucleic acids, DNA
and RNA. Both are
involved in the
storage and flow of
information from
gene to gene product.
DNA
NUCLEIC ACIDS
• ELEMENTS: C, H,
O, N P and S
• MONOMER:
Nucleotides
• USES: DNA and
RNA
– Genetic material
– Controls the cells
activities
NUCLEOTIDES
•SUGAR GROUP
•DEOXYRIBOSE
•RIBOSE (RNA)
•PHOSPHATE GROUP
•NITROGENOUS BASE
•ADENINE
•GUANINE
•CYTOSINE
•THYMINE
•URACIL (RNA)
Nucleotides are Important in Their Own Right
Nucleotides fuel
the cell and
coordinate its
metabolism.
ATP, the cell’s
primary energy
currency.
REACTIONS OF BIOLOGICAL
COMPOUNDS
• HYDROLYSIS REACTIONS
–Water is added to break apart
molecules
• C12H22O11 + H2O
MALTOSE WATER
C6H12O6 + C6H12O6
GLUCOSE GLUCOSE
CONDENSATION /
DEHYDRATION REACTIONS
• CONDENSATION REACTIONS
(DEHYDRATION SYNTHESIS
REACTIONS)
– Joining molecules together by
removing water (-H and –OH are
removed to make a water
molecule)
• C6H12O6 + C6H12O6
GLUCOSE + GLUCOSE
C12H22O11 + H2O
MALTOSE
+ WATER
CATALYST
• SPEEDS UP THE NATURAL
RATE OF REACTIONS
• CAN BE ORGANIC OR
INORGANIC
ENZYMES
• A PROTEIN CATALYST
THAT CONTROLS THE
RATE OF A REACTION
ENZYMES
• LOWER THE ACTIVATION
ENERGY NEEDED TO
CARRY OUT A REACTION
• INCREASES THE RATE OF
REACTIONS
• ENZYME NAMES END IN –ase
• NAME IDENTIFIES A REACTING
SUBSTANCE
– LIPASE – REACTS WITH LIPIDS
– SUCRASE – REACTS WITH SUCROSE
• NAME CAN IDENTIFY FUNCTION
– OXIDASE – CATALYZES OXIDATION
– HYDROLASE – CATALYZES HYDROLYSIS
SUBSTRATES
• Substance acted upon
by an enzyme
ENZYME ACTION: LOCK &
KEY MODEL
• AN ENZYME BINDS A SUBSTRATE IN
A REGION CALLED THE ACTIVE
SITE
• ONLY CERTAIN SUBSTANCES CAN
FIT IN THE ACTIVE SITE
• ENZYME-SUBSTRATE COMPLEX
FORMS
• SUBSTRATE REACTS TO FORM
PRODUCT
• PRODUCT IS RELEASED
LOCK & KEY METHOD
ACTIVE SITE
ENZYME-SUBSTRATE
COMPLEX
ENZYME FUNCTION
FACTORS AFFECTING
ENZYME ACTION
• TEMPERATURE
– LITTLE ACTIVITY AT LOW TEMPS
– RATE INCREASES WITH
TEMPERATURE
– MOST ACTIVE TEMP IN HUMANS
(37ºC)
– ACTIVITY LOST WITH
DENATURATION AT HIGH
TEMPERATURE
TEMPERATURE AFFECTING
ENZYME ACTION
OPTIMUM
TEMPERATURE
RATE OF
REACTION
LOW
HIGH
TEMPERATURE
SUBSTRATE
CONCENTRATION
AFFECTING ENZYME ACTION
MAXIMUM
ACTIVITY
RATE OF
REACTION
LOW
HIGH
SUBSTRATE CONCENTRATION
pH AFFECTING ENZYME
ACTION
OPTIMUM Ph
* Most enzymes
lose activity in
low or high pH
RATE OF
REACTION
LOW
HIGH
pH