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8/11/2019 CHAPTER 1 - Macromolecules
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M ROMOLE ULES
Chapter 1
orliz y ti
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Some very simple carbon compounds are considered
inorganic if the carbon is not bonded to another carbon
or hydrogen.
E.g: CaCO3 (calcium carbonate), carbon dioxides,
simple acids and bases, simple salts.
1. INTRODUCTION
A. INORGANIC COMPOUND
The scallop shells(composed mainly of calcium carbonate).
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Carbon containing compound that is made up of carbonwhich covalently linked to carbon or hydrogen.
It is generally large and complex.
Most macromolecules are organic compound.
1. INTRODUCTION
B. ORGANIC COMPOUND
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Able to form the back bones of the large variety oforganic compounds essential to life.
Each carbon atom form 4 covalent bonds with 4 other
atoms (S,N,O,H) single, double, triple.
Covalent bondsare strong, stable bonds formed when
atoms share valence electrons to form molecules.
Carbon atoms can form straight, branched or can join
into rings.
1. INTRODUCTION
B. ORGANIC COMPOUND
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CARBON
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Single bonde.g. ethane
1. INTRODUCTION
B. ORGANIC COMPOUND
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CARBON
Double bondse.g. ethene
Triple bondse.g. ethyne
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1. INTRODUCTION
B. ORGANIC COMPOUND
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CARBON
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1. INTRODUCTION
C. ISOMERS
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Isomers are compounds with the same molecularformula but different structures and properties:
Structural isomers have different covalent
arrangements of their atoms
Geometric isomers have the same covalent
arrangements but differ in spatial arrangements
Enantiomers are isomers that are mirror images of eachother
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1. INTRODUCTION
C. ISOMERS
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1. INTRODUCTION
C. ISOMERS
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1. INTRODUCTION
C. ISOMERS
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Functional groups (a group of atoms) are the
components of organic molecules that are most commonlyinvolved in chemical reactions.
The characteristics of an organic molecule can be changed
dramatically by replacing one of the hydrogen with a
functional group.
Determine the types of chemical reaction in which the
compound participates.
The types, number and arrangement of functional groups
give each molecule its unique properties.
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1. INTRODUCTION
C. FUNCTIONAL GROUP
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Can significantly altered the properties of hydrocarbon
molecule if it replaces one of the hydrogen of a
hydrocarbon
HYDROXYL
ETHANE (gas) ETHANOL (liquid)
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Consists of a carbon atom that has a double bond with an
oxygen atom.
Polar: Electronegativity of the oxygen.
Hydrophilic: Polar and ionic functional groups associate
strongly with polar water molecules.
CARBONYL
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Have two classes which determines by the position of the
carbonyl group in the molecule.
CARBONYL
ALDEHYDE (RCHO)
A carbonyl group positioned at the
end of the carbon skeleton.
KETONE (RCOR)
Has an internal carbonyl group.
An aldehyde and a ketone are often structural isomers.
Propanal Acetone
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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CARBONYL
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Consists of a carbon double-bonded to an oxygen and alsobonded to a hydroxyl group.
Strongly polar
Act as acid by contributing H+
to solution and becomeionized.
Compound with carboxyl group is called carboxylic acid
CARBOXYL
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Composed of nitrogen bonded to two hydrogen atoms andthe carbon skeleton.
Strongly polar
Act as base by picking up H+
from solution.
Organic compound with amino group is called amines.
AMINO
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Amino acid is the building blocks of protein, contain acarboxyl group and an amino group.
AMINO
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Consists of a phosphorus atom bonded to four oxygen
atom; one oxygen atom is bonded to carbon skeleton.
It is usually ionized and attached to carbon skeleton by
one of its oxygen atoms.
Two oxygen atom carry negative charges.
Compound with phosphate groups are called phosphates.
PHOSPHATE
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Consists of a carbon bonded to three hydrogens.
Compound with methyl group are called methylated
compounds.
METHYL GROUP
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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The subtle differences result in the different actions of
these molecules which help produce the features offemales and males in humans and other vertebrates.
METHYL GROUP
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1. INTRODUCTION
D. FUNCTIONAL GROUP
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Consists of a sulfur atom bonded to an atom of hydrogen.
Components with sulfhydryl is called thiols.
Two sulfhydryl group can interact to help stabilize protein
structure.
SULFHYDRYL
2 WATER
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2. WATER
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Water makes up about 60-95% of the fresh mass of
organism.
Water is an important component of cells, acts as a
solvent, is often a reactant in metabolism and provides an
aqueous environment for many organisms.
Properties of water molecules are due mostly to its ability
to form hydrogen bonds, its polarity and its small size.
Understanding this and the other properties that makewater so important means understanding waters
molecules structure.
2 WATER
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2. WATER
A. POLARITY OF WATER MOLECULE
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The two hydrogen atoms are joined to the oxygen atom by
single covalent bonds.
Since oxygen is more electronegative than hydrogen,
electron of the polar bonds spend more time closer to the
oxygen atom.
Therefore, the bond that hold together the atom in a water
molecule are polar covalent bonds.
2 WATER
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2. WATER
A. POLARITY OF WATER MOLECULE
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Polar molecule: Opposite ends of the molecule have
opposite charges.
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2. WATER
A. POLARITY OF WATER MOLECULE
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The charged regions of a
polar water molecule are
attracted to oppositely
charged parts of neighboring
molecules.
Each molecules can
hydrogen-bond to multiple
partner.
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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The binding together of like molecules, often by hydrogen
bonds.
Water from the root reaches the leaves through a network
of water-conducting cell.
As water evaporates from a leaf, hydrogen cause watermolecule leaving the veins to tug on molecules farther
down.
The upward pull is transmitted through the water-conducting cell all the way down to the root.
COHESION
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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Surface tension: a measure of how difficult it is to stretch
or break the surface of a liquid.
At the interface between water and air is an ordered
arrangement of water molecules, hydrogen-bonded to one
another and to the water below.
This makes water behave as though coated with an
invisible film.
COHESION
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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Adhesion: The attraction between different kind of
molecules
Adhesion of water to the wall of the cells helps counter the
downward pull of gravity.
COHESION
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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2 WATER
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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HEAT AND TEMPERATURE
Heat is a measure of the total amount of kinetic energy
due to molecular motion in a body of matter.
Temperature measures the intensity of heat due to the
average kinetic energy of the molecules.
A calorie (cal) is the amount of heat it takes to raise the
temperature of 1g of water by 1C (1cal = 4.184J)
MODERATION OF
TEMPERATURE
2 WATER
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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SPECIFIC HEAT
Amount of heat that must be absorbed or lost for 1g of that
substance to change its temperature by 1C (1cal/g/C)
Water change temperature by absorbs or loses a relativelylarge quantity of heat for each degree of change.
Heat must be absorbed in order to break hydrogen bonds,
and heat is released when hydrogen bonds form.
MODERATION OF
TEMPERATURE
2 WATER
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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importance
A large body of water can absorb and store a huge amount
of heat from the sun in the daytime and during summer
while warming up only a few degree.
Stabilize ocean temperatures, creating a favorable
environment for marine life.
Organism are more able to resists changes in their own
temperature since they are made primarily of water.
MODERATION OF
TEMPERATURE
2 WATER
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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EVAPORATIVE COOLING
Evaporation: transformation from liquid to gas
Some evaporation occurs at any temperature (why?)
If a liquid is heated, the average kinetic energy of
molecules increases and the liquid evaporates more
rapidly.
MODERATION OF
TEMPERATURE
2 WATER
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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EVAPORATIVE COOLING
Heat of vaporization: quantity of heat a liquid must absorb
for 1g of it to be converted from liquid to gaseous state.
Heat is needed to break hydrogen bonds before themolecules can make their exodus from the liquid.
Evaporative cooling contributes to the stability of
temperature in lakes and ponds and prevents terrestrialorganisms from overheating.
MODERATION OF
TEMPERATURE
2 WATER
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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EVAPORATIVE COOLING
MODERATION OF
TEMPERATURE
2 WATERDENSITY
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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Water expands as it solidify; it is less dense as solid than
liquid.
When water begin to freeze, its molecules is no longer
moving vigorously enough to break their hydrogen bonds.
As temperature falls to 0C, the water becomes locked intoa crystalline lattice, each water molecule bonded to four
partners.
When temperature rise above 0C, hydrogen bondsdisrupted, crystal collapses, ice melts, molecules slip
closer together.
DENSITY
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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DENSITY
2 WATERDENSITY
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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DENSITY
Floating ice
insulate the water
below, preventing it
from freezing.
2 WATERSOLVENT OF LIFE
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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Solution: a liquid that is completely homogenous mixture
of two or more substance.
Solvent: dissolving agent of a solution
Solute: substance that is dissolved
Aqueous solution: solution which water is the solvent
Water is not universal solvent
SOLVENT OF LIFE
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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Hydration shell: sphere of water molecules around each
dissolved ion
SOLVENT OF LIFE
Hydration shell: sphere of water molecules around each
dissolved ion
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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SOLVENT OF LIFE
Large molecules such as protein can dissolve in water if
they have ionic and polar regions on their surface.
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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Hydrophilic: any substance that has an affinity for water
(substance can be hydrophilic without dissolving)
Colloid: a mixture made of a liquid and particles that remain
suspended in that liquid (large size)
Cotton: consists of giant molecule of cellulose
A compound with numerous region of partial negative and
partial positive charges associated with polar bonds.
Waters adhere to the cellulose fiber without being dissolved.
SOLVENT OF LIFE
2. WATERSOLVENT OF LIFE
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2. WATER
B. EMERGENT PROPERTIES OF WATER
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Hydrophobic: any substance that has no affinity for water (nonionic,
nonpolar)
This is because of the nonpolar bonds between carbon and hydrogen
which share electrons almost equally.
Exmple: vegetable oil
SOLVENT OF LIFE
3. POLYMER
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Four main classes of large biological molecules are:
Carbohydrates
Proteins
Nucleic acids (DNA and RNA)
Lipids (not macromolecules/does not true polymers)
Most macromolecules are polymers.
Long molecule consists of many identical or similar building
blocks link together (monomer).
Monomeris a chemical subunit that serves as a building
block of a polymer.
3. POLYMER
A. INTRODUCTION
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3. POLYMER
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Monomers are connected by condensation reaction
(dehydration). Two molecules are covalently bonded to each other through loss
of a water molecule.
B. SYNTHESIS AND BREAKDOWN
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3. POLYMER
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Polymer are disassembled to monomer by hydrolysis
reaction. Bonds between monomer s are broken down by adding of water
molecules.
B. SYNTHESIS AND BREAKDOWN
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4. PROTEIN
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Amino acids are organic molecules with carboxyl and
amino groups Amino acids differ in their properties due to differing side
chains, called R groups
Alpha carbon: an asymmetric carbon at the center of
amino acid. It bind to amino group, carboxyl group, hydrogen atom
and variable group (side chain)
A. AMINO ACID MONOMER
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4. PROTEIN
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A. AMINO ACID MONOMER
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The R group of amino acids can vary in:
structure shape
charge (positive, negative or neutral),
affinity with water and the reactivity with other molecules.
There are 20 amino acids which occur naturally in theproteins of organisms.
The various combinations of 20 different amino acidsproduce a great variety of different proteins containingbetween hundreds to few thousand amino acids.
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A. AMINO ACID MONOMER
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(Hydrophobic)
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A. AMINO ACID MONOMER
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(Hydrophilic)
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A. AMINO ACID MONOMER
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(Hydrophilic)
Acidic: Those with carboxyl group on their side chain that are
generally NEGATIVE
Basic: Those with amino group on their side chain that are generally
POSITIVE
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A. AMINO ACID MONOMER
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Amino acids is an amphoteric molecules that have both
basic and acidic groups.
Molecules with amphoteric properties can function as
buffer- resist any change in pH and try to maintain the
pH.
4. PROTEIN
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A. AMINO ACID MONOMER
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Amino acids dissolve in water to form bipolar ions in
aqueous solution (zwitterion).
An ion with both a negative charge and a positive
charge. Amino is ionised into NH3+, whereas acidic
group is ionised intocoo-
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A. AMINO ACID MONOMER
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TYPES OF AMINO ACIDS
Essential Amino Acidcannot be made in thebody
must be included in thediet.
Non-Essential Amino Acidcan be synthesized in the
body.
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B. AMINO ACID POLYMER
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Amino acids are linked by peptide bonds
An enzyme can cause two amino acids to bind bydehydration reaction
Water molecule will be produced
A polypeptide is a polymer of amino acids
Polypeptides range in length from a few to more than athousand monomers
Each polypeptide has a unique linear sequence of amino
acids.
4. PROTEIN
P id
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B. AMINO ACID POLYMER
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Peptide
bond
Amino end(N-terminus)
Peptide
bond
Side chains
Backbone
Carboxyl end(C-terminus)
(a)
(b)
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C. CLASSIFICATION OF PROTEIN
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Some common methods used to group proteins are
based on:
1. Levels of organization
- Primary structure
- Secondary structure
- Tertiary structure- Quaternary structure
2. Structure
- Globular proteins- Structural proteins
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C. CLASSIFICATION OF PROTEIN
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3. Composition
- Simple proteins
- Conjugated proteins
4. Functions
- Structure- Catalysts
- Signals
- Movement
- Defense- Storage
LEVELS OF ORGANIZATION4. PROTEIN
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The primary structure of a protein is its uniquesequence of amino acids
Secondary structure, found in most proteins, consists
of coils and folds in the polypeptide chain
Tertiary structure is determined by interactions amongvarious side chains (R groups)
Quaternary structure results when a protein consists of
multiple polypeptide chains
LEVELS OF ORGANIZATIONC. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
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Primary Structure Specific linear sequence of amino acids in a polypeptide
chain.
The sequence of amino acids is determined by the
genetic code carried in the DNA molecule in the nucleus. This sequence is unique for a particular protein.
A substitution or deletion of even 1 amino acid in the
primary structure can affect the structure & function of
the protein.
LEVELS OF ORGANIZATIONC. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
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C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
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Secondary Structure
Proteins that have segments of their polypeptide chains
repeatedly coiled or folded,
These coils & folds are the result of hydrogen bonds
between the repeating constituents of the polypeptide
backbone.
The weakly hydrogen atom attached to the nitrogen
atom has an affinity for the oxygen atom of a nearby
peptide bond.
C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
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C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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helix:
The polypeptide chain is coiled to form helical structure. The shape of the helix is maintained by hydrogen bonds between
every 4th amino acid.
Example:
i. Globular proteins
may have single helix structure or multiple stretches of helix
separated by non helical regions.
ii. Fibrous proteins
Some may have the helix formation Eg: -keratin (structural protein of hair) have the helix formation
over most of their length.
C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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pleated sheet:
2 or more polypeptide chains are arranged parallel to
each other & are held together by hydrogen bonds.
The polypeptide chains become folded.
Has high resistance to stretching. It is strong but flexible.
Pleated sheets make up the core of many globular
proteins & also some fibrous proteins.
Example of fibrous protein : the silk protein of a spiderweb.
C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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Tertiary Structure
Formed by folding and coiling of the secondarystructure of polypeptide chains to form precise compactglobular protein which determines its function.
The compact three dimensional shape is maintained byhydrogen bonds, disulphide bonds, ionic bonds and
hydrophobic interactions and van der Waals interactions.
Tertiary structure is determined by interactions between Rgroups, rather than interactions between backboneconstituents.
Example of globular proteins include enzymes, antibodies,protein hormones and myoglobin, the oxygen-storagered pigment in red muscle.
C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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Hydrophobic interaction
occur when nonpolar side chain clusters at the core of theprotein.
Caused by the action of water molecules as they form H-bond
with polar parts
Van der Waals interaction Hold nonpolar side chain together
Hydrogen bond formed between polar side chain
Ionic bond formed between positively and negatively
charged side chain Disulfide bridges formed between two sulfhydryl
groups.
C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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Quaternary structure Results when two or more polypeptide chains form one
macromolecule.
Collagen is a fibrous protein consisting of three
polypeptides coiled like a rope. Hemoglobin is a globular protein consisting of four
polypeptides: two alpha and two beta chains
C. CLASSIFICATION OF PROTEIN
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LEVELS OF ORGANIZATION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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C. CLASSIFICATION OF PROTEIN
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PROTEIN STRUCTURE4. PROTEIN
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Protein are classified according to their structure
a)Fibrous proteins
b)Globular proteins
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PROTEIN STRUCTURE4. PROTEIN
C CLASSIFICATION OF PROTEIN
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C. CLASSIFICATION OF PROTEIN
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COMPOSITION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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Simple proteins consists only of amino acids
do not contain any other substance
Examples:
- Albumins : egg albumin, serum albumin- Globulins : antibodies, fibrinogen
- Histones : protein associated with DNA
- Scleroprotein : keratin, collagen
C. CLASSIFICATION OF PROTEIN
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COMPOSITION4. PROTEIN
C CLASSIFICATION OF PROTEIN
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Conjugated proteins
contain protein & non-protein material (prosthetic group)
The prosthetic group : plays an important role in the
functioning of the protein
C. CLASSIFICATION OF PROTEIN
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4. PROTEIN
D DENATURATION OF PROTEIN
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In addition to primary structure, physical and chemical
conditions can affect structure
Alterations in pH, salt concentration, temperature, or other
environmental factors can cause a protein to unravel
This loss of a proteins native structure is called
denaturation
A denatured protein is biologically inactive
D. DENATURATION OF PROTEIN
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Normal protein Denatured protein
Denaturation
Renaturation
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5. CARBOHYDRATE
A MONOSACCHARIDES
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Simplest carbohydrates; ex: GLUCOSE
The molecule has a carbonyl group and multiple
hydroxyl groups.
Can be either aldose or ketose (depends on the carbonyl
group)
Glucose and galactose differ only in the placement of
parts around one asymmetric carbon.
A. MONOSACCHARIDES
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5. CARBOHYDRATE
A MONOSACCHARIDES
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A. MONOSACCHARIDES
5. CARBOHYDRATE
A. MONOSACCHARIDES
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All monosaccharide is a reducing sugar-can act as
reducing agent in the Benedict test.
Benedict reagentblue in colora cuprum sulphate
solution.
The presence of reducing sugar will reduced the cuprum
(II) sulphate to cuprum (I) sulphate which has the red-
orange colour.
A. MONOSACCHARIDES
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5. CARBOHYDRATE
A. MONOSACCHARIDESGLUCOSE
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Glucose is an aldohexose.
Glucose can be in a linear chain form.
Glucose molecules, as well as most other sugars, form
rings in aqueous solution.
To form the glucose rings, carbon 1 bonds to the oxygen
attached to carbon 5.
A. MONOSACCHARIDES
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5. CARBOHYDRATE
A. MONOSACCHARIDESGLUCOSE
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-glucose is the glucose that have the OH group of the
first carbon projects below the plane of the ring.
-glucose is when the glucose have the OH group
projects above the plane.
A. MONOSACCHARIDES
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5. CARBOHYDRATE
A. MONOSACCHARIDESFUNCTION
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Triose:
intermediate in respiration and photosynthesis. Pentoses:
ribose: constituent of RNA
deoxyribose: constituent of nucleic acid DNA.
Hexoses: Glucose: most common respiratory substratelarge number of
C-H bonds can be broken to release energy;
Fructose: constituents of nectar;
Galactose: constituents of lactose.
Hexoses are the monomers in synthesis of disaccharides,oligosaccharides and polysaccharides.
A. MONOSACCHARIDES
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5. CARBOHYDRATE
B. DISACCHARIDES
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Two monosaccharide joined by a glycosidic linkage.
Disaccharides are formed by the condensation reaction
of two monosaccharides molecules.
Disaccharides are water soluble, sweet tasting and canbe crystallised.
All disaccharides are reducing sugar except for
sucrose (non-reducing sugar).
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5. CARBOHYDRATE
B. DISACCHARIDESMALTOSE
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Bonding of two glucose molecule
1-4 glycosidic linkage
Known as malt sugar
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5. CARBOHYDRATE
B. DISACCHARIDESSUCROSE
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Bonding of glucose and fructose
1-2 glycosidic linkage
Most prevalent disaccharide, table sugar
Taste sweeter than glucose but not as sweet as fructose
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5. CARBOHYDRATE
B. DISACCHARIDESLACTOSE
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Binding of glucose and galactose.
(1-4) glycosidic linkage.
Sugar that present in milk.
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5. CARBOHYDRATEC. OLIGOSACCHARIDES
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Monosaccharides can be linked together to form small
chains termed oligosaccharides. Each oligosaccharides may contain 3 to 14
monosaccharides.
Glycoproteins are the proteins covalently attached to
carbohydrate. Glycolipids are carbohydrate-attached lipids
Oligosaccharides provide energy and serve as markers
for cellular recognition.
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5. CARBOHYDRATEC. OLIGOSACCHARIDES
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Oligosaccharide of the cell surface are attached to
membrane embedded proteins and certain lipid molecules.
5. CARBOHYDRATED. POLYSACCHARIDES
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POLYSACCHARIDES
Storage
Starch
Amylose Amylopectin
Glycogen
Structural
Cellulose Chitin Murein
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Polysaccharides, are macromolecules with a few hundred to
a few thousand monosaccharides joined by glycosidiclinkages.
The structure and function of a polysaccharide are
determined by its sugar monomers and the positions of
glycosidic linkages. Polysaccharides are generally insoluble in water and not
sweet in taste.
Polysaccharides are important as food storage and building
materials for the cell or the whole organism. Example: starch,glycogen and cellulose, chitin and murein.
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5. CARBOHYDRATED. POLYSACCHARIDES
STARCH
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Starch is a polysaccharide formed from condensation of -
glucose units.
Starch grains are found in chloroplast, potato tubers, cereals
and legumes.
Most of the monomers are joined by 1-4 glycosidic linkage.
Made up from two components: Amylose (unbranched) and
amylopectin(branched with 1-6 linkage).
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STARCH
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NLY/ASASI/2013(b) Glycogen: an animal polysaccharide
Starch
GlycogenAmylose
Chloroplast
(a) Starch: a plant polysaccharide
Amylopectin
Mitochondria Glycogen granules
0.5 m
1 m
5. CARBOHYDRATED. POLYSACCHARIDES
STARCH
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Starch is a polysaccharide formed from condensation of -
glucose units.
Starch grains are found in chloroplast, potato tubers, cereals
and legumes.
Most of the monomers are joined by 1-4 glycosidic linkage.
Made up from two components: Amylose (unbranched) and
amylopectin(branched with 1-6 linkage).
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STARCH
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Amylose: linear unbranched polymer of 200 to 1500 -
glucose units in a repeating sequence of -1,4-glycosidiclinkages.
The amylose chain coils into a helix held by hydrogen
bonds formed between hydroxyl groups.
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5. CARBOHYDRATED. POLYSACCHARIDES
STARCH
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Amylopectin is a branched polymer of 2,000 to 200,000 -
glucose units per starch molecules.
Glycosidicbond (1-4 and 1-6)
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5. CARBOHYDRATED. POLYSACCHARIDES
GLYCOGEN
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Glycogen is the major storage form of carbohydrate in
animals. Present in liver & muscle cells where high metabolic activities
take place.
Glycogeninsoluble in water.
Structure: similar with amylopectin but larger in size and havemore branches.
When energy is needed and glucose concentration is low in
the body-glycogen can be hydrolyzed rapidly by enzymes to
produced glucose molecules to be used for cellularrespiration to meet the energy requirements.
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5. CARBOHYDRATED. POLYSACCHARIDES
GLYCOGEN
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NLY/ASASI/2013(b) Glycogen: an animal polysaccharide
Starch
GlycogenAmylose
Chloroplast
(a) Starch: a plant polysaccharide
Amylopectin
Mitochondria Glycogen granules
0.5 m
1 m
5. CARBOHYDRATED. POLYSACCHARIDES
CELLULOSE
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The polysaccharide cellulose is a major component of the
tough wall of plant cells Like starch, cellulose is a polymer of glucose, but the
glycosidic linkages differ
The difference is based on two ring forms for glucose: alpha
() and beta () Cellulose is composed of long unbranched chains of up to
10,000 -glucose units linked by -1,4-glycosidic bonds.
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CELLULOSE
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The chains are grouped together to form microfibrils
arranged in larger bundle to form fibrils.
The fibrils give the plant high tensile strength and rigidity.
The layers of fibrils are freely permeable to water andsolutes.
Commercially-cellulose is used to make cotton goods and
paper for various uses.
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5. CARBOHYDRATED. POLYSACCHARIDES
CELLULOSE
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(a) and glucose ring structures
Glucose Glucose
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CELLULOSE
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(b) Starch: 14 linkage of glucose monomers
(c) Cellulose: 14 linkage of glucose monomers
5. CARBOHYDRATED. POLYSACCHARIDES
CELLULOSE
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Polymers with glucose are helical
Polymers with glucose are straight
In straight structures, H atoms on one strand can bond with
OH groups on other strands
Parallel cellulose molecules held together this way are
grouped into microfibrils, which form strong building
materials for plants
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CELLULOSE
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b Glucosemonomer
5. CARBOHYDRATED. POLYSACCHARIDES
CHITIN
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Carbohydrate use by arthropod to build their exoskeleton.
Pure chitin is leathery, but becomes hardened when
encrusted with calcium carbonate.
Fungi used chitin rather than cellulose as building materialfor their cell wall.
Chitin is similar to cellulose except it contains a nitrogen-
containing appendage.
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CHITIN
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The structureof the chitin
monomer.
(a) (b) (c)Chitin forms theexoskeleton ofarthropods.
Chitin is used to makea strong and flexiblesurgical thread.
5. CARBOHYDRATED. POLYSACCHARIDES
MUREIN
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A polymer consist of sugars and amino acids that forms a mesh-like layer
outside the plasma membrane of bacteria, forming the cell wall.
The sugar component consists of alternating residues of -(1,4) linked N-
acetylglucosamine andN-acetylmuramic acid.
Consist of polysaccharides cross linked with amino acids.
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6. LIPIDA. INTRODUCTION
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Lipids are the one class of large biological molecules that do
not form polymers
Contain carbon, hydrogen and oxygen
3 important groups of lipids are tryglycerides (fats and oils),
phospholipids and steroids.
Other group of lipid waxes (water proof)
The unifying feature of lipids is having little or no affinity for
water
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Lipids are hydrophobic because they consist mostly of
hydrocarbons, which form non-polar covalent bonds
Dissolve in organic solvents such as acetone, ether,
chloroform and alcohol.
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Fats and oils are esters (condensation of one molecule
glycerol and 3 molecules of fatty acids by an esterlinkage)
The process: esterification (involve alcohol &acids)
Glycerol + 3 fatty acids = Triglyceride
Glycerol is a three-carbon alcohol with a hydroxyl group
attached to each carbon
A fatty acid consists of a carboxyl group attached to a
long carbon skeleton
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Dehydration reaction in the synthesis of a fat
Fatty acid(palmitic acid)
Glycerol
One water molecule is removed for each fatty acid joined to
the glycerol
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(b)Fat molecule (triacylglycerol)
Ester linkage
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Fats separate from water
because water molecules form hydrogen bonds with
each other and exclude the fats
Fatty acids vary in length (number of carbons) and in
the number and locations of double bonds
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6. LIPIDB. TRIGLYCERIDE (FAT)
SATURATED FAT
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Saturated fatty acids have the maximum number of
hydrogen atoms possible and no double bonds
Usually solid at room temperature
Example: stearic acid
Straight molecules
Most animal fats are saturated
A diet rich in saturated fats may contribute to cardiovasculardisease through plaque deposits
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6. LIPIDB. TRIGLYCERIDE (FAT)
UNSATURATED FAT
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Unsaturated fatty acids have one or more double bonds
Example: oleic acid and linoleic acid
Bent molecule (due to one or more double bonds). Still can
accept one more hydrogen atom.
Usually liquid at room temperature
Plant fats and fish fats are usually unsaturated
Hydrogenation is the process of converting unsaturated
fats to saturated fats by adding hydrogen
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Hydrogenation is not only producing saturated fat but also unsaturated
fat with trans double bond.
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a a s doub e bo d
6. LIPIDC. PHOSPHOLIPID
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In a phospholipid, two fatty acids and a phosphate group
are attached to glycerol
The two fatty acid tails are hydrophobic, but the
phosphate group and its attachments form a hydrophilic
head
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Fig. 5-13ab
Choline
head
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(b) Space-filling model(a) Structural formula
Fatty acids
Phosphate
Glycerol
Hydrophobic
tails
Hydrophilic
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Phospholipid shows ambivalent behavior towards water
The tails are excluded from water, the head has affinity
toward water
When phospholipids are added to water, they self-
assemble into a bilayer, with the hydrophobic tailspointing toward the interior
The structure of phospholipids results in a bilayer
arrangement found in cell membranes
Phospholipids are the major component of all cell
membranes
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Fig. 5-14
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Hydrophilichead
Hydrophobictail
WATER
WATER
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6. LIPIDD. STEROID
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Steroids are lipids characterized by a carbon skeleton
consisting of four fused rings
Cholesterol, an important steroid, is a component in
animal cell membranes
Steroid are classified as lipids due to their insolubility in
water and solubility in non polar solvents.
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Type Function Description Uses
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Fats Respiratory substrate Released energy
when oxidised
Butter
For energy storage Excess energy isstored in the form
of fat
As heat (thermal) and
electrical insulator
Fat deposited as
adipose tissue
(heat insulator)
Fat acts as an
electrical
insulator (myelin
sheath of nerve
cells)To protect internal
organs
Fat provides
support
(abdomen)and
protection
(kidney)NLY/ASASI/2013
Type Function Description Uses
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Oils For energy
storage
Long-term energy storage
in plants and seeds
Cooking
oils
Phospholipids A component of
plasma
membrane
Providing
structural
support
Involved in formation of
cells
Important component ofplasma membrane, nuclear
membrane and the myelin
sheath
Non-stick
pan spray
Steroids Precursor for
steroid
hormones
All steroid hormones are
synthesized from
cholesterol
Medicines
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7. NUCLEIC ACIDSA. ROLES OF NUCLEIC ACIDS
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There are two types of nucleic acids:
Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)
DNA provides directions for its own replication
DNA directs synthesis of messenger RNA (mRNA).
mRNA controls protein synthesis; translated codedinformation into amino acid sequences.
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7. NUCLEIC ACIDSB. STRUCTURE OF NUCLEIC ACIDS
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Nucleic acids are polymers called polynucleotides.
Each polynucleotide is made of monomers called
nucleotides.
Each nucleotide consists of a nitrogenous base, a pentose
sugar, and a phosphate group.
The portion of a nucleotide without the phosphate group is
called a nucleoside.
Fig. 5-27ab
5' end
5'C
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3'C
5'C
3'C
3' end
(a) Polynucleotide, or nucleic acid
(b) Nucleotide
Nucleoside
Nitrogenousbase
3'C
5'C
Phosphategroup Sugar
(pentose)
7. NUCLEIC ACIDSC. NUCLEOTIDE MONOMER
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NUCLEOTIDE
Pentose Sugar
Ribose Deoxyribose
Nitrogenous Base
Purine Pyrimidine
Phosphate Group
7. NUCLEIC ACIDSC. NUCLEOTIDE MONOMER
PENTOSE SUGAR
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Ribose - Pentose sugar in RNA
Deoxyribose - Pentose sugar in DNA
Ribose (in RNA)Deoxyribose (in DNA)
Sugars
Nucleoside components: sugars
7. NUCLEIC ACIDSC. NUCLEOTIDE MONOMER
NITROGENOUS BASE
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Ring structure containing N.
In DNA
Adenine, Guanine (double ring-purines)
Cytosine, Thymine (single ring-pirimidines).
In RNA
Adenine, Guanine (double ring-purines)
Cytosine, Uracil (single ring-pirimidines).
Fig. 5-27c-1
Nitrogenous bases
Pyrimidines
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(c) Nucleoside components: nitrogenous bases
Purines
Guanine (G)Adenine (A)
Cytosine (C) Thymine (T, in DNA) Uracil (U, in RNA)
7. NUCLEIC ACIDSC. NUCLEOTIDE MONOMER
PHOSPHATE GROUP
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Joined by condensation to the pentose sugargives the
nucleic acids their acidic property.
7. NUCLEIC ACIDSD. NUCLEOTIDE POLYMER
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Nucleotide polymers are linked together to build a
polynucleotide
Adjacent nucleotides are joined by covalent bonds
(phosphodiester bonds) that form between theOH
group on the 3 carbon of one nucleotide and the phosphate
on the 5 carbon on the next
These links create a backbone of sugar-phosphate units
with nitrogenous bases as appendages
The sequence of bases along a DNA or mRNA polymer isunique for each gene
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7. NUCLEIC ACIDSE. DNA DOUBLE HELIX
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A DNA molecule has two polynucleotides spiraling around
an imaginary axis, forming a double helix
In the DNA double helix, the two backbones run in opposite
5 3 directions from each other, an arrangement
referred to as antiparallel
One DNA molecule includes many genes
The nitrogenous bases in DNA pair up and form hydrogen
bonds: adenine (A) always with thymine (T), and guanine(G) always with cytosine (C)
7. NUCLEIC ACIDSE. DNA DOUBLE HELIX
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The base pairing is precise.
Adenine is linked with thymine by 2 hydrogen bonds. Cytosine is joined with guanine by 3 hydrogen bonds.
The two polynucleotide strands are complementary.
The sequence of bases in DNA forms the genetic code that
determines the characteristics of an organism.
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Fig. 5-28
Sugar-phosphatebackbones
3' end5' end
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3' end
5' end
Base pair (joined byhydrogen bonding)
Old strands
New
strands
Nucleotideabout to beadded to a
new strand
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