Download Macromolecules

Macromolecules
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Organic Compounds
• Compounds that contain CARBON
are called organic.
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Carbon (C)
• Carbon can form covalent bonds
with as many as 4 other atoms
(elements).
• Usually bonds with C, H, O or
N.
• Example:
CH4(methane)
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Macromolecules
• Macromolecules are POLYMERS
(chains) of organic molecules.
• Made up of smaller “building blocks”
called MONOMERS.
• Examples of marcromolecules:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids (DNA and RNA)
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Question:
How Are Macromolecules
Formed?
Answer: Dehydration Synthesis
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“Dehydrate” means remove water.
“Synthesis” means build.
• Dehydration is also called “condensation
reaction.”
• Combines monomers by “removing water”
between molecules.
HO
H
HO
H
H2O
HO
H
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Question:
How are Macromolecules
broken down (or
digested)?
Answer: Hydrolysis
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hydro” means water.
“lysis” means split.
• Hydrolysis separates or splits apart
monomers by “adding water”
HO
H
H2O
HO
H HO
H
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Animation
• http://science.nhmccd.edu/BioL/dehydrat
/dehydrat.html
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Carbohydrates
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Functions of carbohydrates
Easy-to-access source of
energy for organism.
Provide structure.
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Carbohydrates
• Sugar molecules – singles,
doubles, or long chains.
• Three types:
A. monosaccharide
B. disaccharide
C. polysaccharide
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A. Monosaccharide: one sugar (single)
Primary example: glucose (C6H12O6)
glucose
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Different Forms of Glucose
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Other important
monosaccharides:
Deoxyribose – in DNA
Ribose – in RNA
Fructose – in honey
Galactose – in milk and some foods
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B. Disaccharide: two sugar units
joined (by dehydration synthesis)
Examples:
– Sucrose (glucose+fructose)
– Lactose (glucose+galactose)
– Maltose (glucose+glucose)
glucose
glucose
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C. Polysaccharide: many sugar units
Examples:
glucose
starch (bread, potatoes)
glycogen (beef muscle)
cellulose (lettuce, corn)
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
glucose
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Lipids
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Lipids
• General term for compounds which are
not soluble in water.
• Lipids are soluble in hydrophobic
solvents.
• Definition of hydrophobic: “water
fearing.” Oils are hydrophobic
solvents.
• Hydrophilic: “water loving.”
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6 Groups :
1.
2.
3.
4.
5.
6.
Fats
Phospholipids
Oils
Waxes
Steroid hormones
Triglycerides
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Lipids
Six functions of lipids:
1. Long term energy storage
2. Protection against heat loss
(insulation)
3. Protection against physical shock
4. Protection against water loss
5. Chemical messengers (hormones)
6. Major component of membranes
(phospholipids)
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Building
blocks of
lipids are
fatty acids
and
glycerol.
Fatty acids
Glycerol
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Lipids
Triglycerides:
Molecules made of 1 glycerol and
3 fatty acids.
H
O
H-C----O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
H-C----O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
fatty acids
H-C----O C-CH -CH -CH -CH
2
2
2
H
glycerol
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Fatty Acids
There are two kinds of fatty acids:
1. Saturated fatty acids: no double bonds between C
(bad for you)
2. Unsaturated fatty acids: double bonds between C
(good)
saturated
O
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
unsaturated C-CH -CH -CH 2
2
2
CH
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Proteins
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Proteins (Polypeptides)
• Long chains of amino acids
• 20 different kinds of amino acids
• Amino acids bonded together by peptide
bonds.
• Six functions of proteins:
1. Storage:
albumin (egg white)
2. Transport:
hemoglobin
3. Regulatory:
hormones
4. Movement:
muscles
5. Structural:
membranes, hair, nails
6. Enzymes:
cellular reactions
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• Amino Acid
• Amino group on 1 end (NH2)
• Carboxyl group on other end (COOH)
•“R” group is variable, from 1 atom to 20.
• Two amino acids can join together to form a dipeptide (by dehydration
synthesis).
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Proteins
Four levels of protein structure:
A.Primary Structure
B. Secondary Structure
C. Tertiary Structure
D.Quaternary Structure
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Primary Structure
Amino acids bonded together
through dehydration
synthesis to form peptide
bonds
Amino Acids (aa)
aa1
aa2
aa3
aa4
aa5
aa6
Peptide Bonds
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Secondary Structure
• 3-dimensional folding arrangement of a
primary structure into coils and pleats
held together by hydrogen bonds.
• Two examples:
Alpha Helix
Beta Pleated Sheet
Hydrogen Bonds
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Tertiary Structure
• Secondary structures bent and folded
into a more complex 3-D arrangement
of linked polypeptides
• Bonds: H-bonds, ionic, disulfide
bridges (S-S)
• Called
“subunit”
Alpha Helix
Beta Pleated Sheet
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Quaternary Structure
• Composed of 2 or more
“subunits”
• Globular in shape
• Form in Aqueous environments
• Example: enzymes (hemoglobin)
subunits
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One important group of
proteins - ENZYMES
• Biological
catalysts* are
called enzymes
• A catalyst reduces
the amount of
activation energy
required in a
chemical reaction.
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• Enzymes are an important class of
catalysts in living organisms
– Mostly protein
– Thousands of different kinds
– Each specific for a different
chemical reaction
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Enzyme Shape due to
tertiary structure of the
protein.
• Enzymes work on
substances called
substrates
• Substrates must fit
into a place on an
enzyme called the
active site
• Enzymes are
reusable!
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Lock and Key Theory
• Enzymes are specific to their
substrates.
• Enzyme fits the substrate like a key fits
a lock.
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Nucleic
Acids
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Functions of nucleic acids:
• Carry genetic information
• Structure of cell parts called
ribosomes
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Basic subunit of a nucleic
acid:
• Nucleotides
• Nucleic acids are composed of
long chains of nucleotides linked
by dehydration synthesis.
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• Two types:
a. Deoxyribonucleic acid (DNAdouble helix)
b. Ribonucleic acid (RNA-single
strand)
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• Nucleotides include 3 parts:
-phosphate group
-pentose sugar (5-carbon)
-nitrogenous base
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There are 5 different nitrogenous
bases
adenine (A)
thymine (T) DNA only
uracil (U) RNA only
cytosine (C)
guanine (G)
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Nucleotide
Phosphate
Group
O
O=P-O
O
5
CH2
O
N
C1
C4
Nitrogenous base
(A, G, C, T, or U)
Sugar
(deoxyribose)
C3
C2
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DNA - double chain of
O
nucleotides
5
3
3
O
P
5
O
C
G
1
P
5
3
2
4
4
2
3
1
P
T
5
A
P
3
O
O
P
5
O
3
5
P
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