Transcript Macromolecules

Macromolecules
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Organic Compounds
• Compounds that contain CARBON
are called organic.
• Macromolecules are large organic
molecules.
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Carbon (C)
• Carbon has 4 electrons
in outer shell.
• Carbon can form
covalent bonds with as
many as 4 other atoms
(elements).
• Usually with C, H, O
or N.
• Example:
CH4(methane)
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Macromolecules
• Large organic molecules.
• Also called POLYMERS.
• Made up of smaller “building blocks”
called MONOMERS.
• Examples:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids (DNA and RNA)
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Four types of organic
compounds
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Question:
How Are
Macromolecules
Formed?
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Answer: Dehydration Synthesis
• Also called “condensation reaction”
• Forms polymers by combining
monomers by “removing water”.
HO
H
HO
H
H2O
HO
H
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Question:
How are
Macromolecules
separated or
digested?
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Answer: Hydrolysis
• Separates monomers by “adding
water”
HO
H
H2O
HO
H
HO
H
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In digestion, polymers are
broken down into monomers
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Carbohydrates
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Characteristics of
Carbohydrates
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•
•
•
Consist of carbon, hydrogen, & oxygen
Energy containing molecules
Some provide structure
Basic building block is a monosaccharide
(CH2O)n ; n = 3,5,6
• Two monosaccharides form a disaccharide
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Carbohydrates
• Small sugar molecules to large
sugar molecules.
• Examples:
A. monosaccharide
B. disaccharide
C. polysaccharide
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Carbohydrates
Monosaccharide: one sugar unit
Examples:
glucose
glucose (C6H12O6)
deoxyribose
ribose
Fructose
Galactose
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Carbohydrates
Disaccharide: two sugar unit
Examples:
– Sucrose (glucose+fructose)
– Lactose (glucose+galactose)
– Maltose (glucose+glucose)
glucose
glucose
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Hydrolysis of a Disaccharide
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Carbohydrates
Polysaccharide: many sugar units
Examples: starch (bread, potatoes)
glycogen (muscle)
cellulose (lettuce, corn)
glucose
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
glucose
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http://www.chemistryland.com/ElementarySchool/BuildingBlocks/BuildingOrganic.htm
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Important Polysaccharides:
Starch
• Consists of glucose subunits
• Plants store energy as starch (potatoes,
grains, legumes)
• Similar to glycogen in animals
• Starch and glycogen can be digested by
animals.
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Glycogen:
-molecule for storing excess glucose in
humans and animals.
-stored in the body predominantly in
the liver and the skeletal muscles.
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Why did the potato cross the road?
Because he saw the fork up ahead.
Ouch!
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Cellulose
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Important Polysaccharides:
Cellulose
• Polymer composed of glucose subunits
• Different bond formed than starch
• Structural component cell walls) in plants: wood,
paper, cotton
• Cannot be digested by animals
glucose
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
glucose
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LIPIDS
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Lipids
Examples:
1.
2.
3.
4.
5.
6.
Fats (triglycerides)
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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Lipid structure: glycerol
+ 3 fatty acids
Composed of Carbon, Hydrogen,
and Oxygen
Greater than 2:1 ratio of H:O
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Lipids
Triglycerides:
composed 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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Synthesis of a Fat
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Glycerol
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Fatty Acid Structure
•Carboxyl group (COOH) forms the acid.
•“R” group is a hydrocarbon chain.
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A Representative Fatty Acid
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Fatty Acids
There are two kinds of fatty acids you may see
these on food labels:
1. Saturated fatty acids: no double bonds
(bad)
O
saturated C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
2. Unsaturated fatty acids: double bonds
(good)
O
unsaturated C-CH2-CH2-CH2-CH
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Unsaturated
Fatty Acid
Saturated
Fatty Acid
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A Phospholipid
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Phospholipids
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Proteins: the
body’s worker
molecules
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Proteins are like long necklaces with
differently shaped beads. Each "bead" is a
small molecule called an amino acid. There are
20 standard amino acids, each with its own
shape, size, and properties.
Proteins typically contain from 50 to 2,000
amino acids hooked end-to-end in many
combinations. Each protein has its own
sequence of amino acids.
Proteins are made of amino acids hooked endto-end like beads on a necklace.
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Proteins: polymers of amino acids
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• C, H, O, and N
• Basic builiding
block of
proteins
• 20 different aas
• “R” group gives
identity
• All have amino
groups and
carboxyl groups
• Amino acids
form
polypeptide
chains, joined
by peptide
bonds
Amino acids
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FUNCTIONS OF EXAMPLES
PROTEINS
1. structure
2. transport
3. movement
4. Control chemical
reactions
5. Chemical
messengers
6. Immune system
1. Keratin (hair) and
collagen (ligaments,
tendons, skin)
2. Hemoglobin,
membrane channels
3. Actin and myosin
(muscle fibers)
4. Enzymes
5. hormones, receptor
molecules
6. Antibodies
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AMINO ACIDS
??? O
Jo
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Formation of a Dipeptide
Dehydration synthesis
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Amino Acid + Amino Acid --> Dipeptide
Amino Acid + Dipeptide --> Tripeptide
A.A. + A.A. + …..+ Tripeptide --> Polypeptide
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Proteins (Polypeptides)
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
by peptide bonds (straight
chains)
Amino Acids (aa)
aa1
aa2
aa3
aa4
aa5
aa6
Peptide Bonds
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To become active, proteins must
twist and fold into their final, or
"native," “conformation."
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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)
• Call a “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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How heat denatures a protein
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Provocative Proteins (several hundred thousand
different proteins in our body)
Spider webs and silk fibers are made of the strong,
pliable protein fibroin. Spider silk is stronger than a
steel rod of the same diameter, yet it is much more
elastic, so scientists hope to use it for products as
diverse as bulletproof vests and artificial joints.
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The light of fireflies (also called lightning
bugs) is made possible by a protein called
luciferase. Although most predators stay
away from the bittertasting insects, some
frogs eat so many fireflies that they glow!
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The deadly venoms of cobras, scorpions, and
puffer fish contain small proteins that act as
nerve toxins. Some sea snails stun their prey
(and occasionally, unlucky humans) with up to
50 such toxins. One of these toxins has been
developed into a
drug called Prialt®,
which is used to
treat severe pain
that is unresponsive
even to morphine.
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Sometimes ships in
the northwest Pacific
Ocean leave a trail of
eerie green light.
The light is produced
by a protein in
jellyfish when the
creatures are jostled
by ships. Because
the trail traces the
path of ships at
night, this green
fluorescent protein
has interested the
Navy for many years.
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If a recipe calls for
rhino horn, ibis
feathers, and
porcupine quills, try
substituting your own
hair or fingernails.
It's all the same
stuff—alpha-keratin,
a tough, waterresistant protein that
is also the main
component of wool,
scales, hooves,
tortoise shells, and
the outer layer of
your skin.
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Nucleic
Acids
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Nucleic
acids:
polymers of
nucleotides
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What are they made of ?
• Simple units called nucleotides,
connected in long chains
• Nucleotides have 3 parts:
1- 5-Carbon sugar (pentose)
2- Nitrogen containing base
(made of C, H and N)
3- A phosphate group ( P )
• The P groups make the links that
unite the sugars (hence a “sugarphosphate backbone”
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What do they do ?
Dictate amino-acid sequence in
proteins
Give information to chromosomes,
which is then passed from parent to
offspring
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Nucleic acids
• Two types:
a. Deoxyribonucleic acid (DNAdouble helix)
b. Ribonucleic acid (RNA-single
strand)
• Nucleic acids are composed of long
chains of nucleotides linked by
dehydration synthesis.
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Nucleic acids
• Nucleotides include:
phosphate group
pentose sugar (5-carbon)
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, or T)
Sugar
(deoxyribose)
C3
C2
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5
DNA
double
helix
O
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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Review film: compounds of carbon
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