Transcript Chapter 5

Chapter 5
Organic Macromolecules
Polymerization is…
– the forming of large organic compounds
(polymers) by the joining of smaller repeating
units called monomers
M
M
M
How does polymerization occur?
By Dehydration Synthesis: the removal of a
water molecule to form a new bond.
HO
1
2
3
H
HO
Short Polymer
Monomer
H2O
Dehydration removes a water
molecule forming a new bond
HO
1
2
H
3
4
H
How are polymers broken?
• by hydrolysis - literally, “Water Splitting”
HO
• Add water to break bonds
2
HO
1
2
3
4
H
HO
H
Hydrolysis adds a water
molecule to break a bond
HO
1
2
3
Short Polymer
H
Monomer
4 Types of Organic Polymers
1)
2)
3)
4)
Carbohydrates
Lipids
Proteins
Nucleic Acids
Carbohydrates
•
•
•
•
•
•
•
Formula (CH2O)n
2:1 ratio of H:O
Carbonyl Groups
Ring form in (aq) solution
Important Energy Source
Cellular Structures
Monomer:
– Monosaccharides
• Polymers:
– Disaccharides
– Polysaccharides
Monosaccharides
Monosaccharides (simple sugars)
– Contain 3-7 Carbons each
• Examples: Glucose
Glucose, Galactose, Fructose
Disaccharides
Disaccharides (two sugars) – joined by
dehydration synthesis
• Examples: Sucrose
Sucrose, Maltose, Lactose
– Maltose = Glucose + Glucose
– Lactose = Glucose + Galactose
Glucose
Fructose
Polysaccharides
Polysaccharides (many sugars, usually
thousands)
• Examples: Starch
Starch, Glycogen, Cellulose
Chloroplast
Starch
Liver Cell
Cellulose
Glycogen
Plant Cells
Starch and Cellulose Structures
(Plant Polysaccharides)
ά – linkages (cis- formation) are easily hydrolyzed, while β linkages (trans-formation)are not
Glycogen and Chitin
(Animals Polysaccharide)
• Glycogen = glucose
polymer
– Stored in
liver/muscle
• Chitin = structural
polymer in
exoskeletons
Lipids
• Elements: C, H, O with H:O ratio > 2:1
• Hydrophobic
• Lipids function in:
– Energy (E) storage,
– forming cell membranes,
– and as chemical messengers
(ex. hormones)
• Monomers: glycerol, fatty acids, sometimes
phosphate groups
• Polymers:
– Fats (triglycerides)
– Phospholipids
– Steroids
Triglycerides
Fats (Triglycerides)
– Glycerol + 3 Fatty Acids
– Saturated = No Double Bonds (solid)
– Unsaturated = Double Bonds (liquid)
OH
OH
OH
OH
OH
Ester Bonds
OH
Phospholipids
Phospholipids
– Glycerol with Phosphate Head +
2 Fatty Acid Chains
– Amphiphilic (“Both” “lover”)
•
•
Hydrophilic headPhosphate
Hydrophobic tail
Glycerol
– Forms 2 layers in water
– Makes up cell membranes
Fatty Acids
Steroids
AKA Sterols
OH
– Lipids whose Carbon Skeleton
consists of 4
fused rings
O
OH
O
– Includes:
•
•
•
HO
Hormones
Cholesterol
Cortisol
– Makes up cell membranes
HO
O
Testosterone
Estrogen
OH
Proteins (Polypeptides)
• Polymers of AA
– 20 AA, all varied in their “R” groups
– 9 essential AA can not be made by the body
• 50% of dry weight of organisms
• Varied fcns: enzymatic, structural,
hormonal, transport, storage, mvmt,
defense, etc.
• Protein function unique with 3-D shape
Proteins
•
Protein monomers are called amino acids
– Peptide Bond:
Bond between 2 Amino Acids:
Amino end
Carboxyl end
R Group =
Side
Chains
H2O
Backbone
Protein Structure
Polypeptides fold and twist to form a specific shape to
create a functional protein
Figure 5.24 Review: the four levels of protein structure
•
•
•
•
Primary
Secondary
Tertiary
Quarternary
Primary Structure
AA sequence
Secondary Structure
• AA H-bonded at
backbone
• (no interaction btwn
side chains)
• α – Helix
• β - Pleated Sheats
Tertiary Structure
• More Complex
Folding
• Interactions btwn side
chains
– H bonds
– Ionic Bonding (+/-)
– Hydrophobic
Interactions
– Disulfide Bridges
Figure 5.22 Examples of interactions contributing to the tertiary structure of a protein
Quarternary Structure
Figure 5.23 The quaternary structure of proteins
• 2 or more polypeptide
chains assemble
• Ex. Hemoglobin (4
polypeptide chains)
Functional Proteins
I am completely
The twisting andI folding
into
tertiary or quarternary
am
an
enzyme.
unchanged,
and
Hi
sweeties,
Do
structures
creates
active
sites
with a specific shape
I am
the
active
site.
I
am
going
to
try
ready
for
some
more
that fits specific
substrates that are responsible for
you
remember
The substrate
binds
I am a product, too.
tosucrose!
convert
you.
catalyzing reactions
me?
to me.
I am a fructose now.
I am now a product.
In addition
I am a glucose
now. to what
you know. I am a
substrate.
Factors That Affect Protein
Formation
• pH
• Salinity
• Temperature (ex.
Boiled egg)
• Denaturization =
unraveling of protein 
loss of shape and
function
• Renaturization can
occur, but not always
Figure 5.25 Denaturation and renaturation of a protein
Nucleic Acids
• Nucleic Acids
– Informational Polymers: Code for all of the
proteins in an organism
– Monomers: Nucleotides
• Phosphate Group
• Pentose 5-C Sugar
– Ribose or deoxyribose
• Nitrogenous base
– Purines (A, G)
– Pyrimidines (T, C, U)
Nucleic Acids
• Polymers
– DNA
– RNA (tRNA, mRNA,
rRNA)
• DNA directs RNA
synthesis
• RNA directs protein
synthesis
Base Pairing Rules
• DNA Base Pair Rules
C=G
A=T
• RNA Base Pair Rules
C=G
A=U