Biologically Important Molecules – II !
Biologically Important Molecules
I. Water
II. Carbohydrates
II. Carbohydrates
A. Structure
1. monomer = monosaccharide
typically 3-6 carbons, and CnH2nOn formula
II. Carbohydrates
A. Structure
1. monomer = monosaccharide
typically 3-6 carbons, and CnH2nOn formula
have carbonyl and hydroxyl groups
II. Carbohydrates
A. Structure
1. monomer = monosaccharide
typically 3-6 carbons, and CnH2nOn formula
have carbonyl and hydroxyl groups
carbonyl is either ketone or aldehyde
II. Carbohydrates
A. Structure
1. monomer = monosaccharide
typically 3-6 carbons, and CnH2nOn formula
have carbonyl and hydroxyl groups
carbonyl is either ketone or aldehyde
in aqueous solutions, they form rings
II. Carbohydrates
A. Structure
1. monomer = monosaccharide
typically 3-6 carbons, and CnH2nOn formula
have carbonyl and hydroxyl groups
carbonyl is either ketone or aldehyde
in aqueous solutions, they form rings
examples:
II. Carbohydrates
A. Structure
1. monomer = monosaccharide
2. polymerization:
dehydration synthesis reaction
II. Carbohydrates
A. Structure
1. monomer = monosaccharide
2. polymerization
3. Polymers = polysaccharides
Disaccharides
Polysaccharides
Polysaccharides
Polysaccharides
The ‘cross-linkages’ in cellulose are not
digestible by starch-digesting enzymes,
so animals cannot eat wood unless they
have bacterial endosymbionts.
Decomposing fungi and bacteria also
have these enzymes, and can access the
huge amount of energy in cellulose.
Polysaccharides
H-bonds link
cellulose molecules
together
Polysaccharides
glucosamine
II. Carbohydrates
A. Structure
B. Function
- energy storage (short and long)
- structural (cellulose and chitin)
CO2
Glucose,
Cellulose,
Starch
H2O
Biologically Important Molecules
I. Water
II. Carbohydrates
III. Lipids
III. Lipids
- not true polymers or macromolecules; an assortment
of hydrophobic, hydrocarbon molecules classes as
fats, phospholipids, waxes, or steroids.
III. Lipids
A. Fats
- structure
III. Lipids
A. Fats
- structure
glycerol (alcohol) with three fatty acids
(or triglyceride)
III. Lipids
A. Fats
- structure
-saturated fats (no double bonds)
Straight chains pack
tightly; solid at room
temperature like butter
and lard.
Implicated in plaque buildup in blood vessels
(atherosclertosis)
Animal fats (not fish oils)
III. Lipids
A. Fats
- structure
-unsaturated fats (no double bonds)
Plant and fish oils
Kinked; don’t pack – liquid at
room temperature.
“Hydrogenation” can make
them saturated and solid, but
the process also produces
trans-fats (trans conformation
around double bond) which
may contribute MORE to
atherosclerosis than
saturated fats)
III. Lipids
A. Fats
- structure
- functions
- long term energy storage (dense)
not vital in immobile organisms (mature plants),
so it is metabolically easier to store energy as
starch. But in seeds and animals (mobile), there is
selective value to packing energy efficiently.
In animals, fat is stored in adipose cells
III. Lipids
A. Fats
- structure
- functions
- long term energy storage (dense)
- insulation (subcutaneous fat)
- cushioning
III. Lipids
A. Fats
B. Phospholipids
- structure
Glycerol
2 fatty acids
phosphate group (and choline)
Hydrophilic and hydrophobic
regions
III. Lipids
A. Fats
B. Phospholipids
- function
selective membranes
In water, they spontaneously
assemble into micelles or
bilayered liposomes.
III. Lipids
A. Fats
B. Phospholipids
C. Waxes
- structure
An alcohol and fatty acid
Wax
Alcohol
Fatty Acid
Carnuba
CH3(CH2)28CH2-OH
CH3(CH2)24COOH
Beeswax
CH3(CH2)28CH2-OH
CH3(CH2)14COOH
Spermacetic
CH3(CH2)14CH2-OH
CH3(CH2)14COOH
III. Lipids
A. Fats
B. Phospholipids
C. Waxes
- structure
- function
Retard the flow of water (plant waxes)
Structural (beeswax)
Signals – waxes on the exoskeleton can signal an insect’s
sexual receptivity.
III. Lipids
A. Fats
B. Phospholipids
C. Waxes
D. Steroids
- structure
typically a four-ring structure with side groups
cholesterol and its hormone derivatives
Cholesterol
Biologically Important Molecules
I.
II.
III.
IV.
Water
Carbohydrates
Lipids
Proteins
IV. Proteins
A. structure
- monomer: amino acids
IV. Proteins
A. structure
- monomer: amino acids
Carboxyl group
Amine group
IV. Proteins
A. structure
- monomer:
amino acids
20 AA’s found in proteins, with
different chemical properties.
Of note is cysteine, which can
form covalent bonds to other
cysteines through a disulfide
linkage.
IV. Proteins
A. structure
- monomer: amino acids
- polymerization: dehydration synthesis
The bond that is formed
is called a peptide bond
IV. Proteins
A. structure
- monomer: amino acids
- polymerization: dehydration synthesis
- polymer: polypeptide
IV. Proteins
A. structure
- monomer: amino acids
- polymerization: dehydration synthesis
- polymer: polypeptide
May be 1000’s of aa’s long
Not necessarily functional (“proteins” are functional polypeptides)
Sequence determines the function
IV. Proteins
A. structure
- monomer: amino acids
- polymerization: dehydration synthesis
- polymer: polypeptide
- protein has 4 levels of structure
1o (primary) = AA sequence
IV. Proteins
A. structure
- monomer: amino acids
- polymerization: dehydration synthesis
- polymer: polypeptide
- protein has 4 levels of structure
1o (primary) = AA sequence
2o (secondary) = pleated sheet or helix
The result of H-bonds between
neighboring AA’s… not involving
the side chains.
Some proteins are functional as
helices - collagen
IV. Proteins
A. structure
- monomer: amino acids
- polymerization: dehydration synthesis
- polymer: polypeptide
- protein has 4 levels of structure
1o (primary) = AA sequence
2o (secondary) = pleated sheet or helix
3o (tertiary) = folded into a glob
The three dimensional structure of the
protein is stabilized by all types of bonds
between the side chains… ionic between
charged AA’s, Hydrogen bonds between
polar AA’s, van der Waals forces, and even
covalent bonds between sulfurs.
IV. Proteins
A. structure
- monomer: amino acids
- polymerization: dehydration synthesis
- polymer: polypeptide
- protein has 4 levels of structure
1o (primary) = AA sequence
2o (secondary) = pleated sheet or helix
3o (tertiary) = folded into a glob
4o (quaternary) = >1 polypeptide
Actin filament in muscle is a sequence of globular actin proteins…
50 myofibrils/fiber
(cell)
http://3dotstudio.com/prenhall/muscle.jpg
IV. Proteins
A. structure
B. functions!
- catalysts (enzymes)
- structural (actin/collagen/etc.)
- transport (hemoglobin, cell membrane)
- immunity (antibodies)
- cell signaling (surface antigens)
IV. Proteins
A. structure
B. functions!
C. designer molecules
If protein function is ultimately determined by AA sequence, why
can’t we sequence a protein and then synthesize it?
IV. Proteins
A. structure
B. functions!
C. designer molecules
If protein function is ultimately determined by AA sequence, why
can’t we sequence a protein and then synthesize it?
Folding is critical to function, and this is difficult to predict because
it is often catalyzed by other molecules called chaparones
IV. Proteins
A. structure
B. functions!
C. designer molecules
If protein function is ultimately determined by AA sequence, why
can’t we sequence a protein and then synthesize it?
Folding is critical to function, and this is difficult to predict because
it is often catalyzed by other molecules called chaparones
Perhaps by analyzing large numbers of protein sequences and
structures, correlations between “functional motifs” and
particular sequences will be resolved.