Transcript MACROMOLECULES - Savitha Sastry

MACROMOLECULES
• Macromolecules (1000’s
of atoms and weigh over
100,000 daltons)
• 4 Kinds of
macromolecules:
Carbohydrates, lipids,
proteins, and nucleic acids
(know this in your sleep!)
MACROMOLECULES ARE:
 POLYMERS:
chainlike molecules
made up of  MONOMERS: (the
repeated units)
 Diversity of Polymers
– different sequences
of the basic 40-50
monomers
How do monomers make polymers?
 Condensation /Dehydration
reaction:
 One monomer provides
an ‘–OH’ and
the other provides a
‘-H’ and together
these form H2O
 H2O is REMOVED; Covalent bond
is formed between MONOMERS =
Polymers are made!
 Needs ATP and Enzymes
 Anabolic/biosynthesis reactions use
this to make macromolecules for
growth/replacement
How do polymers break up?
 Hydrolysis Reaction:
 Covalent Bond is broken;
H2O is added across the
broken bond
 Polymers make Monomers
 Provides ATP and Uses
Enzymes
 Used for digestion, cell
respiration
I) Sugars are all - Carbohydrates
Monomer Unit of
Carbohydrates called:
Monosaccharides
Polymer called
Polysaccharide
General formula: [CH2O]n
– For example, glucose has
the formula C6H12O6.
– Most names for sugars end
in -ose.
SUCROSE (from cane
sugar)
FRUCTOSE (from FRUIT!!)
MALTOSE (from ‘Malt’
– a fermentation product)
DEXTROSE (=glucose)
LACTOSE (from MILK)
Monosaccharide Classification Overview:
1) Based on Aldehyde or Ketone Functional group
(aldose/ketose)
2) Number of Carbon atoms (pentose, hexose…)
3) Arrangement of Carbon Atoms - Isomers
4) Straight chain or ring structure
-
Know how to identify a simple sugar/monosachcharide
by sight as a ring structure and a straight chain structure
Know the glycosidic linkage is represented as an -Owhen 2 monosachcharides are connected
Monosaccharide Classification
1) Based on Functional
Group:
• KETOSE = Ketone
function group (C=O)
• ALDOSE = Aldehyde
functional group
(-CHO)
FRUCTOSE
GLUCOSE
Monosaccharide Classification
2) Based on Number of
Carbons:
 HEXOSE = 6 C
 PENTOSE = 5 C
 TRIOSE = 3C
RIBOSE (5)
GLUCOSE (6)
Monosaccharide Classification
3) Based on Arrangement
of Carbon Atoms:
 Enantiomers: Isomers
(Glucose and
Galactose)
 No test ques. on this
for your level!
Monosaccharide Classification
4) Based on Ring Structure : Linear monomers form rings in
solutions
(Alpha and Beta Rings – based on plane of –OH -skip details)
Monosaccharide to Disaccharide
(dehydration reaction)
- Important Disaccharides (Sucrose – table
sugar, Lactose – Milk, Maltose – Beer)
Glucose
+ Fructose
= Sucrose
Glucose
+ Galactose
=
Lactose
Glucose
+ Glucose
=
Maltose
Monosaccharide to Disaccharide
 A Glucose monomer and a fructose monomer can be
joined using a GLYCOSIDIC LINKAGE to form
SUCROSE (know to identify this link)
 SUCROSE is a DISACCHARIDE
SUCROSE
Glucose
Fructose
Monosaccharide to Disaccharide
 A Glucose monomer and a fructose monomer
can be joined using a GLYCOSIDIC LINKAGE
to form SUCROSE
 SUCROSE (table sugar) is a DISACCHARIDE
SUCROSE
Glucose
Fructose
Monosaccharide to Polysaccharide
- 1000’s of monosaccharides join up to
form POLYSACCHARIDES
G + G +
G + G +
=
………………
Polysaccharide
Carbohydrate Review
Monosacharrides
Disacharrides
(glucose, fructose)
(sucrose, lactose)
Condensation/dehydration reaction
Polysacharrides
Structural
Storage
Cellulose
+
Chitin
Starch
+
Glycogen
(Plant)
(Animals)
a) Storage Polysaccharides
1) STARCH (in potatoes –
‘stored NRG’ in plants)
MONOMER is Glucose
Links up to form starch
many, many glucose molecs)
a) Storage Polysaccharides
1) STARCH has 2 polymers: (skip details)
1-4  linkage of Glucose Monomers (amylose
-helical)
1-6  linkages causes branching (amylopectin)
a) Storage Polysaccharides
2) GLYCOGEN
(in animals – ‘stored ATP’ in
muscle and liver)
MONOMERS – Glucose
b) Structural Polysaccharides
1) CELLULOSE
(in plant cell wall)
Monomers-Glucose
1-4 linkage
b) Structural Polysaccharides
2) CHITIN
(in exoskeleton of
arthropods)
Monomers-Glucose
Glucose has a ‘-N
group’ attached
Starch Test – Lugol’s Iodine
Benedict’s Test
• Will be positive for
Reducing Sugars
(monosaccharides,
disaccharides except
sucrose)
Benedict’s Test
• CuSO4
Cu++ + SO4--
• 2 Cu++ + Reducing
Sugar
Cu+
(electron donor)
• Cu+
Cu2O
II) Lipids
 Lipids – are hydrophobic
(mostly hydrocarbons)
 They are NOT polymers
 Important classes: FATS,
PHOSPHOLIPIDS, and
STEROIDS
FATS
 Fats– are
triglycerides - have
glycerol and
fattyacids linked up
by an ‘ester’ bond
 Glycerol is a 3C
alcohol
 Fatty acid is
RCOOH and can
have long
hydrophobic C-H
chains- these can
have double bonds
or single bonds or a
mixture
Saturated fats - solids at room temp. - have all Carbons SATURATED - that
means every carbon has max. number of hydrogen attached Ex. butter
Unsaturated fats - liquid at room temp. - have some Carbons UNSATURATED that means DOUBLE BONDS from some carbons having less than max. number
of hydrogen attached Ex. Oil.
DOUBLE BONDS = freedom of movement!
CARCINOGENIC
Percent Fatty Acid Present in Triglycerides
Fat or Oil
Saturated
Palmitic
Unsaturated
Stearic
Oleic
Linoleic
Other
Animal Origin
Butter
29
9
27
4
31
Lard
30
18
41
6
5
Beef
32
25
38
3
2
Vegetable Origin
Corn oil
10
4
34
48
4
Soybean
7
3
25
56
9
Peanut
7
5
60
21
7
Olive
6
4
83
7
-
Artherosclerosis-plaque in artery
Fat Substitutes
• Olestra - sucrose (sugar)
with fatty acids (No
digestion!!)
• Hydrogenated Vegetable
Oils: Peanut Butter,
Shortening, Margarine
Fat Functions
• Energy Storage (1 gm of fat =
2 gm starch; fat- 4 cal/gm)
• Plants use starch to store
energy (bulky); seeds have oil
• Animals – store energy as fat
• Insulation; Protect vital organs
• Absorption of Vitamins K, E,
D, A
Phospholipids
• Fatty acids
•• (hydrophobic)+
Two
fatty acids
Phosphate
glycerol+
attached
to–ve
Group
is
phosphate group
glycerol
and
a
• +polar
R – fatty
acid
group
phosphate
(hydrophilic)
hydrocarbon
group
thetails
• The
fattyatacid
chain
third
position
are
hydrophobic,
• X – other
but the phosphate
groups
group
and its
attachments form a
hydrophilic head
• -know to recognize
it!
Steroids
• Consist of 4
fused rings
• Cholesterol,
sex hormones
• Vary in
functional
groups
Lipid Test
• Brown paper turns
translucent with lipid
(grease test)
• Sudan IV Test:
Proteins
• Proteios – first
place!!
• Polymers made up
of Amino Acid
Monomers
Amino Acids
• Have Carboxyl
(COOH) and amino
groups (NH2)
• Center – Alpha
Carbon
• ‘R’ – 20 different
possibilities = 20
amino acids
• Ionized at neutral pH
inside the cell (COOand NH3+)
Amino Acids
• Hydrophobic ‘R’ groups
Amino Acids
• Hydrophilic Polar ‘R’ groups
Amino Acids
• Electrically charged ‘R’ groups (Acidic/ Basic; also
hydrophilic)
Amino Acids
• Peptide Bond Formation: (O=C-NH) Dehydration reaction
linking amino acid monomers into a polypeptide chain- know
this bond!
Amino Acids
• Primary Structure:
Sequence of amino
acid chain - is it ValHis-Leu… or ValGlu-Leu….
• Change in Primary
Structure can cause
protein to function
abnormally (DUH!)
Lysozyme
 Helix
 Pleated Sheets
Amino Acids
• Secondary
Structure: Result of
H Bonding between
O=C and N-H
(atoms in this
secondary structure
are in the
polypeptide
backbone)
•  Helix (coils) –
every 4th aa linked
•  Pleated Sheets
(folds)
Amino Acids
• Tertiary Structure: Result of
H Bonding between side
chain ‘R’ groups
 H bonds among polar and/or
charged groups;
 ionic bonds between charged
R groups, and hydrophobic
interactions
 and van der Waals
interactions among
hydrophobic Rgroups
 Disulfide Bridges (know this is
important in tertiary
structure!)
Amino Acids
• Quarternary Structure:
Result of noncovalent
interactions between
polypeptide chains
 Dimers, Trimers,
Tetramers – aggregations
of many polypeptide
subunits
Why is folding important?
“Diseased prions
induce healthy
prion proteins to
change their
shape, and
clusters of
disease build,
leaving holes in
the brain.” – SF
Chronicle
Denaturation
• Protein Denaturation – Loss of biological activity
• Loss of Native Confirmation/folding due to changes in pH, salt
concentration, temperature
• Protein can come back to original confirmation (Renatured)
Chaperonins
• The folding of many proteins is protected in cells by
chaperonin proteins that shield out bad influences.
Biuret Test
• Biuret Reagent has
CuSO4 and KOH
• Blue-violet = proteins
• Purple/pink = peptides
• Will not detect free amino
acids
Nucleic Acids
• Amino Acid
Sequence of a
Polypeptide is
coded by a GENE
• A gene is a specific
sequence of DNA
• DNA is made of
Nucleic Acids
Nucleic Acids
• GENE codes for a
messenger RNA in
the nucleus
• mRNA is
translated in the
cytoplasm
• Protein is
synthesized using
the mRNA
Nucleic Acids
• DNA and RNA are
Nucleic Acids
• Nucleic Acids are
Polymers
• The monomers are called
NUCLEOTIDES
Nucleotides
• NUCLEOTIDES
are made of:
• Pentose Sugar
• Nitrogen Base
• Phosphate group
NucleotidesNitrogen Base
• Nitrogen Base can be
of 2 types:
• Purine – 2 rings;
Adenine and Guanine
• Pyrimidine – 1 ring;
Cytosine, Uracil, and
Thymine
NucleotidesNitrogen Base
• Purines and
Pyrimidines bond
with each other
• A can form a bond
with T or U
• G can form a bond
with C
Nucleotides-Sugar
• Pentose Sugar is Ribose
• DNA has Deoxy Ribose
• RNA has Ribose
NucleosidesNo Phosphate group
• Pentose Sugar + Nitrogen Base
Nucleotides
• Pentose Sugar + Nitrogen Base + Phosphate
Nucleotides join together to make Nucleic Acids
Sugar – Phosphate
backbone
DNA is a double helix – 2 strands are
complementary
1953
DNA Spooling