Transcript Macromolecules - Thornapple Kellogg High School

Chapter 5
The Structure and
Function of
Macromolecules
Focus on:
Elements
in each molecule
How molecules are linked
and unlinked
Examples and functions of
each type of molecule
Macromolecules
Large
molecules formed by
joining many subunits
together.
Also known as “polymers”.
Monomer
A
building block of a polymer.
Condensation Synthesis
or Dehydration Synthesis
The
chemical reaction that
joins monomers into
polymers.
Covalent bonds are formed
by the removal of a water
molecule between the
monomers.
Hydrolysis
Reverse
of condensation
synthesis.
Hydro- water
Lysis - to split
Breaks polymers into
monomers by adding water.
Four Main Types Of
Macromolecules
Carbohydrates
Lipids
Proteins
Nucleic
acids
For each Macromolecule
know the following:
Elements
it contains
Monomer units and
structures
Examples
Uses or roles
Carbohydrates
Used
for fuel, building
materials, and receptors.
Made of C,H,O
General formula is CH2O
C:O ratio is 1:1
Types Of
Carbohydrates
Monosaccharides
Disaccharides
Oligosaccharides
Polysaccharides
Monosaccharides
Mono
- single
Saccharide - sugar
Simple sugars.
3 to 7 carbons.
Can be in linear or ring
forms.
Monosaccharides
Can
be “Aldoses” or
“Ketoses” depending on the
location of the carbonyl
group.
Examples
Glucose
Galactose
Ribose
Fructose
- OSE
Word
ending common for
many carbohydrates.
Disaccharides
Sugar
formed by joining two
monosaccharides through a
“glycosidic linkage”.
Examples
Maltose
= glucose + glucose
Lactose = glucose + galactose
Sucrose = glucose + fructose
Oligosaccharides
2
- 10 joined simple sugars.
Used in cell membranes.
Polysaccharides
Many
joined simple sugars.
Used for storage or structure.
Examples:
Starch
Cellulose
Glycogen
a glucose and b glucose
Starch
Made
of 1-4 linkages of
a glucose.
Linkage makes the molecule
form a helix.
Fuel storage in plants.
a glucose
Cellulose
Made
of 1-4 linkages of
b glucose.
Linkage makes the molecule
form a straight line.
Used for structure in plant
cell walls.
b glucose
Comment
Most
organisms can digest
starch (1- 4 a linkage), but
very few can digest cellulose
(1- 4 b linkage).
Another example of the link
between structure and
function.
Glycogen
“Animal
starch”
Similar to starch, but has
more 1-6 linkages or
branches.
Found in the liver and muscle
cells.
Starch
Glycogen
Lipids
Diverse
hydrophobic molecules.
Made of C,H,O
No general formula.
C:O ratio is very high in C.
Fats and Oils
Fats
- solid at room
temperature.
Oils - liquid at room
temperature.
Fats and Oils
Made
of two kinds of smaller
molecules.
Fatty
Acids
Glycerol
Fatty Acids
A
long carbon chain (12-18 C)
with a -COOH (acid) on one
end and a -CH3 (fat) at the
other.
Acid
Fat
Neutral Fats or
Triacylglycerols
Three
fatty acids joined to
one glycerol.
Joined by an “ester” linkage
between the -COOH of the
fatty acid and the -OH of the
alcohol.
Saturated Fats
Unsaturated Fats
Saturated
- no double bonds.
Unsaturated - one or more
C=C bonds. Can accept more
Hydrogens.
Double bonds cause “kinks”
in the molecule’s shape.
Question
Why
do fats usually contain
saturated fatty acids and oils
usually contain unsaturated fatty
acids?
The double bond pushes the
molecules apart, lowering the
density, which lowers the
melting point.
Fats
Differ
in which fatty acids are
used.
Used for energy storage,
cushions for organs,
insulation.
Question ?
Which
has more energy, a kg
of fat or a kg of starch?
Fat - there are more C-H
bonds which provide more
energy per mass.
Phospholipids
Similar
to fats, but have only
two fatty acids.
The third -OH of glycerol is
joined to a phosphate
containing molecule.
Result
Phospholipids
have a
hydrophobic tail, but a
hydrophilic head.
Self-assembles into micells
or bilayers, an important part
of cell membranes.
Steroids
Lipids
with four fused rings.
Differ in the functional
groups attached to the rings.
Examples:
cholesterol
sex
hormones
Proteins
The
molecular tools of the cell.
Made of C,H,O,N, and
sometimes S.
No general formula.
Uses Of Proteins
Structure
Enzymes
Antibodies
Transport
Movement
Receptors
Hormones
Proteins
Polypeptide
chains of Amino
Acids linked by peptide
bonds.
Amino Acids
All
have a Carbon with four
attachments:
-COOH (acid)
-NH2 (amine)
-H
-R (some other side group)
R groups
20
different kinds:
Nonpolar
- 9 AA
Polar - 6 AA
Electrically Charged
Acidic
- 2 AA
Basic - 3 AA
Amino Acids
Amino Acids
R groups
Contain
the S when present
in a protein.
Cysteine
or Cys
Methionine or Met
The
properties of the R
groups determine the
properties of the protein.
Polypeptide Chains
Formed
by dehydration
synthesis between the
carboxyl group of one AA
and the amino group of the
second AA.
Produce a backbone of:
(N-C-C)X
Levels Of Protein
Structure
Organizing
the polypeptide
into its 3-D functional shape.
Primary
Secondary
Tertiary
Quaternary
Primary
Sequence
of amino
acids in the
polypeptide chain.
Many different
sequences are
possible with
20 AAs.
Secondary
3-D
structure formed by hydrogen
bonding between parts of the
peptide backbone.
Two main secondary
structures:
a
helix
pleated sheets
Tertiary
Bonding
between the R groups.
Examples:
hydrophobic
interactions
ionic bonding
Disulfide bridges
(covalent bond)
Quaternary
When
two or more
polypeptides unite to form a
functional protein.
Example: hemoglobin
Is Protein Structure
Important?
Denaturing Of A
Protein
Events
that cause a protein to
lose structure (and function).
Example:
pH
shifts
high salt concentrations
heat
Comment
Many
other amino acids are
possible (change the R group)
Whole new group of proteins
with new properties can be
made
Genetic engineering can use
bacteria to make these new
proteins
Nucleic Acids
Informational
polymers
Made of C,H,O,N and P
No general formula
Examples: DNA and RNA
Nucleic Acids
Polymers
of nucleotides
Nucleotides have three parts:
nitrogenous
base
pentose sugar
phosphate
Nitrogenous Bases
Rings
of C and N
The N atoms tend to take up
H+ (base).
Two types:
Pyrimidines
(single ring)
Purines (double rings)
Pentose Sugar
5-C
sugar
Ribose - RNA
Deoxyribose – DNA
RNA and DNA differ in a
–OH group on the 2nd carbon.
Nucleosides and
Nucleotides
Nucleoside
= base + sugar
Nucleotide = base + sugar + Pi
DNA
Deoxyribonucleic
Makes
Acid.
up genes.
Genetic information
for life.
RNA
Ribonucleic
Acid.
Structure and protein
synthesis.
Genetic information for a few
viruses only.
DNA and RNA
More
will be said about DNA
and RNA in future lessons.
Summary
Role
of hydrolysis and
dehydration synthesis
For each macromolecule, know
the following:
Elements
and monomers
Structures
Functions