Transcript Macromolecules

Chapter 5:
The Structure and
Function of Large
Biological Molecules
Essential Knowledge
 3.a.1 – DNA, and in some cases RNA, is the primary
source of heritable information (5.5).
 4.a.1 – The subcomponents of biological molecules and
their sequence determine the properties of that molecule
(5.1-5.5).
 4.b.1 – Interactions between molecules affect their
structure and function (5.4).
 4.c.1 – Variation in molecular units provides cells with a
wider range of functions (5.1-5.5).
Macromolecules
 Large molecules formed by joining many
subunits together.
 Macro = giant, large
 Also known as “polymers”.
 Ex: Carbs, proteins, lipids, nucleic acids
Polymers and Monomers
 Polymer—many units bonded together to
make a larger macromolecule

Poly = many
 Monomer - A building block
of a polymer

Mono = one
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
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids
Carbohydrates
 Used for fuel, building materials, and
receptors.
 Made of C,H,O
 General formula is CH2O
 C:H:O ratio is 1:2:1
 Monomers joined by glycosidic linkage
(covalent bond)
Types Of Carbohydrates
1. Monosaccharides
2. Disaccharides
3. 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.
 Aldose – end of chain
 Ketose – middle of chain
 Notice: names of end in -ose
Examples
 Glucose
 Galactose
 Ribose
 Fructose
-ose Names
Word
ending is common for many
sugar/carbohydrates
Disaccharides
 Sugar formed by joining two monosaccharides
through a “glycosidic linkage”
 Examples:
 Maltose = glucose + glucose
 Lactose = glucose + galactose
 Sucrose = glucose + fructose
Polysaccharides
 Many joined simple sugars
 Used for storage or structure
 Polymers made of glucose monomers (either a or
b glucose)
 Examples:
 Starch
 Cellulose
 Glycogen
 Chitin
Starch
 Made of 1-4 linkages of a glucose
 Linkage makes the molecule form a helix
 Fuel storage in plants
Cellulose
 Made of 1-4 linkages of b glucose
 Linkage makes the molecule form a straight
line
 Used for structure in plant cell walls
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
Chitin
 Used by insects, spiders, crustaceans to build
exoskeletons
 Also found in cell walls
 Differs from cellulose – chitin has nitrogen
branch connected to glucose monomer
Monomer:
Glucosamine
Polymer:
Chitin
Lipids – On Your Own First
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online.com/Objects/Vie
wObject.aspx?ID=AP132
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 Visit this website and take notes over the material
presented; we will go through the ppt after to
catch anything missed!
Lipids
 Diverse hydrophobic molecules
 Made of C,H,O
 No general formula
 C:O ratio is very high in C
Lipid monomers
 Made of two kinds of smaller monomers.
 1) Fatty Acids
A long carbon chain (12-18 C) with a -COOH
(acid) on one end and a -CH3 (fat) at the other
 2) Glycerol

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 vs. 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
Fats
 Differ in which fatty acids are used
 Used for energy storage, cushions for organs,
insulation
Oils vs. Fats
 Oil = liquid
 Fats = solid
 Most animal fats are saturated FATS (like lard
and butter.)
 Solids
 Most plant fats are unsaturated fats—we call
these OILS (like olive, veggie oil)
 Liquids
Nutrition and Diet
 Diets high in saturated fats cause heart
disease
 Hydrogenated vegetable oil is a product
whose unsaturated fats have been converted
to saturated fats by adding H
Question???
 Which has more energy, a kg of fat (lipid)
or a kg of starch (carb)?
 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.
 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
Other Lipids…
 Soaps and detergents
 Waxes
 Certain pigments
 Cosmetics
Proteins
 The molecular tools of the cell
 Made of C,H,O,N, and sometimes S
 No general formula
 Polypeptide chains of Amino Acids linked by peptide
bonds
Uses Of Proteins
 Structure
 Enzymes
 Antibodies
 Transport
 Movement
 Receptors
 Hormones
Protein monomers: 20
Amino Acids
 All have a Carbon with four attachments:
 -COOH (acid)
 -NH2 (amine)
 -H
 -R (some other side group)
Amino acid “R” groups
 The properties of the R groups determine the properties
of the protein.
 20 different kinds:
 Nonpolar - 9 AA
 Polar - 6 AA
 Electrically Charged


Acidic - 2 AA
Basic - 3 AA
Polypeptide Chains
 Formed by
dehydration
synthesis between
the carboxyl group of
one AA and the
amino group of the
second AA.
 Produce an 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 structures:
 a helix
 pleated sheets
Tertiary
 Bonding between the R groups.
 Examples:
 hydrophobic interactions
 Hydrogen bonding
 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 (confuses chemical interactions)
 high salt concentrations (confuses chemical
interactions)
 heat (usually renders proteins inactive)
Denaturing, cont.
 Ex: white of an egg turns “white” (denatured protein
due to heat)
 Ex: why extreme temps are so deadly to
people/animals
Nucleic Acids
 Informational polymers
 Pass genetic info from
parent to offspring
 Made of C,H,O,N and P
 No general formula
 Examples: DNA and RNA
Nucleic Acids
 Polymers of nucleotides
 Called polynucleotides
 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)-b/c of neg
charge
 Two types:
 Pyrimidines (single ring)-C,T,U
 Purines (double rings)-A,G
Pentose Sugar
 5-C sugar
 Ribose - RNA
 Deoxyribose – DNA
 RNA and DNA differ in an –OH group on the 3rd carbon
DNA
 Deoxyribonucleic Acid
 Makes up genes
 Genetic information source for
most life
 Found inside nucleus
 Copied during cell cycle
(Interphase)
RNA




Ribonucleic Acid.
Structure and protein synthesis.
Genetic information for a few viruses only.
Found in
 Nucleus and near ribosomes in cytoplasm
 Three types
 Messenger (m)
 Ribosomal (r)
 Transfer (t)
 Contains: Uracil
Macromolecule
Monomer
Polymer
Carbohydrate
Monosaccharide
Disacc, Oligio, Polysacc
Protein
Amino acid
Polypeptide chain
Nucleic acid
Nucleotide
DNA, RNA
(Polynucleotide)
Lipids
Fatty acid, glycerol
Fats, waxes, oils, steroids
Summary
 Recognize how dehydration synthesis can be used to





build polymers from monomers.
Recognize how hydrolysis can be used to break down
polymers into monomers.
Identify the elemental composition, general formula,
types and uses of carbohydrates.
Identify the elemental composition, types and uses of
lipids.
Identify the elemental composition, levels of structure
and uses of proteins.
Identify the elemental composition and general uses of
nucleic acids.