Focus on: u Elements in each molecule u How molecules are linked and unlinked u Examples and...
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Transcript of Focus on: u Elements in each molecule u How molecules are linked and unlinked u Examples and...
Focus on:
Elements in each molecule How molecules are linked
and unlinked Examples and functions of
each type of molecule
Chapter 3 The Chemical Building
Blocks of Life
Macromolecules
Large molecules formed by joining many subunits together.
Also known as “polymers”.
Monomer
A building block of a polymer.
AP Biology
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 Protein 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
glucose and glucose
Starch
Made of 1-4 linkages of glucose.
Linkage makes the molecule form a helix.
Fuel storage in plants.
glucose
Cellulose
Made of 1-4 linkages of glucose.
Linkage makes the molecule form a straight line.
Used for structure in plant cell walls.
glucose
Comment
Most organisms can digest starch (1- 4 linkage), but very few can digest cellulose (1- 4 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.
Glycogen
Starch
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 FatsUnsaturated 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 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 secondary structures: 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 Acid. Makes 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