Download - Chapter 5 Macromolecules. Four Classes 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids
Chapter 5
Macromolecules
Macromolecules
Four Classes 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids
Polymer
Chain of linked monomers
polymer monomer
Carbohydrates sugar
Proteins amino acids
Nucleic acids nucleotides
Composite molecule
Lipids glycerol + fatty acid(s)
Bonds
macromolecule bond/link type
Carbohydrates glycosidic linkage
Lipids ester linkage
Proteins peptide bond
Nucleic acids phosphodiester bond
Chemical Reactions
Dehydration synthesis (Condensation) - remove a water molecule, polymerize
Requires enzymes HO 1 2 3 H OH H
H20
short polymer
1 2 3 4HO H
longer polymer
Chemical Reactions
Hydrolysis - add a water molecule, depolymerize
HO H
HO H
H2O
H OH
Metabolism
Anabolism - synthesize molecules polymerization dehydration
Catabolism - breakdown molecules depolymerization hydrolysis
Carbohydrates
CHO sugars function: energy storage (fuel for cellular
work), most are hydrophilic three groups:
monosaccharides disaccharides polysaccharides
Monosaccharides
empirical formula = (CH2O) n n = 3 to 7 n=5 pentose n=6 hexose Examples of hexoses (C6H12O6)
glucose fructose galactose
Disaccharides
monosaccharides disaccharide
glucose + glucose = maltose
glucose + galactose = lactose
glucose + fructose = sucrose
formed through dehydration
Formation of Disaccharaides
glucose glucose maltose
glucose fructose sucrose
Polysaccharide
Covalently bonded glucose unitsGlycosidic linkage - covalent bond between glucose units
amylose(unbranched)
amylopectin
Starch(plants)
Glycogen(animals)
glycogengranules
Cellulosecell wall
cellulose microfibrils in a plantcell wall (about 8O molecules)
unbranched β glucosepolymer
unbranched, alternating OH groupsfound in plant cell walls
Chitin
Glucose plus a nitrogen apendage
Present in exoskeleton of arthropods
used to make strong and flexible surgical thread
Lipids
CHO Function: long-term energy storage
fats other lipids: phospholipids, steroids, pigments
water-insoluble, nonpolar
Fats
Glycerol + fatty acid (s) monoglyceride diglyceride triglyceride
glycerol - 3C alcohol
monoglyceride(palmitic acid)
trigryceride (triacylglycerol)
Fats, cont.
ester linkage - bond between carboxyl (f.a.) and hydroxyl (glycerol)
fatty acids saturated unsaturated
esther linkage
Saturated Fatty Acids
maximum number of H no double/triple bonds usually solid ex. animal fats
(butter, lard)
Unsaturated Fatty Acids
usually liquid 1 double bond
monounsaturated more than 1 double bond
polyunsaturated
ex. Oils (nut and seed) hydrogenation causes it
to solidify peanut oil peanut butter
fats yeald 9 cal/gr
oleic acid
Other Lipids
Phospholipids phosphate + 2 f.a. + glycerol
Steroids Hormones and cholesterol
Pigments chlorophylls xanthophylls carotenes anthocyanins
fatty acids
glycerol
phosphate
choline
hydrophilic
hydrophobic
Proteins
CHON Function: diverse
structures, contraction, storage, defense, transport, messengers, enzymes
monomer: amino acid
Proteins cont.
amino acids (20): most contain -central C -amino group -carboxyl group -H atom -functional group (R)
glycine alanine valine leucine isoleusine
methionine phenylalanine tryptophan proline
serine threonine cysteine tyrosine aspargine glutamine
asparctic ac. glutamic acid lysine arginine histine
Non polar
polar
electricallycharged
R-group
acidic basic
Proteins cont.
*Peptide bonds *between 2 amino acids *dehydration reaction
protein synthesis
side chain
backbone
Levels of Protein Structure The following determine the shape of the
protein (polypeptides): primary secondary tertiary quaternary
Primary Structure of a Protein
+H3N(amino end)
C OH-O(carboxyl end)
amino acid subunits
Start: N-terminus (amino) End: C-terminus (carboxyl)
Secondary Structure of a Protein Bending and H-bonding to form coils and folds forming
alpha helices (coils) and beta pleated sheets (folds)
α- helix
β pleated sheet
Tertiary Structure of a Protein
overall conformation of the polypeptide hydrophobic interactions ionic and hydrogen bonds disulfide bridges
polypeptidebackbone
Quaternary Structure of a Protein Relationship between 2 or more polypeptides
that make up the protein
Protein Conformation
Altering any level will change the final conformation
denaturation - unravel the protein caused by several different factors
Nucleic Acids
CHONP Function: store information monomer - nucleotide
ex. DNA, RNA RNA Genomics - branch of biotech
concerned with mapping and sequencing DNA (genomes)
Nucleotide
Phosphate + sugar + N-base phosphodiester bond between phosphate and sugar
DNA
nucleus Deoxyribonucleic acid double strand A, G, C, T
nucleotide: phosphate + sugar + N-base
The sequence of nitrogenous bases in DNA carries genetic information
stretches of DNA are genes
RNA
cytoplasm Ribonucleic acid single strand RNA
nucleotide: phosphate + sugar + N-base
A, G, C, U
N-bases Purines (A, G)Pyrimidines (C, T, U)Purine-Pyrimidine
A = T
C = G
Activity: DNA
What will the other strand be?
DNA
A
G
C
T
?
?
?
?
DNA
5'
3'
Activity
What will the RNA strand be?
DNA
A
G
C
T
?
?
?
?
RNA
5'
3'
The End