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Macromolecules Chapter 4-5 1
MacromoleculesSome molecules called macromolecules because of
their large sizeUsually consist of many repeating units
Resulting molecule is a polymer (many parts) Repeating units are called monomers
Some examples:
NucleotideDNA, RNANucleic Acids
Amino acidPolypeptideProteins
MonosaccharidePolysaccharideCarbohydrates
Glycerol & fatty acidsTriglycerideLipidsSubunit(s)ExampleCategory
These moleculesare more obviouslypolymers
Polymer Monomer
Macromolecules Chapter 4-5 2You should be able to recognizethe following macromolecules
.
(Label the following as either fats, proteins, amino acids, carbohydrates or nucleic acids)
a. ________ b. ________ c. ________ d. ________
e. ________ f. ________ g. ________
Macromolecules Chapter 4-5 3How macromolecules are made and used.Dehydration and Hydrolysis
Know:a. Organic polymers are made via a metabolic process calledDehydration synthesis
b. Polymers are taken apart by a process called hydrolisis (this name should remind you that one water molecule us produced by this process.)
Macromolecules Chapter 4-5 4
Dehydration Synthesis Fig. 5.2 p69
Macromolecules Chapter 4-5 5
Hydrolysis of a polymer
Macromolecules Chapter 4-5 6Examples of the 4 classes of macromolecules.1 - Carbohydrates
I.Monosaccharides: (single sugar molecules) Glucose - 6 carbon sugars used by animals and plants for cellular respiration Ribose, deoxyribose – 5 carbon sugars which are components of DNA and RNA
II. Disaccharides: (Two monosaccharides joined by dehydration)
Sucrose – common form of plant sugars (glucose + fructose)
III. Polysaccharides: (Polymers of monosaccharides)• Starch, cellulose, chitin – storage and structural form of sugars.
7Models for Representing
Glucose Molecules
Formula: C6H12O6
8Synthesis Disaccharides
Maltose and Fructose
Macromolecules Chapter 4-5 9Two general forms of Carbohydrates1. Storage forms of carbohydrates.
Polymers of monosaccharidesLow solubility; not sweet to tasteExamples
Starch = Polymer of glucoseUsed for short-term energy storage
Amylose = Plant starch (eg. corn starch)- unbranched chain, or slightly branched
Glycogen = Animal starch- Highly branched- in liver and muscles
10Starch structure
and function
Storage form of carbs in plants
Fig. 5.6 p72
11Glycogen structure
and function
Storage form of carbs in animals
Macromolecules Chapter 4-5 12
Structural forms of carbohydrates
I. Cellulose Long, coiled polymer of glucose Glucoses connected differently than in starch Structural element for plants Main component of wood and many natural fibers Indigestible by most animals
II. Chitin Polymer of glucose Each glucose with an amino group Very resistant to wear and digestion Arthropod exoskeletons, cell walls of fungi
III. Peptidoglycans- Bacterial cell walls.
Macromolecules Chapter 4-5 13
2. Carbohydrates as structural materials
chitin
notes:Carbohydrates for
structural material :
a. In plants, cellulose
b. In some animals (insects and crustaceans), chitin
c. In bacteria, peptidoglycan.
14Cellulose structure and Function
Notice alternate orientation
Fig. 5.7 p.71
15Starc
hExocycliccarbonsAllonthesameSide!
Macromolecules Chapter 4-5 16
Carbohydrate summary:
1. Monosacharides: ex. Glucose, Fructose2. Disacharides : Sucrose (glucose + fructose)3. Polysacharides:
a) Starch (plants), Glycogen (animals) -Storageb) Cellulose (structural in plants) –alternation of bond orientation
c) Chitin (structural in insects and crabs etc. )d) Peptidoglycan (structural in bacteria).
Macromolecules Chapter 4-5 17Four Classes of Organics:2 - Lipids
Insoluble in water Long chains of repeating CH2 units Renders molecule nonpolar
Types of Lipids
Cholesterol, TestosteroneEstrogen, Progesterone, etc
Component of plasma membrane; hormonesSteroids
PhospholipidsComponent of plasma membranePhospholipids
Fatty AcidsLong-term energy storage in plants and their seeds “Oils”
TriglyceridesLong-term energy storage & thermal insulation in animals “Fats”
CompoundsOrganismal UsesType
Di, and Triesters..Wear resistance; retain waterWaxes
TG’S
18Types of Lipids:I. Fatty acids
Saturated
A.
B.
Fig. 5.11 p75
Macromolecules Chapter 4-5 19Types of Lipids:II. Triglycerides
Animals typically store fatty acids in groups of 3 attached to a glycerol molecule.
Triglycerides (Fats) Long-term energy storage Backbone of one glycerol molecule Three-carbon alcohol Each has an OH- group Each fatty acid may be
Saturated - no double bonds between carbons or Unsaturated - 1 double bonds between carbons
Carboxylic acid at one end Carboxylic acid connects to –OH on glycerol in
dehydration reaction
20Dehydration Synthesis of Triglyceridefrom Glycerol and Three Fatty Acids
Macromolecules Chapter 4-5 21Types of Lipids:III. Phospholipids
Phospholipids Glycerol backbone Two fatty acids attached instead of three Third fatty acid replaced by phosphate group The fatty acids are nonpolar and hydrophobic (“hates water)
The phosphate group is polar and hydrophilic (“likes water)
Molecules self arrange when placed in water Polar phosphate “heads” next to water (= hydrophilic) Nonpolar fatty acid “tails” overlap and exclude water
(hydrophobic) Spontaneously form double layer & a sphere (cell membrane)
22Phospholipids Form Membranes
Polar headOrients towardwater
Fig. 5.12p76
Macromolecules Chapter 4-5 23Types of Lipids:IV. Steroids & Waxes
SteroidsCholesterol, testosterone, estrogenSkeletons of four fused carbon rings
WaxesLong-chain fatty acid bonded to a long-chain alcoholHigh melting pointWaterproofResistant to degradation
Macromolecules Chapter 4-5 24
Steriods
Know this basic structure!!
Side chains willvary
25Waxes
26Additional Wax structures
Macromolecules Chapter 4-5 27Four Classes of Organics:3 -Proteins
Functionsa. Support – Collagenb. Enzymes – Almost all enzymes are proteinsc. Transport – Hemoglobin; membrane proteinsd. Defense – Antibodiese. Hormones – Many hormones; insulinf. Motion – Muscle proteins, microtubules(see fig. 5.13, p. 76)
Know these six functions of proteins
Macromolecules Chapter 4-5 28Protein Subunits:The Amino Acids
There are 20 different amino acids that make up proteinsAll of them have basically the same structure except for what occurs at the sidechain R
Proteins are polymers of amino acids
29Physical / Chemical properties of amino acids:
3 Main Groups
Nonpolar
1.
Fig. 5.16 p79
30
2.Polar
3.
charged
Macromolecules Chapter 4-5 31Proteins:Making polypeptides from amino acids.
Amino acids joined together end-to-end Special name for this bond - Peptide Bond Can have 3 or 4 amino acids (AA) joined
together, or several thousand Characteristics of a protein are determined by
composition and sequence of AA’s Virtually unlimited number of proteinsEx. 10 AA’s can have 1020 different sequences.
32Synthesis of a PeptideDehydration synthesis forms a peptide bond between the
carboxyl group of one amino acid and the amino group of another.
Or:Taken apart (digestion)by hydrolysis!
Macromolecules Chapter 4-5 33Protein Molecules:Levels of Structure
Primary: Literally, the sequence of amino acids A string of beads (up to 20 different colors)
Secondary: The way the amino acid chain coils or folds
Tertiary: Overall three-dimensional shape of a polypeptide Describing how the coils and folds interact with
eachotherQuaternary:
Consists of more than one polypeptide Like several completed knots glued together
34Levels of Protein Organization
A. Primary structure
35Levels of Protein Organization
B. Secondary Structure
Macromolecules Chapter 4-5 36
Protein Folding
nonpolar
polar
charged
Where in a proteinwould you expect tofind each of these groupsof amino acids?
37Levels of Protein Organization
C. Tertiary Structure
Hydrophobic interactions
-COOH--
Charged amino acids
Fig. 5.18 p81
38Levels of Protein Organization
D. Quaternary Structure
1o 2o 3o 4o
39Examples of Fibrous Proteins
Keratin
Fibroin
Beta-mercaptoethanolused to add moredisulfide bonds
(between which aminoacids ?)
Alpha helices
Beta-pleated sheets
Fibroin
Macromolecules Chapter 4-5 40
Protein Folding Chaperones
Defective protein foldingIs involved in human Disease:
Ex:
• Alzheimer's• CJD –Creutzfeldt Jacobs(“Mad Cow Disease”)
Macromolecules Chapter 4-5 41Four Classes of Organics:4 -Nucleic Acids
Polymers of nucleotides (C,T, A, G, U) Very specific cell functions
DNA (deoxyribonucleic acid) Double-stranded helical spiral (twisted ladder) Serves as genetic information center In the nucleus of cells in chromosomes.
RNA (ribonucleic acid) Part single-stranded, part double-stranded** Serves primarily in assembly of proteins (several types:
tRNA, mRNA, rRNA and snRNP’s) In nucleus and cytoplasm of cell
Macromolecules Chapter 4-5 42The Nucleotides ofNucleic Acids
Three components:1. 5 carbon ribose sugar2. phosphate group3. nitrogenous base group
Nucleotide subunits connected end-to-end to make nucleic acid
Sugar of one connected to the phosphate of the next
Sugar-phosphate backbone
Macromolecules Chapter 4-5 43The Structure ofNucleic Acids
Nucleotide subunits connected end-to-end to make nucleic acid
Sugar of one connected to the phosphate of the next
Sugar-phosphate backbone
44
Nucleotides
45DNA StructureThe double alpha-helixstructure of DNA that was determined byWatson and Crick 1953
46RNA Structure
RNA is mostly singlestranded or folds backon itself to form doublestranded structures Called “Stem-loops”
Macromolecules Chapter 4-5 47
NoYesHelixInterprets genetic info; protein synthesis
Heredity; cellular control centerFunction
Cell nucleus and cytoplasm
Chromosomes of cell nucleusWhere
Comparison of DNA & RNA
Mostly single strandedDouble-stranded; Pairing across strandsStrands
Cytosine, guanine;adenine, uracil
Cytosine, guanine;adenine, thymineBases
RiboseDeoxyriboseSugarRNADNAFeature
Macromolecules Chapter 4-5 48Other Nucleic AcidsATP – the energy currency of cells
ATP (adenosine triphosphate) is composed of adenine, ribose, and three phosphates
In cells, one phosphate bond is hydrolyzed – Yields:The molecule ADP (adenosine diphosphate)An inorganic phosphate molecule pi
Energy
Other energy sources used to put ADP and pi back together again
49ATPThe three “high energy” phosphate bonds of ATP are whatMake this molecule so useful in many enzymatic reactions.
Macromolecules Chapter 4-5 50
Review
Organic vs Inorganic
Functional Groups / Isomers
Macromolecules1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids
– covalent C, O, H, N versus ionic metals and salts
- Amino, carboxyl, phosphate, sulhydryl. - Iosomers = same formula, different structure
- starch, glycogen, (made from polymerized glucose)- Cellulose, chitin = structural forms.
-fatty acids 3 together form triglycerides, 2 together + phosphate formsA phospholibid (membranes), can be saturated or unsaturated, steroids Are different (shape) , Waxes = long chain fatty acids + alcohols
- Chains of 20 different amino acids linked by peptide bonds
- Chains of 4 different nucleotides linked by a sugar-phoshateBackbone, DNA = double stranded genetic material, RNA =primary function in interpreting genenetic code into protein.