Chapter 05 Macromolecules

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.