CHAPTER 5CHAPTER 5THE STRUCTURE & THE STRUCTURE &

FUNCTION OF FUNCTION OF MACROMOLECULESMACROMOLECULES

CARBOHYDRATES, LIPIDS, CARBOHYDRATES, LIPIDS, PROTEINS, NUCLEIC ACIDSPROTEINS, NUCLEIC ACIDS

Objectives:Objectives: Macromolecules are polymersMacromolecules are polymers Sugars (smallest carbohydrate) are used for fuel and Sugars (smallest carbohydrate) are used for fuel and

carbon sourcescarbon sources Polysaccharides (polymers of sugar) have storage and Polysaccharides (polymers of sugar) have storage and

structural rolesstructural roles Fats store large amounts of energyFats store large amounts of energy Phospholipids are a part of the cell membranePhospholipids are a part of the cell membrane Steroids = cholesterol and hormonesSteroids = cholesterol and hormones Proteins' function depends on its shapeProteins' function depends on its shape Nucleic Acids store and transmit hereditary infoNucleic Acids store and transmit hereditary info RNA and DNARNA and DNA

Root Words:Root Words:

Con – Con – Di – Di – Glyco – Glyco – Hydro – Hydro – Macro – Macro – Meros – Meros – Mono – Mono – Poly – Poly – Tri – Tri –

MOLECULES TO

RECOGNIZE

Basic Protein Structure Cellulose

Amino Acid Structure Glycogen

Steroids Glucose

Phospholipids

The The Synthesis Synthesis

&&

Breakdown Breakdown of of

Polymers.Polymers.

Fig. 5.2Fig. 5.2

Monosaccharides - Simple Sugars (Fig. 5.3)

Note: Asymmetric Carbons in Hexose Sugars:

CarbohydratesCarbohydrates - “Carbon” “Hydrated” - “Carbon” “Hydrated”

( 1:2:1 ratio ) ( C ) ( H( 1:2:1 ratio ) ( C ) ( H22O )O )

Sugars - Major role - Energy. Fig. 5.4)Sugars - Major role - Energy. Fig. 5.4)

DisaccharideDisaccharide - Dehydration Synthesis & - Dehydration Synthesis & Glycosidic Linkage. (Fig. 5.5)Glycosidic Linkage. (Fig. 5.5)

Sucrose = Glucose & Fructose

Lactose = Glucose & Galactose

1-4 & 1-2 1-4 & 1-2 LinkageLinkage

Starch is in the form of Amylose & Amylopectin (Fig. 5.7)

(in PLANTS)

GLYCOGEN GLYCOGEN

is also called animal starch, stored in muscles & liver.

POLYSACCHARIDES -3 OR MORE MONOSACCHARIDES.

1. Structural:

a. Cellulose - cell walls of plants.

b. Chitin - exoskeleton of arthropods (insects; spiders etc.) and exterior of mushrooms

2. Storage - Starch & Glycogen

LIPIDS - Diverse Hydrophobic Molecules (Fig. 5.10)

Made of 1 Made of 1 glycerol & glycerol & 3 fatty 3 fatty acids (16 acids (16 to 18 to 18 carbons).carbons).

C-H on C-H on fatty fatty acids acids make make lipids lipids hydrophohydrophobicbic

FATS:

Saturated Fatty Acids - have no double bonds between the carbons in the chain (solids at room temp)

Unsaturated Fatty Acids - have double bonds between the carbons in the chain. (Liquids at room temp due to “kinks” in the fatty acid which prevents it from solidifying)

Fat Molecules are storage for energy.

Second Type of Lipid: PhospholipidPhospholipidHave 2 fatty acids NOT 3 like lipids

Major components of cell membranes.

Hydrophilic head

Hydrophobic tail.

Kink in one fatty acid means it has double bonds

(Fig. 5.12)

Phospholipid Bilayer is found in cell membrane.

Fig. 5.13 Outside of cellInside of cell

3rd Type of Lipid3rd Type of Lipid - Steroids

Lipids with carbon skeleton of 4 interconnected rings.

Cholesterol

Cholesterol - common component of cell membranes. (Fig. 5.14).

Also precursor for other steroids such as hormones including sex hormones.

Sex Hormones:Sex Hormones:

What is the male sex hormone?What is the male sex hormone? What is the female sex hormone?What is the female sex hormone?

Nucleic Acids:Nucleic Acids:

DNADNA RNARNA

ProteinProteinss•StorageStorage•Structural supportStructural support•Transport of Transport of substancessubstances•Cell to cell signalingCell to cell signaling•MovementMovement•Defense against Defense against foreign substancesforeign substances•Enzymes – speed up Enzymes – speed up chemical reactionschemical reactions

Amino AcidsAmino Acids

Amino acids – contain carboxyl and Amino acids – contain carboxyl and amine functional groupamine functional group

Link together by peptide bonds to Link together by peptide bonds to form a polypeptide chainform a polypeptide chain

Only 20 amino acidsOnly 20 amino acids

Protein StructureProtein Structure

4 levels4 levels– Primary Structure: precise sequence of Primary Structure: precise sequence of

amino acidsamino acids– Secondary Structure: coils or folds within Secondary Structure: coils or folds within

the sequence due to Hydrogen bonding.the sequence due to Hydrogen bonding. The H bonds are weak, but can support a The H bonds are weak, but can support a

particular shapeparticular shape Alpha (a) helix - coilAlpha (a) helix - coil Beta (B) pleated sheet - foldBeta (B) pleated sheet - fold

Protein Structure Cont.Protein Structure Cont.

– Tertiary Structure: Tertiary Structure: Irregular looping and folding of the Irregular looping and folding of the

protein bc of interactions of side groupsprotein bc of interactions of side groups

– Quaternary StructureQuaternary Structure The addition of one or more polypeptide The addition of one or more polypeptide

chains to the original structurechains to the original structure

Changes in ProteinChanges in Protein

Denature – when a protein Denature – when a protein unravels due to changes in pH, salt unravels due to changes in pH, salt concentration, temperature and concentration, temperature and environmentenvironment