CHAPTER 5The Structure and Function of

Macromolecules

“You are what you eat!”

Standards

•Distinguish among proteins, carbohydrates, lipids, and nucleic acids.

•Identify the major structural components and functions of the four major macromolecules

Objectives

Shoulder Partners

Flip Books

Take out your flip books for notes

Turn to last page – it should be open for notes about definitions and reactions

Building Macromolecules

Take out the pieces of macromolecules that you colored and cut out last

class period

You also need one sheet of construction paper

What is a MACROmolecule?

A Large molecule with a complex structure

A polymer built from monomers

“little” moleculeMacromolecule

Poly - mer

• A long molecule made of monomers bonded together

Many Parts

Mono - mer

The “building blocks” of polymersA monomer is a sub-unit of a polymer.

One Part

Three of life’s organic macromolecules are polymers• Carbohydrates, Proteins, Nucleic acids

EXAMPLES

Think – Pair – Share

Explain to your partner how these Lego structures are like Polymers

How are Polymers made?How do monomers bind to form

polymers?• condensation reactions called

dehydration synthesis (removal of water)

How do polymers break down?

Hydrolysis reaction• Hydro – lysis

• Water is added to break the bonds that hold the polymer together.

Water To Break

Hydrolysis

Think – Pair – Share

Why would polymers need to be “broken down”?

Classes of Organic Macromolecules:

• Carbohydrates• Lipids• Proteins• Nucleic Acids

CARBOHYDRATES

Monomer• Monosaccharide

• (“mono” = one; “saccharide” = sugar)

Polymers• Disaccharides (di = two)• Polysaccharides (poly = many)

Carbo - hydrate

Carbon Water

Think – Pair – Share

What are some functions of carbohydrates?

Functions of Carbohydrates in living things:• Major fuel/energy source• Energy storage • Can be used as raw materials for

other Macromolecules• Structural/building material in

plants

Structure of Monosaccharides

Contain only C, H, O

All have the molecular formula - (CH2O)n

In aqueous solutions many monosaccharides form rings:

Structure of DisaccharidesConsists of two monosaccharides

The monosaccharides are joined by a glycosidic linkage (bond)

Polar Bears

What reaction forms the glycosidic linkage (bond) between the monosaccharides to become a disaccharide?• Dehydration synthesis

Build a Carbohydrate

Assemble a disaccharide sugar.• The building block/monomers of

carbohydrates are ____________.

• Place ________of these into a chain • Use the triangle water to point to

the bond site. Draw an arrow to show if water is being added or released during this reaction.

Label as a dissaccharide

simple sugars

2

Build a Carbohydrate

H2O

Polysaccharides

Structure: Polymers of a few hundred or a few thousand monosaccharides.

Functions: • energy storage molecules • structural support

Examples of Carbs:

Starch - plant storage form for energy• easily broken down into glucose units

Cellulose - fiber-like structural material made of glucose monomers • used in plant cell walls

Why is Cellulose so strong? Glucose monomers are flipped to expose

equal Hydroxyl groups on either side of the chain

When Cellulose chains are lined up next to each other, they Hydrogen Bond making a strong material that’s difficult to break!

Glycogen is the animal short-term storage form of energy• Glucose monomers

Penguins

What reaction breaks the glycosidic linkage (bond) between the glucose molecules in glycogen so the monomers can be used for fuel?• Hydrolysis

Chitin is a polysaccharide used as a structural material in arthropod exoskeleton and fungal cell walls.

Build a Carbohydrate

Assemble the remaining carbohydrate monomers into a polysaccharide sugar.

Place the remaining carbohydrate monomers into a chain. Use the triangle water to point to the bond site. Draw an arrow to show if water is being added or released during this reaction.

Standards

Distinguish among proteins, carbohydrates, lipids, and nucleic acids.

Identify the major structural components and functions of the four major macromolecules

Objectives

PROTEINS

Proteins Monomer

• amino acids • connected by peptide bonds

• Have a 3 dimensional globular shape

Amino Acids• Molecules with carboxyl and

amino groups• Differ in their properties due to

differing side chains, called R groups

20 different amino acids

•The sequence of amino acids determine the shape of the protein

Did you know?

•Our body can only synthesize 12 of the 20 amino acids.

Think – Pair – ShareWhere do we get the other 8 amino acids?

Polymers = polypeptides

Peptide bonds connect amino acids to form polypeptide chains

Examples of Protein FunctionsImmune System

• Antibodies (proteins) bind to foreign substances

Transport• Membrane transport proteins - move

substances across cell membranes• Hemoglobin carries oxygen, iron,

and other substances through the body.

Muscle ContractionsSignaling - Hormones such as insulin

regulate sugar levels in blood.

Proteins are very complex! Their specific structure determines their

function.

HEMOGLOBIN: Transport of gases and iron in blood ACTIN: Filament involved in

muscle contraction

Four Levels of Protein Structure

Primary structure• Is the

unique sequence of amino acids in a polypeptide

Figure 5.20–

Amino acid subunits

+H3NAmino end

oCarboxyl end

oc

GlyProThrGlyThr

Gly

GluSeuLysCysProLeu

MetVal

Lys

ValLeu

AspAlaVal ArgGly

SerPro

Ala

Gly

lle

SerProPheHisGluHis

Ala

GluVal

ValPheThrAlaAsn

AspSer

GlyProArg

ArgTyrThr

lleAla

Ala

Leu

LeuSer

ProTyrSerTyrSerThr

Thr

Ala

ValVal

ThrAsnProLysGlu

ThrLys

SerTyrTrpLysAlaLeu

GluLle Asp

O C α helix

β pleated sheet

Amino acidsubunits NC

H

C

O

C NH

CO

H

R

C N

H

C

O H

C

R

NH

H

R C

O

R

C

H

N

H

C

OHN

CO

R

C

H

N

H

HC

R

C

O

C

O

C

N

HH

R

C

C

O

NH

H

C

R

C

O

N

H

R

C

HC

ONH

H

C

R

C

O

N

H

R

C

H C

ONH

H

C

R

C

O

N H

H C R

N H O

O C N

C

RC

HO

CH R

N H

O C

RC H

N H

O C

H C R

N H

CC

N

RH

O C

H C R

N H

O C

RC H

HC

RNH

CO

C

N

H

R

C

HC

O

NH

C

Secondary structure• Is the folding of the polypeptide one

time• Forms an α helix or a β pleated sheet

Tertiary structure• Is the overall three-

dimensional shape of a polypeptide

CH2CH

OH

O

CHO

CH2

CH2 NH3+ C-O CH2

O

CH2SSCH2

CH

CH3

CH3

H3C

H3C

Hydrophobic interactions and van der Waalsinteractions

Polypeptidebackbone

Hydrogenbond

Ionic bond

CH2

Disulfide bridge

Quaternary structure• Is the overall protein structure that

results from the combination of two or more polypeptide subunits

Polar Bears

Explain the four levels of protein structure to your penguin

Sic

kle

Cell D

isease

Sickle Cell Disease: A simple change in Primary Structure

Enzymes proteins that act as a catalyst

Penguins

List at least 2 factors that effect protein structure

Environmental Factors That Effect Protein Shape

pHTemperatureSalinityDenatured protein is biologically

inactiveCan sometimes “renature” if primary

structure is unchanged.

Build a Protein

Assemble a 4-monomer polypeptide.• The building block/monomers of

proteins are ____________.

• Place 4 of these into a chain • Use the triangle water to point to

the bond site. Draw an arrow to show if water is being added or released during this reaction.

Label as a 4-monomer polypeptide

Amino Acids

Build a Protein

Assemble the remaining monomers into a polypeptide.• Use the triangle water to point to

the bond site. Draw an arrow to show if water is being added or released during this reaction.

Label as a ___-monomer polypeptide

?

Standards

Distinguish among proteins, carbohydrates, lipids, and nucleic acids.

Identify the major structural components and functions of the four major macromolecules

Objectives

LIPIDS What are Lipids?• Fats, phospholipids, steroids, waxes, pigments• Hydrophobic (“hydro”=water; “phobic” = fearing)• Consist mostly of hydrocarbons• Do NOT consist of polymers

Monomers• The building blocks of all lipids

are called • Fatty Acids

Functions of Lipids in living things:• Energy storage • Cell membrane structure• Protecting against desiccation (drying out). • Insulating against cold.• Absorbing shocks. • Regulating cell activities by hormone actions.

Structure of Common Fats - Triglycerides

Consist of a single glycerol and usually three fatty acids

Glycerol – an alcohol with three carbons Fatty Acid - Long Hydrocarbon chains with a

Carboxyl group at one end.

Saturated and Unsaturated Fats Unsaturated fats :

• one or more double bonds between carbons in the fatty acids allows for “kinks” in the tails

• liquid at room temp• most plant fats

Saturated fats:• No double bonds in

fatty acid tails• solid at room temp• most animal fats

(a) Saturated fat and fatty acid

Stearic acid

(b) Unsaturated fat and fatty acidcis double bondcauses bending

Oleic acid

Saturated fatty acid

Saturated fatty acid

Unsaturated fatty acid

Build a Lipid

Assemble a triglyceride.• The building block/monomers of

lipids are ____________.• Use your notes to assemble w/

correct structure/components• Use the triangle water to point to

the bond site. Draw an arrow to show if water is being added or released during this reaction.

Label as a triglyceride

Fatty Acids

Phospholipids

Structure: Glycerol + 2 fatty acids + phosphate group.

Function: Main structural component of membranes, where they arrange in bilayers.

Phospholipids in Water

Draw a Phospholipid

Next to your triglyceride, draw a phospholipid Label the parts/components Label the drawing as a phospholipid

Waxes

Function:• Lipids that serve as coatings for

plant parts and as animal coverings.

SteroidsStructure: Four carbon rings with no

fatty acid tailsFunctions:

• Component of animal cell membranes (Ex: Cholesterol)

• Modified to form sex hormones

Standards

Distinguish among proteins, carbohydrates, lipids, and nucleic acids.

Identify the major structural components and functions of the four major macromolecules

Objectives

NUCLEIC ACIDS

Nucleic Acid Monomers = Nucleotides

Nucleotide = 5 carbon sugar, phosphate, and nitrogenous base

Deoxyribose in DNA Ribose in RNA

Two Types of Nucleic Acids Polymers

DNA (Deoxyribonucleic acid)• double stranded• can self replicate• makes up genes which

code for proteins is passed from one generation to another

RNA (Ribonucleic acid)• single stranded • functions in actual

synthesis of proteins coded for by DNA

• is made from the DNA template molecule

Function of Nucleic Acids : The stuff of Genes

Nucleic acids store and transmit hereditary information

Genes• Are the units of inheritance• Code for the sequence of

amino acids(making polypeptides)

• Made of nucleic acids

Both polymer

s function togethe

r for protein synthes

is

Building the Polymer

Phosphate group of one nucleotide forms strong covalent bond with the #3 carbon of the sugar of the other nucleotide.

DNA:

• Double helix

• 2 polynucleotide chains wound into the double helix

• Base pairing between chains with H bonds

• A - T

• C - G

Building DNA

The building block/monomers of lipids are ____________.• Build 2 nucleotides

• Use your notes to assemble w/ correct structure/components

• Link the 2 nucleotides together • The phosphate group of one nucleotide binds to the pentose sugar of the next

Label as DNA

nucleotides

Building DNA

Use your notes to assemble w/ correct structure/components• Use the triangle water to point to

the bond site. Draw an arrow to show if water is being added or released during this reaction.

Label as a triglyceride

Summary of the Organic Molecules: