The Structure & Function of The Structure & Function of MacromoleculesMacromolecules

Your Goal

Name the monomers of the 4 macromolecules

Explain how those monomers are joined into polymers

Describe the uses of each macromolecule in living things

MacromoleculesMacromolecules

Macromolecules are giant molecules made up of many small organic molecules joined together

This is analogous to links joined together to make a chain

Most Macromolecules are Most Macromolecules are PolymersPolymers Built from Built from MonomersMonomers

Pectin is an example of a polymer. It is made up of repeating units of pectic acid and pectinic acid. These acid rings, then, are the monomers that link together to form pectin.

Polymer

Each ring, or link, in the chain is a monomer

The Synthesis of PolymersThe Synthesis of Polymers

In order to covalently bond, the 2 monomers lose –H & -OH atoms which combine to form water as a bi-product. Thus this reaction is

known as dehydration synthesis The process is then repeated many times to synthesize a

large polymer.Note: Some texts may refer to this as a condensation reaction

……And the Breakdown of And the Breakdown of PolymersPolymers

The reverse reaction for a dehydration synthesis is hydrolysis. A water molecule is used to break, or lyse, the covalent bond between two monomers. When the bonds

are broken, energy is released.

When one organism eats another, macromolecules are broken down & their monomers can be reused and/or rearranged to make new polymers with different functions.

Polymer DiversityPolymer Diversity

Variations among organisms is primarily a result of molecular differences; namely in their DNA & protein

Although there’s a HUGE variety of polymers, but only 40-50 monomers exist!

**The variety results from the order of a sequence of monomers. As a simple example, 4 monomers can be ordered in several configurations to yield polymers that have different structures and functions.

STOP

POTS

TOPS

It’s sort of like letters of the alphabet; different

arrangements of the same letters form different words with very different meanings

Quick Think with your food buddy

Draw a monomer and a polymer

Four Biological Four Biological MacromoleculesMacromolecules

Carbohydrates Serve as Carbohydrates Serve as Fuel & Building MaterialFuel & Building Material

Carbohydrates are sugars & starches

There are 3 levels of carbohydrate complexity:

Monosaccharides

Disaccharides

Polysaccharides

(Mono means 1, saccharide refers to a sugar)

(Di = 2)

(Poly = Many) Vocab. Tip: Most sugars end in the suffix –ose. Glucose,Maltose,Lactose, etc

Monosaccharides-simplest of the sugars;

consist of 1 ring

Examples: Glucose & FructoseMain fuel for cells cellular respiration; used for quick energy. Monosaccharides that are left unused become linked by dehydration synthesis to form disaccharides & polysaccharides.Basic molecular formula = CH2O where there are generally twice as many H as C or O. Example: glucose C6H12O6

Like other sugars, glucose forms rings in water

Disaccharides – Consist of two monosaccharides

joined together

Examples: Maltose, Lactose, Sucrose

2 glucose monomers bond to make maltose, which has different chemical characteristics than glucose

Name of bond between C1 & C4

Glucose + Fructose = Sucrose

Polysaccharides- Polymers of 100s to 1,000s of

monosaccharides linked together

Storage polysaccharides: Polymer Name

Monomer Location Function

In Plants Starch Glucose Plastids of cells

Store surplus glucose

In Animals Glycogen Glucose Liver & muscle cells

Fuel storage used when glucose is

unavailable

Structural Polysaccharides-insoluble & hard to break down (e.g. dietary fiber):Example in plants = cellulose

Long, straight chains of glucose that are H-bonded to each other at their hydroxyl groups = microfibrils that form cell wall

Example in animals = chitin

Monomer is glucose with 1 hydroxyl group replaced with an acetylamino group

Polysaccharides

Quick Think with your best thing buddy

Draw a monosaccharide Draw a polysaccharide Give one biological use for these

molecules

Lipids are a DiverseLipids are a Diverse Group Group of Hydrophobic Moleculesof Hydrophobic Molecules

Lipids are macromolecules that ARE NOT polymers

Hydro = waterPhobic = fearing

Lipids are mostly hydrocarbons and, therefore, are hydrophobic

Three biologically important lipids:

1. Fats

2. Phospholipids

3. Steroids

FatsFatsEach molecule is made of 1 glycerol & 3 fatty acids

Bonds form by dehydration synthesis

Carboxyl group = fatty “acid”

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Saturated fat = no double bonds between C in fatty acid chainUnsaturated fat = 1 or more double bonds between C in fatty acid chain

FatsFatsFunction = Energy storage

*1 gram of fat stores more than twice as much energy as 1g of carbohydrate!

*The fat molecules in animals are stored in adipose cells

-Adipose layers protect organs & insulate

Adipose Cells (40X)

Whale Blubber

PhospholipidsPhospholipidsMade of 1 glycerol & only 2 fatty acidsCharged

phosphate group makes the head hydrophilic

In water, phospholipids arrange into a bilayer according to their hydrophobic & hydrophilic regions

Slightly positive H in water attracts negative phosphate group in phospholipids

SteroidsSteroidsSteroids have this 4-ringed basic structure attached to a functional group

This functional group makes this molecule cholesterol.

*Cholesterol is a major component of animal cell membranes*Many sex hormones are made from cholesterol

Quick Think with your super hero buddy

Why are fats NOT polymers?

Name one biological use for lipids.

Proteins Have Many Structures, Proteins Have Many Structures, Resulting in a Wide Range of FunctionsResulting in a Wide Range of Functions

Some protein functions:

Enzymatic proteins- catalyze rxns

Structural proteins- support

Storage Proteins- storage of amino acids

Transport proteins- transport other molecules

Hormonal proteins- regulate organism’s activities

Receptor proteins- allow cells to respond to stimuli

Contractile proteins- movement

Defensive proteins- protection against disease

Hair

Protein in seedsHemoglobin

Found in muscle cells

PolypeptidesPolypeptides•A protein is 1 or more polypeptides folded & coiled into a specific shape

•A polypeptide is a polymer of amino acids

One amino acid monomer linked to a chain of others.

All of the amino acids linked together form a polypeptide chain

Polypeptides:Polypeptides:Amino Acid MonomersAmino Acid Monomers

R group

R group

Leucine Serine

Carboxyl groupAmino group

Variable side group

Each of the 20 different amino acids has a different R group which gives it its unique characteristics

Polypeptides:Polypeptides:Amino Acid PolymersAmino Acid Polymers

Peptide Bond

R

group

R

group

R

group

R

group

Amino group

Carboxyl group

N-terminus C-terminus

Amino Acid chains are held together by peptide bonds which are formed by a dehydration reaction

The number, type, & sequence of amino acids determine the shape and function of the polypeptide

Note that both the C & N-terminus ionize in aqueous solutions

Protein Conformation Protein Conformation & Function& Function

The function of a protein is an emergent property resulting from its unique shape

Model of receptor protein Model of enzyme

In each example, the protein’s ability to perform its function is dependant on the specific shape of the protein

Protein Conformation & Function:Protein Conformation & Function:Four Levels of Protein StructureFour Levels of Protein Structure

Primary Structure: a protein’s unique, linear sequence of amino acids which is determined by genetic information

Protein Conformation & Function:Protein Conformation & Function:Four Levels of Protein StructureFour Levels of Protein Structure

Secondary Structure: the result of H-bonding between partially negative oxygen & nitrogen of the polypeptide backbone and hydrogen on the backbone.

Primary Structure

α-helix structure: coiling that results from H-bonding between every 4th amino acid

β-pleated sheet: polypeptide backbone folds on itself, forming H-bonds

Protein Conformation & Function:Protein Conformation & Function:Four Levels of Protein StructureFour Levels of Protein Structure

Tertiary structure: the overall shape of the polypeptide resulting from interactions between R-groups of amino acids.

Hydrophobic interactions contribute to tertiary structure: hydrophobic R-groups are organized so that they are in the center of the protein. Hydrophilic amino acid R-groups end up on the outer surface of

the protein.Note disulfide bridge reinforces protein conformation

Protein Conformation & Function:Protein Conformation & Function:Four Levels of Protein StructureFour Levels of Protein Structure

Quaternary structure: forms when two or more polypeptide chains aggregate to make one molecule

Protein Conformation & Function:Protein Conformation & Function:Four Levels of Protein StructureFour Levels of Protein Structure

•A protein’s shape is sensitive to the surrounding environment

Unfavorable temperature and pH changes can cause a protein to unravel and lose its shape. This is called denaturation

Quick Think with your love buddy <3

Draw and label the 4 levels of protein structure

Nucleic AcidsNucleic Acids Store & Transmit Store & Transmit Hereditary InformationHereditary Information

•Nucleic acids store the instructions for building proteins

•Two types: Deoxyribonucleic Acid (DNA) & Ribonucleic Acid (RNA)

•The flow of genetic information:

DNA RNA protein

Nucleic Acid StructureNucleic Acid Structure

Nucleic acids are polymers of nucleotides. Each nucleotide has 3 parts: 5-carbon sugar, phosphate group, & a nitrogenous base

Nucleic Acid Structure:Nucleic Acid Structure: Nucleotide MonomersNucleotide Monomers

Nucleotides can have 1 of 4 different nitrogenous bases: cytosine, thymine –uracil in RNA- (pyrimidines) or adenine, guanine (purines)

Thymine (T) Cytosine (C)

Adenine (A) Guanine (G)

purines

pyrimidines

Nucleic Acid Structure:Nucleic Acid Structure: Nucleotide PolymersNucleotide Polymers

Bond occurs at -OH on 3’ C of one nucleotide and the phosphate group on the 5’ C of the other nucleotide

Bond formed is called a phosphodiester bond

This process creates a sugar-phosphate backbone with the nitrogenous bases sticking out

The DNA Double HelixThe DNA Double HelixThe two strands of the double helix are antiparallel, running in the 5’ 3’ direction

H-Bonds

DNA & Proteins as Tape DNA & Proteins as Tape Measures of EvolutionMeasures of Evolution

The sequence of nucleotides in DNA and the sequence of amino acids in proteins can be used to determine evolutionary relationships…closely related species have fewer differences in their sequences.

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Amino aciddifferencescomparedwith humanhemoglobin

Quick Think

What are the names of the bonds between:

1. Sugars in a polysaccharide

2. Amino acids in a protein

3. Nucleotides in a nucleic acid