Carbon & Carbon & Biochemistry Biochemistry

BIOL-101 Section 802RLBIOL-101 Section 802RLMr. FuscoMr. Fusco

Chapter 4: Carbon and the Molecular Diversity of Life

Chapter 5: The Structure & Function of Large Biological Molecules

Chemistry of LifeChemistry of Life Carbon is essential to lifeCarbon is essential to life

Although cells are 70–95% water, the rest Although cells are 70–95% water, the rest

consists mostly of carbon-based compoundsconsists mostly of carbon-based compounds AnAn is any carbon-containing compound is any carbon-containing compound

Organic compounds in living organisms: Organic compounds in living organisms: -proteins, amino acids, carbohydrates, fats-proteins, amino acids, carbohydrates, fats (lipids), nucleic acids, etc…(lipids), nucleic acids, etc…

Carbon Carbon StructureStructure

CarbonCarbon-----Enables carbon to form large molecules-Enables carbon to form large molecules

Electron configuration is the key to an atom’s Electron configuration is the key to an atom’s characteristicscharacteristics

Electron configuration determines the Electron configuration determines the an atom an atom will form with other atomswill form with other atoms

Fig. 4-4Fig. 4-4

Hydrogen(valence = 1)

Oxygen(valence = 2)

Nitrogen(valence = 3)

Carbon(valence = 4)

H O N C

Valence ElectronsValence Electrons

Carbon Backbones:Carbon Backbones:HydrocarbonsHydrocarbons

HydrocarbonsHydrocarbons are are

Many organic molecules, such as Many organic molecules, such as fats, have hydrocarbon fats, have hydrocarbon componentscomponents

Hydrocarbons can undergo Hydrocarbons can undergo reactions that release a large reactions that release a large amount of energyamount of energy

With four valence electrons, carbon With four valence electrons, carbon can form can form with a with a variety of atomsvariety of atoms

Fig. 4-6Fig. 4-6

(a) Mammalian adipose cells (b) A fat molecule

Fat droplets (stained red)

100 µm

Hydrocarbon BondingHydrocarbon Bonding

1) C – H bonds1) C – H bonds

-only single bonds-only single bonds

2) C – C bonds (different shapes and 2) C – C bonds (different shapes and numbers)numbers)

Chain Branched Ring

Single Double Triple

a) b)

Carbon - CarbonCarbon - CarbonBond NumbersBond Numbers

Single = has a

tetrahedral shape

Double = ,

the molecule has a flat shape

Triple = , the

molecule has a linear shape

Carbon - CarbonCarbon - CarbonBonding TypesBonding Types

Straight Chains

Branched Chains

Rings

Fig. 4-3Fig. 4-3

NameMolecular Formula

Structural Formula

Ball-and-StickModel

Space-FillingModel

(a) Methane

(b) Ethane

(c) Ethene (ethylene)

IsomersIsomers

IsomersIsomers are compounds with are compounds with the the

:: Structural isomersStructural isomers have have

of their atoms of their atoms Geometric isomersGeometric isomers have have

the same covalent the same covalent arrangements but arrangements but

EnantiomersEnantiomers are isomers are isomers that are that are of of each othereach other

CH3CH2CH2CH2CH2CH3

Hexane:C6H14

Isohexane:C6H14

CH3

l

CH3CH2CHCH2CH3

Chemical Formula

Structural Formula

Enantiomers are important in the Enantiomers are important in the industryindustry

Two enantiomers of a drug may have Two enantiomers of a drug may have different effectsdifferent effects

Differing effects of enantiomers demonstrate Differing effects of enantiomers demonstrate that that

Example: L-dopa is used to treat symptoms of Example: L-dopa is used to treat symptoms of Parkinson’s disease, while R-dopa (its Parkinson’s disease, while R-dopa (its enantiomer) has no effectenantiomer) has no effect

EnantiomersEnantiomers

Functional GroupsFunctional Groups

Functional groupsFunctional groups are the components of are the components of organic molecules that organic molecules that are are

The The of of

functional groups give functional groups give each molecule its each molecule its unique properties unique properties

The seven functional groups that are The seven functional groups that are most important in the chemistry of life:most important in the chemistry of life:

Hydroxyl groupHydroxyl group Carbonyl groupCarbonyl group Carboxyl groupCarboxyl group Amino groupAmino group Sulfhydryl groupSulfhydryl group Phosphate groupPhosphate group Methyl groupMethyl group

Functional GroupsFunctional Groups

Fig. 4-10aFig. 4-10aHydroxylCHEMICAL

GROUP

STRUCTURE

NAME OF COMPOUND

EXAMPLE

FUNCTIONALPROPERTIES

Carbonyl Carboxyl

(may be written HO—)

In a hydroxyl group (—OH), ahydrogen atom is bonded to anoxygen atom, which in turn isbonded to the carbon skeleton ofthe organic molecule. (Do notconfuse this functional groupwith the hydroxide ion, OH–.)

When an oxygen atom isdouble-bonded to a carbonatom that is also bonded toan —OH group, the entireassembly of atoms is calleda carboxyl group (—COOH).

Carboxylic acids, or organicacids

Ketones if the carbonyl group iswithin a carbon skeleton

Aldehydes if the carbonyl groupis at the end of the carbonskeleton

Alcohols (their specific namesusually end in -ol)

Ethanol, the alcohol present inalcoholic beverages

Acetone, the simplest ketone Acetic acid, which gives vinegarits sour taste

Propanal, an aldehyde

Has acidic propertiesbecause the covalent bondbetween oxygen and hydrogenis so polar; for example,

Found in cells in the ionizedform with a charge of 1– andcalled a carboxylate ion (here,specifically, the acetate ion).

Acetic acid Acetate ion

A ketone and an aldehyde maybe structural isomers withdifferent properties, as is thecase for acetone and propanal.

These two groups are alsofound in sugars, giving rise totwo major groups of sugars:aldoses (containing analdehyde) and ketoses(containing a ketone).

Is polar as a result of theelectrons spending more timenear the electronegative oxygen atom.

Can form hydrogen bonds withwater molecules, helpingdissolve organic compoundssuch as sugars.

The carbonyl group ( CO)consists of a carbon atomjoined to an oxygen atom by adouble bond.

Fig. 4-10bFig. 4-10bCHEMICALGROUP

STRUCTURE

NAME OFCOMPOUND

EXAMPLE

FUNCTIONALPROPERTIES

Amino Sulfhydryl Phosphate Methyl

A methyl group consists of acarbon bonded to threehydrogen atoms. The methylgroup may be attached to acarbon or to a different atom.

In a phosphate group, aphosphorus atom is bonded tofour oxygen atoms; one oxygenis bonded to the carbon skeleton;two oxygens carry negativecharges. The phosphate group(—OPO3

2–, abbreviated ) is anionized form of a phosphoric acidgroup (—OPO3H2; note the twohydrogens).

P

The sulfhydryl groupconsists of a sulfur atombonded to an atom ofhydrogen; resembles ahydroxyl group in shape.

(may bewritten HS—)

The amino group(—NH2) consists of anitrogen atom bondedto two hydrogen atomsand to the carbon skeleton.

Amines Thiols Organic phosphates Methylated compounds

5-Methyl cytidine

5-Methyl cytidine is acomponent of DNA that hasbeen modified by addition ofthe methyl group.

In addition to taking part inmany important chemicalreactions in cells, glycerolphosphate provides thebackbone for phospholipids,the most prevalent molecules incell membranes.

Glycerol phosphate

Cysteine

Cysteine is an importantsulfur-containing aminoacid.

Glycine

Because it also has acarboxyl group, glycineis both an amine anda carboxylic acid;compounds with bothgroups are called amino acids.

Addition of a methyl groupto DNA, or to moleculesbound to DNA, affectsexpression of genes.

Arrangement of methylgroups in male and femalesex hormones affectstheir shape and function.

Contributes negative chargeto the molecule of which it isa part (2– when at the end ofa molecule; 1– when locatedinternally in a chain ofphosphates).

Has the potential to reactwith water, releasing energy.

Two sulfhydryl groupscan react, forming acovalent bond. This“cross-linking” helpsstabilize proteinstructure.

Cross-linking ofcysteines in hairproteins maintains thecurliness or straightnessof hair. Straight hair canbe “permanently” curledby shaping it aroundcurlers, then breakingand re-forming thecross-linking bonds.

Acts as a base; canpick up an H+ fromthe surroundingsolution (water, in living organisms).

Ionized, with acharge of 1+, undercellular conditions.

(nonionized) (ionized)

ATPATP One phosphate molecule, One phosphate molecule, adenosine triphosphateadenosine triphosphate

((ATPATP), is the ), is the

ATP consists of an organic molecule called ATP consists of an organic molecule called attached to a string of attached to a string of

Energy is Energy is when a phosphate group is when a phosphate group is from ATP to form ADP (from ATP to form ADP (adenosine diphosphateadenosine diphosphate))

Energy is Energy is when a phosphate group is when a phosphate group is to ADP to form ATPto ADP to form ATP

P P P P i P PAdenosine Adenosine

ADPATP Inorganic phosphate

Reacts with H2O

Energy

MacromoleculesMacromolecules

All living things are made up of four classes All living things are made up of four classes of large biological molecules: of large biological molecules:

Within cells, small organic molecules are Within cells, small organic molecules are joined together to form larger moleculesjoined together to form larger molecules

are large molecules are large molecules composed of thousands of covalently composed of thousands of covalently connected atomsconnected atoms

One key concept is that One key concept is that

MacromoleculesMacromolecules

A A monomermonomer is a is a (building block)(building block)

A A polymer polymer is a is a

Macromolecules are polymers, and Macromolecules are polymers, and identified by their specific subunits identified by their specific subunits (monomers)(monomers)

Monomers are covalently bonded in Monomers are covalently bonded in to make to make

macromoleculesmacromolecules

A A condensation condensation reaction, reaction, or more or more specifically specifically dehydration dehydration synthesis, synthesis, occurs occurs when when

Polymers are digested Polymers are digested to monomers by to monomers by hydrolysishydrolysis, a reaction , a reaction that that

The Synthesis and The Synthesis and Breakdown of PolymersBreakdown of Polymers

Fig. 5-2aFig. 5-2a

Dehydration removes a watermolecule, forming a new bond

Short polymer Unlinked monomer

Longer polymer

Dehydration reaction in the synthesis of a polymer

HO

HO

HO

H2O

H

HH

4321

1 2 3

(a)

Fig. 5-2bFig. 5-2b

Hydrolysis adds a watermolecule, breaking a bond

Hydrolysis of a polymer

HO

HO HO

H2O

H

H

H321

1 2 3 4

(b)

Macromolecules TypesMacromolecules Types

The four types of macromolecules The four types of macromolecules include:include:

CarbohydratesCarbohydrates Lipids (fats)Lipids (fats) ProteinsProteins Nucleic AcidsNucleic Acids

CarbohydratesCarbohydrates

Carbohydrates Carbohydrates include include sugars and the polymers of sugars and the polymers of sugarssugars

Sugar Sugar polymerspolymers made of made of

The simplest carbohydrates The simplest carbohydrates are are , or single sugars, or single sugars

Simple to complex:Simple to complex:Monosaccharides Monosaccharides

Disaccharides Disaccharides PolysaccharidesPolysaccharides

Carbs may be as much as Carbs may be as much as 70% of an Endurance 70% of an Endurance

Athlete’s Diet!Athlete’s Diet!

Lance Armstrong

6500Kcal/day

Michael Phelps

8400 Kcal/day

Our Primary Energy Source Our Primary Energy Source

from monosaccharidesfrom monosaccharides- glucose, fructose, galactose- glucose, fructose, galactose

from polysaccharidesfrom polysaccharides-glycogen (in animals)-glycogen (in animals)-starch (in plants)-starch (in plants)

-structural components of cells (ex. cellulose in -structural components of cells (ex. cellulose in

plant cell walls)plant cell walls)-Fiber in our diets-Fiber in our diets

MonosaccharidesMonosaccharidesmono- “mono- “ ” saccharide- “” saccharide- “ ””

Monosaccharides Monosaccharides have have molecular formulas that are molecular formulas that are usually multiples of CHusually multiples of CH22OO

(C(C66HH1212OO66) is the ) is the most common most common monosaccharide (right) and monosaccharide (right) and our our

Another is Another is (C(C66HH1212OO66) )

Monosaccharides serve as a Monosaccharides serve as a

Glucose and FructoseGlucose and Fructose

MonosaccharidesMonosaccharides IsomersIsomers CC66HH1212OO66

Glucose is the form Glucose is the form of sugar carried in of sugar carried in our bloodour blood

Fructose is the Fructose is the sweet sugar found sweet sugar found in most fruits and in most fruits and sweetssweets Glucose Galactose

Hexoses (C6H12O6)

DisaccharidesDisaccharidesdi- “di- “ ” -saccharide “” -saccharide “ ””

Disaccharides are Disaccharides are This covalent bond is called a This covalent bond is called a Molecular formula of Molecular formula of Examples include:Examples include:

Sucrose Sucrose (glucose + fructose)(glucose + fructose) This is table sugarThis is table sugar

Lactose (glucose + galactose)Lactose (glucose + galactose) This is a milk sugarThis is a milk sugar

Maltose (glucose + glucose)Maltose (glucose + glucose) This is a grain sugarThis is a grain sugar

Fig. 5-5Fig. 5-5

(b) Dehydration reaction in the synthesis of sucrose

Glucose Fructose Sucrose

MaltoseGlucoseGlucose

(a) Dehydration reaction in the synthesis of maltose

1–4glycosidic

linkage

1–2glycosidic

linkage

PolysaccharidesPolysaccharidespoly-: “poly-: “ ” -saccharides: “” -saccharides: “ ””

Polysaccharides are long sugar Polysaccharides are long sugar chainschains

Often not water soluble due to Often not water soluble due to great sizegreat size

Used primarily for Used primarily for (Plants store (Plants store

surplus starch as granules surplus starch as granules within chloroplasts and other within chloroplasts and other plastids) plastids)

(Humans (Humans and other vertebrates store and other vertebrates store glycogen mainly in liver and glycogen mainly in liver and muscle cells)muscle cells)

Polysaccharides: Glycogen and Polysaccharides: Glycogen and StarchStarch

CelluloseCellulose The polysaccharide The polysaccharide cellulose cellulose is a is a

major major Like starch, cellulose is a Like starch, cellulose is a

, but the glycosidic linkages , but the glycosidic linkages differdiffer

Cellulose in human food passes Cellulose in human food passes through the digestive tract as through the digestive tract as

What evidence do we have of this?What evidence do we have of this? Many herbivores, from cows to Many herbivores, from cows to

termites, have symbiotic termites, have symbiotic relationships with microbes that relationships with microbes that use enzymes to digest celluloseuse enzymes to digest cellulose

CelluloseCellulose

ChitinChitin

ChitinChitin, another , another structural structural polysaccharide, polysaccharide, is found in the is found in the

Chitin also Chitin also provides provides

LipidsLipids Lipids Lipids are the one class of large are the one class of large

biological molecules that biological molecules that The unifying feature of lipids is having The unifying feature of lipids is having

Lipids are Lipids are because becausethey they

consist mostly of hydrocarbons, which consist mostly of hydrocarbons, which form form

The most biologically important lipids The most biologically important lipids are fats, phospholipids, and steroidsare fats, phospholipids, and steroids

4.5 Kcal/g in 4.5 Kcal/g in carbscarbs

VS. VS.

9 Kcal/g in 9 Kcal/g in fatsfats

LipidsLipids

The major function of fats is The major function of fats is Humans and other mammals store Humans and other mammals store

their fat in their fat in Adipose tissue also Adipose tissue also

Energy storageEnergy storage-Stored mostly as -Stored mostly as

Other functionsOther functions-Steroid hormones-Steroid hormones-Plasma membrane structural -Plasma membrane structural

stabilitystability

FatsFats Fats Fats are constructed from are constructed from

is a three-is a three-carbon alcohol with a hydroxyl carbon alcohol with a hydroxyl group attached to each carbongroup attached to each carbon

A A consists of consists of a carboxyl group attached to a a carboxyl group attached to a long carbon skeletonlong carbon skeleton Many C-H bondsMany C-H bonds

Structure is a fatty acid chain Structure is a fatty acid chain bonded to a carboxyl groupbonded to a carboxyl group

2 Types:2 Types:1) saturated 1) saturated 2) unsaturated2) unsaturated

Most common form of a fat is a

Triglycerides Triglycerides

Joined by an Joined by an Our primary lipid storage molecule Our primary lipid storage molecule Form through Form through Fats separate from water because water Fats separate from water because water

molecules form hydrogen bonds with each molecules form hydrogen bonds with each other and exclude the fatsother and exclude the fats

Fig. 5-11bFig. 5-11b

Fat molecule (triacylglycerol)

Ester linkage

FatsFatsSaturated vs. Saturated vs.

UnsaturatedUnsaturated

as possible, as possible, so “saturated” with so “saturated” with hydrogenhydrogen

chainchain

Generally Generally at at room temperatureroom temperature

Example: Example: fats; butterfats; butter

, so , so less hydrogen less hydrogen

chain chain (b/c of C=C bonds)(b/c of C=C bonds)

Generally Generally at at room temperatureroom temperature

Example Example fats; vegetable oil fats; vegetable oil

FatsFats

Triglycerides & Triglycerides & TransTrans Fats Fats

A diet rich in saturated fats may contribute to A diet rich in saturated fats may contribute to through plaque deposits through plaque deposits is the process of converting unsaturated fats to saturated fats by adding is the process of converting unsaturated fats to saturated fats by adding

hydrogenhydrogen Hydrogenating vegetable oils also creates unsaturated fats with Hydrogenating vegetable oils also creates unsaturated fats with transtrans double bonds double bonds

((transtrans fats) fats) TransTrans fats fats levels “bad” cholesterol and levels “bad” cholesterol and levels of “good” cholesterol levels of “good” cholesterol These These trans trans fats may contribute more than saturated fats to cardiovascular diseasefats may contribute more than saturated fats to cardiovascular disease

PhospholipidsPhospholipids

Make up Make up of a cell of a cell In a In a phospholipidphospholipid, , The two fatty acid tails are The two fatty acid tails are , but the phosphate , but the phosphate

group and its attachments form a group and its attachments form a head head Hydrophobic (“water fearing”) tailHydrophobic (“water fearing”) tail

-nonpolar-nonpolar Hydrophilic (“water loving”) headHydrophilic (“water loving”) head

-polar-polar The nucleus, mitochondria and endomembrane The nucleus, mitochondria and endomembrane

system all are surrounded by their own phospholipid system all are surrounded by their own phospholipid bilayersbilayers

Fig. 5-13Fig. 5-13

(b) Space-filling model(a) (c)Structural formula Phospholipid symbol

Fatty acids

Hydrophilichead

Hydrophobictails

Choline

Phosphate

Glycerol

Hyd

rop

ho

bic

tai

lsH

ydro

ph

ilic

hea

d

PhospholipidPhospholipid

TEM Image: Plasma TEM Image: Plasma MembraneMembrane

PhospholipidsPhospholipids

When phospholipids are added to When phospholipids are added to water, they self-assemble into a water, they self-assemble into a bilayer, with the bilayer, with the

The structure of phospholipids results The structure of phospholipids results in a in a

Phospholipids are the major Phospholipids are the major component of all cell membranescomponent of all cell membranes

Fig. 5-14Fig. 5-14

Hydrophilichead

Hydrophobictail WATER

WATER

SteroidsSteroids

are lipids characterized by a are lipids characterized by a carbon skeleton consisting of four fused ringscarbon skeleton consisting of four fused rings

, an important steroid, is a , an important steroid, is a component in animal cell membranescomponent in animal cell membranes

Although cholesterol is essential in animals, Although cholesterol is essential in animals,

In plasma membranes, cholesterol provides extra In plasma membranes, cholesterol provides extra structural support structural support

are are similar in structure to similar in structure to cholesterolcholesterol

1)Testosterone1)Testosterone2)Estrogen2)Estrogen

Cholesterol (form other steroids from it)Made into sex hormones

Estrogen Testosterone

Anabolic SteroidsAnabolic Steroids

Anabolic SteroidTestosterone

Mimic First used for anemia and muscle disease Misuse can cause

Facial bloating/ Violent damageIncreased

Reduced

ProteinsProteins

Proteins account for Proteins account for of the of the dry mass of most cellsdry mass of most cells

Provide structural support (about 15% of our Provide structural support (about 15% of our mass)mass)

-- Strengthen immune system (Strengthen immune system ( )) Chemical messengers (Chemical messengers ( )) Carry oxygen (Carry oxygen ( )) Cell growth and repairCell growth and repair

Table 5-1Table 5-1

ProteinsProteins Proteins are Proteins are (subunits or (subunits or

building blocks)building blocks) 20 different amino acids20 different amino acids Amino acidsAmino acids are like letters while are like letters while proteinsproteins are like are like

wordswords Amino acids have an Amino acids have an bound to its original bound to its original

carboncarbon Amino acids are joined by Amino acids are joined by through through

to create proteinsto create proteins They fold and twist to form shapes unique to each proteinThey fold and twist to form shapes unique to each protein Reminder: The Reminder: The of a molecule determines its of a molecule determines its

Fig. 5-UN1Fig. 5-UN1

Aminogroup

Carboxylgroup

carbon

Fig. 5-17Fig. 5-17Nonpolar

Glycine(Gly or G)

Alanine(Ala or A)

Valine(Val or V)

Leucine(Leu or L)

Isoleucine(Ile or )

Methionine(Met or M)

Phenylalanine(Phe or F)

Trypotphan(Trp or W)

Proline(Pro or P)

Polar

Serine(Ser or S)

Threonine(Thr or T)

Cysteine(Cys or C)

Tyrosine(Tyr or Y)

Asparagine(Asn or N)

Glutamine(Gln or Q)

Electricallycharged

Acidic Basic

Aspartic acid(Asp or D)

Glutamic acid(Glu or E)

Lysine(Lys or K)

Arginine(Arg or R)

Histidine(His or H)

Amino Acid PolymersAmino Acid Polymers There is no such thing as a There is no such thing as a

monopeptide since monopeptide since

Dipeptides are Dipeptides are linked togetherlinked together

A A polypeptidepolypeptide is a is a

Polypeptides range in Polypeptides range in length from a few to more length from a few to more than a thousand monomers than a thousand monomers

Each polypeptide has a Each polypeptide has a unique linear sequence of unique linear sequence of amino acidsamino acids

Protein FunctionsProtein Functions The function of a protein is The function of a protein is

dependent on its structuredependent on its structure In almost every case, the In almost every case, the

function depends on its function depends on its ability to ability to Example: Example:

interaction in the interaction in the body (right)body (right)

Of all protein types, we will Of all protein types, we will focus a bit more on focus a bit more on enzymes because of their enzymes because of their value in biological sciences.value in biological sciences.

EnzymesEnzymes

EnzymesEnzymes are a type of protein that are a type of protein that acts as a acts as a catalystcatalyst to to

Enzymes can perform their functions Enzymes can perform their functions repeatedly, functioning as workhorses repeatedly, functioning as workhorses that carry out the processes of lifethat carry out the processes of life

Enzyme animationEnzyme animation

Fig. 5-16Fig. 5-16

Enzyme(sucrase)

Substrate(sucrose)

Fructose

Glucose

OH

HO

H2O

Protein StructureProtein Structure A A protein consists of one or protein consists of one or

more polypeptides more polypeptides The sequence of amino acids determines a The sequence of amino acids determines a

protein’s protein’s Again, a protein’s structure determines its Again, a protein’s structure determines its

functionfunction There are 4 levels of protein structureThere are 4 levels of protein structure

PrimaryPrimary SecondarySecondary TertiaryTertiary QuaternaryQuaternary

Protein StructureProtein Structure

Primary StructurePrimary Structure

Amino Acid protein

Primary structure, the of amino acids in a protein, is like the order of letters in a long word

Primary structure is

Animation

Secondary StructureSecondary Structure

The of secondary structure result from

between repeating constituents of the polypeptide backbone

Typical secondary structures are a

and a

Tertiary StructureTertiary Structure

Tertiary structure is determined by

, rather than interactions between backbone constituents

These interactions between R groups include

Strong covalent bonds called

may reinforce the protein’s structure

Quaternary StructureQuaternary Structure

Quaternary structure results when

(connective tissue protein) is a fibrous protein consisting of three polypeptides coiled like a rope

is a globular protein consisting of four polypeptides: two alpha and two beta chains

Protein StructureProtein Structure

DiseaseDisease

A slight change in primary structure can affect a protein’s structure and ability to function

Sickle-cell disease, an inherited blood disorder, results from a

Denatured ProteinsDenatured Proteins When a protein loses its structural integrity, and its tertiary When a protein loses its structural integrity, and its tertiary

(3-D) structure is destroyed(3-D) structure is destroyed This This is called is called denaturationdenaturation A denatured protein is A denatured protein is Factors that cause protein denaturation include: Factors that cause protein denaturation include:

-- temperaturetemperature (on the stove)(on the stove)-- (in your stomach) (in your stomach)--

As a result:As a result:-Losses its ability to function-Losses its ability to function-Properties can change (become insoluble, or change -Properties can change (become insoluble, or change color)color)

Fig. 5-23Fig. 5-23

Normal protein Denatured protein

Denaturation

Renaturation

Nucleic AcidsNucleic Acids The amino acid sequence of a polypeptide is programmed by The amino acid sequence of a polypeptide is programmed by

a unit of inheritance called a a unit of inheritance called a genegene Genes are made of DNA, a Genes are made of DNA, a nucleic acidnucleic acid Nucleic acids are Nucleic acids are

Nucleic acids & proteins are the only macromolecules containing Nucleic acids & proteins are the only macromolecules containing Made up of approximately Made up of approximately

They create the two types of nucleic acids:They create the two types of nucleic acids:

Our genetic code (DNA)Our genetic code (DNA)

Information for protein formation (RNA)Information for protein formation (RNA) TourTour into DNAinto DNA

Nucleotide StructureNucleotide Structure

Pentose (5-carbon) Pentose (5-carbon) sugarsugar (ribose or (ribose or deoxyribose)deoxyribose)

Phosphate groupPhosphate group Nitrogenous baseNitrogenous base

connects the connects the nucleotides togethernucleotides together

Pentose (5-C) SugarsPentose (5-C) Sugars

Nitrogenous BasesNitrogenous Bases

There are two There are two families of families of nitrogenous bases:nitrogenous bases:

Pyrimidines Pyrimidines (cytosine, thymine, (cytosine, thymine, and uracil)and uracil)

Purines Purines (adenine (adenine and guanine) have a and guanine) have a

Nucleic AcidsNucleic Acids

Nucleic acids are polymers called Nucleic acids are polymers called

The portion of a nucleotide without the The portion of a nucleotide without the phosphate group is called a phosphate group is called a

Nucleoside = nitrogenous base + sugarNucleoside = nitrogenous base + sugar Nucleotide = nucleoside + phosphate groupNucleotide = nucleoside + phosphate group In DNA, In DNA, the sugar is the sugar is ; in ; in

RNA, the sugar is RNA, the sugar is In DNA, nitrogenous bases are adenine (A), In DNA, nitrogenous bases are adenine (A),

cytosine (C), guanine (G), and thymine (T)cytosine (C), guanine (G), and thymine (T) In RNA, In RNA,

DNA and RNADNA and RNA

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

DNADNA DDeoxyriboeoxyriboNNucleic ucleic AAcid - DNAcid - DNA DNA is a recipe book for proteinsDNA is a recipe book for proteins One strand has 100’s to 1000’s of One strand has 100’s to 1000’s of

genesgenes DNA is arranged into a structure DNA is arranged into a structure

called a called a 2 strands of polynucleotides2 strands of polynucleotides Nitrogenous bases bonded to Nitrogenous bases bonded to

each other by each other by , vice versa, vice versa , vice versa, vice versa

DNA Double HelixDNA Double Helix A DNA molecule has two A DNA molecule has two

polynucleotides spiraling around an polynucleotides spiraling around an imaginary axis, imaginary axis,

In the DNA double helix, the two In the DNA double helix, the two backbones run in opposite 5backbones run in opposite 5 →→ 3 3 directions from each other, an directions from each other, an arrangement referred to as arrangement referred to as

The nitrogenous bases in DNA pair The nitrogenous bases in DNA pair up and form hydrogen bonds: up and form hydrogen bonds: adenine (A) always with thymine (T), adenine (A) always with thymine (T), and guanine (G) always with and guanine (G) always with cytosine (C)cytosine (C)

Race for the Double Race for the Double HelixHelix

James Watson and James Watson and Francis Crick Francis Crick (pictured right) are (pictured right) are credited with the credited with the discovery of DNA discovery of DNA as a double helixas a double helix

Proposed in 1953Proposed in 1953 Rosalind Franklin Rosalind Franklin

may have played a may have played a major role but major role but never received never received creditcredit

RNARNA

RRiboiboNNucleic ucleic AAcid cid - RNA- RNA

RNA is a RNA is a of of

nucleotidesnucleotides Many types of Many types of

RNA are used to RNA are used to help create help create

Review QuestionsReview Questions1. Explain the importance of carbon as a compound of life.2. Define organic compounds and hydrocarbons.3. Define isomers and differentiate between the 3 different types.4. Differentiate between 7 different biological functional groups.5. Explain the use and functioning of ATP.6. Name the 4 different classes of macromolecules and the subunits of

each.7. Differentiate between dehydration (condensation) synthesis and

hydrolysis.8. Describe carbohydrates, noting the functions and differences within

the three main categories, along with multiple examples of each.9. Differentiate between starch, glycogen, chitin, and cellulose.10.Describe lipids, noting the functions and differences within the three

main categories, along with multiple examples of each.11.Describe 3 differences between unsaturated and saturated fats,

naming an example of each.12.Describe the importance of phospholipids, along with their parts.13.Define steroids and differentiate between the 3 examples discussed

in class.14.Describe proteins, including 6 different examples and their

respective functions.15.Identify and describe the parts of an amino acid.

Review Questions cont’dReview Questions cont’d16. Discuss the importance of enzymes to life processes.17. Differentiate between the 4 levels of protein structure and

organization.18. Describe denaturation and name factors that cause protein

denaturation.19. Identify and describe the 3 parts of a nucleotide.20. Differentiate between the functions of DNA and RNA.21. Describe 3 structural differences between DNA and RNA.22. Differentiate between purines and pyrimidines.23. Name 3 people important to the discovery of DNA as a double helix.