carbon & biochemistry biol-101 section 802rl mr. fusco
DESCRIPTION
Carbon & Biochemistry BIOL-101 Section 802RL Mr. Fusco. Chapter 4: Carbon and the Molecular Diversity of Life Chapter 5: The Structure & Function of Large Biological Molecules. Chemistry of Life. Carbon is essential to life - PowerPoint PPT PresentationTRANSCRIPT
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.