biocompuestos en los seres vivos

CARACTERISTICAS(DE(LA(VIDA(

M.SC.(PAOLA(ESCOBAR(RAMOS(UNIVERSIDAD(DEL(ATLANTICO(

2014((


Organismos(formados(por(celulas(Unicelulares(MulFcelulares(Membrana(plasmFca(y(organelos(

Dos(Fpos(de(clulas:( Procarita(( Eucarita(((

A

View

of Life 3

Th e regulation of glucose (a simple sugar) concentration in

the blood of complex anim

als is a good example of a hom

eostatic m

echanism. Your cells require a constant supply of glucose m

ol-ecules, w

hich they break down to obtain energy. Th e circulatory

system delivers glucose and other nutrients to all the cells. W

hen the concentration of glucose in the blood rises above norm

al lim-

its, glucose is stored in the liver and in muscle cells. W

hen you have not eaten for a few hours, the glucose concentration begins to fall. Your body converts stored nutrients to glucose, bringing the glu-cose concentration in the blood back to norm

al levels. When the

glucose concentration decreases, you also feel hungry and restore nutrients by eating.

Some of the sim

plest life-forms, such as protozoa, are uni-

cellular organisms, m

eaning that each consists of a single cell ( FIG

. 1-1). In contrast, the body of a dog or a maple tree is m

ade of billions of cells. In such com

plex multicellular organism

s, life pro-cesses depend on the coordinated functions of com

ponent cells that m

ay be organized to form tissues, organs, and organ system

s.Every cell is enveloped by a protective plasm

a mem

brane that separates it from

the surrounding external environment. Th e

plasma m

embrane regulates passage of m

aterials between the cell and its environm

ent. Cells have specialized m

olecules that con-tain genetic instructions and transm

it genetic information. In m

ost cells, the genetic instructions are encoded in deoxyribonucleic acid, m

ore simply know

n as DN

A. Cells typically have internal

structures called organelles that are specialized to perform specifi c

functions.Th ere are two fundam

entally diff erent types of cells: prokary-otic and eukaryotic. Prokaryotic cells are exclusive to bacteria and to m

icroscopic organisms called archaea. All other organism

s are characterized by their eukaryotic cells. Th ese cells typically contain a variety of organelles enclosed by m

embranes, including

a nucleus, which houses D

NA

. Prokaryotic cells are structurally sim

pler; they do not have a nucleus or other mem

brane-enclosed organelles.

Organism

s grow and develop

Biological growth involves an increase in the size of individual

cells of an organism, in the num

ber of cells, or in both. Grow

th m

ay be uniform in the various parts of an organism

, or it may be

greater in some parts than in others, causing the body proportions

to change as growth occurs. Som

e organisms

most trees, for

example

continue to grow throughout their lives. Many anim

als have a defi ned grow

th period that terminates w

hen a characteristic adult size is reached. An intriguing aspect of the grow

th process is that each part of the organism

typically continues to function as it grows.

Living organisms develop as well as grow. D

evelopment in-

cludes all the changes that take place during an organisms life.

Like many other organism

s, every human begins life as a fertilized

egg that then grows and develops. Th e structures and body form

that develop are exquisitely adapted to the functions the organism

must perform

.

Organism

s regulate their metabolic processes

Within all organism

s, chemical reactions and energy transform

a-tions occur that are essential to nutrition, the grow

th and repair of cells, and the conversion of energy into usable form

s. Th e sum of

all the chemical activities of the organism

is its metabolism

.M

etabolic processes occur continuously in every organism,

and they must be carefully regulated to m

aintain homeostasis,

an appropriate, balanced internal environment. W

hen enough of a cell product has been m

ade, its manufacture m

ust be decreased or turned off . W

hen a particular substance is required, cell processes that produce it m

ust be turned on. Th ese homeostatic m

echanisms

are self-regulating control systems that are rem

arkably sensitive and effi cient.

FIGU

RE 1-1 U

nicellular and multicellular life-form

s

(a) Unicellular organism

s consist of one intricate cell that performs

all the functions essential to life. Ciliates, such as this Param

ecium,

move about by beating their hairlike cilia.

250 m

Mike Abbey/Visuals Unlimited, Inc.

(b) M

ulticellular organisms, such as this A

frican buffalo (Syncerus caffer) and the plants on w

hich it grazes, may consist of billions of

cells specialized to perform specific functions.

McMurray Photography

3929_Solomon_Ch01pp1-25.indd 3


8/16/10 12:43:05 PM8/16/10 12:43:05 PM

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).

Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Organismos(crecen(y(se(desarrollan( Clulas,(tamao(y(nmero(

Desproporcin(( Desarrollo,(madurez(sexual(

Regulacion(del(metabolismo,(homeostasis(

A

View

of Life 3




eostatic m


ol-ecules, w




al lim-



al levels. When the


Some of the sim








ponent cells that m



a mem



plasma m







ore simply know

n as DN







embranes, including


NA




Organism

s grow and develop




th m


, or it may be



e organisms

most trees, for

example








evelopment in-






must perform

.

Organism


Within all organism




s. Th e sum of


is its metabolism

.M










echanisms



FIGU

RE 1-1 U


s




ecium,


250 m


(b) M








8/16/10 12:43:05 PM8/16/10 12:43:05 PM




Regulacion(del(metabolismo,(homeostasis(Regulacion(de(la(glucosa(

Responden(a(esFmulos,(sico(o(qumicos(

A

View

of Life 3




eostatic m


ol-ecules, w




al lim-



al levels. When the


Some of the sim








ponent cells that m



a mem



plasma m







ore simply know

n as DN







embranes, including


NA




Organism

s grow and develop




th m


, or it may be



e organisms

most trees, for

example








evelopment in-






must perform

.

Organism


Within all organism




s. Th e sum of


is its metabolism

.M










echanisms



FIGU

RE 1-1 U


s




ecium,


250 m


(b) M








8/16/10 12:43:05 PM8/16/10 12:43:05 PM




Responden(a(esFmulos,(sico(o(qumicos(Colos(Apariencia(Movimiento((Ssiles((

4 Chapter 1

Organisms respond to stimuliAll forms of life respond to stimuli, physical or chemical changes in their internal or external environment. Stimuli that evoke a re-sponse in most organisms are changes in the color, intensity, or direction of light; changes in temperature, pressure, or sound; and changes in the chemical composition of the surrounding soil, air, or water. Responding to stimuli involves movement, though not always locomotion (moving from one place to another).

In simple organisms, the entire individual may be sensitive to stimuli. Certain unicellular organisms, for example, respond to bright light by retreating. In some organisms, locomotion is achieved by the slow oozing of the cell, the process of amoeboid movement. Other organisms move by beating tiny, hairlike exten-sions of the cell called cilia or longer structures known as fl agella (FIG. 1-2). Some bacteria move by rotating their fl agella.

Most animals move very obviously. Th ey wiggle, crawl, swim, run, or fl y by contracting muscles. Sponges, corals, and oysters have free-swimming larval stages, but most are sessile as adults, meaning that they do not move from place to place. In fact, they may remain fi rmly att ached to a surface, such as the sea bott om or a rock. Many sessile organisms have cilia or fl agella that beat rhyth-mically, bringing them food and oxygen in the surrounding water. Complex animals, such as grasshoppers, lizards, and humans, have highly specialized cells that respond to specifi c types of stimuli. For example, cells in the retina of the vertebrate eye respond to light.

Although their responses may not be as obvious as those of ani-mals, plants do respond to light, gravity, water, touch, and other stim-

uli. For example, plants orient their leaves to the sun and grow toward light. Many plant responses involve diff erent growth rates of various parts of the plant body. A few plants, such as the Venus fl ytrap of the Carolina swamps, are very sensitive to touch and catch insects (FIG. 1-3). Th eir leaves are hinged along the midrib, and they have a scent that att racts insects. Trigger hairs on the leaf sur-face detect the arrival of an insect and stimulate the leaf to fold. When the edges come together, they inter-lock, preventing the insects escape. Th e leaf then secretes enzymes that kill and digest the insect. Th e Venus fl ytrap usually grows in nitrogen-defi cient soil. Th e plant obtains part of the nitrogen required for its growth from the insects it eats.

Organisms reproduceAt one time, people thought worms arose spontaneously from horsehair in a water trough, maggots from de-caying meat, and frogs from the mud

1 m

Flagella

A. B

. Dow

sett/

Scie

nce

Phot

o Lib

rary

/Pho

to R

esea

rche

rs, I

nc.

FIGURE 1-2 Biological movementThese bacteria (Helicobacter pylori), equipped with fl agella for locomo-tion, have been linked to stomach ulcers. The photograph was taken using a scanning electron microscope. The bacteria are not really red and blue. Their color has been artifi cially enhanced.

(a) Hairs on the leaf surface of the Venus flytrap (Dionaea muscipula) detect the touch of an insect, and the leaf responds by folding.

David

M. D

enni

s/To

m S

tack

& A

ssoc

iate

s

(b) The edges of the leaf come together and interlock, preventing the flys escape. The leaf then secretes enzymes that kill and digest the insect.

David

M. D

enni

s/To

m S

tack

& A

ssoc

iate

s

FIGURE 1-3 Plants respond to stimuli

3929_Solomon_Ch01pp1-25.indd 43929_Solomon_Ch01pp1-25.indd 4 8/16/10 12:43:07 PM8/16/10 12:43:07 PM

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Organismos(se(reproducen(Asexual(Sexual((

Poblaciones(evolucionan(y(se(adaptan(al(medio(

A View of Life 5

ther. Th is genetic variation is important in the vital processes of evolution and adaptation.

Populations evolve and become adapted to the environmentTh e ability of a population to evolve over many generations and adapt to its environment equips it to survive in a changing world. Adaptations are inherited characteristics that enhance an organ-isms ability to survive in a particular environment. Th e long, fl ex-ible tongue of the frog is an adaptation for catching insects, the feathers and lightweight bones of birds are adaptations for fl ying, and the thick fur coat of the polar bear is an adaptation for surviving frigid temperatures. Adaptations may be structural, physiological, biochemical, behavioral, or a combination of all four (FIG. 1-5). Ev-ery biologically successful organism is a complex collection of co-ordinated adaptations produced through evolutionary processes.

ReviewWhat characteristics distinguish a living organism from a nonliving object?What would be the consequences to an organism if its homeostatic mechanisms failed? Explain your answer.What do we mean by adaptations?

1.3 LEVELS OF BIOLOGICAL ORGANIZATION

LEARNING OBJECTIVE3 Construct a hierarchy of biological organization, including levels char-

acteristic of individual organisms and levels characteristic of ecological systems.

of the Nile. Th anks to the work of several scientists, including the Italian physician Francesco Redi in the 17th century and French chemist Louis Pasteur in the 19th century, we know that organisms arise only from previously existing organisms.

Simple organisms, such as amoebas, perpetuate themselves by asexual reproduction (FIG. 1-4a). When an amoeba has grown to a certain size, it reproduces by splitt ing in half to form two new amoe-bas. Before an amoeba divides, its hereditary material (set of genes) is duplicated, and one complete set is distributed to each new cell. Except for size, each new amoeba is similar to the parent cell. Th e only way that variation occurs among asexually reproducing organ-isms is by genetic mutation, a permanent change in the genes.

In most plants and animals, sexual reproduction is carried out by the fusion of an egg and a sperm cell to form a fertilized egg (FIG. 1-4b). Th e new organism develops from the fertilized egg. Off spring produced by sexual reproduction are the product of the interaction of various genes contributed by the mother and the fa-

(a) Asexual reproduction. One individual gives rise to two or more offspring that are similar to the parent. Difflugia, a unicellular amoeba, is shown dividing to form two amoebas.

100 m

Cabi

sco/

Visu

als U

nlim

ited,

Inc.

(b) Sexual reproduction. Typically, each of two parentscontributes a gamete (sperm or egg). Gametes fuse to producethe offspring, which has a combination of the traits of bothparents. A pair of tropical flies are shown mating.

L. E.

Gilb

ert/

Biol

ogica

l Pho

to S

ervic

e

FIGURE 1-4 Asexual and sexual reproduction

FIGURE 1-5 AdaptationsThese Burchells zebras (Equus burchelli), photographed in Tanzania, are behaviorally adapted to position themselves to watch for lions and other predators. Stripes are thought to be an adaptation for visual protection against predators. They serve as camoufl age or to break up form when spot-ted from a distance. The zebra stomach is adapted for feeding on coarse grass passed over by other grazers, an adaptation that helps the animal survive when food is scarce.

McM

urra

y Pho

togr

aphy3929_Solomon_Ch01pp1-25.indd 53929_Solomon_Ch01pp1-25.indd 5 8/16/10 12:43:10 PM8/16/10 12:43:10 PM


A View of Life 5

ther. Th is genetic variation is important in the vital processes of evolution and adaptation.

Populations evolve and become adapted to the environmentTh e ability of a population to evolve over many generations and adapt to its environment equips it to survive in a changing world. Adaptations are inherited characteristics that enhance an organ-isms ability to survive in a particular environment. Th e long, fl ex-ible tongue of the frog is an adaptation for catching insects, the feathers and lightweight bones of birds are adaptations for fl ying, and the thick fur coat of the polar bear is an adaptation for surviving frigid temperatures. Adaptations may be structural, physiological, biochemical, behavioral, or a combination of all four (FIG. 1-5). Ev-ery biologically successful organism is a complex collection of co-ordinated adaptations produced through evolutionary processes.

ReviewWhat characteristics distinguish a living organism from a nonliving object?What would be the consequences to an organism if its homeostatic mechanisms failed? Explain your answer.What do we mean by adaptations?

1.3 LEVELS OF BIOLOGICAL ORGANIZATION

LEARNING OBJECTIVE3 Construct a hierarchy of biological organization, including levels char-

acteristic of individual organisms and levels characteristic of ecological systems.

of the Nile. Th anks to the work of several scientists, including the Italian physician Francesco Redi in the 17th century and French chemist Louis Pasteur in the 19th century, we know that organisms arise only from previously existing organisms.

Simple organisms, such as amoebas, perpetuate themselves by asexual reproduction (FIG. 1-4a). When an amoeba has grown to a certain size, it reproduces by splitt ing in half to form two new amoe-bas. Before an amoeba divides, its hereditary material (set of genes) is duplicated, and one complete set is distributed to each new cell. Except for size, each new amoeba is similar to the parent cell. Th e only way that variation occurs among asexually reproducing organ-isms is by genetic mutation, a permanent change in the genes.

In most plants and animals, sexual reproduction is carried out by the fusion of an egg and a sperm cell to form a fertilized egg (FIG. 1-4b). Th e new organism develops from the fertilized egg. Off spring produced by sexual reproduction are the product of the interaction of various genes contributed by the mother and the fa-

(a) Asexual reproduction. One individual gives rise to two or more offspring that are similar to the parent. Difflugia, a unicellular amoeba, is shown dividing to form two amoebas.

100 m

Cabi

sco/

Visu

als U

nlim

ited,

Inc.

(b) Sexual reproduction. Typically, each of two parentscontributes a gamete (sperm or egg). Gametes fuse to producethe offspring, which has a combination of the traits of bothparents. A pair of tropical flies are shown mating.

L. E.

Gilb

ert/

Biol

ogica

l Pho

to S

ervic

e

FIGURE 1-4 Asexual and sexual reproduction

FIGURE 1-5 AdaptationsThese Burchells zebras (Equus burchelli), photographed in Tanzania, are behaviorally adapted to position themselves to watch for lions and other predators. Stripes are thought to be an adaptation for visual protection against predators. They serve as camoufl age or to break up form when spot-ted from a distance. The zebra stomach is adapted for feeding on coarse grass passed over by other grazers, an adaptation that helps the animal survive when food is scarce.

McM

urra

y Pho

togr

aphy




A View of Life 7

OrganismOrgan systemswork togetherin a functionalorganism.

Organ system(e.g., skeletalsystem) Tissuesand organs makeup organ systems.

Organ(e.g., bone)Tissues formorgans.

Tissue(e.g., bone tissue)Cells associateto form tissues.

Cellular levelAtoms and moleculesmake up the cytoplasmand form organelles, such as the nucleus and mitochondria (the site of many energytransformations). Organelles performvarious functionsof the cell.

Chemical levelAtoms join to formmolecules. Macro-molecules are largemolecules such asproteins and DNA.

BiosphereEarth and all ofits communitiesconstitute thebiosphere.

EcosystemA communitytogether withthe nonlivingenvironmentforms anecosystem.

CommunityThe populationsof different species thatpopulate the same area makeup a community.

PopulationA populationconsists of organisms of thesame species.Organism

Population

Community

Ecosystem

Biosphere

Organ system

Organ

Tissue

Cell

Organelle

Macromolecule

Molecule

Water

Oxygen atom

Bone cells

Nucleus

Hydrogen atoms

FIGURE 1-6 Animated The hierarchy of biological organization



M.SC.(PAOLA(ESCOBAR(RAMOS(UNIVERSIDAD(DEL(ATLANTICO(

2014(

BIOCOMPUESTOS(EN(LOS(SERES(VIVOS(

AGUA(

2(Hidrogeno(y(un(Oxgeno(

Enlaces(covalentes( Molcula(bipolar(

AGUA(

Puentes(de(hidrgeno(Estado(liquida(Punto(de(ebullicin(100C(

Menos(densa(Alta(solubilidad(

AGUA(

Puentes(de(hidrgeno(Ocurren(entre(H,(O(y(N(

Tensin(supercial( Cohesin( Adhesin(

Accin(capilar( Imbibicin((Resistencia(a(la(temperatura(

AGUA(

Ionizacin(

Solucin(cida,(No.(H(>(No.(OH( Solucin(cida,(No.(OH(>(No.(H(

pH( Srensen(( Logaritmo(negaFvo(de(la(concentracin(del(ion(hidrgeno(

pH(=(^(log([H+]!! Valores(bajos(de(pH((((((((((((altas([H+]((( Valores(altos(de(pH((((((((((((bajas([H+]((((

!Los(cidos,(donadores(de(protones(!Las(bases,(aceptores(de(protones(((((((((

pH(

Formas(de(calcular(el(pH:(

Colorimtrico( Electromtrico(( Clculos(matemFcos(

pH(sanguneo(7.35((7.45(

Acidosis:((aumento(de([H+](en(la(sangre((

Metablica:((deporte,(ayunos(prolongados,(ingesFn(de(cidos(

Si(aumenta([H+](entonces,(aumenta(el([H2Co3](y(el([CO2]((

pH(disminuido((y(HCO3(disminuido(

Acidosis(respiratoria:(pH(disminuido(y(CO2(elevado(

Causas:((apneas(y(enfermedades(que(reducen(el(ritmo(respiratorio(

pH(sanguneo(7.35((7.45((

Alcalosis:(aumento(de(la([OH^](en(sangre(

Metablica:((vmitos,(ingesFn(de(bicarbonato(o(anFcidos(

Al(aumentar(la([OH],((los(OH(se(combinan(con(H+(=(H2O.((Al(disminuir(la([H+](aumenta(la(disociacin(del(H2CO3.((

Al(disminuir(la([H2CO3](el(CO2(disuelto(en(el(plasma(+(H2O(=(H2CO3((

pH(elevado(y(HCO3(elevado((((A(nivel(renal,(la(compensacin(consiste(en(una(disminucin(en(la(secrecin(de(H+(y(en(una(disminucin(en(la(reabsorcin(del(HCO3((plasmFco)(

Alcalosis:(pH(elevado(y(CO2(disminuido(

Respiratoria:((hipervenFlacin,(stress,(ansiedad(

La(disminucin(del(CO2(disuelto(en(la(sangre(provoca(que(el(CO2(en(estado(gaseoso(en(los(pulmones(se(disuelva(en(el(plasma(para(restablecer(el(equilibrio,(lo(que(hace(disminuir(la(presin(parcial(del(CO2(gaseoso(en(los(pulmones.(

pH:(Buer(Fisiolgicos(

Orgnicos:(!Aminocidos(y(protenas(!Sistema(hemoglobina(reducida/oxihemoglobinato(

Inorgnicos:(!Sistema(fosfato(monocido/dicido(!Sistema(carbnico/bicarbonato(

FUNDAMENTACION(QUIMICA(DE(LA(VIDA(

BIOMOLCULAS(

El(cuerpo(se(compone(de(cuatro(elementos(principales(

Elemento( Porcentaje( Elemento( Porcentaje(

Carbono(( 50( Potasio( 1(

Oxgeno( 20( Azufre( 0.8(

Hidrgeno(( 10( Sodio(( 0.4(

Nitrgeno( 8.5( Cloro( 0.4(

Calcio(( 4( Magnesio( 0.1(

Fsforo( 2.5( Hierro( 0.01(

Manganeso(( 0.001(

Yodo( 0.00005(

BIOMOLCULAS(

El(cuerpo(se(compone(de(cinco(biomolculas(principales(Biomolcula((( Bloque(estructural(( Funciones(principales(

DNA( DesoxirribonucleFdo( Material(genFco(

RNA( RibonucleFdo( Molde(para(la(sntesis(de(protenas(

Protenas( Aminocidos(Molculas(que(realizan(funciones(celulares((enzimas)(

Polisacridos( Glucosa( Almacenamiento(de(energa(

Lpidos(( cidos(grasos( Compomentes(dde(la(membrana(plasmFca(

MOLCULAS:(FUNCIN(BIOLGICA(

MACROMOLECULAS( ELEMENTOS(UNITARIOS(PARA(CONSTRUIR(MACROMOLCULAS(

INTERMEDIARIOS(METABOLICOS(

MOLCULAS(CON(DIVERSAS(FUNCIONES(

GRUPOS(FUNCIONALES(

Agrupamiento(de(tomos(

BIOMOLCULAS:(CARBOHIDRATOS!

Distribudos(:(animales(y(vegetales( ParFcipacin:(estructural(y(metablica(("Vegetales:(fotosntesis("Animales:(grasas(y(protenas(

"(Mayor(volmen(de(los(vegetales(

"Glucosa((


(Importancia!de!la!Glucosa!!!! Carbohidratos,(se(absorben(como(glucosa(a(

travs(del(torrente(sanguneo( Formacin(de(otros(carbohidratos( CombusFble(Fsular( CombusFble(para(el(feto( Desempea(funciones(especcas((

# Glucgeno,(almacenamiento(# Ribosa,(cidos(nuclecos(# Galactosa,(lactosa(de(la(leche(


! Clasicacin(("Monosacridos:(triosas,(hexosas,(pentosas("Disacridos:(sacarosa("Oligosacridos:(maltotriosa("Polisacridos:(almidones(


! Presentan(variantes(isomricas(# Esteroismeros((

Estructuras(cclicas(piranosa(y(furanosa(

Anmeros(alfa(y(beta( Isomerismo(aldosa^cetosa(


! Presentan(variantes(isomricas(# Esteroismeros((

Isomerismo(D(y(L( Estructuras(cclicas(piranosa(y(furanosa(

Anmeros(alfa(y(beta( Epmeros(( Isomerismo(aldosa^cetosa(


!

BIOMOLCULAS:(LPIDOS(

BIOMOLCULAS:(LPIDOS(

Grupo(heterogneo(de(compuestos,(vinculados(por(sus(propiedades(ssicas.(

Propiedades(comunes:("Insolubles(en(compuestos(polares:(agua("Solubles(en(compuestos(no(polares:(ter,(benceno,(cloroformo(

Valor(energFco(

BIOMOLCULAS:(LPIDOS:!Importancia!Biomdica(

Tejido(adiposo( Aislante(trmico( Aislante(elctrico( ConsFtuyente(en(el(tejido(nervioso( ConsFtuyente(de(la(membrana(plasmFca(y(mitocondriales(

Medio(de(transporte(

BIOMOLCULAS:(LPIDOS:!Clasicacin(

" Saturada(carecen(de(dobles(enlace(

" Insaturada(poseen(de(dobles(enlaces(

BIOMOLCULAS:(LPIDOS:!Clasicacin(

Esteroides(( Fosfolpidos((

BIOMOLCULAS:(COLESTEROL(

Colesterol((Arterioesclerosis( Precursor(de(esteroides(# cidos(biliares(# Hormonas(# CorFcosuprarrenales(# Hormonas(sexuales(# Vitamina(D(# Glucsidos(cardacos(

BIOMOLCULAS:(COLESTEROL(

Distribudo(ampliamente(en(el(cuerpo("Sistema(nervioso(

ConsFtuyente(de(la(membrana(plasmFca(y(lipoprotenas(plamFcas(

Presente(en(grasas(animales( El(ergosterol(presente(en(vegetales(y(levaduras;(precursor(de(la(vitamina(D(

BIOMOLCULAS(PROTENAS!

BIOMOLCULAS:(ANIMOCIDOS(

Poseen(un(grupo(amino(y(un(grupo(carboxilo(

Cada(animocido(se(une(a(otros(dos(animocidos(formando(una(cadena(de(polippFdos(


Los(animocidos(que(componen(una(cadena(de(polippFdos(se(unen(por(enlaces(ppFdicos(


Residuo,(N^terminal(grupo(amino( Residuo,(C^terminal(grupo(carboxilo(


El(grupo(R(le(conere(versaFlidad(a(las(protenas(

BIOMOLCULAS:(ANIMOCIDOS:!Clasicacin(

BIOMOLCULAS:(ANIMOCIDOS:!Importancia(

Monmeros(de(las(protenas( Cumplen(funciones(especcas( En(las(protenas,(los(aminocidos,(realizan(funciones(estructurales,(hormonales,(catalFcas(esenciales(para(la(vida(

Alta(especicidad( AnFcuerpos(o(inmunoglobulinas(

BIOMOLCULAS:(ANIMOCIDOS:!Estructura(

Esturctura(Primaria(Lineal(20n(

Estructura(secundaria(Helice((Helice((


Esturctura(terciaria(Proteinas(brosa((uas,(pelo)( colagena!

Protenas(globulares((musculo)( mioglobina(


Esturctura(terciaria(Proteinas(brosa((uas,(pelo)( colagena(

Protenas(globulares((musculo)( mioglobina!


Esturctura(cuaternaria(Mas(de(una(unidad,(hemoglobina(

Homodmero(Heterodmero((

BIOMOLCULAS(CIDOS!NUCLEICOS(

BIOMOLCULAS:(ACIDOS!NUCLEICOS(

ENZIMAS(

ENZIMAS( Son( protenas( que(disminuyen(la(canFdad(de( energa( que( se(requiere( para( llevar( a(cabo(una(reaccin(

E s t a ( a c F v i d a d(catalFca(es(especca.(

A c t a n ( c o m o(c a t a l i z a d o r e s(biolgicos.(

CATALIZADOR(Sustancia(que(aumenta(o(disminuye(la(velocidad(de(una(reaccin(

qumica,(sin(verse(alterada(en(el(proceso(global(

CATALIZADORES(QUMICOS( Reacciones(lentas.( Temperaturas(mayores(de(

100(C.( Presiones(elevadas.( pH(extremos.( Menor(ecacia(catalFca.(

CATALIZADORES(BIOLGICOS( Reacciones(rpidas.( Temperaturas(menores(de(

100(C.( Presiones(bajas.( pH(cercanos(a(la(

neutralidad.( Mayor(ecacia(catalFca.(

ENZIMAS:((CARACTERSTICAS((

$ ConsFtuidas(por(ms(de(100(aminocidos.($ Disminuyen(la(energa(de(acFvacin.($ Alta(especicidad.(($ Se(requieren(en(canFdades(mnimas.($ Pueden(ser(reguladas((alostricas)($ Son(sensibles((temperatura(y(pH)($ Modican( la( estructura( qumica( del( sustrato( segn( el( Fpo( de(

reaccin(que(catalicen.(

$ No(alteran(el(equilibrio(de(las(reacciones.(

ENZIMAS:(DE(ACUERDO(AL(TIPO(DE(REACCIN(

SITIO(ACTIVO(

$Es(la(regin(especca(de(la(enzima(donde(se(une(el(sustrato((

CaractersFcas:(

SITIO(ACTIVO:(CaractersFcas(

(# Tamao,(relaFvamente(pequeo.(# Forma(tridimensional.(# Unin,(fuerzas(relaFvamente(dbiles.(# Interaccin,( forma( un( complejo( al( unirse( con( el(sustrato.(

# Especicidad,( para( cada( sustrato( hay( un( siFo(acFvo.(

COMPLEJO(ENZIMA^SUSTRATO:((CaractersFcas(

$Se( modican( las( propiedades( ssicas( de( la(enzima.(La(solubilidad(y(la(estabilidad(al(calor.(

$El( complejo( se( ha( comprobado( mediante(tcnicas( de( microscopa( electrnica( de(transmisin(y(cristalograsa(de(rayos(X.(

$E l ( c o m p l e j o ( p u e d e( s e r ( a i s l a d o(experimentalmente.(

MODELOS(ENZIMTICOS(

COENZIMAS($Poseen( estructuras( orgnicas( complejas( que( no(

pueden( sinteFzarse( por( los(mamferos.( Las( vitaminas(hidrosolubles,( aquellas( que( normalmente( se(denominan(como(el(complejo(de(la(vitamina(B,(son(los(precursores(metablicos(de(diversas(coenzimas.((

CaractersFcas($Termoestables.($Derivadas(de(la(vitamina(B.($Algunas( veces( funcionan( como( cosustratos( al( ser(modicadas( durante( la( reaccin( pero( retornando( su(estado(original(en(otra(reaccin(

8/29/14( CARMEN(QUINTERO( 68(

COENZIMAS(

COFACTORES($Son( molculas( de( naturaleza( no( proteica( necesarias(

para(que(las(enzimas(realicen(la(catlisis.(

CaractersFcas((

$Aumentan( la( capacidad( catalFca( de( la( enzima( y(adquiere(especicidad(por(el(sustrato.(

$Puede(formar(complejo(con(el(sustrato(y(el(siFo(acFvo(de(la(enzima(permiFendo(as(la(catlisis.(

$Funcionan(como(poderosos(atrayentes(de(electrones.(

COFACTORES(

GRUPOS(PROSTTICOS(

$Enzimas,(grupos(no(protenicos(e(iones(metlicos(

$Apoenzima,(enzima(inacFva($Coenzima(o(cofactor($Holoenizma,(enzima(acFva(

FACTORES(QUE(AFECTAN(LA(ACTIVIDAD(ENZIMTICA(

Fsicos($Temperatura($pH(

Qumicos:(Inhibidores(enzimFcos($Molculas(capaz(de(enlazarse(a(una(enzima(y(disminuir(

su(acFvidad($Frmacos($AnFbiFcos(($Plaguicidas(


Inhibidores(enzimFcos($Reversibles(compeFFvos:(compiten(con(el(sustrato(por(el(siFo(acFvo(de(la(enzima.($AnFvirales($AnFbiFcos(($AnFtumorales((


Inhibidores(enzimFcos($Reversibles(no(compeFFvos:(sustrato(e(inhibidor(no(compiten(por(un(siFo(de(enlace(


Inhibidores(enzimFcos($Irreversibles:(se(unen(fuertemente(a(una(enzima($Plaguicidas((paraFon)($Venenos(((cianuro)($AnFbiFcos((penicilina)(

$Gases(nerviosos(


Inhibidores(enzimFcos($Alostrico:(se(unen(a(un(lugar(de(la(enzima(diferente(del(siFo(acFvo(cambiando(la(conguracin(de(ste(

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