PROTEINSPROTEINSSTRUCTURAL AND

FUNCTIONAL COMPOUNDS OF UNIVERSAL IMPORTANCE

TO ALL LIVING THINGS

PROTEINSPROTEINS

MADE OF MONOMERS CALLED AMINO ACIDS OFTEN REFERRED TO AS POLYPEPTIDES

BECAUSE OF THE TYPE OF BONDING INVOLVED EACH SPECIES HAS THOUSANDS OF UNIQUE

PROTEINS• VARY IN THE NUMBER OF AMINO ACID RESIDUES• VARY IN THE SEQUENCE OF AMINO ACID RESIDUES• VARY IN THE SPECIFIC AMINO ACIDS PRESENT IN

EACH PROTEIN• VARY IN SECONDARY FEATURES LIKE CROSS-

BONDING BETWEEN AMINO ACIDS

STRUCTURE OF AMINO ACIDSSTRUCTURE OF AMINO ACIDS

CCNH

H

HH

O

O

RAMINEGROUP

CARBOXYLGROUP

RADICALGROUP

ONLY THE RADICAL GROUP VARIES BETWEENAMINO ACIDS

AMINO ACIDSAMINO ACIDS

CCNH

H

HH

O

O

H

THREONINE

GLYCINE

SERINE

CCNH

H

HH

O

O

HHH C

ALANINE

CCNH

H

HH

O

O

C HH

OH

CCNH

H

HH

O

O

HC

OC HH

HH

H

PEPTIDE BONDINGPEPTIDE BONDING

CCNH

H

HH

O

O

R

CCNH

H

HH

O

O

R

CCNH

H

H

O

R

CCNH HH

O

O

R

H2O

AMINO ACIDS

DIPEPTIDEONLY 2 AMINO ACIDS

POLYPEPTIDESPOLYPEPTIDES

CCNH

H

H

O

R

CCNH H

O

R

CCNH H

O

R

CCNH HH

O

O

R

COMPOSED OF 3 OR MORE AMINO ACIDS

EnergyEnergy Chemical energy – found in food serves Chemical energy – found in food serves

as the primary source.as the primary source. Energy is the ability to move or change Energy is the ability to move or change

mattermatter Exists in many forms (heat, light, Exists in many forms (heat, light,

chemical, mechanical, and electrical)chemical, mechanical, and electrical) Can be converted from one form to Can be converted from one form to

another.another. Can be stored or released by chemical Can be stored or released by chemical

reactions.reactions.

Chemical ReactionsChemical Reactions Process during which chemical bonds Process during which chemical bonds

between atoms are broken and new ones are between atoms are broken and new ones are formed.formed.

Reactants – the starting materials of a Reactants – the starting materials of a chemical reaction.chemical reaction.

Products – newly formed substances formedProducts – newly formed substances formed

Reactants Reactants Products Products Arrow means “changes to or yields”Arrow means “changes to or yields”

HH22 + O + O22 H H22OO

Energy in Chemical ReactionsEnergy in Chemical Reactions

Energy is absorbed or released when Energy is absorbed or released when chemical bonds are broken or when chemical bonds are broken or when new bonds are formed.new bonds are formed.

Endothermic reactions – when energy is Endothermic reactions – when energy is absorbed to change reactants to absorbed to change reactants to products.products.

Exothermic reactions – when energy is Exothermic reactions – when energy is released as reactants are changed into released as reactants are changed into products.products.

Activation EnergyActivation Energy The energy needed to start a chemical The energy needed to start a chemical

reaction reaction Like the match needed to start a fire or the Like the match needed to start a fire or the

spark from the spark plug needed to ignite spark from the spark plug needed to ignite the gasoline in an engine.the gasoline in an engine.

Like a chemical “push” that starts a chemical Like a chemical “push” that starts a chemical reaction.reaction.

All chemical reactions require some activation All chemical reactions require some activation energy, even exothermic reactionsenergy, even exothermic reactions

ENZYMESENZYMES

PROTEINS THAT ACT AS PROTEINS THAT ACT AS CATALYSTS IN CATALYSTS IN

INTERMEDIARY METABOLISMINTERMEDIARY METABOLISM

ENZYMESENZYMES ESSENTIAL FOR THE PROPER FUNCTIONING OF ANY

CELL SPEED UP SPECIFIC CHEMICAL REACTIONS BY

LOWERING ACTIVATION ENERGY NECESSARY FOR REACTION

REACTANT IS KNOWN AS THE SUBSTRATE FORMS A LOCK AND KEY ARRANGEMENT WHICH IS

BELIEVED TO WEAKEN CHEMICAL BONDS WITHIN THE SUBSTRATE

THUS IT REQUIRES LESS ENERGY TO MAKE THE REACTION HAPPEN

THE ENZYME IS NOT USED UP IN THE REACTION AND THEREFORE CAN GO ON TO CATALYZE ADDITIONAL REACTIONS

LOCK AND KEY MECHANISMLOCK AND KEY MECHANISM

ENZYME

SUBSTRATE

ENZYME

PRODUCTSENZYME

SUBSTRATE ENZYME BINDS IN AN EXACT FIT TO A SPECIFIC SITE ON A SUBSTRATE MOLECULE

ENZYME - SUBSTRATE COMPLEXPLACES STRESS ON BONDS LOWERINGACTIVATION ENERGY

FINALLY BONDS ARE WEAKENEDENOUGH TO BREAK AND PRODUCTSSEPERATE AND ARE RELEASED FOR USE BY THE CELL

NUCLEIC ACIDSNUCLEIC ACIDS

COMPLEX ORGANIC MOLECULES WHICH STORE IMPORTANT INFORMATION

WITHIN A CELL

NUCLEIC ACIDSNUCLEIC ACIDS

C G

TAS

S

S

S

PP

P

P

TA

CG

S

S

S

S

PP

P

P

CG

T AS

S

S

S

PP

P

P

C G

TAS

S

S

S

PP

P

P

TA

CG

S

S

S

S

PP

P

P

CG

T AS

S

S

S

PP

P

P

DNADNADEOXYRIBONUCLEIC ACID

STORES INFORMATION ESSENTIALTOMOST CELL ACTIVITIES SUCH AS CELLDIVISION AND PROTEIN SYNTHESIS

NUCLEIC ACIDSNUCLEIC ACIDS

U

C

S

S

P

P

G

U S

S

P

P

C

A S

S

P

P

C S

G

U S

S

P

P

U S

P

P

C

A S

S

P

P

RNARNARIBONUCLEIC ACID

STORES AND TRANSFERS INFORMATIONNECESSARY FOR THE MANUFACTURE OFPROTEINS WITHIN THE CELL

NUCLEIC ACIDSNUCLEIC ACIDSPHOSPHATE

GROUPPO4

PENTOSESUGAR NITROGEN

BASE

ADENINETHYMINECYTOSINEGUANINE

RIBOSE ORDEOXYRIBOSE

NUCLEOTIDEBASIC UNIT OF ALL NUCLEIC ACIDS