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A little intro to each of the different

Macromolecules

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Biological Molecules

• The framework of biological molecules consists of carbon bonded to other carbon molecules, or other types of atoms.

– Hydrocarbons consist of carbon and hydrogen.

Covalent bonds store considerable energy.

Make good fuels

3

Biological Molecules

• Functional groups– specific groups of atoms attached to

carbon backbones retain definite chemical properties

• Macromolecules.– proteins– nucleic acids– lipids– carbohydrates

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Hydroxyl

Carbonyl

Carboxyl

Amino

Sulfhydryl

Phosphate

Methyl

Acetic acid

Functional Group

StructuralFormula

Example

Acetaldehyde

Alanine

-mercaptoethanol

Glycerol phosphate

Pyruvate

HS

P

O–

O

O

HC

H

H

OH

O

OHC

H

HN

CO

Ethanol

C

H

H

CH

H

H

OH

CH

H

HC

O

OH

H

CH3

OH

CCHO NH

CH

H

HHC

O

CHOH

H HS HC

H

CH

OH

HC

OH

H HOC

H

P

O

C

O

C

O

HHC

H

O–

O–

O–

O–

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Macromolecules

• Macromolecules are often polymers.– long molecule built by linking together

small, similar subunits Dehydration synthesis removes OH and

H during synthesis of a new molecule. Hydrolysis breaks a covalent bond by

adding OH and H.

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MACROMOLECULES

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Carbohydrates• Carbohydrates are loosely

defined as molecules that contain carbon, hydrogen, and oxygen in a 1:2:1 ratio.

– monosaccharides - simple sugars

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– disaccharides - two monosaccharides joined by a covalent bond

DisaccharideMaltose

Monosaccharide2 X Glucose

C

C

C

O

C

C

H

H

C

H

OHH

OH

OH

H

HOH

HC

C

C

O

C

C

OH

H

H

C

H

OHH

OH

OH

H

H

H

O

C

C

C

O

C

C

OH

H

H

C

H

OHH

OH

OH

H

HOH

HC

C

C

O

C

C

OH

H

H

C

H

OHH

OH

OH

H

HOH

H

H2OH2O

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– polysaccharides - macromolecules made of monosaccharide subunits

isomers - alternative forms of the same substance – Many C6H1206

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Carbohydrate Transport and Storage

• Transport disaccharides– Humans transport glucose as a simple

monosaccharide.– Plants transform glucose into a

disaccharide transport form.• Storage polysaccharides

– plant polysaccharides formed from glucose – starches

most is amylopectin– Animal starch is glycogen

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Structural Carbohydrates

• Cellulose - plants– alpha form or beta

form of ring

Chitin - arthropods and fungi

modified form of cellulose

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Lipids• Lipids are loosely defined as groups of

molecules that are insoluble in water.– fats and oils

• Phospholipids form the core of all biological membranes.

– composed of three subunits Glycerol - backbone fatty acid – long tail phosphate group – head

Polar head - hydrophilicNonpolar tail - hydrophobic

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Phospholipids form membranes

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Fats and Other Lipids• Fats consist a of glycerol

molecule with three attached fatty acids (triglyceride / triglycerol).

– Saturated fats - all internal carbon atoms are bonded to at least two hydrogen atoms – maximum # of H

– Unsaturated fats - at least one double bond between successive carbon atoms

Polyunsaturated - contains more than one double bond

usually liquid at room temperature

Double bonds in the tail

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Fats as Energy Storage Molecules

• Fats, on average, yield about 9 kcal per gram versus 4 kcal per gram for carbohydrates.

– Animal fats are saturated while most plant fats are unsaturated.

Consumption of excess carbohydrates leads to conversion into starch, glycogen, or fats for future use.

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Proteins

A. Amino acids

B. Peptide bonds

C. Polypeptide chains

H - N - C - C - OH

OH

H

Amine Group

Acid Group

R

H

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Protein Function

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Amino Acids

• contain an amino group (-NH2), a carboxyl group (-COOH) and a hydrogen atom, all bonded to a central carbon atom

– twenty common amino acids grouped into five classes based on side groups

nonpolar amino acids polar uncharged amino acids charged amino acids aromatic amino acids special-function amino acids

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Amino Acids

• Peptide bond links two amino acids.– A protein is composed of one or more long

chains of amino acids linked by peptide bonds (polypeptides).

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Alanine(Ala)

Leucine(Leu)

Isoleucine(Ile)

Phenylalanine(Phe)

Tryptophan(Trp)

Tyrosine(Tyr)

Glutamine(Gln)

Asparagine(Asn)

Threonine(Thr)

Serine(Ser)

Glycine(Gly)

Glutamicacid (Glu)

Asparticacid (Asp

Histidine(His)

Lysine(Lys)

Arginine(Arg)

Charged

Polar uncharged

Nonpolar

NONAROMATIC AROMATIC

Valine(Val)

CH3

C C

H O

CH

C C

H O

C C

H O

CH

C C

H O

H C

C C C C

H O

NH

C

C C

H O

OH

H C OH

C C

H O

C C

H O

C

NH2

O

CH2

C C O–

H O

OH

C

C C

H O

O

H

C C

H O

C C

H O

CO

C C

H O

NH

C

C C

H O

C C

H O

C N

HC NH+

CH

H

C C

H O

CO

CH3 CH3

CH3 CH3CH3

CH3 CH2

CH2

CH2

CH2

CH2

CH2CH2

NH2

CH3

CH2

NH2

H3N+ H3N+ H3N+ H3N+ H3N+ H3N+O–O–O–O–O–

H3N+H3N+H3N+H3N+H3N+

O–

O–

O– O– O– O– O–

CH2

CH2CH2 CH2 CH2

CH2

CH2

CH2

CH2

CH2

CH2

NH2+

NH3+

O–

H O

H3N+ H3N+ H3N+ H3N+ H3N+ H3N+O–O–O–O–O–

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Protein Structure The shape of proteins is extremely important and

can determine the function Water’s tendency to hydrophobically exclude

nonpolar molecules literally shoves the nonpolar portions of the protein to the interior

Many shapes Primary – the specific amino acid sequences Secondary – formed by hydrogen bonding

Alpha helix – coils Beta pleated sheet - foldbacks

motifs - folds or creases supersecondary structure

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N N N

H

H

H

H

H H

HC C C C C C N C C N CCC

O

OO

O H H

OH H

R

R

R R

R R

Motifs

Primary structure1

2

3

helix

turn motif motif

pleated sheet

Secondarystructure

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Protein Structure

Tertiary - final folded shape of globular protein (3-dimensional shape) based on bonding of side groups

Domains – independent functional units of the protein 100–200 amino acids long - encoded by a specific DNA sequence (exon)

Quaternary - forms when two or more polypeptide chains associate to form a functional protein

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Tertiarystructure

Domains

Quaternary structure

Domain 3

Domain 2

Domain 1

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Chaperone Proteins

• Chaperone proteins are special proteins which help new proteins fold correctly.

– Chaperone deficiencies may play a role in facilitating certain diseases.

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Unfolding Proteins• Denaturation refers to the

process of changing a protein’s shape.

– usually rendered biologically inactive

pH temperature Ionic concentration -

salt-curing and pickling used to preserve food

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Nucleic Acids

• Deoxyribonucleic Acid (DNA)– Encodes information used to assemble

proteins.• Ribonucleic Acid (RNA)

– Reads DNA-encoded information to direct protein synthesis.

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Nucleic Acid Structure

• Nucleic acids are composed of long polymers of repeating subunits, nucleotides.

– five-carbon sugar– Phosphate group– nitrogenous base

Purines double ringed adenine and

guanine Pyrimidines – single

ringed cytosine, thymine,

and uracil

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59

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P

P

P

P

OH

5-carbonsugar

Nitrogenous base

Phosphate group

Phosphodiesterbonds

Adenine

O

O

O

O

Guanine

CCNN

N

C

H N

CCH

O

H

Cytosine(both DNAand RNA)

Thymine(DNA only)

Uracil(RNA only)

HCCNC

HN

CNH2

N

NCH

OCCNC

HN

CHH

OCCNC

HN

CO

HH3CH

OCCNC

HN

CO

HHH

PURINES

PYRIMIDINES

NH2

NH2

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Nucleic Acid Structure

• DNA exists as double-stranded molecules.

– double helix– complementary base pairing

Chargaff’s rule hydrogen bonding

• RNA exists as a single stand.– contains ribose instead of

deoxyribose– contains uracil in place of thymine

                                                                     

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Structure of DNA