Chemical Bldg Blocks of Life Chapter 3

8/11/2019 Chemical Bldg Blocks of Life Chapter 3

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The Chemical Building

Blocks of Life

1


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Organic Chemistry

Organic molecules contain carbon

Abundant in living organisms

Macromolecules are large, complex organic

molecules

2


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3

Carbon

Framework of biological moleculesconsists primarily of carbon bonded to

Carbon

O, N, S, P or H

Can form up to 4 covalent bonds

Hydrocarbonsmolecule consisting only

of carbon and hydrogen Nonpolar

Functional groups add chemical properties


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4

Hydroxyl

Carbonyl

Carboxyl

Amino

Sulfhydryl

Phosphate

Methyl

Example

OH

O

C

O

OH

C

H

H

N

S H

O

proteins

proteins

H

H

Glycerol phosphate

Alanine

Cysteine

Alanine

Acetic acid

Acetaldehyde

Ethanol

COOH

NH2

HH

H

HH

C OHC

O

H C C

H

H

H

H C

O

OHH

C

O H

N

H

HCH3

H C HSCH2

NH2

OH OH H

P

O

P O

O

O

OCCCH

H H H

O H

HO C C

H C H

H

O

O

H

C

HO C C

H

Found

In

carbo-

hydrates,

proteins,

nucleic

acids,

lipids

carbo-

hydrates,

nucleic

acids

proteins,

lipids

proteins,

nucleic

acids

nucleic

acids

Functional

Group

Structural

Formula


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5

Isomers

Molecules with the same molecular or

empirical formula

Structural isomers

Stereoisomersdiffer in how groups attached

Enantiomers

mirror image molecules

chiral

D-sugars and L-amino acids


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6

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

C

W

Y

W

Y

C

Z

X

Z

X

Mirror


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7

Macromolecules

Polymerbuilt by linking monomers

Monomersmall, similar chemical subunits


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8


O

P

P

OH

HO

H

OH

H

OHOH

H

H

H

O

Cellular Structure Polymer Monomer

Chromosome DNA strand Nucleotide

MonosaccharideStarchStarch grains in a chloroplast

5-carbon sugar

Phosphate

group

Nitrogenous base

CH2OH

Carbohydrate

Nuc

leicAcid

P

P

P

PP

P

P

G

C

T

A

A

T

P

A

P

P

P

P

G

C

P

P

T

A

G

C

P


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9

AlaAla

ValVal

Ser O

NH

C

H

OHH

C

CH3

Intermediate filament Polypeptide Amino acid

Protein


HO H H H H H H H H H H

HHO C C C C C C C C C C C C

H H H H H H H H H H H

Adipose cell with fat dropletsTriglyceride

Fatty acid

Lipid


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Dehydration synthesis

Formation of large molecules by the removal of water

Monomers are joined to form polymers

Hydrolysis

Breakdown of large molecules by the addition of

water

Polymers are broken down to monomers

HO

HO H

HO HH HHO

HO H HHO

a.Dehydration reaction b .Hydrolysis reaction

H2O H2O



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Carbohydrates

Molecules with a 1:2:1 ratio of carbon,

hydrogen, oxygen

Empirical formula (CH2O)

n

CH covalent bonds hold much energy

Carbohydrates are good energy storage

molecules

Examples: sugars, starch, glucose


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13

H

CH2OH

H

OH

OH HH

H

C

CC

C

C

C

C

H

C H

HO

OHH

OHH C

OHH C

OHH C

H

O H

C HH

OH

H

OH

H

O H

H

OH

H

OH HH

H

C

CC

C

C O

OH

OH HH

H

C

CC

C

OC

OH

OH

O

H23

5

14

6

5

4

3

2

1

23

5

6

14

23

5

14

-glucoseor

-glucose

OO

CH2OH



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14

Fructose Glucose Galactose

H OH

O

C

C

C

C

C

C

H

H

HO H

H OH

H OH

H OH

H

OC

C

C

C

C

H

H

HO H

OH

H OH

H OH

OC

C

C

C

C

C

H

H

H

HO H

OH

H OH

H OH

CH OH HO H

Stereo-

isomer

Structural

isomer



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Disaccharides

2 monosaccharides linked together by

dehydration synthesis

Used for sugar transport or energy storage

Examples: sucrose, lactose, maltose

OH

SucroseFructose-glucose

HO

CH2OH

H

OH

H

OHH

H

H

O

H

OH H

HO

HO

H

OH

H

OH OHH

H

O

H OH

OH H

HO

+

a. b.

Maltose

HO

H

OH

H

OH OH

H

H

O H

OH

H

OH

OH

HH

H

O

OHHO

H2O

CH2OH CH2OH CH2OH CH2OH CH2OH

CH2OH CH2OH



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Polysaccharides

Long chains of monosaccharides

Linked through dehydration synthesis

Energy storage

Plants use starch

Animals use glycogen

Structural support Plants use cellulose

Arthropods and fungi use chitin


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Glycogen

Amylose + Amylopectin

b .

a. c. 3.3 m


-glucose

HO

CH2OH

H

OH

H

OH H

H

H

O

OH

4 1

-1 4 linkages

CH2OH

OH

H

OH H

H

O

CH2OH

OH

H

OH H

H

O

CH2OH

OH

H

OH H

H

O

O O

H

-1 4 linkage

a -1

CH2OH

O

H

OH

H

OH H

H

H

O

CH2

H

OH

H

OH H

H

H

O

O

CH2OH

H

OH

H

OH H

H

H

O

6 linkage

b: Asa Th oresen/Photo Researchers, Inc .; c: J. Carson/Custom Medical Stock Photo

7.5 m


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HO

CH2OH

H

OH

H

OH HH

H

OCH2OH

H H

OH

H

OH HH

H

O

O

CH2OH

H

OH

H

OH HH

H

O

OHH

HO H H

H

CH2OH

O

-1 4 linkages

OHO O

O

4 1


b: Science VU/Visuals Unlimited

-glucose

500 mb.

a.


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Nucleic acids

Polymernucleic acids

Monomersnucleotides

sugar + phosphate + nitrogenous base

sugar is deoxyribose in DNA or ribose in RNA

Nitrogenous bases include Purines: adenine and guanine

Pyrimidines: thymine, cytosine, uracil

Nucleotides connected by phosphodiesterbonds

19


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21

5

3

P

P

P

P

OH

Phosphate group

O

O

NH2CC

NN

N

C

HN

C

CH

O

H

H

OC

NC

H

N

C

NH2

H

CH

a.

b .O

O

O

C

NC

H

N

CH3C

CH

H

O

O

C

NC

H

N

CH

CH

CC

NN

N

C

HN

C

CHH

O

4

5

1

3 2

4

5

1

3 2

4

5

1

3 2

4

5

1

32

Phosphodiester bonds

5-carbon sugar

Nitrogenous

base

NH2

GuanineAdenine

Purines

Pyrimidines


Cytosine

(both DNA and RNA)

Thymine

(DNA only)

Uracil

(RNA only)


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Deoxyribonucleic acid (DNA)

Encodes information for amino acid

sequence of proteins

Sequence of bases

Double helix2 polynucleotide strands

connected by hydrogen bonds

Base-pairing rules

A with T (or U in RNA)

C with G

22


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5 end

P

P

P

P

P

C

G

A

A

OH

T

T

Phosphodiesterbonds

3 end

Sugarphosphatebackbone

Hydrogenbonds

between

nitrogenous bases


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Ribonucleic acid (RNA)

RNA similar to DNA except

Contains ribose instead of deoxyribose

Contains uracil instead of thymine

Single polynucleotide strand

RNA uses information in DNA to specify

sequence of amino acids in proteins

Copyright The McGraw Hill Companies Inc Permission required for reproduction or display


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P

P

P

P

PP

P

P

P

P

P

P

P

P

P

G

C

G

C

T

A

A

A

A

T

T

G

Bases

Hydrogen bonding

Occurs between base-pairs

P

P

PP

P

P

P

G

G

C

A

A

U

U

Bases

Deoxyribose-phosphate

backbone

Ribose-phosphatebackbone

RNA

DNA


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Other nucleotides

ATP adenosine triphosphate

Primary energy currency of the cell

NAD+and FAD+

Electron carriers for many cellular reactions

4

56

2

394

8

7

1

3 2

5

1

CH2

OOO

O

OH OH

NH2

N

N

N

N

O

O O O OP P P

Triphosphate group

5-carbon sugar

O

Nitrogenous base

(adenine)

O O



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Proteins

Protein functions include:

1. Enzyme catalysis

2. Defense

3. Transport

4. Support

5. Motion

6. Regulation

7. Storage


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Proteins are polymers

Composed of 1 or more long, unbranched

chains

Each chain is a polypeptide

Amino acids are monomers

Amino acid structure

Central carbon atom

Amino group

Carboxyl group

Single hydrogen

Variable R group


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Amino acids joined by dehydration

synthesis

Peptide bond

RH

H

R

H O

R

OH

RH

OH

H2O

H

O

H

OH OH

O HH

CC C C

CC CC

N

N N

NH H

Amino acid

Dipeptide

Amino acid


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4 Levels of structure

The shape of a protein determines its

function

1. Primary structuresequence of amino acids

2. Secondary structureinteraction of groups

in the peptide backbone

helix

sheet


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4 Levels of structure

3. Tertiary structurefinal folded shape of a

globular protein

Stabilized by a number of forces

Final level of structure for proteins consisting

of only a single polypeptide chain

4. Quaternary structurearrangement of

individual chains (subunits) in a protein with2 or more polypeptide chains

32



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Primary Structure

Secondary Structure Secondary Structure

Tertiary Structure Quaternary Structure

N

H

H H

C C C N C C NC

O

O H

OH H

R

R

R

-pleated sheet -helix

C

H

R

The primary structure can foldInto a pleated sheet, or turn into a helix


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Additional structural characteristics

Motifs

Common elements of secondary structure

seen in many polypeptides

Useful in determining the function of unknownproteins

Domains

Functional units within a larger structure Most proteins made of multiple domains that

perform different parts of the proteins function

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Domain 3 Domain 2

Domain 1

DomainsMotifs


--motif

Helix-turn-Helix

motif


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Once thought newly made proteins folded

spontaneously

Chaperone proteins help protein fold

correctly

Deficiencies in chaperone proteins

implicated in certain diseases

Cystic fibrosis is a hereditary disorder

In some individuals, protein appears to have

correct amino acid sequence but fails to fold

Chaperones


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Chance for protein to refold

ADP + P

Cap

ATP


Correctly

folded

protein

Misfolded

protein

Chaperoneprotein


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Denaturation

Protein loses

structure and function

Due to environmental

conditions pH

Temperature

Ionic concentration of

solution

38

Properly folded protein

Denaturation

Denatured

protein



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Lipids

Loosely defined group of molecules with

one main chemical characteristic

They are insoluble in water

High proportion of nonpolar CH bonds

causes the molecule to be hydrophobic

Fats, oils, waxes, and even some vitamins


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Fats

Triglycerides Composed of 1 glycerol and 3 fatty acids

Fatty acids

Need not be identical Chain length varies

Saturatedno double bonds between carbonatoms

Higher melting point, animal origin

Unsaturated1 or more double bonds Low melting point, plant origin

Trans fats produced industrially


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C

C

H

H

C

H

H

C

H

H

O

C

H

CH C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

C

H H

C

H

C C

HH H H

C

H

C C

H

O

H

HH H

CH

H

CH

H

O

C

H

CH CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

CH

CH

C

H

CH

CHH H

C

H

CH

CH H

O

H

H H

C

H

H

C

H

H

O

C

H

CH C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

C

H H

C

H H

C

H

C

H

H

C

H H

C

HH

C

H H

CO

O

C

H

C

H

H

C

H

H

C

H

H

CH C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

O

O

C

H

C

H

H

C

H

H

C

H

H

CH C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

O

O

C

H

CH

H

CH

H

CH

H

CH CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

C

H

H

C

H

H

H

C

H

H

C

H

H

H

CH

H

CH

HO

H

H

Structural Formula Structural Formula

Space-Filling Model Space-Filling Model

a. b.



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Phospholipids

Composed of

Glycerol

2 fatty acidsnonpolar tails

A phosphate grouppolar head

Form all biological membranes


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Nonpolar

HydrophobicTails

PolarHydrop

hilicHeads

Choline

Phosphate

Glycerol

a. b. c. d.

CH2

CH2

CH2H2C

O

OO P

C

O O

OO

C

H

C

O-

N+(CH3)3


F

attyacid

F

attyacid

CH

CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH3

CH

CH2CH2CH2CH2CH2CH2CHCHCH2CH2CH2CH2CH2CH2CH2CH3


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Documents

Chemical Bldg Blocks of Life Chapter 3