SCI.9-12.B-3.4 - [Indicator] - Summarize how the structures of organic molecules (including proteins, carbohydrates, and fats) are related to their relative

• SCI.9-12.B-3.4 - [Indicator] - Summarize how the structures of organic molecules (including proteins, carbohydrates, and fats) are related to their relative caloric values.

• SCI.9-12.B-3.5 - [Indicator] - Summarize the functions of proteins, carbohydrates, and fats in the human body.

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*Organic *Organic CompoundsCompounds

• CompoundsCompounds that contain CARBONCARBON are called organicorganic.

• MacromoleculesMacromolecules are large organic moleculesorganic molecules.

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*Carbon (C)*Carbon (C)• CarbonCarbon has 4 electrons4 electrons in

outer shell.

Usually bonds with C, H, O or C, H, O or NN.

• Example:Example: CHCH44(methane)(methane)


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*Macromolecules*Macromolecules

• Large organic molecules.Large organic molecules.• Also called POLYMERSPOLYMERS.• Made up of smaller “building

blocks” called MONOMERSMONOMERS.• Examples:Examples:

1. Carbohydrates1. Carbohydrates2. Lipids2. Lipids3. Proteins3. Proteins4. Nucleic acids (DNA and RNA)4. Nucleic acids (DNA and RNA)


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*Question:*Question:How Are How Are

MacromolecMacromolecules ules

Formed?Formed?copyright cmassengale

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*Answer:*Answer: Dehydration Dehydration SynthesisSynthesis

• Also called “condensation “condensation reaction”reaction”

• Forms polymerspolymers by combining monomersmonomers by “removing “removing water”water”.

HO H

HO HO HH

H2O


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*Question:*Question: How are How are

Macromolecules Macromolecules separated or separated or

digested?digested?


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*Answer: *Answer: HydrolysisHydrolysis

•Separates monomersmonomers by “adding water”“adding water”

HO HO HH

HO H

H2O





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CarbohydratCarbohydrateses


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*I. Carbohydrates*I. Carbohydrates

• Small sugar moleculesSmall sugar molecules to large sugar moleculeslarge sugar molecules.

• Examples:Examples:A.A. monosaccharidemonosaccharideB.B. disaccharidedisaccharideC.C. polysaccharidepolysaccharide


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*Carbohydrates*CarbohydratesMonosaccharide: one sugar Monosaccharide: one sugar

unitunit

Examples:Examples: **glucose (glucose (C6H12O6)

deoxyribosedeoxyribose

riboseribose

FructoseFructose

GalactoseGalactose

glucoseglucose


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*Carbohydrates*CarbohydratesDisaccharide: two sugar unitDisaccharide: two sugar unit

Examples: Examples: – *Sucrose (glucose+fructose) *Sucrose (glucose+fructose)

table sugartable sugar– *Lactose (glucose+galactose)*Lactose (glucose+galactose)– Maltose (glucose+glucose)Maltose (glucose+glucose)

glucoseglucoseglucoseglucose


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*Carbohydrates*CarbohydratesPolysaccharide: many sugar unitsPolysaccharide: many sugar units

Examples:Examples: starch (bread, starch (bread, potatoes)potatoes)

glycogen (beef glycogen (beef muscle)muscle)

cellulose (lettuce, cellulose (lettuce, corn)corn)





cellulosecellulose





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*II. Proteins *II. Proteins • Amino acids (20 different kinds of aa)

bonded together by peptide bondspeptide bonds (polypeptidespolypeptides). Essential and non-essential

• Six functions of proteins:Six functions of proteins:1.1. Storage:Storage: albumin (egg white)albumin (egg white)2.2. Transport: Transport: hemoglobinhemoglobin3.3. Regulatory:Regulatory: hormoneshormones4.4. Movement:Movement: musclesmuscles5.5. Structural:Structural: membranes, hair, nailsmembranes, hair, nails6.6. Enzymes:Enzymes: cellular reactionscellular reactions


• Amino acids– Are organic molecules possessing both

carboxyl and amino groups– Differ in their properties due to differing side

chains, called R groups

Twenty Amino Acids

• 20 different amino acids make up proteins

O

O–

H

H3N+ C C

O

O–

H

CH3

H3N+ C

H

C

O

O–

CH3 CH3

CH3

C C

O

O–

H

H3N+

CH

CH3

CH2

C

H

H3N+

CH3CH3

CH2

CH

C

H

H3N+

C

CH3

CH2

CH2

CH3N+

H

C

O

O–

CH2

CH3N+

H

C

O

O–

CH2

NH

H

C

O

O–

H3N+ C

CH2

H2C

H2N C

CH2

H

C

Nonpolar

Glycine (Gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile)

Methionine (Met) Phenylalanine (Phe)

C

O

O–

Tryptophan (Trp) Proline (Pro)

H3C

Figure 5.17

S

O

O–

O–

OH

CH2

C C

H

H3N+

O

O–

H3N+

OH CH3

CH

C C

HO–

O

SH

CH2

C

H

H3N+ C

O

O–

H3N+

C C

CH2

OH

H H H

H3N+

NH2

CH2

OC

C CO

O–

NH2 O

C

CH2

CH2

C CH3N

+

O

O–

O

Polar

Electricallycharged

–O O

C

CH2

C CH3N

+

H

O

O–

O– O

C

CH2

C CH3N

+

H

O

O–

CH2

CH2

CH2

CH2

NH3+

CH2

C CH3N

+

H

O

O–

NH2

C NH2+

CH2

CH2

CH2

C CH3N

+

H

O

O–

CH2

NH+

NHCH2

C CH3N

+

H

O

O–

Serine (Ser) Threonine (Thr)Cysteine

(Cys)Tyrosine

(Tyr)Asparagine

(Asn)Glutamine

(Gln)

Acidic Basic

Aspartic acid (Asp)

Glutamic acid (Glu)

Lysine (Lys) Arginine (Arg) Histidine (His)

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*Primary Structure

Amino acids bonded together by peptide peptide bonds (straight chains)bonds (straight chains)

aa1 aa2 aa3 aa4 aa5 aa6

Peptide Bonds

Amino Acids (aa)


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Proteins Proteins (Polypeptides)(Polypeptides)

Four levels of protein Four levels of protein structure:structure:

A.A. Primary StructurePrimary Structure

B.B. Secondary Structure Secondary Structure

C.C. Tertiary Structure Tertiary Structure

D.D. Quaternary Structure Quaternary Structure


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Secondary StructureSecondary Structure

• 3-dimensional folding arrangement of a primary primary structurestructure into coilscoils and pleatspleats held together by hydrogen bondshydrogen bonds.

• Two examples:Two examples:

Alpha HelixAlpha Helix

Beta Pleated SheetBeta Pleated Sheet

Hydrogen BondsHydrogen Bondscopyright cmassengale

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Tertiary StructureTertiary Structure• Secondary structuresSecondary structures bentbent and

foldedfolded into a more complex 3-D more complex 3-D arrangementarrangement of linked polypeptides

• Bonds: H-bonds, ionic, disulfide Bonds: H-bonds, ionic, disulfide bridges (S-S)bridges (S-S)

• Call a “subunit”.“subunit”.

Alpha HelixAlpha Helix

Beta Pleated SheetBeta Pleated Sheetcopyright cmassengale

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Quaternary Quaternary StructureStructure

•Composed of 2 or more “subunits”•Globular in shape•Form in Aqueous environments•Example: enzymes (hemoglobin)enzymes (hemoglobin)

subunitssubunits





*Proteins must be in a certain shape

to function. If you take it out of its shape, you have denatured it and it can not longer work. Heat and pH can denature a protein.

Proteins often change colors when they are denatured. Cooking egg white is an example.

•Denaturation is when a protein unravels and loses its native conformation(shape)

Denaturation

Renaturation

Denatured protein

Normal protein

Figure 5.22

*2 types of amino acids• Non-essential amino acids are those

your body can make. There are 12.• Essential amino acids are those you

must get in your diet because your body cannot make them. There are 8.

• If you don’t get the essential aa, you develop kwashiorkor.


Review of Protein Structure

+H3NAmino end

Amino acidsubunits

helix




Enzyme reactions

enzyme + substrate enzyme-substrate complex

*Enzymes -- Are defined as a BIOLOGICAL catalyst i.e. something that speeds up a reaction. Up to 1012 fold– *Usually end in ‘…ase’ and named for

what they do or act on (sucrase breaks down sucrose)

– Discovered in 1900 in yeasts. Some 40,000 in human cells

– *Control almost every metabolic reaction in living organisms

– Are globular proteins coiled into a very precise 3-dimentional shape with hydrophilic side chains making them soluble

– Possess an active site into which other substrate molecules can bind to form an enzyme-substrate complex

– *Once the substrate has been either synthesised or split, enzymes can be re-used.

– Do not ‘create’ reactions– Widely used in industrial cleaning– Often require co-factors (co-enzymes)

to function – metal ions, or vitaminsSUCROSE IS SUBSTRATE – SUCRASE IS ENZYME

Enzyme reactions


E +S ES

Enzyme reactions

enzyme + productenzyme-substrate complex

E +PES


E +S ES

*Enzyme activity

How fast an enzyme is workingRate of Reaction

Rate of Reaction = Amount of substrate changed (or amount product formed) in a given period of time.

Rate

of

React

ion

Enzyme activity

Variable you are looking at

*Enzyme activity

Four Variables

*Enzyme activity

Four Variables

TemperaturepH

Enzyme Concentration

Substrate Concentration

Rate

of

React

ion

Temperature

Rate

of

React

ion

Temperature

0 20 30 5010 40 60

Rate

of

React

ion

Temperature

0 20 30 5010 40 60

40oC - denatures

5- 40oC Increase in Activity

<5oC - inactive

*Effect of heat on enzyme activty

If you heat the protein above its optimal temperature, bonds break and the protein loses it secondary and tertiary structure.

Cooking an egg denatures the proteins and it goes white. Cooking meat denatures the proteins and it turns brown.

Effect of heat on enzyme activty

Denaturing the protein

Effect of heat on enzyme activty

Denaturing the protein

ACTIVE SITE CHANGES SHAPE SO SUBSTRATE NO LONGER FITS

Rate

of

React

ion

pH

1 3 42 5 6 7 8 9

Rate

of

React

ion

pH

1 3 42 5 6 7 8 9

Narrow pH optima

Rate

of

React

ion

pH

1 3 42 5 6 7 8 9

Narrow pH optima

WHY?

Rate

of

React

ion

pH

1 3 42 5 6 7 8 9

Narrow pH optima

Disrupt Ionic bonds - Structure

Effect charged residues at activesite




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*III. Lipids*III. Lipids• General term for compounds which are not not

soluble in watersoluble in water.• Lipids are soluble in hydrophobic solventsare soluble in hydrophobic solvents.• Remember:Remember: “stores the most energy”“stores the most energy”• Examples:Examples: 1. Fats1. Fats

2. Phospholipids2. Phospholipids3. Oils3. Oils4. Waxes4. Waxes5. Steroid hormones5. Steroid hormones6. Triglycerides6. Triglycerides

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*Lipids*LipidsSix functions of lipids:Six functions of lipids:

1.1. Long term Long term energy storageenergy storage2.2. Protection against heat loss Protection against heat loss (insulation)(insulation)3.3. Protection against physical shockProtection against physical shock4.4. Protection against water lossProtection against water loss5.5. Chemical messengers (hormones)Chemical messengers (hormones)6.6. Major component of membranes Major component of membranes ((phospholipids)phospholipids)


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*Fatty Acids*Fatty AcidsThere are two kinds of fatty acidsfatty acids you may see these on

food labels:

1.1. Saturated fatty acids:Saturated fatty acids: no double bonds (bad) no double bonds (bad)

2.2. Unsaturated fatty acids:Unsaturated fatty acids: double bonds (good) double bonds (good)O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

=

saturatedsaturated

O

C-CH2-CH2-CH2-CH=CH-CH2 -CH

2 -CH2 -CH

2 -CH3

=

unsaturated


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*Lipids*LipidsTriglycerides:Triglycerides:

ccomposed of 1 glycerol1 glycerol and 3 3 fatty acidsfatty acids.

H

H-C----O

H-C----O

H-C----O

H

glycerol

O


=

fatty acids

O


=

O

C-CH2-CH2-CH2-CH =CH-CH2 -CH

2 -CH2 -CH

2 -CH3

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*Steroid


Steroids are always four fused rings.Cholesterol is the precursor for all steroid hormones.•Testosterone•Estrogen

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*IV. Nucleic acids*IV. Nucleic acids• Two types:Two types:

a. Deoxyribonucleic acid a. Deoxyribonucleic acid (DNA-(DNA- double helix) double helix) b. Ribonucleic acid (RNA-single b. Ribonucleic acid (RNA-single strand) strand)

• Nucleic acids Nucleic acids are composed of long chains of nucleotidesnucleotides linked by dehydration synthesisdehydration synthesis.


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*Nucleic acids*Nucleic acids• Nucleotides include:Nucleotides include:

phosphate groupphosphate grouppentose sugar (5-carbon)pentose sugar (5-carbon)nitrogenous bases:nitrogenous bases:

adenine (A)adenine (A)thymine (T) DNA onlythymine (T) DNA onlyuracil (U) RNA onlyuracil (U) RNA onlycytosine (C)cytosine (C)guanine (G)guanine (G)


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NucleotideNucleotide

OO=P-O O

PhosphatePhosphate GroupGroup

NNitrogenous baseNitrogenous base (A, G, C, or T)(A, G, C, or T)

CH2

O

C1C4

C3 C2

5

SugarSugar(deoxyribose)(deoxyribose)


*Nucleotides are bonded to each other by the process of dehydration synthesis, forming phosphodiester bonds.

The arrows in the next slide are pointing to these bonds.


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DNA - double helixDNA - double helix

P

P

P

O

O

O

1

23

4

5

5

3

3

5

P

P

PO

O

O

1

2 3

4

5

5

3

5

3

G C

T A


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SCI.9-12.B-3.4 - [Indicator] - Summarize how the structures of organic molecules (including proteins, carbohydrates, and fats) are related to their relative