3.2 Molecules of Life(Show PPT w/clips)

What four main classes of organic compounds are essential to life processes?

1.carbs 2. lipids 3.proteins 4.nucleic acids

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Carbohydrates

•Carbohydrates include:• Small sugar molecules in

soft drinks•Long starch molecules in

pasta and potatoes

Carbohydrates tend to have the ratio of 1C:2H:1O

-monosaccharides is a carb monomer.

This simple sugar is 1:2:1 and the general formula is (CH2O)n

n is a whole number from 3 to 8So, (CH2O)6 = C6H12O6

The most common sugars/monosaccharides are:

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Cellular Fuel

•Monosaccharides are the main fuel that cells use for cellular work

ATP

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Monosaccharides:• Called simple sugars

Include glucose, fructose, & galactoseHave the same chemical, but different structural formulasC6H12O6

Glucose=cell energy

Fructose=fruit sugar

Galactose=milk sugar

All three have the same formula but have difference structures. These are known as Isomers pg 55

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Monosaccharides

•Glucose is found in sports drinks

Fructose is found in fruitsHoney contains both glucose & fructoseGalactose is called “milk sugar”

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Isomers

•Glucose & fructose are isomers because they’re structures are different, but their chemical formulas are the same

• Disaccharide is 2 monomers in a condensation reaction. Fruc. + Gluc. = Sucrose.

• Polysaccharide is complex with 3 or more monosaccharides.

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Disaccharides

•A disaccharide is a double sugar

They’re made by joining two monosaccharides

Involves removing a water molecule (dehydration)

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Disaccharides

• Common disaccharides include:

Sucrose (table sugar)Lactose (Milk Sugar)Maltose (Grain sugar)

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Disaccharides

•Sucrose is composed of glucose + fructose

Maltose is composed of 2 glucose moleculesLactose is made of galactose + glucose GLUCOSE

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Starch

• Starch is an example of a polysaccharide in plants

Plant cells store starch for energy

Potatoes and grains are major sources of starch in the human diet

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Glycogen• Glycogen is an example of

a polysaccharide in animals

Animals store excess sugar in the form of glycogenGlycogen is similar in structure to starch

Proteins-

• organic compounds composed mainly of C,H,O, & N

• Proteins are formed from amino acids linked together.

• 20 diff. Amino acids. Amino acids have basically the same structure except their R group. See page 56.

• Q- The R groups give proteins their different shapes. What do the different shapes allow it to do?

• Two amino acids = Dipeptides• Long amino chains = Polypeptides• Condensation reaction of two or more amino

acids yields a peptide bond and a water molecule release.

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Proteins

• Proteins are polymers made of monomers called amino acids

All proteins are made of 20 different amino acids linked in different ordersProteins are used to build cells, act as hormones & enzymes, and do much of the work in a cell

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Four Types of Proteins

Structural

Contractile

Storage

Transport

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Denaturating ProteinsChanges in temperature & pH can denature (unfold) a protein so it

no longer worksCooking denatures protein in eggs

Milk protein separates into curds & whey when it denatures

ENZYMES

• ENZYMES- RNA or protein molecules that act as biological catalysts. Enzymes are specific to the substrate that they will fit.

• The enzyme reduces the activation energy needed by weakening or breaking bonds. Changes in pH, Temp, etc may cause the enzyme to not be as effective.

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Proteins as Enzymes

• Many proteins act as biological catalysts or enzymes

Thousands of different enzymes exist in the bodyEnzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction

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Enzymes

Their folded conformation creates an area known as the active site.

Enzymes are globular proteins.

The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.

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Enzyme + Substrate = Product

LIPIDS

• LIPIDS- large, nonpolar molecules that do not dissolve in water. They include Triglycerides, Phospholipids, Steroids, Waxes, and Pigments.

• These have a higher ratio of carbon and hydrogen to oxygen that carbs do. Because of this high ratio of C-H bonds, they store more energy.

• FATTY ACIDS- unbranched carbon chains that make up most lipids. These have long carbon chains with a –COOH carboxyl group.

• Due to the –COOH polarity, it is Hydrophilic or attracted to water molecules and the opposite end is Hydrophobic. Pg 59

• Q-What is the difference between saturated and unsaturated fats?

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Types of Fatty Acids• Unsaturated fatty acids have less than the

maximum number of hydrogens bonded to the carbons (a double bond between carbons)

Saturated fatty acids have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons)

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Types of Fatty Acids

Single Bonds in Carbon chain

Double bond in carbon chain

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Triglyceride

• Monomer of lipidsComposed of Glycerol & 3 fatty acid chainsGlycerol forms the “backbone” of the fat Organic

Alcohol

• TRIGLYCERIDES-saturated=butter and fats-unsaturated =found in plant seeds for germination

• Triglycerides- composed of three molecules of fatty acid joined to one molecule of the alcohol glycerol.

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Fats in Organisms• Most animal fats have a high proportion of

saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)

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Fats in Organisms• Most plant oils tend to be low in saturated

fatty acids & exist as liquids at room temperature (oils)

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Fats• Dietary fat consists largely of the molecule

triglyceride composed of glycerol and three fatty acid chains

Glycerol

Fatty Acid Chain

Dehydration links the fatty acids to Glycerol

• FAT SUBSTITUTES were approved by the FDA in 1996. It passes through the body without being digested or absorbed. For some, it created cramps, diarrhea, and loss of fat-soluble vitamins and betacarotene. Try to weigh the benefits of this against the side effects. What do you think?

• Food Eating Contest and Fats Video Clip

• PHOSPHOLIPIDS-have 2 fatty acids attached to a molecule of glycerol. How is this different than Triglycerides? They have a phosphate group attached to the third carbon of the glycerol. Our cells have a cell membrane that is composed of two layers of phospholipids called the LIPID BILAYER. It acts like a club bouncer and only allows certain things in and out of the cell. Pg 59.

• WAXES-a type of structural lipid that is a long fatty acid chain joined to a long alcohol chain. They are waterproof. What benefits do plants have by having a cuticle that is a waxy layer on its leaves? Why do we have earwax?

STEROIDS

• STEROIDS- composed of four fused carbon rings with various functional groups. We have natural steroids in our body.

• It is not just what sports players use.

• What are our natural steroids?

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Steroids

•The carbon skeleton of steroids is bent to form 4 fused rings

Cholesterol is the “base steroid” from which your body produces other steroidsEstrogen & testosterone are also steroids

Cholesterol

TestosteroneEstrogen

• Cholesterol Clip

http://lovemymuscles.com/features/articles/anabolic-steroids/

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Synthetic Anabolic Steroids

•They are variants of testosterone

Some athletes use them to build up their muscles quicklyThey can pose serious health risks

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20 Amino Acid Monomers

NUCLEIC ACIDS-

• complex organic molecules found in our DNA and RNA.

• RNA can also act like an enzyme.• DNA and RNA are polymers with thousands of

monomers called nucleotides. They contain a phosphate group, five carbon sugar, and ring shaped nitrogen base.

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Nucleic Acids

•Store hereditary information

Contain information for making all the body’s proteinsTwo types exist --- DNA & RNA

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Nucleic AcidsNitrogenous base

(A,G,C, or T)

Phosphategroup

Thymine (T)

Sugar(deoxyribose)

Phosphate

BaseSugar

Nucleic acids are polymers of nucleotides

Nucleotide

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Bases

•Each DNA nucleotide has one of the following bases:

Thymine (T) Cytosine (C)

Adenine (A) Guanine (G)

–Adenine (A)–Guanine (G)–Thymine (T)–Cytosine (C)