3.3 Molecules of Life3.3 Molecules of Life

ObjectivesObjectives

8.8. Define monosaccharide, disaccharide, Define monosaccharide, disaccharide, and polysaccharide, and discuss their and polysaccharide, and discuss their significance to organismssignificance to organisms

9.9. Relate the sequence of amino acids to the Relate the sequence of amino acids to the structure of proteinsstructure of proteins

10.10. Relate the structure of lipids to their Relate the structure of lipids to their functionsfunctions

11.11. List two essential functions of nucleic List two essential functions of nucleic acidsacids

CarbohydratesCarbohydrates

organic compounds in a ratio of 2 organic compounds in a ratio of 2 hydrogen atoms to one oxygen atom; hydrogen atoms to one oxygen atom; the # of carbon atoms varies the # of carbon atoms varies

Obj 8: Define monosaccharide, Obj 8: Define monosaccharide, disaccharide, and polysaccharide, and disaccharide, and polysaccharide, and discuss their significance to organismsdiscuss their significance to organisms

MonosaccharideMonosaccharidea monomer of a a monomer of a

carbohydratecarbohydratesimple sugars made simple sugars made

mostly by green mostly by green plantsplants

have have oneone carbon ring carbon ringused for energyused for energy

Ex. glucose, Ex. glucose, fructose, galactose, fructose, galactose, and dextrose these and dextrose these examples are examples are isomersisomers to each to each otherotherall have all have samesame

molecularmolecular formula formula – C– C66HH1212OO66

have have differentdifferent structuralstructural formulas formulas – diff. shape– diff. shape

DisaccharideDisaccharidecomplex sugarscomplex sugars twotwo carbon rings carbon rings formed by formed by

combining of 2 combining of 2 monosaccharides monosaccharides in a in a condensation condensation reactionreaction

Ex. Ex. glucose + galactose = lactose (milk glucose + galactose = lactose (milk

sugar) + H2Osugar) + H2Oglucose + glucose = maltose (malt glucose + glucose = maltose (malt

sugar) + H2Osugar) + H2Oglucose + fructose = sucrose (table glucose + fructose = sucrose (table

sugar) + H2Osugar) + H2O““-ose” ending tells you it’s a sugar-ose” ending tells you it’s a sugar

PolysaccharidePolysaccharidecomposed of three or more composed of three or more monosaccharidesmonosaccharidesEx. Ex. 1. glycogen (animal starch)1. glycogen (animal starch)

hundreds of glucose monomers strung together in hundreds of glucose monomers strung together in highly highly branchedbranched chains chains

2. cellulose (plant starch)2. cellulose (plant starch)thousands of glucose monomers linked in long, thousands of glucose monomers linked in long,

straightstraight chains chainsSo monomer is glucoseSo monomer is glucose

Obj 9: Relate the sequence of Obj 9: Relate the sequence of amino acids to the structure of amino acids to the structure of

proteinsproteinsAmino Acids - the building blocks of proteinsAmino Acids - the building blocks of proteins there are 20there are 20basic structure is:basic structure is:

a central carbon atom bonded toa central carbon atom bonded to1. a single hydrogen atom,1. a single hydrogen atom,2. a carboxyl group (-COOH),2. a carboxyl group (-COOH),3. an amino group (-NH2), and3. an amino group (-NH2), and4. a 4. a functional groupfunctional group (called the R group) (called the R group)

differences in a.a.’s found in their R groupsdifferences in a.a.’s found in their R groupsdiff R groups of a.a.’s give proteins their diff R groups of a.a.’s give proteins their

shape – diff shapes have different shape – diff shapes have different functionsfunctions

((structure related to functionstructure related to function))2 a.a.’s bond to form a 2 a.a.’s bond to form a dipeptidedipeptide

covalent bond is called a covalent bond is called a peptide bondpeptide bondis a condensation reactionis a condensation reaction

long strands of a.a.’s called long strands of a.a.’s called polypeptidespolypeptides

Protein - an organic Protein - an organic macromoleculemacromolecule– – composed of long strands of composed of long strands of

polypeptidespolypeptides

sequence or order, #, and kind of sequence or order, #, and kind of amino amino acidsacids will determine the structure (what will determine the structure (what proteinprotein is produced) is produced)

- temperature can affect the structure - temperature can affect the structure (shape), and so function(shape), and so function

enzymes - special enzymes - special proteins that act as proteins that act as catalysts in catalysts in reactionsreactions

rxns depend on rxns depend on physical fit btwn physical fit btwn enzyme and enzyme and substratesubstrate (reactant (reactant being catalyzed) – being catalyzed) – called a lock-and-called a lock-and-key modelkey model

can be affected (& can be affected (& so fail to work) w/ so fail to work) w/ temp or pH changetemp or pH change

Obj 10: Relate the structure of Obj 10: Relate the structure of lipids to their functionslipids to their functions

LipidsLipids(fats) - large, nonpolar molecules(fats) - large, nonpolar moleculesdo not dissolve in waterdo not dissolve in waterhave large #’s of carbon-hydrogen have large #’s of carbon-hydrogen

bondsbondsstore energy efficientlystore energy efficiently

Fatty AcidsFatty Acidsunbranchedunbranched carbon chains (12 to 28 carbon chains (12 to 28

carbons)carbons)- have a carboxyl group (-COOH) at one end- have a carboxyl group (-COOH) at one endcarboxyl end is carboxyl end is polarpolar, so , so hydrophilichydrophilic, ,

“water-loving”“water-loving”other hydrocarbon end is other hydrocarbon end is nonnonpolar, so tends polar, so tends

notnot to react w/ water – termed to react w/ water – termed hydrophobichydrophobic or “water-fearing”or “water-fearing”

- make up most lipids- make up most lipids

2 types: 2 types:

1) saturated (“full”)1) saturated (“full”)each carbon has 4 bondseach carbon has 4 bondsall single bondsall single bonds

2) unsaturated2) unsaturated less than 4 bondsless than 4 bondssome double bonds some double bonds

4 types of lipids – 1st 3 contain fatty 4 types of lipids – 1st 3 contain fatty acids and an alcohol acids and an alcohol

1.1. triglyceridetriglycerides – structure: 3 f.a.’s & 1 s – structure: 3 f.a.’s & 1 alcohol (glycerol)alcohol (glycerol) function: Saturated vs. Unsaturatedfunction: Saturated vs. Unsaturated

• saturated have high melting points, saturated have high melting points, and tend to be solid @ room temp.and tend to be solid @ room temp.ex. margarine, lardex. margarine, lard

unsaturated - liquid @ room tempunsaturated - liquid @ room temp- found in - found in plant seeds and fruitsplant seeds and fruits energy source for sprouting plantsenergy source for sprouting plants

2. phospholipid2. phospholipids – structure: 2 f.a.’s joined by s – structure: 2 f.a.’s joined by glycerolglycerol

function:function: form 2 layers of cell membraneform 2 layers of cell membrane waterproof barrier for cellwaterproof barrier for cell insulationinsulation

3. wax3. waxes – structure: es – structure: 1 long f.a. chain 1 long f.a. chain joined to a long joined to a long alcohol chainalcohol chainfunction:function:

highly highly waterproofwaterproof

protective protective coating in plants coating in plants & animals& animals

ex. earwax vs. ex. earwax vs. microorganismsmicroorganisms

4. steroids – structure: composed of 4 4. steroids – structure: composed of 4 fused carbon rings w/fused carbon rings w/various functional groupsvarious functional groupsfunction:function:

needed for normal nerve cell needed for normal nerve cell functionfunction

ex. cholesterolex. cholesterolmale development (testosterone)male development (testosterone)

Obj 11: List two essential functions Obj 11: List two essential functions of nucleic acidsof nucleic acids

Nucleic AcidNucleic Acid• DNA (deoxyribonucleic acid) – stores DNA (deoxyribonucleic acid) – stores

genetic informationgenetic information• ribonucleic acidribonucleic acid ( (RNARNA) – transfers ) – transfers

info. for building proteinsinfo. for building proteins Both DNA & RNA are polymers Both DNA & RNA are polymers

composed of repeating monomers composed of repeating monomers called called nucleotidesnucleotides

Have 3 components (parts)Have 3 components (parts)a 5-carbon sugar (deoxyriba 5-carbon sugar (deoxyriboseose))a phosphate groupa phosphate groupa ring-shaped nitrogenous basea ring-shaped nitrogenous base

4 monomers: adenosine, thymine, 4 monomers: adenosine, thymine, guanine, cytosineguanine, cytosine