Nucleic acids

II. Nucleic Acids Elements: C, H, O, N, P

Nucleic Acids Function: Stores genetic information genes blueprint for building proteins DNA  RNA  proteins transfers information blueprint for new cells blueprint for next generation DNA proteins

Function: store hereditary info II. Nucleic Acids Function: store hereditary info DNA RNA Double-stranded helix N-bases: A, G, C, Thymine Stores hereditary info Longer/larger Sugar: deoxyribose Single-stranded N-bases: A, G, C, Uracil Carry info from DNA to ribosomes tRNA, rRNA, mRNA, RNAi Sugar: ribose

Nucleotides: monomer of DNA/RNA Nucleotide = Sugar + Phosphate + Nitrogen Base

Nucleotide phosphate A – T Nitrogen G – C base 5-C sugar Purines Pyrimidines Adenine Guanine Cytosine Thymine (DNA) Uracil (RNA) Double ring Single ring 5-C sugar

“Students at AG (middle school) are still PURE. Memory Help: “Students at AG (middle school) are still PURE.

Dehydration Synthesis forms the Sugar-Phosphate Backbone

N-bases

Information flow in a cell: DNA  RNA  protein

Carbohydrates

III. Carbohydrates Ratio of 1 carbon: 2 hydrogen: 1 oxygen or CH2O Monomers = Monosaccharides (eg. glucose, ribose)

III. Carbohydrates monosaccharide  disaccharide  polysaccharide

Sugars 6 5 3 Most names for sugars end in -ose Classified by number of carbons 6C = hexose (glucose) 5C = pentose (ribose) 3C = triose (glyceraldehyde) Glyceraldehyde H OH O C OH H HO CH2OH O Glucose H OH HO O Ribose CH2OH 6 5 3

Functional groups determine function carbonyl aldehyde carbonyl ketone

The structure and classification of some monosaccharides

Linear and ring forms of glucose

III. Carbohydrates Examples/Types: Simple sugars: Fructose, Glucose, Ribose Complex Polysaccharides: Starch, Cellulose, Glycogen

Differ in position & orientation of glycosidic linkage III. Carbohydrates Functions: Fuel (energy) and building material Storage (plants-starch, animals-glycogen) Structure (plant-cellulose, arthropod/fungi-chitin) Differ in position & orientation of glycosidic linkage

Building sugars Dehydration synthesis monosaccharides disaccharide H2O maltose | glucose | glucose | maltose glycosidic linkage

Building sugars Dehydration synthesis monosaccharides disaccharide H2O sucrose = table sugar | glucose | fructose | sucrose (table sugar)

Carbohydrate synthesis

Cellulose vs. Starch Two Forms of Glucose:  glucose &  glucose

Cellulose vs. Starch Starch =  glucose monomers Cellulose =  glucose monomers

Storage polysaccharides of plants (starch) and animals (glycogen)

Linear vs. branched polysaccharides starch (plant) energy storage Can you see the difference between starch & glycogen? Which is easier to digest? Glycogen = many branches = many ends Enzyme can digest at multiple ends. Animals use glycogen for energy storage == want rapid release. Form follows function. APBio/TOPICS/Biochemistry/MoviesAP/05_07Polysaccharides_A.swf glycogen (animal)

Polysaccharide diversity Molecular structure determines function in starch in cellulose isomers of glucose structure determines function…

Structural polysaccharides: cellulose & chitin (exoskeleton)

Lipids: Fats & Oils

IV. Lipid Structure Elements: Monomers: C, H, O Fatty Acids Glycerol*

IV. Lipids Fats (triglyceride): store energy Glycerol + 3 Fatty Acids saturated, unsaturated, polyunsaturated Steroids: cholesterol and hormones Phospholipids: lipid bilayer of cell membrane hydrophilic head, hydrophobic tails Hydrophilic head Hydrophobic tail

Phospholipid

The structure of a phospholipid

Phospholipids Structure: glycerol + 2 fatty acids + PO4 PO4 = negatively charged It’s just like a penguin… A head at one end & a tail at the other!

Phospholipids Hydrophobic or hydrophilic? fatty acid tails = PO4 head = split “personality” hydrophobic hydrophillic “attracted to water” Come here, No, go away! interaction with H2O is complex & very important! “repelled by water”

Phospholipids in water Hydrophilic heads “attracted” to H2O Hydrophobic tails “hide” from H2O can self-assemble into “bubbles” bubble = “micelle” can also form a phospholipid bilayer early evolutionary stage of cell? water bilayer water

Why is this important? Phospholipids create a barrier in water define outside vs. inside they make cell membranes! Tell them about soap!

Hydrophobic/hydrophilic interactions make a phospholipid bilayer

Building Fats Triacylglycerol 3 fatty acids linked to glycerol ester linkage = between OH & COOH hydroxyl carboxyl BIG FAT molecule!!

Dehydration synthesis H2O dehydration synthesis enzyme H2O Pulling the water out to free up the bond enzyme H2O enzyme H2O

Saturated Unsaturated Polyunsaturated “saturated” with H, so NO double bonds Have some C=C (double bonds), result in kinks In animals In plants Solid at room temp. Liquid at room temp. Eg. butter, lard Eg. corn oil, olive oil

Cholesterol, a steroid

Cholesterol Important cell component animal cell membranes precursor of all other steroids including vertebrate sex hormones high levels in blood may contribute to cardiovascular disease

Cholesterol Important component of cell membrane helps keep cell membranes fluid & flexible

From Cholesterol  Sex Hormones What a big difference a few atoms can make! Same C skeleton, different functional groups