ChemistryHydrogen Bonds: weak bonds BETWEEN MOLECULES

Organic Molecules

Carbs:Monsaccharides:GlucoseFructoseGalactose

Properties of Water

-solventpoles of H2O molecules interact w/ ionic/polar covalent substances and separate them into ions

-high heat capacitytemperatures of large bodies of water are very stable in response to surrounding temp. change

-Ice is less densewater expands when frozen; weak hydrogen bonds b/w H2O mc become rigid and form a crystal that keeps mc separated and less dense; insulates

-strong cohesionhydrogen bonding

-strong surface tensionb/c of strong cohesionstrong surface for insects to walk on

-strong adhesioncapillary action

Disaccharides: glycosidic linkageGlucose+glucose=maltoseGlucose+fructose=sucroseGlucose+galactose=lactose

Polysaccharides:

Starchalpha-glucoseenergy storage in plants

Glycogenalpha-glucosedifferent from starch bc of polymer branchingenergy storage in animals

Cellulosebeta-glucosestructure in plant cells

Chitinbeta-glucose has a nitrogen-containing group attached to ringstructure in walls of fungus cells and exoskeletons of arthropods and mollusks

*alpha glycosidic linkages can be easily digested by humans and other animals

*beta glycosidic linkages can only be broken down by specialized organisms such as bacteria in guts of termites

Lipids:

1. Triglycerides/lipid: fats and oils

Polyunsaturated: 2 or more double bonds

2. Phospholipid: like a lipid, but one fatty acid chain is replaced by phosphate group

AMPHIPATHIC 2 tailshydrophobic; Phosphate group with radical grouphydrophilic

3. Steroids: four linked carbon rings, one of them is a pentose ex. Cholesterol (in cell membranes), hormones (testosterone, estrogen)

Proteins: polymers (polypeptide) of amino acids bonded by peptide bonds

20 different aaStructural proteins (keratin in hair and horns, collagen in connective tissues, silk in spider webs)Storage proteins (casein in milk, ovalbumin in egg whites, zein in corn seeds)Transport proteins (hemoglobin, proteins in cell membrane that transport materials in and out of cell)Defensive proteins (antibodies)Enzymes (regulate rate of chemical reaction)

Four levels of protein structure:

1. Primary Structure: order of aa ex. Cys-Tyr-Phe2. Secondary Structure: 3D shape that results from hydrogen bonding between NH2 and COOH groups of adjacent

aaspiral (alpha helix) or folded (beta pleated sheet) often form fibrous proteins (structural or storage proteins; generally insoluble)

3. Tertiary Structure: additional 3D shaping and often dominates the structure of globular proteins Factors that contribute to tertiary structure: -hydrogen bonding b/w R groups of aa -ionic bonding b/w R groups of aa -Hydrophobic effect that occurs when hydrophobic R groups move toward center of protein and away from water -formation of disulfide bonds when sulfur atom in cysteine bonds to S atom of another Cyshelps maintain turns of aa chain 4. Quaternary Structure: 2 or more separate peptide chains ex. Hemoglobin (globular)4 chains that are held together by H bonding, interactions among R groups, and disulfide bonds

Nucleic Acids

DNA polymer of nucleotides (nitrogen base, 5C sugar aka deoxyribose, and phosphate group)

Purine—double ring base—Adenine, Guanine

Pyrimidine—single ring base—Thymine, Cytosine

Weak hydrogen bondsspiraled double helix

How is RNA different from DNA?-ribose instead of deoxyribose-thymine replaced by uracil-single stranded, no helixChemical Rxns in Metabolic Processes

Catalyst: accelerates rate of reaction by lowering activation energyCatabolism: breakdown of substancesSynthesis/Anabolism: formation of new productsCommon metabolic characteristics:

1.Chemical Equilibrium

2. Enzymes (globular proteins that act as catalysts)-substrate: substance upon which the enzyme acts ex. Amylase catalyzes breakdown of substrate amylose (starch)-enzymes are substrate specific ex. Amylase can break down alpha-glycosidic linkage in starch but cannot break beta-glycosidic linkage in cellulose-enzyme is unchanged as a result of rxn-enzyme catalyzes a rxn in both forward and reverse directions-efficiency of an enzyme is affected by temperature and pHabove 104 F, enzymes become denatured (lose 3D shape as bonds break) ex. Pepsinogen (digest proteins in STOMACH) only active low pH-standard suffix for enzymes =”ase” -How enzymes work: induced fit modelwithin enzyme/protein, there is an active site with which reactants readily interact bc of shape, polarity, and other characteristics of active site; interaction b/w substrate and enzyme causes enzyme to change shape; new position places substrate mc into a position favorable to their rxn; once rxn takes place, product is released3. Cofactors (nonprotein mc that assist enzymes)-holoenzyme (union of the cofactor and enzyme (called apoenzyme when part of a holoenzyme))-coenzyme: organic cofactors that usually function to donate or accept some component of a rxn such as electrons ex. Vitamins-inorganic cofactors: metal ions ex. Fe+2 and Mg+2

4. ATP (adenosine triphosphate)RNA adenine nucleotide with 2 additional phosphate groups

How ATP supplies energy: ATPADP+P(sub-i)

How are new ATP mc assembled? Phosphorylation: ADP+P(sub-i) with energy from energy rich mc such as glucose

How do living systems regulate chemical rxns? regulate enzyme

1. Allosteric enzymes2 binding sites (one active site for substrate and one allosteric site for allosteric effector2 types)

-Type 1: Allosteric Activator: binds to enzyme and induces enzyme’s active form-Type 2: Allosteric inhibitor: binds to enzyme and induces inactive form-Feedback inhibition: end product of series acts as an allosteric inhibitorshuts down one of the enzymes catalyzing the rxn series

2. Competitive Inhibition: substance that mimics substrate inhibits enzyme by occupying active site

3. Noncompetitive Inhibition: substance inhibits action of an enzyme by binding to enzyme at a location other than active siteinhibitor changes shape of enzyme disable enzymatic activity ex. Toxins and antibiotics

4.Cooperativity: enzyme becomes more receptive to additional substrate mc after one substrate mc attaches to an active site; occurs in enzymes with quaternary structure (each unit has its own active site) ex. Hemoglobin (not an enzyme)—binding capacity to additional O2 mc increases after first O2 binds to an active site