Huge molecules: carbohydrates, proteins, and nucleic acids

Polymers built from monomers

Polymer - a long molecule consisting of many similar or identical building blocks linked by covalent bonds

Monomer - a shorter molecule; the repeating units that serve as the building blocks of a polymer

The way in which monomers are connected;

a reaction in which two molecules are covalently bonded to each other through loss of a water molecule.

aka a dehydration reaction, because water is the molecule that is lost.

Each monomer contributes part of the H2O molecule that is lost: On provide the hydroxyl group (--OH) while the other provides the hydrogen (--H)

facilitate the dehydration process;

specialized macromolecules that speed up chemical reactions in cells.

A process that is essentially the reverse of the dehydration reaction.  Dissembles polymers to monomers.

Bonds between monomers broken by the addition of water molecules

EX: digestion

Carbohydrates, lipids, proteins, and nucleic acids;

Carbohydrates, proteins, and nucleic acids are macromolecules

include both sugars and polymers of sugars;

this includes: monosaccharides, disaccharides, polysaccharides

have a multiple unit of CH₂O.

EX: GLUCOSE C₆H₁₂O₆

Molecules have a carbonyl group and multiple hydroxyl groups;

Depending on where the carbonyl group is, a sugar is either an aldose (aldehyde sugar) or a ketose (ketone sugar).

Geometry: form rings;

Major nutrients for cells

consists of 2 monosaccharides joined by glycosidic linkage (covalent bond formed between two monosaccharides by a dehydration reaction)

EX: maltose is a disaccharide formed by the linking of two glucose molecules

EX2: sucrose (table sugar) with glucose and fructose as combined monomers.

EX3: Lactose = glucose + galactose molecules

macromolecules; polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages.

Some serve as storage material; Others as building material for structures that protect the cell/organism.

Function is determined by its sugar monomers and positions of its glycosidic linkages.

Plants and animals both store sugars for later use in the form of storage polysaccharides.

Plants store Starch - glucose monomers in alpha formation - as granules within cellular structures (plastids); represents stored energy; retrieved through hydrolysis; most glucose monomers in starch joined by 1-4 linkages (number 1 carbon to number 4 carbon); shape is helical

Animals store glycogen - polymer of glucose in alpha formation - Stored in liver and muscle cells; Hydrolysis of them releases glucose when in demand for sugar increases

Cellulose - major component for the tough walls that enclose plant cells; most abundant organic compound on earth; polymer of glucose is in Beta formation (different from starch); geometry is mostly straight; never branched and hydroxyl groups are free to hydrogen bond w/ other cellulose molecs. lying parallel to it.  molecules held together like this are called microfibrils

Enzymes that digest the alpha linkages cannot digest beta linkages of cellulose b/c of the diff. shapes of the molecs.  Part of healthy diet b/c lines the walls for food to pass through

Chitin - used by arthropods (spiders, insects, etc..) to build their exoskeleton; similar to cellulose but contains a nitrogen containing appendage.

mix poorly (if at all) with water; hydrophobic;

include: fats, phospholipids, and steroids

large molecules (not polymers) assembled from smaller molecules [glycerol (an alcohol with three carbons each with a hydroxyl group) and fatty acids (a long carbon skeleton with a carboxyl group on the end carbons that are attached to long hydrocarbon chains that are nonpolar - hence the hydrophobia)] by dehydration rxn;

3 fatty acid molecs. join to a glycerol --> triglycerol

Fats = ENERGY STORAGE!

Saturated - when there are no double bonds in the hydrocarbon chain, as many hydrogens as possible bond to the carbon skeleton; "saturated" with hydrogen.  Usually in animal fats - solid at room temp b/c of flexibility

Unsaturated - has one or more double bonds, formed by the removal of hydrogen atoms from the carbon skeleton; usually in plants/fish fats - liquid at room temp. b/c kink prevents closeness

unsaturated fats with trans double bonds produced from the hydrogenating of vegetable oils; prevalent in baked goods; very bad for you

make up cell membranes; similar to fat molecule but only has 2 fatty acids attached to glycerol

hydrocarbon tails are still hydrophobic; but the phosphate group form a hydrophilic head.  When added to water, delf assemble in two layers that shield the hydrophobic hydrocarbons from the water; this occurs on the membrane of the cell that is in contact with aqueous soln.  cells couldn't exist without phospholipids b/c they act as a boundary between the cell and its external environment.

Hormones, e.g. cholesterol, which are lipids characterized by a carbon skeleton consisting of four fused rings;

Cholesterol - common component of animal cell membranes and what other steroids are synthesized from.

mostly proteins; regulate metabolism by acting as catalysts, chemical agents that selectively speed up chemical reactions without being consumed by the reaction;

Protein

consists of one or more polypeptides, polymers of the 20 amino acids, each folded and coiled into a special 3D structure

organic molecules possessing both carboxyl and amino groups; 20 total

Nonpolar: glycine, alanine, valine, leucine, isoleucine, methionine, phenylalanine, tryptophan, proline

Polar: Serine, Threonine, Cysteine, Tyrosine, Asparagine, Glutamine

Electrically charged: acidic - aspartic acid, glutamic acid; basic - lysine, arginine, histidine

Amino Acid Polymers: When two amino acids are placed next to each other so that the carboxyl group of one is adjacent to the amino group of the other, they are combined by a dehydration rxn.; this results in a peptide bond.  When this is repeated, a polypeptide forms.

proteins = a bunch of polypeptides twisted, folded, and foiled into a molecule of unique shape.  Either spherical (globular proteins) or shaped like long fibers (fibrous proteins)

Four Levels of Protein Structure

Primary - unique sequence of amino acids; determined by inherited genetic info

Secondary - consists of coils and folds in the polypeptide chain; result from hydrogen bonds b/w repeating constituents of the polypeptide backbone; coiled (alpha helix) or folded (Beta pleated sheet)

Tertiary - determined by interactions among various side chains (R groups); hydrogen bonds, ionic bonds, hydrophobic interactions, and van der Waals interactions; disulfide bridges - strong covalent bonds that reinforce the protein's structure

Quaternary - results when a protein consists of mulitple polypeptide chains; 2+ polypeptides form one macromolecule

Loss of a protein's native structure due to alterations in pH, salt concentration, temperature, and other environmental factors that cause a protein to unravel.

Denature proteins are biologically inactive

protein molecules that assist the proper folding of other proteins

DNA: provides directions for its own replication; directs synthesis of messenger RNA and controls protein synthesis through RNA (in ribosomes)

Nucleic Acids are polymers aka polynucleotides; each is made of monomers called nucleotides; each nucleotide consists of a nitrogenous base, a pentose sugar, and a phosphate group; part without the phosphate group is called a nucleoside (a nitrogenous base + sugar)

Two families of nitrogenous bases: 

Pyrimidines: have a single six-membered ring

Purines: have a six-membered ring fused to a five membered ring

a DNA molecule has two polynucleotides spiraling around an imaginary axis, forming a double helix.

In the double helix: two backbones run in opposite 5'-->3' directions from each other, this is referred to as antiparallel.