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The Structure and Function of Large Biological Molecules

Polymer

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

Monomers

the smaller, repeating units that serve as the building blocks of a polymer

Enzymes

specialized macromolecules that speed up chemical reactions (proteins)

Dehydration Reaction

Reaction in which two molecules are covalently bonded to each other, with the loss of a water molecule (a.k.a. synthesis reaction, anabolic, condensation)

Hydrolysis

Process that disassembles polymers, means to break using water (a.k.a. decomposition reaction, catabolic, digestion)

Carbohydrates

include both sugars and polymers of sugars, ratio of two hydrogen to each oxygen (contain only C, H, and O)

Monosaccharides

simplest carbohydrate, active alone or serving as a monomer larger saccharides. The molecular formulas are generally some multiple of CH2O (Carbonyl group and multiple hydroxyl groups, is either an aldehyde or ketone)

Disaccharide

consists of two monosaccharides joined by a glycosidic linkage

Glycosidic linkage

a covalent bond formed between two monosaccharides by a dehydration reaction

Polysaccharides

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

Starch

Stored by plants, a polymer of glucose (alpha) monomers, as granules within cellular structures known as plastids, doesn't attract water

Maltose

A disaccharide made up of two glucose units (joined number 1 and number 4 carbon)

Sucrose

A disaccharide made up of a glucose and fructose unit, table sugar

Lactose

A disaccharide made up of glucose and galactose

Amyloplasts

colorless plastids that store starch

Glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

Cellulose

a polysaccharide that is a major component of all plant tissues and fibers, especially the tough walls that enclose plant cells (beta glucose units) insoluble, undigestible, aka fiber

Chitin

structural polysaccharide that makes up the cell walls of fungi and found in the external skeletons of arthropods

Lipids

do not include true polymers, generally not considered macromolecules, made mainly from carbon and hydrogen atoms; includes fats, phospholipids, steroids and waxes (do not mix well, if at all, with water)

Fat

constructed from the glycerol alcohol and three fatty acids

Fatty Acids

long carbon skeleton (usually 16 to 18 carbon atoms in length) contains a carboxyl group, relatively non-polar

Triacylglycerol

three fatty acids linked to one glycerol molecule, also known as triglyceride

Esther Linkage

Covalent bond between hydroxyl group and a carboxyl group

Saturated Fatty Acid

hydrocarbon chain structure contains no double bonds, saturated with hydrogen, solid at room temperature

Unsaturated Fatty Acid

hydrocarbon chain structure containing one or more (poly-) double bonds, with one fewer hydrogen atom for each double-bonded carbon causing a kink in the hydrocarbon chain, liquid at room temperature, oils

Trans Fat

result of hydrogenated vegetable oils creating trans double bonds instead of cis double bonds

Phospholipids

only has two fatty acids attached to a glycerol , which is attached to a phosphate group, has a negative electrical charge creating a hydrophilic head and hydrophobic tail, make up cell membranes

Steroids

lipids characterized by a carbon skeleton consisting of four fused rings

Cholesterol

crucial molecule in animals, component of animal membranes, precursor from which other steroids are synthesized (in liver and obtained from the diet)

Polypeptides

polymers of amino acids

Catalysts

chemical agents that selectively speed up chemical reactions without being consumed by the reaction, enzymatic proteins

Protein

functional molecule that consists of one or more polypeptides, each folded and coiled into a specific three dimensional structure (HCNO sometimes S)

Amino Acid

organic molecule possessing a central (alpha) carbon bonded to a hydrogen atom, an amino group, a carboxyl group, and an R group (there are 20 amino acids/R groups)

Peptide Bond

the bond formed between the carboxyl group of one amino acid and the amino group of another, joined through a dehydration reaction forming a covalent bond

Frederick Sanger

pioneer in determining the amino acid sequence of proteins through insulin

Primary Structure

linked series of amino acids with a unique sequence

Secondary Structure

alpha helix or beta pleated sheets resulting from hydrogen bonds between the repeating constituents of the polypeptide backbone

Tertiary Structure

overall shape of a polypeptide resulting from interactions between the side chains of the various amino groups (disulfide bridges (covalent bonds) and hydrophobic interactions (van der Waals) hydrogen bonds between polar side chains, ionic bonds between between charged chains)

Quaternary Structure

overall protein structure that results from the aggregation of polypeptide subunits

Denaturation

unraveling of a protein so it loses its native shape, occurs due to changes in pH, salt concentration, temperature, or other environmental changes

Chaperonins

protein molecules that assist the proper folding of other proteins

Gene

consist of DNA, unique units of inheritance that provide the codes for the amino acid sequence of polypeptides

Nucleic Acids

polymers made up of monomers called nucleotides

Deoxyribonucleic Acids (DNA)

inherited from parents, present in all cells, directs RNA synthesis and through it protein synthesis, lacking oxygen

Ribonucleic Acid (RNA)

direct production of a polypeptide, contains U nitrogenous base

Polynucleotides

polymers of nucleotides

Nucleotides

composed of three parts, nitrogenous base, a pentose sugar, and one or more phosphate groups (contain CHON and P)

Pyrimidine

one family of nitrogenous bases, has six-membered ring of carbon and nitrogen atoms (C, T, and U)

Purines

one family of nitrogenous bases, large, six-membered ring fused to a five-membered ring (A, G)

Prime Carbon

5th or 3rd carbon not attached to nitrogenous base, mark the ends of polynucleotides

Double Helix

formed by DNA strands spiraled around an imaginary axis

Antiparallel

arrangement of opposite running sugar-phosphate backbones in DNA

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