macromolecules

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Monomer

The subunit that serves as the building block of a polymer.

Macromolecule

A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction. Polysaccharides, proteins, and nucleic acids are macromolecules.

Condensation reaction

A reaction in which two molecules become covalently bonded to each other through the loss of a small molecule, usually water; also called dehydration reaction.

Hydrolysis

A chemical process that lyses, or splits, molecules by the addition of water; an essential process in digestion.

Carbohydrate

A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides).

Monosaccharide

The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, the molecular formulas of monosaccharides are generally some multiple of CH2O. 3 to 7 carbon atoms.

Disaccharide

A double sugar, consisting of two monosaccharides joined by dehydration synthesis.

Polysaccharide

A polymer of up to over a thousand monosaccharides, formed by dehydration reactions. Used for storage in animals (glycogen) and structure in plants (cellulose)

Glycosidic Linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

Starch

A storage polysaccharide in plants consisting entirely of glucose.

Glycogen

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

Cellulose

A structural polysaccharide of cell walls, consisting of glucose monomers joined by b-1, 4-glycosidic linkages.

Chitin

A structural polysaccharide of an amino sugar found in many fungi and in the exoskeletons of all arthropods.

lipid

One of a family of compounds, including fats, phospholipids, and steroids, that are insoluble in water.

fat

A biological compound consisting of three fatty acids linked to one glycerol molecule.

phospholipid

A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.

steroid

A type of lipid characterized by a carbon skeleton consisting of four rings with various functional groups attached.

triacylglycerol

Three fatty acids linked to one glycerol molecule.

protein

A three-dimensional biological polymer constructed from a set of 20 different monomers called amino acids. One or more polypeptide chains folded into a specific three-dimensional conformation

amino acid

An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of proteins.

polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

peptide bond

The covalent bond between two amino acid units, formed by a dehydration reaction.

primary structure

Specific sequence of amino acids.

secondary structure

The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between peptide linkages.

tertiary structure

Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.

quaternary structure

The particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide.

disulfide bridge

Strong covalent bonds formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer.

denaturation

For proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. For DNA, the separation of the two strands of the double helix. Denaturation occurs under extreme conditions of pH, salt concent

nucleic acid

A polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The two types are DNA and RNA.

nucleotide

The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.

pyrimidine

One of two families of nitrogenous bases found in nucleotides. Cytosine (C), thymine (T), and uracil (U) are examples.

purine

One of two families of nitrogenous bases found in nucleotides. Adenine (A) and guanine (G) are examples

DNA

A double-stranded, helical nucleic acid molecule capable of replicating and determining the inherited structure of a cell's proteins.

RNA

A type of nucleic acid consisting of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single-stranded; functions in protein synthesis and as the genome of some viruses.

pentose

5-carbon sugars

Metabolism

The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways.

Potential energy

The energy stored by matter as a result of its location or spatial arrangement.

Spontaneous reaction

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Equilibrium

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Activation energy

The amount of energy that reactants must absorb before a chemical reaction will start.

Coenzymes

An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions.

Catabolic pathways

A metabolic pathway that releases energy by breaking down complex molecules to simpler compounds.

thermodynamics

(1) The study of energy transformations that occur in a collection of matter. See first law of thermodynamics and second law of thermodynamics. (2) A phenomenon in which external DNA is taken up by a cell and functions there.

free energy

The portion of a system's energy that can perform work when temperature is uniform throughout the system.

catalyst

A chemical agent that changes the rate of a reaction without being consumed by the reaction.

inhibitors

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competitive inhibitors

A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics.

anabolic pathways

A metabolic pathway that synthesizes a complex molecule from simpler compounds.

exergonic

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induced fit

The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.

noncompetitive inhibitors

A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics.

kinetic energy

The energy of motion, which is directly related to the speed of that motion. Moving matter does work by imparting motion to other matter.

active site

The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds.

cofactors

Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis.

feedback inhibition

A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

Explain how organic polymers contribute to biological diversity:

Polymers make up DNA and proteins, so any variation in polymers will affect DNA and proteins.

Describe how covalent linkages are formed and broken in organic polymers:

Formed by condensation (dehydration) and broken by hydrolysis

Saturated fats

contain only single bonds. Maximum amount of hydrogen atoms. Solid at room temperature

Unsaturated fats

contain double bonds in one or more tails. Liquid at room temperature

Free energy

G

Total energy

H

Entropy

S

Allosteric regulators

Does not directly block the active site. This is noncompetitive inhibition. Changes the active sites shape, preventing it from binding to substrate