Biochemistry, Enzymes, and Digestion

Covalent Bond

A chemical bond formed when two atoms share electrons

Electronegativity

measures the ability of an atom to attract electrons when the atom is in a compound

Nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms

Polar covalent

a type of bond that forms when electrons are not shared equally

Ionic Bond

Formed when one or more electrons are transferred from one atom to another

Hydrogen bond

Attraction between a slightly positive hydrogen atom and a slightly negative atom.

van der Waal interactions

weak intermolecular forces that only occur when the olecules are close together

reactants

a substance that takes part in and undergoes change during a reaction.

products

The elements or compounds produced by a chemical reaction.

cohesion

an attraction between molecules of the same substance

adhesion

An attraction between molecules of different substances

surface tension

A measure of how difficult it is to stretch or break the surface of a liquid

kinetic energy

energy due to motion

heat

The energy transferred between objects that are at different temperatures

specific heat

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celcius

heat of vaporization

The amount of energy required for the liquid at its boiling point to become a gas

evaporative cooling

The process in which the surface of an object becomes cooler during evaporation, a result of the molecules with the greatest kinetic energy changing from the liquid to the gaseous state.

solution

A homogeneous mixture of two or more substances

solute

A substance that is dissolved in a solution.

solvent

A liquid substance capable of dissolving other substances

hydration shell

the sphere of water molecules around each dissolved ion

acid PH

below 7

base PH

above 7 pH

organic compound

a covalently bonded compound that contains carbon, excluding carbonates and oxides

hydrocarbons

Compounds composed of only carbon and hydrogen

functional groups

A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions.

monomer

one unit

polymer

many monomers

dehydration reaction

occurs when two monomers bond together through the loss of a water molecule

carbohydrates

sugar, quick energy

monosaccharides

one sugar

disaccharide

two sugars

hydrolysis

occurs when water is added to split large molecules

glycosidic linkage

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

Polysaccharides

many sugars

starch

energy storage in plants, rice potatoes, wheat, and corn

glycogen

short term energy storage in animals

cellulose

makes up plant cell walls

chitin

makes up insect exoskeletons and fungal cell walls

lipids

functions are: long-term energy storage, insulation, communication, cell membranes

hydrophobic and non-polar

fat

triglyceride

fatty acid

hydrocarbon chain often bonded to glycerol in a lipid

triacylglycerol

Three fatty acids linked to one glycerol molecule; also called a fat or a triglyceride

saturated fatty acid

contains the maximum number of hydrogen atoms and no double bonds

unsaturated fatty acid

contains one or bent double bonds, bent

Phosopholipids

two fatty acids and a phosphate group attached to glycerol

steroids

lipids characterized by a carbon skeleton consisting of four fused rings

cholesterol

component of animal cell membranes

catalysts

Chemical agents that selectively speed up chemical reactions without being consumed by the reaction.

polypeptides

unbranched polymers built from the same set of 20 amino acids

protein

polymer, biologically function molecule that consist of one or more polypeptides

contains a nitrogenous base, pentose sugar, and one or more phosphate groups

amino acids

monomers of proteins

functions of proteins

defense, storage, transport, cellular communication, movement, and structural support

peptide bond

bonds between amino acids

4 levels of protein structure

primary, secondary, tertiary, quaternary

primary structure

unique sequence of amino acids held by peptide bonds

secondary structure

consists of alpha helix and beta sheets due to hydrogen bonds

tertirary structure

3D globular structure due to interactions among R groups

held by ionic bonds, hydrogen bonds, hydrophobic interactions, disulfide bridges, and van der waals interactions

denaturation

loss of a protein's native structure, biologically inactive

chaperones

oversees the structure of proteins

nucleic acids

store, transmit, and help express hereditary information

deoxyribonucleic acid (DNA)

gives directions for its own replication and directs the synthesis of rNA, and through this controls protein synthesis ; double-stranded

ribonucleic acid (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.

polynucleotides

polymers of nucleic acids

nucleotides

monomers of nucleic acids

pyrimidine

single-ring nitrogenous base, cytosine, thymine, uracil

purines

two-ring nitrogenous base, adenine and guanine

ribose

A five-carbon sugar present in RNA

dexoyribose

A five-carbon sugar that is a component of DNA nucleotides

Hydroxyl group

Carbonyl group

Carboxyl group

Amino group

Sulfhydryl group

Phosphate group

Methyl group

antiparallel

The strands each run from 5' to 3' and run in antiparallel, or opposite, directions from one another.