Biology Vocab Unit 2

Activation Energy

The amount of energy needed to start a reaction.

Active Site

Where the enzyme and substrate touch, causes a chemical reaction.

Adhesion

When water molecules stick to other substances.

Amino Acid

Building blocks of protein.

Bond

The sharing of valence electrons between two or more atoms.

Buffer

Substance that helps to neutralize the pH of a substance. Ex: in human body ensures blood pH remains close to neutral.

Capillary Action

Combination of adhesion and cohesion; when water moves up a thin tube.

Carbohydrate

Often called "sugars" and end in "ose." Used by cells to store and release energy; composed of carbon, hydrogen and oxygen. Provide the body with quick bursts of energy and are made of carbon, hydrogen and oxygen.

Cellulose

A glucose polymer that forms the cell walls of plants and gives them structural support.

Cohesion

When water sticks to other water molecules.

Denatured Enzyme

When the shape of the enzyme is altered by a pH change or a temperature increase.

Disaccharide

A two sugar carbohydrate; made of two monosaccharide molecules. Example: sucrose.

Enzymes

Proteins that speed up chemical reactions by lowering the activation energy needed to start the reaction. Typically end in "ase," are catalysts, and attach to substrates. Important to break down toxic substrates or provide the body with necessary products.

Glycogen

A polysaccharide that stores excess sugar in the liver and muscles of animals.

Hemoglobin

Protein molecule that contains iron. Binds to oxygen and carries it from the lungs to the body's cells.

Hormone

Chemicals produced in one part of an organism and transported to another part. Causes a physiological change.

Insulin

A protein hormone that lowers the amount of glucose in the blood and helps maintains homeostasis.

Lipid

Large organic compounds made mostly of more carbon than hydrogen and oxygen. Usually made of 3 fatty acids bound to a glycerol molecule. Insoluble in water. Used in cells for energy storage, make up cell membrane, used for insulation, and protective coatings. Provide twice as many calories as proteins/carbs and are non-polar. 

Lock and Key Model

How a substrate binds to an enzyme. Enzymes are shape specific, shows how they fit together.

Monomer

Building blocks of polymers. Smallest molecules in each class of biomolecules.

Monosaccharide

The simplest and smallest type of carbohydrate. Examples are glucose and fructose.

Nucleic Acid

Complex biomolecules that store cellular information in cells in the form of a code. Examples are DNA and RNA. Contains carbon, hydrogen, oxygen, nitrogen, and phosphorous.

Nucleotide

Subunits of a nucleic acid. Formed from a simple sugar, a phosphate group, and a nitrogenous base.

Organic

A substance that contains both hydrogen and carbon. Examples include proteins, carbohydrates, lipids, and nucleic acids.

Peptide Bond

Covalent bonds between amino acids to build proteins.

ph

Measurement of how acidic or basic something is. Ranges from 0-14, 1-6 is acidic, 8-14 is basic. 7 is neutral.

Polarity

The property by which a molecule has an unequal distribution of charge; results in a positive end and a negative end.

Polymer

Large molecule formed by smaller molecules bound together.

Polypeptide

Long chain of amino acids linked together. Precursor to a protein; not fully functional yet.

Polysaccharide

Largest carbohydrate moldecules, composed of many monosaccharides. Examples are starch, glycogen, chitin and cellulose.

Product

On the right side of a chemical equation, new substance(s) formed from chemical reaction.

Protein

Large, complex polymer essential to all life. Composed of hydrogen, carbon, nitrogen, and oxygen. Provides structure for tissues and organs and helps carry out cell metabolism. Made of amino acids. Job determined by shape, acts as a catalyst.

Reactant

On the left side of the chemical equation, substance before chemical change occurs.

Starch

Polysaccharide that plants store glucose as.

Steroid

A cholesterol-based hormone that plays a role in many physiological functions.

Substrate

Binds to an enzyme. Are either toxic to the body or their products are necessary.