Biology A - Unit 2 Key Terms

Dehydration synthesis

Removing water molecules to link monomers together / Build by removing water

Hydrolysis

Adding water to break apart polymers

Indicator

Shows the presence of certain substances by changing color

Buffer

A solution that helps to maintain the pH of a solution

Litmus paper

Indicator for acid or base (Red = Acid

Phenolphthalein

Indicator for bases (Turns clear to pink)

Iodine

Indicator for starch (Turns amber to blue/black)

Bromthymol Blue

Indicator for CO2 (Turns blue to green/yellow)

Benedict's Solution

Indicator for simple sugars like glucose (Turns blue to orange/red after heating)

Organic molecules

Molecules that contain both Carbon and Hydrogen

Inorganic molecules

Molecules that do not contain both Carbon and Hydrogen

Hydrocarbons

Organic molecules made up only of carbon and hydrogen

Monomers

Small molecules that link together to form long chains called polymers

Polymers

Long chains made of smaller units called monomers

Products

Ending materials in a chemical reaction

Solvent

A substance that dissolves another substance

Solute

Substance being dissolved

Solution

Uniform mixture of two or more substances

Mixture

Combination of two or more substances that are easily separated where substances keep their own properties

Acid

Substances with a pH below 7

Base

Substances with a pH above 7

pH Scale

Describes how acidic or basic a substance is

Neutral

A substance with a pH of 7

Matter

Anything that occupies space and has mass

made of elements

Element

Pure substance that cannot be broken down into other substances

Compounds

A substance containing two or more elements chemically combined

Atom

Smallest particle of an element consisting of a nucleus containing protons and neutrons surrounded by swirling electrons

Atomic Number

Number of protons a particular element will contain

Isotope

Alternative forms of the same element that have different numbers of neutrons

Radioactive Isotope

An isotope with an unstable nucleus that breaks down over time

Chemical Bond

Forces holding atoms together by transferring or sharing electrons to make the outer shell full

Molecule

Two or more atoms bonded together

Chemical Reaction

When two or more substances interact and form new ones by breaking or creating bonds

Reactants

Starting materials in a chemical reactio