CHAPTER 5.2: MATTER, ENERGY, CHEMISTRY, AND LIFE PROCESSES

Watt

The unit used to measure power; one watt is equal to one joule of energy used per second.

Joule

A unit used to measure energy.

Energy

The ability to do work or cause change in a system.

Radiation/Radiant heat

Energy transferred through electromagnetic waves, including heat energy from the Sun.

Organic matter

Material that comes from living organisms or contains carbon-based compounds.

Matter

Anything that has mass and takes up space.

Law of conservation of matter

The principle stating that matter cannot be created or destroyed; it only changes form.

Atom

The smallest unit of an element that retains the properties of that element.

Compound

A substance made of two or more different elements chemically combined.

Molecule

A group of two or more atoms held together by chemical bonds.

Acid

A compound that gives away or releases hydrogen ions.

Base

A compound that captures or accepts hydrogen ions.

pH

A scale used to measure how acidic or basic a substance is.

Oxidation

The process in which an atom loses electrons during a chemical reaction.

Reduction

The process in which an atom gains electrons during a chemical reaction.

Reduced

An atom that receives electrons is said to be reduced.

Oxidized

An atom that loses electrons during a chemical reaction is said to be oxidized.

Redox reaction

A chemical reaction involving both oxidation and reduction.

Covalent bond

A chemical bond formed when atoms share electrons.

Ionic bond

A chemical bond formed when one atom transfers electrons to another atom, creating charged ions.

Hydrogen bonding

A weak attraction between a hydrogen atom and another electronegative atom, important in water and biological molecules.

Octet rule

The principle stating that atoms tend to gain, lose, or share electrons to achieve a stable outer shell of eight electrons.

Cell

The basic unit of life; all living organisms are made of cells.

Lipids

Organic compounds that do not dissolve in water and include fats, oils, and waxes.

Carbohydrates

Organic compounds used mainly as a source of energy for organisms.

Proteins

Large biological molecules made of amino acids that perform many functions in living organisms.

Nucleic acids

Biological molecules that store and transmit genetic information.

Photosynthesis

The process where plants use sunlight energy to convert carbon dioxide and water into glucose and oxygen.

Photosynthesis equation

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂

Photosynthesis in words

Carbon dioxide + water + sunlight energy → glucose + oxygen.

Respiration

The process where organisms break down glucose to release usable energy.

Cellular respiration equation

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP)

Respiration in words

Glucose + oxygen → carbon dioxide + water + energy.

Arrow symbol in chemical equations

Means "produces" or "yields."

Sunlight clue in equation

Indicates photosynthesis.

Energy clue in equation

Indicates respiration.

Water

One of the most abundant compounds on Earth and essential for life.

Extremophiles

Organisms that live in extreme environments with conditions that are usually harsh for most life forms.

Xerophiles

Extremophiles that live in extremely dry environments such as deserts.

Foot and water

Common limiting resources for animals.

Limiting resource

A resource required for survival that is available only in limited quantities in the environment.