Chemistry of Living Things

Matter is anything that takes up space and has mass. Matter is made up of atoms. Atoms are made up of a nucleus with protons, neutrons, and electrons.

Elements are made of atoms that are alike. Each element has its own chemical symbol. Ninety elements occur naturally on Earth. Everything including you, is made of one, or a combination of these elements.

SymbolElementPercent OOxygen65.0 CCarbon18.5 HHydrogen 9.5 NNitrogen 3.3 CaCalcium 1.5 PPhosphorus 1.0 KPotassium 0.4 SSulfur 0.3 NaSodium 0.2 ClChlorine 0.2 MgMagnesium 0.1

The atoms of elements combine chemically to form new substances called compounds.

A mixture is a combination of substances in which individual substances retain their own properties. Example sugar and salt mixture. They do Not combine chemically. Mixtures can be solids, liquids, or gases, or any combination of them.

A solution is a mixture in which two or more substances are mixed evenly. Example solution: milk, orange juice, or coffee. A suspension is a mixture in which substances are evenly spread through a liquid or a gas. Particles in a suspension eventually sink to the bottom Example suspension: Blood

Compounds in living organisms are classified as either organic or inorganic compounds. Most compounds containing carbon are organic compounds.

See page 419 of your textbook.

Carbohydrates are organic compounds made of carbon, oxygen, and hydrogen. Carbohydrates supply energy for cell processes.

Lipids, commonly called fats and oils are organic compounds that store and release larger amounts of energy than carbohydrates.

Proteins are the building blocks of organisms. Proteins are scattered through out cells and are made up of small molecules called amino acids. Certain proteins are called enzymes that regulate all chemical reactions in cells without being changed. The enzyme remains behind for future use for more chemical reactions.

Nucleic Acids store large organic molecules that store important coded information in cells. One nucleic acid is DNA found in the nucleus of cells. Another nucleic acid is RNA that carries information to make proteins and enzymes.

Inorganic Compounds are made from elements other than carbon. Example: Water which contains no carbon elements.

Occurs when molecules of a substance move from areas of a high concentration to areas of low concentration. Example: Cut an onion, the onion molecules have a high concentration of onion molecules at the onion. The onion molecules mix with the atmosphere and move as far as they can to other parts of the room a low concentration of onion molecules.

When molecules of one substance are spread evenly throughout another substance.

The diffusion of water through a cell membrane.

The movement of substances through a cell membrane without the use of energy.

Transport proteins are used to transport materials through a cell membrane using energy.

The process by which organisms obtain material by surrounding the material and enclosing it within the cell. Example: An amoeba surrounds its food and engulfs it into the cell. Endo- meaning to enter

Process in which organisms excrete materials through the cell membrane. Example: To get rid of waste the cell forces it out of the cell through the cell membrane. Exo- meaning to exit.

The total of all chemical reactions in an organism.

Organisms that make their own food. Example: Green plants

Organisms that can’t make their own food. These organisms eat other producers and / or other consumers.

The process in which producers make their own food. CO2 + H2O + Sun (light energy) -> (yields) C6H12O6 (sugar) + O2 (oxygen)

The process of cells in which food is broken down to release energy. This is the reverse of photosynthesis. Example: In cells glucose and oxygen combine to release energy, carbon dioxide and water vapor.

A form of respiration that releases energy from glucose when no oxygen is present.