Chapter 2: Section 3 Chemistry of Cells Most matter in your body that is NOT water is made of organic compounds. 4 Principle Classes of Organic Compounds: Carbohydrates Lipids Proteins Nucleic Acids

Carbohydrates Made up of Carbon, Hydrogen, and Oxygen atoms Key source of energy Found in foods such as Fruits, Vegetables, and Grains.

Sugars Disaccharides –2 or more sugars Monosaccharides Polysaccharides – such as starch, are chains of 3 or more monosaccharides. Monosaccharides The building blocks of carbohydrates. Single sugars such as glucose and fructose.

Lipids Lipids are nonpolar molecules that are NOT soluble or mostly insoluble in water. Include Fats, Phospholipids, Steroids, & Waxes Important in the structure & function of cell membranes.

Lipids Fats are lipids that store energy.

Protein/ Amino Acids Amino acids are the building blocks of proteins. Some proteins are enzymes. The protein, collagen, is found in skin, ligaments, tendons, and bones Your hair and muscles contain proteins Proteins called antibodies help your body defend against infection.

Foods as Fuels Most foods contain a mixture of carbohydrates, proteins, and fats. Your body’s cells harvest the energy in food molecules for metabolism.

Nucleic Acids All of your cells contain nucleic acids Two types: DNA RNA

ATP The ATP molecule stores energy when food molecules are broken down inside cells. Cells need a steady supply of ATP to function.

Section 3 Energy is the ability to move or change matter. Energy is in Food Energy exists in many forms Light Heat Chemical and mechanical energy Electrical energy

Energy Chemical Reactions absorb or release energy. Starting a chemical reactions requires activation energy. Metabolism –describes all of the chemical reactions that occur within an organism.

Activation Energy Activation energy is a “push” that starts a chemical reaction.

ENZYMES Enzymes are substances that increase the speed of a chemical reaction. Enzymes help organisms maintain homeostasis. Without enzymes, chemical reactions would not occur quickly enough to sustain life.

Enzymes Substrate – a substance on which an enzyme acts during a chemical reaction. Enzymes act ONLY on specific substrates. An enzyme’s shape determines its activity.

Enzymes Factors such as temperature and pH affect enzyme activity.

Energy and Chemical Reactions