Chapter 2 - The chemical context of life. In this chapter, you should now be able to: Identify the four major elements; distinguish between the following pairs of terms: neutron and proton, atomic number and mass number, atomic weight and mass number; distinguish between and discuss the biological importance of the following: nonpolar covalent bonds, polar covalent bonds, ionic bonds, hydrogen bonds, and van der Waals interactions. | Chapter 2 The Chemical Context of Life Overview: A Chemical Connection to Biology Biology is a multidisciplinary science. Living organisms are subject to basic laws of physics and chemistry. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Matter consists of chemical elements in pure form and in combinations called compounds Organisms are composed of matter. Matter is anything that takes up space and has mass. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Elements and Compounds Matter is made up of elements. An element is a substance that cannot be broken down to other substances by chemical reactions. A compound is a substance consisting of two or more elements in a fixed ratio. A compound has characteristics different from those of its elements. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The emergent properties of a compound Sodium Chlorine Sodium chloride Figure The emergent properties of a compound Essential Elements of Life: C H O N About 25 of the 92 elements are essential to life. Carbon, hydrogen, oxygen, and nitrogen make up 96% of living matter. Most of the remaining 4% consists of calcium, phosphorus, potassium, and sulfur. Trace elements are those required by an organism in minute quantities. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Human Body Table 2-1 (a) Nitrogen deficiency (b) Iodine deficiency The effects of essential-element deficiencies Figure The effects of essential-element deficiencies An element’s properties depend on the structure of its atoms Each element consists of unique atoms. An atom is the smallest unit of matter that still retains the properties of an element. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Subatomic Particles Atoms are composed of subatomic particles. Relevant subatomic particles include: Neutrons (no electrical charge) Protons . | Chapter 2 The Chemical Context of Life Overview: A Chemical Connection to Biology Biology is a multidisciplinary science. Living organisms are subject to basic laws of physics and chemistry. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Matter consists of chemical elements in pure form and in combinations called compounds Organisms are composed of matter. Matter is anything that takes up space and has mass. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Elements and Compounds Matter is made up of elements. An element is a substance that cannot be broken down to other substances by chemical reactions. A compound is a substance consisting of two or more elements in a fixed ratio. A compound has characteristics different from those of its elements. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The emergent properties of a compound Sodium Chlorine Sodium chloride Figure The emergent
