Lecture Campbell biology (9th edition) - Chapter 2: The chemical context of life. This chapter presents the following content: Matter consists of chemical elements in pure form and in combination called compounds, an element's properties depends on the structure of its atoms, the formation and function of molecules depend on chemical bonding between atoms, chemical reaction make and break chemical bonds. | The Chemical Context of Life Chapter 2 Concept : 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 © 2011 Pearson Education, Inc. 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 © 2011 Pearson Education, Inc. Figure Sodium Chlorine Sodium chloride Figure The emergent properties of a compound. The metal sodium combines with the poisonous gas chlorine, forming the edible compound sodium chloride, or table salt. The Elements of Life About 20–25% 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, . | The Chemical Context of Life Chapter 2 Concept : 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 © 2011 Pearson Education, Inc. 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 © 2011 Pearson Education, Inc. Figure Sodium Chlorine Sodium chloride Figure The emergent properties of a compound. The metal sodium combines with the poisonous gas chlorine, forming the edible compound sodium chloride, or table salt. The Elements of Life About 20–25% 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 © 2011 Pearson Education, Inc. Table Table Elements in the Human Body Concept : 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 © 2011 Pearson Education, Inc. Subatomic Particles Atoms are composed of subatomic particles Relevant subatomic particles include Neutrons (no electrical charge) Protons (positive charge) Electrons (negative charge) © 2011 Pearson Education, Inc. Neutrons and protons form the atomic nucleus Electrons form a cloud around the nucleus Neutron mass and proton mass are almost identical and are measured in daltons © 2011 Pearson Education, Inc. Figure Cloud of negative charge (2 electrons) Electrons Nucleus (a) (b) Figure Simplified models of a helium (He) atom. The helium nucleus .
