BIOM 121 1st Edition Lecture 1Outline of Last Lecture I. No Previous LectureOutline of Current Lecture II. Matter Consists of Chemical Elementsa. Elements and CompoundsIII. Structure of an Atoma.Subatomic Particlesb.IsotopesCurrent LectureMatterI. Organisms are composed of matter.a. Matter is anything that takes up space and has massII. Matter is made up of elements.a. An element is a substance that cannot be broken down to other substances by chemical reactions.b. A compound is a substance that consists of two or more elements in a fixed ratio.III. The Elements of Lifea. 20-25 % of the 92 elements are essential for life. Carbon, hydrogen, oxygen, and nitrogen make up 96% of living matter.b. Trace Elements are elements that are required by an organism in small quantities.i. Examples include calcium, phosphorous, potassium, and sulfur.c. Some elements can be toxic, like arsenic, but some species have adapted to the environment that contain these elements.The Structure of an AtomI. All elements consist of atoms. An atom is the smallest unit of matter that still retains the properties on an element.a. Atoms are composed of smaller particles called subatomic particles.i. Neutrons (Neutral charge)ii. Protons (Positive Charge)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.iii. Electrons (Negative Charge)b. Neutrons and protons are in the center of the atom and form the nucleus.c. Electrons are located outside the nucleus and form a cloud.II. Atoms of all of the various elements have different numbers of subatomic particles.a. Atomic Number = # of Protonsb. Mass Number = Neutrons + Protonsc. Atomic Mass = can be approximated by the mass numberIII. Isotopesa. While all atoms of a specific element have the same number of protons, they may differ in their number of neutrons. Two atoms of an element that have different numbers of neutrons are called Isotopes.b. Radioactive Isotopes are isotopes that decay spontaneously and they give off particles and energy as they decay.Uses of radioactive isotopesi. Dating Fossilsii. Tracing atoms through metabolic processesiii. Diagnosing medical
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