Chapter 2 [8_31 - 9_5].docx

Chapter 2 [8_31 - 9_5].docx - The Chemical Context of Life...

This preview shows page 1 - 2 out of 6 pages.

The Chemical Context of Life Basic Concepts All life is built from combinations of chemical elements Elements : Pure form of chemicals Molecules : Combinations of elements Atomic Structure Chemical bonding between atoms creates molecules Chemical reactions break and make chemical bonds Elements and Compounds All life is composed of matter , which is anything that takes up space and has mass, which is made up of elements . Element : a substance that cannot be broken down to other substances by chemical reactions. Compound : a substance consisting of two or more elements in a fixed ratio. Emergence : At higher levels of structure molecular function is determined by the nature of the building blocks of each molecule. A compound has characteristics different from those of its elements. Primary Elements in the Human Body. Element Symbol Percentage of Body Mass + H20 Oxygen O 65.0% Carbon C 18.5% Hydrogen H 9.5% Nitrogen N 3.3% Calcium Ca 1.5% Phosphorus P 1.0% Potassium K 0.4% Sulfur S 0.3% Sodium Na 0.2% Chlorine Cl 0.2% Magnesium Mg 0.1% The primarily used atoms for Biology are atoms #1-18. Atomic Structure
Image of page 1

Subscribe to view the full document.

Structure Mass Charge Protons 1 daltons +1 Electrons 0 -1 Neutrons 1 daltons 0 Atoms have Protons, Neutrons, and Electrons. The Identity of an atom is based on the number of protons and neutrons contained in the nucleus. The number of electrons determine the electronegativity, and reactivity of an atom. Atomic Number: Number of protons in an atom. Defines the element. Element Symbol: The symbol used to represent the atom. Atomic Mass: Mass of atom. (# Protons + # Neutrons). Calculated in Daltons # Protons = # Electrons Taking electrons/ sharing, alters the atoms charge. Changing The Number of Neutrons Isotopes : Two forms of the same element with different numbers of neutrons in their nuclei.
Image of page 2
You've reached the end of this preview.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern