CHEMICAL BASIS OF LIFE, CHAPTER 2
- All life is composed of matter
• It’s the “stuff”.
- Matter composed of chemical elements
- Element= any substance that cannot be broken down into other substances by chemical
- every element has unique chemical properties
Ex: carbon (C), oxygen (O), iron (Fe)
- there are 92 naturally occurring elements; 25 are essential to life
- water is 96% of body, carbon 18.5%, hydrogen 9.5%, nitrogen 3%, 4% other elements
- trace elements= element requires in very tiny quantities, but indispensable (crucial) for life.
- deficiency of trace elements results in abnormal functioning of organs, glands, etc.
- may prevent essential life processes from occurring
MOLECULES & COMPOUNDS
- molecule: 2 or more atoms held together (ex: O2, CO) (covalent)
- compound: substance composes of 2 or more different atoms in fixed ratio (ionic)
- organic compounds: compounds synthesized by cell and containing carbon (C)
- nucleus contains protons & neutrons, and the electrons orbit around the core. They don’t s