BIO 111 Lecture Notes - Lecture 1: Gaiters, Thyroid, Atomic Number
Friday, September 11, 2015
The Chemistry of Life
Biochemistry: the structure and function of biological molecules
Cytology: the structure of cellular components
Genetics: heredity
Elements & Compounds
•Matter is made up of elements
•An element is a substance that can not be broken down by a chemical reaction
•A compound is an element that consists of 2 or more elements
Elements of Life
•Trace elements are those required by an organism
Example: Iodine, without it the body develops gaiters (swelling of the thyroid gland)
because it is inefficient in the body
96% of the body is made up of:
~Oxygen
~Carbon
~Hydrogen
~Nitrogen
An elements properties depend of 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
Subatomic Particles
•Atoms are composed of them
•Subatomic particles include neutrons (no charge), protons (positive charge) and
electrons (negative charge).
Atomic Number & Mass
•Atoms of the various elements amount of subatomic particles differ
!1
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Friday, September 11, 2015
•An atoms atomic number is the amount of protons in its nucleus
•An elements mass number is the sum of the protons plus the neutrons in its nucleus
Isotopes
•Iso - equal
•Tope - place
•Therefore an isotope is an element that is located at the same place as another on
the periodic table
•Atoms of an element have the same amount of protons but have different number of
neutrons
•An isotope are 2 atoms of an element that differ in the amount of neutrons
•Radioactive isotopes decay spontaneously, giving off particles & energy
Energy Levels of Electrons
•Energy is the capacity used to cause change
•Potential energy is the energy that matter has because of its location and/or structure
•Electrons of an atom differ in their amounts of potential energy
•An electrons state of potential energy is called its energy level, or electron shell.
Excitation of Electrons
•Electrons within a green photosynthetic pigment (chlorophyll) can be excited by a
photon of invisible light.
Electron Distribution & Chemical Propreties
•An atoms chemical behaviour depends non its distribution of electrons amongst its
outermost shell
•Valence electrons are those on the outermost shell, also known as the valence shell
•Elements with a full valence shell are inert
Chemical Reactions
•Atoms are most stable when their valence shell is full
•Most atoms don’t have full valence shells
!2
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Document Summary
Biochemistry: the structure and function of biological molecules. Elements & compounds: matter is made up of elements, an element is a substance that can not be broken down by a chemical reaction, a compound is an element that consists of 2 or more elements. Elements of life: trace elements are those required by an organism. Example: iodine, without it the body develops gaiters (swelling of the thyroid gland) because it is inef cient in the body. 96% of the body is made up of: An elements properties depend of 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. Subatomic particles: atoms are composed of them, subatomic particles include neutrons (no charge), protons (positive charge) and electrons (negative charge). Atomic number & mass: atoms of the various elements amount of subatomic particles differ.
