The Chemical Context of Life

Elements & Compounds Organisms are made up of matter. Matter is anything that takes up space and has mass. Matter is made up of elements. Elements are substances that cannot be broken down to other substances. There are about 92 natural elements recognized by chemists today. http://www.ptable.com/

Key Concepts Matter Consists of chemical elements in pure form and in combinations called compounds. Atoms are the smallest unit of matter. An element’s properties depend on the structure of its atoms. Chemical reactions make and break chemical bonds between elements.

Elements & Compounds A Compound is a substance consisting of 2 or more different elements combined in a fixed ratio. NaCl table salt (1:1 ratio) is edible. Pure Sodium (Na) is a metal Chlorine (Cl) is a toxic gas A compound has characteristics different from those of its elements

Essential Elements of Life 25 elements are known to be essential to life. 4 of these elements make up 96% of all living matter. Carbon – (C) Oxygen – (O) Hydrogen – (H) Nitrogen – (N) Phosphorus – (P)

Essential Elements of Life Potassium, Sulfur, Calcium, Phosphorous, Sodium and a few others account for the other 4% Trace Elements – required by organisms in minute quantities Some trace elements such as iron (Fe) are needed for all forms of life. Others are needed only by certain species.

Elements Each element consists of a certain kind of atom that is different from the atoms of any other element. Atom – smallest unit of matter that retains the properties of the element.

Subatomic Particles Atoms are composed of smaller parts called subatomic particles. Neutrons Protons Electrons

Neutrons and Protons are found in the center of the atom, the atomic nucleus.

Electrons – move at almost the speed of light form a cloud around the nucleus.

Electrons have a negative charge Protons have a positive charge Neutrons are electrically neutral

Atomic Number Also known as the proton number The number of protons found in the nucleus of an atom Equal to the number of electrons of a particular atom

Atomic Weight The atomic weight is the average mass of the isotopes of the element. It is the sum of the mass of the protons and neutrons in the nucleus.

Macromolecules What is a macromolecule?

Macromolecules What is a macromolecule? A very large molecule made up of many smaller molecules Macromolecules = Polymers Smaller molecules that make up macromolecules = monomers

Bohr Model

Trace Elements Nitrogen Deficiency

Isotopes Isotopes are atoms of the same element(those with equal numbers of protons) that have different numbers of neutrons and therefore different masses. For example 12C and 14C are isotopes of carbon. Both have 6 protons and are therefore carbons atoms, but carbon-12 has 6 neutrons while carbon- 14 has 8 neutrons.

Trace Elements Iodine deficiency

Isotopes

Radioactivity  emission of energy rays (electrons alpha particles), from unstable atomic nuclei or from a nuclear reaction.

Radioisotopes Irene Joliot- Curie Madame Marie Curie

Radioactive Isotopes  A medical isotope is a very small amount of radioactive material used to perform nuclear medicine imaging tests. Different formulations of isotopes are injected into patients, where they give off energy that is read by special cameras. They are crucial to helping doctors diagnose major diseases like heart disease and cancer.

Radioisotopes in Medicine

PET Scan

Cancer Treatments Radiation therapy uses high energy x-rays to kill or shrink cancer cells. The radiation may come from outside the body or from radioactive materials placed directly into or near the tumor.