Chemistry of Life UEQ: How do the properties and structures of materials determine their uses? What determines the type and extent of a chemical reaction? 1. What is an atom? 2. What are isotopes? What makes an isotope radioactive? 3. What are the different types of chemical bonds? 4. What is the difference between an acid and a base? 1. Why is water considered a polar molecule? 2. What properties result from water’s polarity? General Chemistry Water Organic Molecules 1.What are organic polymers? 2.How are organic polymers made? 3.What is an enzyme? 4.What role does each play in homeostasis?

Warm UP! 1. What is an atom? 2. What are isotopes? What makes an isotope radioactive? 3. What are the different types of chemical bonds?

Chemical Basis for Life Chapter 6

Why do we need Chemistry in Biology? An understanding of biology requires a little knowledge of chemistry, and an understanding of chemistry requires a little knowledge of mathematics. It is important to know aspects of chemistry to make biology come alive. Modern biology overlaps with chemistry in explaining the structure and function of all cellular processes at the molecular level.

is made of atoms, which are the smallest particles of an element that still have all the properties of an element. is anything that takes up space and has mass.

 Living organisms require about 20 elements (There are 92 elements in nature and 19 made)  Oxygen, Carbon, Hydrogen, and Nitrogen make up more than 95% of the human body.  The other elements include: calcium, phosphorus, potassium, sulfur, chlorine, sodium, magnesium and many other trace elements (meaning they have a very small amount: iron, zinc, copper, etc)

 Smallest amount of an element  Made up of 3 subatomic particles ◦ Neutrons (o) = neutral/no charge ◦ Protons (+) = positive charge ◦ Electrons (-) = negative charge

Protons and Neutrons are found in the nucleus of the atom. Why is this important and what does it have to do with biology?.  Electrons are in motion in the space around the nucleus. # E- = # P+

The positive charge from the Proton and the Negative charge from the electron balance out the charge of the atom. These charges are what eventually aid in forming combinations of atoms- or chemical compounds …for example: water is made from Hydrogen and Oxygen.

Proton (+) Electron (-) Neutron (o)  The electron is attracted to it’s opposite charge (the proton +) so it remains in orbit around the nucleus, but it plays “hard to get” by maintaining a velocity that is fast enough that it’s never pulled into the nucleus. The neutron is there to support the nucleus but it never gets involved.

Isotopes …say an atom is missing a neutron or has an extra neutron. That type of atom is called an isotope. An atom is still the same element if it is missing an electron. The same goes for isotopes. They are still the same element. They are just a little different from every other atom of the same element. If we look at the C-14 atom one more time we can see that C-14 does not last forever. There is a point where it loses those extra neutrons and becomes C-12. That loss of the neutrons is called radioactive decay. For carbon, the decay happens in a couple of thousand years.

Chemical compounds are formed by chemical bonds. Atoms either lose electrons, gain electrons or share their electrons in order to form a bond with other atoms.

Atoms that lose or gain and electrons are called ions Gain electrons = negatively charged ion Loose electrons = positively charged ion The opposite charges attract and form a bond called an ionic bond. These bonds exchange electrons.

Click on diagram to See animation Example: Na+Cl- Na loses an electron Cl gains an electron

Covalent bonds form when atoms share their electrons instead of exchanging them. Example: Click on covalent Bond to see video

H and O form a covalent bond that creates the molecule water.

Chemical Reactions: Acids and Bases Chemical reactions can only take place in the right environment. Chemical reactions depend on the proper pH of the environment within the organism. pH is the measure of how acidic or basic a solution is.

pH Substances below a pH of 7 are considered acidic Substances above a pH of 7 are considered basic Substances around a pH of 7 are considered neutral

pH Activity!