1. What is biology? Energy & Nutrients
Biology is the science that deals with the study of living organisms
Living organisms:
Have a life cycle (grow and reproduce)
Are composed of cells which, in turn, have DNA
Maintain homeostasis (by responding to external stimuli and via metabolism)
Catabolism (breakdown of substances) is exergonic (releases energy)
Anabolism (synthesis of substances) is endergonic (consumes energy)
Anabolism
Energy & Nutrients
Catabolism

2. What is biology?
Anatomy is the study of the organs and organ systems of a species
Physiology is the study of the processes that enable a species to maintain homeostasis
Genetics is the study of DNA and how it determines a species’/individual’s traits
Evolution is the study of how species genetically change over time
Ecology is the study of the interactions of organisms with their environment
Microbiology is the study of microscopic organisms
Cellular Biology is the study of cell organelles and processes
Molecular Biology is the study of the characteristics of cell macromolecules and their interactions with one another
Biochemistry is the study of the chemical makeup (atomic structure) of molecules involved in cellular processes and chemical reactions that involve them

3. Why do we need to know chemistry to understand biology?
Chemistry is the science that deals with the basic properties of matter, and is necessary to understand metabolism
Matter is everything that has volume and takes up space
What is the universe made of?
Matter
Energy
Empty Space
Dark Matter???

4. What are atoms? Matter is made out of atoms Nucleus
Protons – positively charged – 1 AMU (atomic mass unit)
Neutrons – no charge – 1 AMU
Electrons
Negatively charged (attracted to positive charge of nucleus)
Much smaller than protons and neutrons
Orbit nucleus at fixed distance called an orbital (2, 8, 8 Rule)
Move so fast they form a cloud or shell

5. What are atoms?
There are 92 different types of naturally occurring atoms (the remainder are synthetic and are unstable)
Matter that consists of only one type of atom is called an element and each type of atom (element) has its own chemical symbol
Each element is defined by the number of protons it has, which is its atomic number
Atomic number
Chemical Symbol

6. What are atoms? Fussion – two atoms combine
If you change the number of protons, the atom becomes a new element with a new atomic number
Fussion – two atoms combine
Fission – an atom splits into two
The energy emitted from stars, including our sun, comes from fusion

7. What are atoms?
Uncharged (neutral) atoms always have equal numbers of protons and electrons (so the atomic number tells you how many p+ and this is also the number of e- if the atom is neutral)
If the number of electrons changes because one or more electrons is lost or gained, the atom becomes an ion (charged)
Take away electrons  + charge (cation)
Add electrons  - charge (anion)
Electron lost
cation

9. What are atoms?
Valence electrons are the electrons in the outermost shell (orbital)
The number of valence electrons an atom has is determined by the rule of octets
1st orbital can hold 2 e-
2nd orbital can hold 8 e-
3rd orbital can hold 8 e-
Ions have different numbers of valence electrons than their non-ionic counterparts (Ex: O has 6 valence electrons but O- has seven)

10. What are atoms?
How many valence electrons does chlorine have? (atomic number 17)
How many valence electrons does Cl- have?

11. O Cl Mg H - Practice +2 + 8 Find the following for a given atom:
# of protons?
# of electrons?
# of valence electrons? - Cl 17 12 Mg +2 1 H +

12. What are atoms?
Ions are atoms that have a different number of electrons than protons
Isotopes are atoms that have a different number of neutrons than protons
Protons + neutrons = mass number (in “atomic mass units” or “amu”)
Isotopes are identified by their mass number (ex: carbon-12 versus carbon-13)
The atomic mass shown on the periodic table is an average of the mass of the isotopes of that element
Radioactive isotopes are unstable; they lose their extra neutrons at a constant rate The escaping neutrons = radiation (scientists can use this to date rocks, etc)
1 amu
2 amu
16 amu
17 amu