The Chemical Basis Of Life

Submitted By hedhall12
Words: 550
Pages: 3

Biology 240-75
Professor Rabin
Chapter 2
SI Leader: Jeannette Oropilla

CHAPTER TWO: The Chemical Basis of Life

What is an element?

Many elements are important in biological systems, but what are Biology's four most important elements? Also know as the essential elements.

What exactly is an atom?

What subatomic particles make up an atom?

What is the difference between atomic number and mass number?

What is an isotope?

Carbon dating is a way to determine the age of an object by measuring the amount of 14C that has decayed. How many protons and neutrons does 14C have? What about 13C and 12C?

What about an atom determines it's charge?

Explain the location of the electron orbitals of an atom. How many electrons can fill the first shell? How many are needed to fill the second? What are the valence electrons?

Why are the noble or inert gases in the last column of the periodic table distinctive?

Atoms that are not noble/inert will react to become like the inert atoms by forming bonds. Describe the different types of bonds:

1. Covalent Bond



triple: polar:


What is electronegativity?

2. Ionic Bond

What is an ion? If you have an atom with one more electron than it has protons, is it negatively or positively charged?

3. Hydrogen Bond

What molecular shape does water represent? Why is molecular structure important to the function of a living cell?

Practice Questions:

1) In atoms of one particular element, one or more __________ could be added to or removed from the atom, without causing the atom to be changed into another element.

a. protons
b. neutrons
c. electrons
d. protons or neutrons
e. electrons or neutrons

2) A cation with two units of charge has 10 neutrons and 8 protons. The ion also has:

a. 10 electrons
b. 8 electrons
c. 12 electrons
d. 6 electrons
e. 14 electrons

3) When an atom or molecule, such as chlorophyll, emits light, one or more