Pre AP Biology
SGN3 – Essential Chemistry for Biology
I. All matter is made of ______________, whether the matter is solid, liquid or gas
A. Matter has ___________ and takes up space
B. An atom has two basic parts (as far as biology is concerned)
1. The _______________ is a structure at the center of the atom
2. ________________ orbit the nucleus in a series of expanding electron orbitals
a. In biologically important atoms no more than __ electrons in the inner orbital, ___ in
most of the remaining orbitals
II. _____________________ are different kinds of atoms
A. Different kinds of atoms (elements) have _____________ of different size, and have a
different __________________ of electrons
1. The number of electrons an element has determines how it ___________ with other
elements
2. There are 5 primary elements necessary to build a cell; these are ___________,
______________, ________________, _________________ and _________________
3. In most living things about 20 other elements are also necessary, but in smaller amounts
(__________________ elements); examples of important trace elements are…
4. The _____________________ __________ is a chart that uses letters to symbolize
elements, and it organizes elements according to size
a. It also groups elements according to how they react with other elements
III. Elements join together with bonds to form compounds and larger structures
A. Bonds are interactions involving ___________________, which join two nuclei
B. A _______________________ is 2 or more atoms joined by certain types of bonds
C. There are two major types of bonds and 2 major types of compounds, and many
intermediate types
1. Ionic bonds create __________, or charged atoms or groups of atoms
a. These bonds form when an atom or group of atoms ________ electrons from another
atom
b. The electron acceptor takes on a ________________ charge while the electron donor
takes on a ______________ charge, forming an ionic bond between the two charged
atoms or groups of atoms
c. Nuclei involved in an ionic bond are attracted positive to negative charge but do not
have to be _____________ together
d. Important examples are ______________, _________________
2. Elements joined together with covalent bonds form __________________
a. These bonds form when nuclei _____________ electrons; nuclei must stay close
together
b. Molecules can include only two to _______________ of atoms
c. Important examples are _________, ___________, large proteins and strands of DNA
d. A covalent bond does not produce a _____________ but a molecule can be …
- completely _________________, with electrons shared equally
- polar, with unequal sharing of electrons and partial charge (see SGN 4)
- under different conditions parts of molecules can lose electrons and be charged
Please turn over
D. Multiple compounds are often drawn together by a variety of bonds to form large,
__________________________ complexes (See enzymes described in SGN6 or DNA
described in SGN14)
1. Hydrophilic and hydrophobic bonds will be described in SGN 4
IV. Important types of compounds are ______________ and ________________
A. Acids are compounds that will increase the concentration of ______________ ______(H+)
in solution
1. Hydrogen ions are ______________, so an acid tends to disrupt other compounds
2. An acidic solution is high in hydrogen ions (H+), measuring __________ 7 on the pH
scale
a. The pH scale indicates the ____________________________ of H+ in a solution
B. Bases are compounds that will ______________ the concentration of hydrogen ions in
solution, and increase the concentration of ____________________ ions (OH-)
1. Basic ions are reactive, so a base tends to disrupt other compounds
2. A basic solution is low in hydrogen ions, measuring _______________ 7 on the pH scale
C. A neutral solution (pH = 7) has an ______________ concentration of H+ and OHD. pH and biology
1. Maintaining the proper pH inside cells and organisms is an important part of __________
a. Improper pH disrupts chemical reactions and cellular structures
2. Environmental pH, especially in _________________ ecosystems, influences organismal
biochemistry
V. Compounds interact and recombine in chemical _________________________
A. In a chemical reaction ________________ are broken and reformed, elements are
rearranged and energy is transferred (See SGN9)
B. Chemical reactions are symbolized with chemical _____________________
1. Students should know how to read a chemical equation
C. In a chemical reaction _______________ are converted into ________________
1. But atoms are not created or destroyed; this is shown in a ________________ chemical
equation