Name:_____________________________ Date:_____________ Period:_________
Chapter 6 – Chemistry in Biology
Section 1: Atoms, Elements, and Compounds
Section 2: Chemical Reactions
Section 3: Water and Solutions
Section 4: The Building Blocks of Life
6.1 Atoms, Elements, and Compounds
Atoms:


Chemistry is the study of _______________.
____________ are the building blocks of matter.
 _____________ and _____________ are located at the center of the atom.
 Protons are _____________ charged particles
 Neutrons are particles that have ______________________.
 Electrons are _____________ charged particles that are located outside the
nucleus.
Elements
An element is a ____________________that cannot be broken down into other
substances by physical or chemical means.
 There are over 100 known elements, ________ of which occur naturally.
 Each element has a unique name and symbol.
 The Periodic Table of Elements
o Horizontal rows are called ______________.
o Vertical columns are called ______________.
Isotopes
 Atoms of the same element that have the _____________ number of protons and
electrons but have a _____________ number of neutrons

Radioactive Isotopes
When a _____________ breaks apart, it gives off radiation that can be
1
detected and used for many applications.
Compounds



A pure substance formed when two or more _____________ elements combine
Compounds are always formed from a specific combination of elements in a fixed ratio.
Compounds cannot be broken down into simpler compounds or elements by ____________
means.
o List some physical changes that can be made to compounds without change:
Chemical Bonds
1) Covalent bonds - Chemical bond that forms when electrons are ____________
a. A molecules is a compound in which the atoms are held together by covalent bonds
2) Ionic Bonds
a. Ionic Bonds - Electrical attraction
between two oppositely charged
atoms or groups of atoms
b. Some atoms tend to donate or
accept electrons more easily than
other atoms.
The elements identified as metals
tend to ____________ electrons.
The elements identified as nonmetals tend to __________ electrons.
c. Most ionic compounds are _________________ at room temperature and have
higher melting points than molecular compounds formed by covalent bonds.
3) van der Waals Forces
a. When molecules come close together, the ______________ forces between
slightly positive and negative regions pull on the molecules and hold them together.
b. The ____________ of the attraction depends on the size of the molecule, its
shape, and its ability to attract electrons. The ability of geckos to climb on sheer
surfaces is attributed to van der Waals force. A gecko can hang on a glass surface
using only one toe.
c. It is important to remember that van der Waals' forces are forces that exist
between MOLECULES of the same substance. (two H2O molecules – H-bonding)
6.2 Chemical Reactions
A chemical reaction is the process by which atoms or groups of atoms in substances are
reorganized into different substances.
 Clues that a chemical reaction has taken place include the production of heat or light, and
formation of a gas, liquid, or solid.
 4Fe + 3O2 = 2Fe2O3. A chemical reaction occurs when atoms join together or break apart
to form new and different combinations of atoms
iron + water
Fe
+
H2O
+
air
+
O2
=
rust
Fe2O3
Chemical Equations
Chemical formulas describe the substances in the reaction and arrows indicate the process of
change. __________________ are the starting substances, on the left side of the arrow
2

__________________ are the substances formed during the reaction, on the right side
of the arrow (draw)
Glucose and oxygen react to form carbon dioxide and water. (write out a generalized
reaction for aerobic respiration)
Balanced Equations


The ___________________________states matter cannot be created or destroyed.
The _______________ of atoms of each element on the ______________ side must
equal the ___________ of atoms of the same element on the ___________ side. Write
out the balanced equation for aerobic respiration.
Energy of Reactions

The _________________ energy is the minimum amount of energy needed for reactants
to form products in a chemical reaction.
This reaction is _________________ and released heat
energy.
The energy of the ___________ is __________ than
the energy of the reactants.
This reaction is ________________ and absorbed heat
energy
 The energy of the ____________ is
__________ than the energy of the reactants.
Enzymes
A _____________ is a substance that lowers the
activation energy needed to start a chemical reaction.
Enzymes are usually proteins.
Enzymes does not increase _____________ product is
made and it does not get _____________ in the reaction.
Enzymes are biological catalysts, usually made of proteins.
3


The reactants that bind to the enzyme are called ____________________.
The specific location where a substrate binds on an enzyme is called the
_________________

The _________________
changes shape and forms the
enzyme-substrate complex, which
helps chemical bonds in the
reactants to be broken and new
bonds to form.
Factors such as ___________, __________________, and other _________________
affect enzyme activity.

6.3 Water and Solutions
Water and Polarity
Molecules that have an unequal distribution of charges are called polar molecules.
______________ is the property of having two opposite poles. (positive and negative)
A hydrogen bond is a weak interaction involving a hydrogen atom and a fluorine, oxygen, or
nitrogen atom
Homogenous Mixtures
A mixture that has a uniform composition throughout
A ________________is a substance in which another substance is dissolved
A ________________ is the substance that is dissolved in the solvent.
Heterogeneous Mixtures

In a ______________________mixture, the components remain distinct.
Acids and Bases
Substances that release _________________ (H+) when dissolved in water are called acids.
Substances that release _________________ (OH–) when dissolved in water are called bases.
 The measure of concentration of H+ in a solution is called pH.
 Acidic solutions have pH values________ than 7, which means higher H+ concentration.
 Basic solutions have pH values _________ than 7, which means lower H+ concentrations.
 ___________________ are mixtures that can react with acids or bases to keep the pH
within a particular range.
4
6.4 The Building Blocks of Life
Organic Chemistry




The element __________ is a component of almost all biological molecules.
Carbon has four electrons in its outermost energy level.
One carbon atom can form _____________________ with other atoms.
Carbon compounds can be in the shape of:
straight chains, branched chains, or rings.
Macromolecules



Carbon atoms can be joined to form carbon molecules.
________________________ are large (__________) molecules formed by joining
smaller organic molecules together
___________________are molecules made from repeating units of identical or nearly
identical compounds linked together by a series of covalent bonds.
Table of Biological Macromolecules
Group
Function










Stores energy
Provides structural support
Stores energy
Provides steroids
Waterproofs coatings
Transports substances
Speeds reactions
Provides structural support
Provides hormones
Stores and communicates genetic information
Carbohydrates






Compounds composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two
hydrogen atoms for each carbon atom—(CH2O)n
Values of n ranging from three to seven are called simple sugars, or monosaccharides.
Two _____________________ joined together form a ________________.
Longer carbohydrate molecules are called __________________.
Animals store energy as ____________ in liver and muscle cells for immediate energy.
Do you think glycogen would be a monosaccharide or a polysaccharide?
Plants store energy as starch. Do you think glycogen would be a monosaccharide or a
polysaccharide?
Lipids



Molecules made mostly of carbon and hydrogen
A triglyceride lipid is a fat if it is solid at room temperature and oil if it is liquid at room
temperature.
Lipids that have tail chains with only single bonds between the carbon atoms are called
__________________ (less healthy).
5

Lipids that have at least one double bond between carbon atoms in the tail chain are called
___________________ fats (more healthy unless partially hydrogenated like “transfats” then very unhealthly). Fats with more than one double bond in the tail are called
polyunsaturated fats.
Proteins





Are made of monomers called ________________.
Amino acids are small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and
sometimes sulfur.
Amino acids have a central carbon atom. One of the four carbon bonds is with hydrogen.
The other three bonds are with an amino group (–NH2), a carboxyl group (–COOH), and a
variable group (–R).
The number and the order in which the amino acids are joined define the protein’s
__________ structure. After an amino acid chain is formed, it folds into a unique threedimensional shape, which is the protein’s _______________ structure.
Essential amino acids
•
•
•
Humans can produce _____of the 20 amino acids. The others must be supplied in the food.
Failure to obtain enough of even 1 of the 10 essential amino acids, those that we cannot
make, results in ________________of the body's proteins—muscle and so forth—to
obtain the one amino acid that is needed.
Unlike fat and starch, the human body does not store excess ________________ for
later use—the amino acids must be in the food every day.
Nucleic acids
Nucleic acids are complex macromolecules that store and transmit genetic information
 Nucleic acids are made of smaller repeating subunits called nucleotides, composed of
carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms.
DNA: ___________________________
RNA: ___________________________
• DNA contains four different nucleotide bases: _______________(A),
______________(C), ______________ (G), and ________________ (T).
• RNA contains the bases adenine (A), cytosine (C), and guanine (G); however, RNA does not
contain thymine, instead, RNA's 4th nucleotide is the base ________ (U).
• Unlike the double-stranded __________molecule, _______ is a single-stranded molecule.
Diagnostic Questions
1) Which of the following particles is negatively charged?
2) Isotopes are created by a change in the number of what particle of an atom?
3) Identify the proteins that speed up the rate of chemical reactions.
4) What particles are in an atom’s nucleus?
5) What causes the overall charge of an atom to be zero?
6) What type of substance is water?
7) What provides the energy for all living processes?
6
8) Which is a chemical reaction?
9) Which chemical reaction is endothermic?
10) How does an enzyme increase the rate of a chemical reaction?
11) Why is water able to dissolve a wide variety of solutes?
12) What type of bonds attracts water molecules to each other and to other substances?
13) Which ion, when released in water, causes a solution to be basic?
14) What is the name for a substance that keeps the pH in cells within the 6.5 to 7.5 pH
range?
15) Which element do almost all biological molecules contain?
16) How many covalent bonds can carbon form with other atoms?
17) What type of biological molecule is an enzyme?
18) What are fats, oils, and waxes composed of?
19) What are the monomers that make up proteins?
20) Which biological molecule transports substances between cells?
21) Look at the following figure. Determine what the upward curve represents.
?
22) Explain why chemical equations must be balanced.
23) Which is a result of van der Waals forces?
24) What is true of this chemical reaction?
7
25) Which fruit contains a higher concentration of hydrogen ions?
26) What do cellulose and chitin have in common?
27) Which polysaccharide stores energy in muscle and liver tissue?
28) What is the function of this biological macromolecule?
29) Which is a characteristic of all lipids?
8