I. All living things are made up of four classes of ______________: carbohydrates,
lipids, proteins, and nucleic acids
a. Within cells, small organic molecules are joined together to form
larger molecules
i. Macromolecules are large molecules composed of thousands of
covalently connected atoms
ii. Molecular structure and function are inseparable
II. Concept 5.1: Macromolecules are polymers, built from monomers
a. A ______________: is a long molecule consisting of many similar or
identical building blocks
b. These small building-block molecules are called ______________:
c. Three of the four classes of life’s organic molecules are polymers:
i. Carbohydrates
ii. ____________________________
iii. Nucleic acids
d. When two monomers bond together through the
__________________________________________ molecule a condensation
reaction or more specifically a ___________________reaction
i. Enzymes are macromolecules that speed up the dehydration
process
e. Polymers are disassembled to monomers by ___________________, a
reaction that is essentially the ___________________of the dehydration
reaction
f. Each cell has thousands of different kinds of macromolecules
i. Macromolecules vary among cells of the
___________________organism, vary more within a species, and
vary even more between species
ii. An immense variety of polymers can be built from a small set
of monomers
iii. These monomers can be connected in many combinations, just
as ___________________in the alphabet are used to create words.
Lecture Questions 5.1 The Molecules of Life
1. List the four major classes of macromolecules.
III. Concept 5.2: Carbohydrates serve as fuel and building material
a. Carbohydrates include sugars and the polymers of sugars
i. The simplest carbohydrates are monosaccharides, or single
sugars
ii. Carbohydrate macromolecules are polysaccharides, polymers
composed of many sugar building blocks
b. ___________________have molecular formulas that are usually multiples of
___________________
i. Glucose (C6H12O6) is the most common monosaccharide
ii. Monosaccharides are classified by
1. The location of the carbonyl group (as
___________________or ___________________)
2. The number of carbons in the carbon skeleton
a. Though often drawn as linear skeletons, in
aqueous solutions many sugars form
___________________
c. Monosaccharides serve as a major fuel for cells and as raw material
for building molecules
d. A disaccharide is formed when a dehydration reaction joins two
monosaccharides
i. This covalent bond is called a glycosidic linkage
e. Polysaccharides, are polymers of hundreds and thousands of
___________________, have storage and structural roles
i. The structure and function of a polysaccharide are determined
by its sugar monomers and the positions of glycosidic linkages
1. ___________________, a storage polysaccharide of plants,
consists entirely of glucose monomers
2. Plants store surplus starch as granules within
chloroplasts and other plastids. Animals that feed on
those plants have digestive enzymes that
___________________the starch to glucose.
3. ___________________is a storage polysaccharide in animals
a. Humans and other vertebrates store glycogen
mainly in liver and muscle cells
ii. The polysaccharide ___________________is a major component of
the tough wall of plant cells
1. Like starch, cellulose is a polymer of glucose, but the
glycosidic linkages differ
a. The difference is based on two ring forms for
glucose: alpha () and beta ()
i. Polymers with  glucose are helical
ii. Polymers with  glucose are straight
2. Enzymes that digest starch by hydrolyzing  linkages
can’t hydrolyze  linkages in cellulose
3. Cellulose in human food passes through the digestive
tract as ______________________ ________________
4. Some microbes use enzymes to digest cellulose
5. Many herbivores, from cows to termites, have symbiotic
relationships with these cellulose-digesting
___________________.
iii. ___________________, another structural polysaccharide, is found in
the exoskeleton of arthropods
1. Chitin also provides structural support for the
___________________ ___________________of many fungi
Lecture Questions 5.2 Carbohydrates Serve as Fuel and Building Material
1. Distinguish between the glycosidic linkages found in starch and cellulose. Explain
why the difference is biologically important.
IV. Concept 5.3: Lipids are a diverse group of hydrophobic molecules
a. Lipids are the one class of large biological molecules that do not form
polymers
b. The unifying feature of ___________________is having little or no affinity
for water
i. Lipids are ___________________because they consist mostly of
hydrocarbons, which form nonpolar covalent bonds
ii. The most biologically important lipids are fats, phospholipids,
and steroids
c. ___________________are constructed from two types of smaller molecules:
___________________and ___________________ ___________________
i. Glycerol is a three-carbon alcohol with a hydroxyl group
attached to each carbon
ii. A fatty acid consists of a carboxyl group attached to a long
carbon skeleton
iii. Fats separate from water because water molecules form
hydrogen bonds with each other and exclude the fats
1. In a fat, three fatty acids are joined to glycerol by an
ester linkage, creating a ___________________, or triglyceride
iv. Fatty acids vary in length (number of carbons) and in the
number and locations of double bonds
v. ___________________ ___________________ ___________________ have the
maximum number of hydrogen atoms possible and no double
bonds
vi. ___________________ ___________________ ___________________ have one
or more double bonds
1. Fats made from saturated fatty acids are called
saturated fats, and are solid at room temperature
2. Most animal fats are saturated
3. Fats made from unsaturated fatty acids are called
unsaturated fats or oils, and are liquid at room
temperature
4. Plant fats and fish fats are usually unsaturated
5. A diet rich in saturated fats may contribute to
cardiovascular disease through plaque deposits
a. Hydrogenation is the process of converting
unsaturated fats to saturated fats by adding
hydrogen
b. Hydrogenating vegetable oils also creates
unsaturated fats with trans double bonds
c. These trans fats may contribute more than
saturated fats to cardiovascular disease
vii. The major function of fats is energy storage
1. Humans and other mammals store their fat in adipose
cells
2. Adipose tissue also cushions vital organs and insulates
the body
viii. In a ___________________, two fatty acids and a phosphate group
are attached to glycerol
1. The two fatty acid tails are hydrophobic, but the
phosphate group and its attachments form a
hydrophilic head
2. When phospholipids are added to water, they selfassemble into a bilayer, with the hydrophobic tails
pointing toward the interior
3. The structure of phospholipids results in a
___________________arrangement found in cell membranes
4. Phospholipids are the major component of all cell
membranes
d. Steroids are lipids characterized by a carbon skeleton consisting of
four fused rings
i. ___________________, an important steroid, is a component in
animal cell membranes
ii. Although cholesterol is essential in animals, high levels in the
blood may contribute to cardiovascular disease
Lecture Questions 5.3 Lipids are a Diverse Group of Hydrophobic Molecules
1. Describe the building-block molecules, structure, and biological importance of fats,
phospholipids, and steroids.
2. Distinguish between saturated and unsaturated fats
V. Concept 5.4: Proteins have many structures, resulting in a wide range of
functions
a. Proteins account for more than 50% of the dry mass of most cells
i. Protein functions include structural support, storage,
transport, cellular communications, movement, and defense
against foreign substances
b. ___________________are a type of protein that acts as a ___________________to
speed up chemical reactions
i. Enzymes can perform their functions repeatedly, functioning
as workhorses that carry out the processes of life
c. __________________ ___________________ are organic molecules with carboxyl
and amino groups
i. Amino acids differ in their properties due to differing side
chains, called R groups
ii. Amino acids are linked by ___________________ ___________________
1. Polypeptides are polymers built from the same set of 20
amino acids
2. A polypeptide is a polymer of amino acids
3. Polypeptides range in length from a few to more than a
thousand monomers
4. Each polypeptide has a unique linear sequence of amino
acids
5. A protein consists of one or more polypeptides
d. A functional protein consists of one or more polypeptides twisted,
folded, and coiled into a unique shape
i. The sequence of amino acids determines a protein’s threedimensional structure
ii. A protein’s structure determines its function
e. Four Levels of Protein Structure
i. The ___________________ ___________________ of a protein is its unique
sequence of amino acids
ii. Secondary structure, found in most proteins, consists of coils
and folds in the polypeptide chain
iii. Tertiary structure is determined by interactions among
various side chains (R groups)
iv. Quaternary structure results when a protein consists of
multiple polypeptide chains
f. Primary structure, the sequence of amino acids in a protein, is like the
order of letters in a long word
i. Primary structure is determined by inherited genetic
information
ii. Consists of ___________________and disulfide bonds.
iii. Even a _____________________ _________________in the primary
structure can affect a protein’s ability to function
g. The coils and folds of ___________________ ___________________ result from
hydrogen bonds between repeating constituents of the polypeptide
backbone
i. Typical secondary structures are a coil called an
___________________ ___________________and a folded structure called
a ___________________ ___________________
h. ___________________ ___________________ is determined by interactions
between R groups, rather than interactions between backbone
constituents
i. These interactions between R groups include hydrogen bonds,
ionic bonds, hydrophobic interactions, and van der Waals
interactions
ii. Strong covalent bonds called ___________________ ___________________
may reinforce the protein’s structure
i.
___________________ ___________________ results when two or more
polypeptide chains form one macromolecule
i. Collagen is a fibrous protein consisting of three polypeptides
coiled like a rope
ii. Hemoglobin is a globular protein consisting of four
polypeptides: two alpha and two beta chains
j. A slight change in primary structure can affect a protein’s
structure and ability to function.
i. Sickle-cell disease, an inherited blood disorder, results from a
single amino acid substitution in the protein hemoglobin
k. What Determines Protein Structure?
i. In addition to primary structure, physical and chemical
conditions can affect structure
1. Alterations in pH, salt concentration, temperature, or
other environmental factors can cause a protein to
unravel
2. This loss of a protein’s native structure is called
___________________
a. A denatured protein is biologically inactive
Lecture Questions 5.4
Proteins have Many Structures, Resulting in a Wide Range of Functions
1. Explain how a peptide bond forms between two amino acids.
2. List and describe the four major components of an amino acid. Explain how amino
acids may be grouped according to the physical and chemical properties of the R
group.
3. List four conditions under which proteins may be denatured.
VI. Concept 5.5: Nucleic acids store and transmit hereditary information
a. The amino acid sequence of a polypeptide is programmed by a unit of
inheritance called a gene
i. Genes are made of DNA, a ___________________ ___________________
ii. The Roles of Nucleic Acids
1. There are two types of nucleic acids:
a. ______________________________________
b. ______________________________________
iii. DNA provides directions for its own replication
iv. DNA directs synthesis of messenger RNA (mRNA) and, through
mRNA, controls protein synthesis
v. Protein synthesis occurs in ribosomes
b. In RNA, the sugar is ___________________; in DNA, the sugar is
___________________
i. The nitrogenous base pairs in RNA are ___________________; in
DNA they are ___________________
1. Nucleotide = nucleoside + phosphate group
c. Nucleic acids are polymers called ___________________
i. Each polynucleotide is made of monomers called
___________________
ii. Each nucleotide consists of a nitrogenous ___________________, a
pentose ___________________, and a ___________________group
iii. The portion of a nucleotide without the phosphate group is
called a nucleoside
d. Nucleoside = nitrogenous base + sugar
i. There are two families of nitrogenous bases:
1. ___________________ (cytosine, thymine, and uracil) have a
single six-membered ring
2. ___________________ (adenine and guanine) have a sixmembered ring fused to a five-membered ring
Lecture Questions 5.5 Nucleic Acids Store and Transmit Hereditary Information
1. List the major components of a nucleotide, and describe how these monomers are
linked to form a nucleic acid.
2. Distinguish between:
a. pyrimidine and purine
b. nucleotide and nucleoside
c. ribose and deoxyribose
d. 5 end and 3 end of a nucleotide