Biochemistry
Chapters 4 & 5
A. The Importance of Carbon
• 1. Organic chemistry is the study of carbon
compounds
2. Carbon atoms are the most versatile
building blocks of molecules
3. Variation in carbon skeletons
contributes to the diversity of organic
molecules
Carbon atoms have unique
bonding properties.
• Carbon forms covalent bonds with up to
four other atoms, including other carbon
atoms.
• Carbon-based molecules have three
general types of structures. – straight chain
– branched chain
– ring
B. Functional Groups
• 1. Functional groups also contribute to the
molecular diversity of life
• a. hydroxyl group and alcohols
b. carbonyl group and aldehydes and
ketones
c. carboxyl group and carboxylic acids
d. amion groups and amines
e. sulfhydryl group and thiols
f. phosphate groups
C. Polymer Principles
• 1. Most macromolecules are polymers
2. A limitless variety of polymers can be
built from a small set of monomers
• Many carbon-based molecules are made
of many small subunits bonded together.
– Monomers are the individual subunits.
– Polymers are made of many monomers.
D. Carbohydrates: Fuel and
Building Material
• 1. Sugars
• a. smallest carbohydrates
b. serve as fuel and carbon sources
• 2. Polysaccharides
• a. polymers made of sugars
b. storage and structure
Four main types of carbon-based
molecules are found in living
things.
• Carbohydrates are made of carbon,
hydrogen, and oxygen.
Four main types of carbon-based
molecules are found in living
things.
• Carbohydrates are made of carbon,
hydrogen, and oxygen.
– Carbohydrates include
sugars and starches.
– Monosaccharides are
simple sugars.
– Polysaccharides include
starches, cellulose
(fiberous plants), and
glycogen (in muscles)
• Carbohydrates can be broken down to
provide energy for cells.
• Some carbohydrates are part of cell structure.
Polymer (starch)
Starch is a polymer of
glucose monomers that
often has a branched
structure.
Polymer (cellulose)
monomer
Cellulose is a polymer
of glucose monomers
that has a straight, rigid
structure
E. Lipids: Diverse Hydrophobic
Molecules
• 1. Fats store large amounts of energy
2. Phospholipids are major components of
cell membranes
3. Steroids include cholesterol and certain
hormones
• Lipids are nonpolar molecules that include fats, oils, and
cholesterol.
– Many contain carbon chains called fatty acids.
– Fats and oils contain fatty acids bonded to glycerol.
Triglyceride
• Lipids have several different functions.
– broken down as a source of energy
– make up cell membranes
– used to make hormones
• Fats and oils have different types of fatty
acids.
– saturated fatty acids
– unsaturated fatty acids
• Phospholipids make up all cell
membranes.
– Polar phosphate “head”
– Nonpolar fatty acid “tails”
Phospholipid
F. Proteins: The Molecular Tools
of the Cell
• 1. A polypeptide is a polymer of amino
acids connected in a specific sequence
2. A protein's function depends on its
specific conformation
• Proteins are polymers of amino acid
monomers.
– Twenty different amino acids are used to build proteins
in organisms.
• Proteins are polymers of amino acid monomers.
– Twenty different amino acids are used to build proteins
in organisms.
– Amino acids differ in side groups, or R groups.
• Proteins are polymers of amino acid monomers.
– Twenty different amino acids are used to build proteins
in organisms.
– Amino acids differ in side groups, or R groups.
– Amino acids are linked by peptide bonds.
• Proteins differ in the number and order of
amino acids.
– Amino acids interact to give a protein its shape.
Hemoglobin
hydrogen bond
– Incorrect amino acids change a protein’s structure
and function.
G. Nucleic Acids: Informational
Polymers
• 1. Nucleic acids store and transmit
hereditary information
2. A nucleic acid strand is a polymer of
nucleotides
3. Inheritance is based on replication of
the DNA double helix
4. DNA and proteins can serve as tape
measures of evolution
• Nucleic acids are polymers of monomers
called nucleotides.
• Nucleic acids are polymers of monomers called
nucleotides.
– Nucleotides are made of a sugar,
phosphate group, and a nitrogen base.
A phosphate group
deoxyribose (sugar)
nitrogen-containing molecule,
called a base
• Nucleic acids are polymers of monomers called
nucleotides.
– Nucleotides are made of a sugar, phosphate
group, and a nitrogen base.
– DNA stores
genetic
information.
DNA
– RNA builds proteins. RNA