This document discusses macromolecules and their structure and function. It focuses on proteins, carbohydrates, and lipids. Proteins are polymers of amino acids and their structure ranges from primary to quaternary levels. Carbohydrates include monosaccharides, disaccharides, and polysaccharides like starch and cellulose. Lipids are nonpolar and include triglycerides, fatty acids, and phospholipids that form cell membranes. The document explains the structure and properties of these macromolecules.

1. Chapter 3
Proteins, Carbohydrates,
and Lipids

2. Macromolecules
Polymers with molecular weights >1,000
Made up of smaller molecules called
monomers
Four Main Groups:
Proteins (Amino Acids)
Carbohydrates (Simple Sugars)
Lipids (Fatty Acids)
Nucleic Acids (Nucleotides - Chapter 4)

3. Functional
Groups
Groups of atoms with
specific chemical
properties and consistent
behavior

4. Isomers
Molecules with the same chemical formula, but
atoms are arranged differently
Structural Isomers: differ in how their atoms
are joined together

5. Optical Isomers
Occur when a carbon
atom has four
different atoms or
groups of atoms
attached to it.
Optical isomers result
from asymmetrical
carbons.

6. Macromolecules Found in
Living Tissues

7. Functions of Macromolecules
• Energy Storage • Maintenance and
• Structural Support Homeostasis
• Catalysts • Movement
• Transport • Growth
• Protection and • Development
Defense • Heredity
• Regulation of • Information Storage
Metabolic Activities

8. Condensation Reactions
Polymers are formed in
condensation reactions.
Monomers are joined by
covalent bonds.
A water is removed; so
they are also called
dehydration reactions.

9. Hydrolysis Reactions
Polymers are broken
down into monomers
in hydrolysis
reactions.

10. Protein Structure
Proteins are polymers of 20 different amino acids.
Polypeptide chain: single, unbranched chain of amino
acids.
The chains are folded into specific three dimensional
shapes defined by the sequence of the amino acids.
Proteins can consist of more than one type of
polypeptide chain.

11. Functions of Proteins
enzymes—catalytic proteins
defensive proteins (e.g., antibodies)
hormonal and regulatory proteins—control physiological
processes
receptor proteins—receive and respond to molecular signals
Storage proteins store amino acids.
Structural proteins provide physical stability and movement.
Transport proteins carry substances within the organism (e.g.,
hemoglobin).
Genetic regulatory proteins regulate when, how, and to what
extent a gene is expressed.

12. Building Blocks of Proteins:
Amino Acids
α-carbon is “asymmetric”
4 Main Groups
• Amino Group
• Carboxyl Group
• Hydrogen
• Side Chain (R)
–Specific to each type of
amino acid D-amino acids (dextro, “right”)
L-amino acids (levo, “left”)
•Optical Isomers (this form is found in organisms)

13. Types of Amino Acid Side Chains (R)
These hydrophylic amino acids attract
ions of opposite charges.

14. Types of Amino Acid Side Chains (R)
Hydrophylic amino acids with polar but
uncharged side chains form hydrogen bonds.

15. Types of Amino Acid Side Chains (R)
Hydrophobic amino acids

16. Types of Amino Acid Side Chains (R)
Cysteine: Can form disulfide bridges
Glycine: Smallest a.a. (Unique why?)
Proline: Causes “kinks” in protein structure

17. Peptide Bonds
N-terminus: start of a polypeptide chain
C-terminus: end of a polypeptide chain

18. Levels of Protein Structure:
Primary Structure
Made up of a single chain of amino acids
bound together (polypeptide)
The number of different proteins that can
be made from 20 amino acids is
enormous!

19. Levels of Protein Structure:
Secondary Structure
α helix: right-handed coil
resulting from
hydrogen bonding
between N—H groups
on one amino acid and
C=O groups on
another.
β pleated sheet: two or
more polypeptide
chains are aligned;
hydrogen bonds from
between the chains.
Bonds do NOT form between side chains!

20. Levels of Protein Structure:
Tertiary Structure
• Bending and
folding results in a
macromolecule
with specific three-
dimensional
shape.
• Bonds form
between side
chains

21. Levels of Protein Structure:
Quaternary Structure
Results from the
interaction of subunits
by hydrophobic
interactions, van der
Waals forces, ionic
bonds, and hydrogen
bonds.
Each subunit has its
own unique tertiary
structure.

22. Environmental Conditions
affect Protein Folding
Conditions that affect secondary and
tertiary structure:
• High temperature
• pH changes
• High concentrations of polar molecules
• Nonpolar substances

23. Denaturation

24. Chaperones
Help some proteins fold correctly

25. Carbohydrates
Carbohydrates have the general formula
Cn(H2O)n
Source of stored energy
Transport stored energy

26. Types of Carbohydrates
Monosaccharides: simple sugars
Disaccharides: two simple sugars linked
by covalent bonds
Oligosaccharides: three to 20
monosaccharides
Polysaccharides: hundreds or thousands
of monosaccharides—starch,
glycogen, cellulose

27. Monosaccharides
Simple Sugars
Hexoses: six
Pentoses: five carbons
Glyceraldehyde: three
carbons

28. Monosaccharides: Glucose
All cells use glucose (monosaccharide) as an
energy source.
Exists as a straight chain or ring form. Ring is
more common—it is more stable.

29. Glycosidic Linkages
Monosaccharides bind together in
condensation reactions to form glycosidic
linkages.
Glycosidic linkages can be α or β.

30. Oligosaccharides
Often covalently bonded to proteins and
lipids on cell surfaces and act as
recognition signals.
Human blood groups get specificity from
oligosaccharide chains.

31. Polysaccharides
Giant polymers of monosaccharides.
Starch: storage of glucose in plants
Glycogen: storage of glucose in animals
Cellulose: very stable, good for structural
components

32. Carbohydrates can be modified by the addition
of functional groups

33. Lipids
Nonpolar hydrocarbons
Not polymers in the strict sense, because they are not
covalently bonded.
FUNCTION:
1) Fats and oils store energy
2) Phospholipids—structural role in cell membranes
3) Carotenoids and chlorophylls—capture light energy in plants
4) Steroids and modified fatty acids—hormones and vitamins
5) Animal fat—thermal insulation
6) Lipid coating around nerves provides electrical insulation
7) Oil and wax on skin, fur, and feathers repels water

34. Triglycerides
Simple fats and oils
Glycerol: 3 —OH groups (an alcohol)
Fatty acid: nonpolar hydrocarbon with a polar
carboxyl group
Carboxyls bond with hydroxyls of glycerol in an
ester linkage. (condensation reaction)

35. Ester Linkage

36. Types of Fatty Acids
Saturated fatty acids: no double bonds
between carbons—it is saturated with
H atoms.
Unsaturated fatty acids: some double
bonds in carbon chain.
monounsaturated: one double bond
polyunsaturated: more than one

37. Types of Fatty Acids
Saturated Unsaturated

38. Phospholipids
Fatty acids bound to
glycerol; a phosphate
group replaces one fatty
acid.
Hydrophilic “head”
Hydrophobic “Tails”
Amphipathic:
Have opposing chemical
properties

39. Phospholipid Bilayer
• In water, phospholipids line up with the
hydrophobic “tails” together and the
phosphate “heads” facing outward, to form a
bilayer.

40. Other Fats