Transcript 2. Explain how organic polymers contribute to

Chapter 5 Reading Quiz
1.
What does “hydrolysis” literally mean?
Splitting water
2. What element composes the backbone of the
4 macromolecules?
Carbon!
3. What subunits come together to make a
protein? Amino acids
Carbohydrates
Lipids
4. List the 3 other macromolecules. Nucleic acids
5. What is the main function of DNA? information
1. List the four major classes of
biomolecules.
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids
2. Explain how organic polymers contribute to
biological unity and diversity.
Unity – there are only 40 – 50
monomers used to make all
macromolecules
Diversity – new properties emerge
when these monomers are arranged in
different ways…leading to the
diversity of life 
3. Describe how covalent linkages are
formed (condensation) and broken
(hydrolysis) in organic polymers.
Condensation
Polymerization
reaction where
monomers are
covalently linked,
removing a water
molecule
Hydrolysis
Reaction process
that breaks
covalent bonds
between monomers
by adding water
molecules
Remove H2O molecule
Add H2O molecule 
4. Explain how carbohydrates are
classified.
Carbohydrates are
classified by the
number of simple
sugars
They are organic
molecules made of
sugars and their
polymers 
5. List four characteristics of sugar.
1.
An –OH group is attached to each carbon
except one, which is =O
2. The size of the carbon skeleton varies
from 3-7 carbons
3. Spatial arrangement around asymmetric
carbons may vary (ex: enantiomers)
4. In aqueous solutions, many simple sugars
form rings. (chemical equilibrium favors
ring structures) 
6. Identify a glycosidic linkage and
describe how it is formed.
Glycosidic linkage – the covalent bond
formed by a condensation reaction
between 2 sugar monomers
Sugar + Sugar
(monosaccharides)

(glycosidic
linkage)
Big Sugar
(disaccharide) 
7. Describe the important biological
functions of polysaccharides.
1. Energy storage – in the form of
starch and glycogen
2. Structural support – in the form of
cellulose and chitin 
8. Distinguish between the glycosidic
linkages found in starch and cellulose.
Starch
Glucose monomers in
α configuration
• -OH group is
BELOW ring’s plane
Cellulose
Glucose monomers in
β configuration
• -OH group is
ABOVE ring’s plane
α 1-4 linkage
β 1-4 linkage 
9. Explain what distinguishes lipids from
other major classes of macromolecules.
Lipids –
• Are insoluble in water!
• Due to nonpolar C-H bonds
• Known as fats and oils 
10. Describe the unique properties,
building block molecules and biological
importance of the three important groups
of lipids: fats, phospholipids and steroids.
Fats –
made with glycerol, a 3 carbon
alcohol and a fatty acid (carboxylic with a
hydrocarbon tail)
Used for:
• Energy storage
• Compact fuel reserves
• Cushioning and insulating 
10. Continued….
Phospholipids –
made with a glycerol, 2
fatty acids, a phosphate group, and a small
chemical group
Characteristics:
• Tails are hydrophobic
• Will cluster in water
• Forms cell membrane bilayers 
10. Continued….
Steroids –
are lipids that have 4 fused
carbon rings with various functional groups
attached
Example:
• Cholesterol
- precursor to sex hormones and bile acids
- common in cell membranes
-atheriosclerosis 
11. Identify an ester linkage and describe
how it is formed.
Ester linkage –
• Bond formed between a hydroxyl group
(-OH) and a carboxyl group (-COOH)
• Forms fat through condensation reactions
that link glycerol to a fatty acid
-OH + -COOH 
12. Distinguish between saturated and unsaturated
fat, and list some unique emergent properties that
are a consequence of these structural differences.
Saturated Fats
• No double bonds
between carbons in
tail
• Has maximum number
of hydrogens
• Solid at room
temperature – most
animal fats
C-C-C-C
Unsaturated Fats
• One or more double
bonds in tail
• Tail kinks at C=C so
molecules do not pack
closely enough to
solidify
• Liquid at room
temperature – most
plant fats
C=C-C=C

13. Distinguish proteins from the other
major classes of macromolecules and
explain the biologically important functions
of this group.
Proteins – a macromolecule that consists of
one or more polypeptide chains folded and
coiled into specific conformations
• Made up of various 20 amino acids
• Vary widely in structure and function
• Abundant – about 50% of cellular dry
weight (weight of cell minus water bulk) 
13. Continued…important functions
1.
2.
3.
4.
5.
Structural support
Storage of amino acids
Transport (hemoglobin)
Signaling (chemical messengers)
Cellular response to chemical stimuli
(receptor proteins)
6. Movement (contractile proteins)
7. Defense against foreign substances &
disease-causing organisms (antibodies)
8. Catalysis of biochemical reactions
(enzymes) 
14. List and recognize four major
components of an amino acid, and explain
how amino acids may be grouped according
to the physical and chemical properties of
the side chains.
Four components:
1. Hydrogen atom
2. Carboxyl group (-COOH)
3. Amino group (-NH2)
4. Variable ‘R’ group (specific to each amino acid)
- the properties of the side chain determine
the uniqueness of each amino acid 
15. Identify a peptide bond and
explain how it is formed.
Peptide bond = the covalent bond formed
by a condensation reaction that links the
carboxyl (-COOH) group of one amino acid
to the amino (-NH2) group of another. 
16. Explain what determines protein
conformation and why it is important.
• It is the 3D shape of a protein
• Enables a protein to recognize & bind specifically
to another molecule (ex: hormone receptor)
• It is the consequence of the specific linear
sequence of amino acids in the polypeptide
• Produced when new chains coil & fold
spontaneously (due to hydrophobic interactions)
• It is stabilized by chemical bonds & weak
interactions between neighboring regions of the
folded protein 
17. Define primary structure and describe
how it may be deduced in the laboratory.
•
•
In
1.
2.
•
It is the unique sequence of amino acids in a
protein
Determined by genes – slight changes can affect
function (ex: sickle-cell)
a laboratory…
Determine amino acid composition by complete
acid hydrolysis of peptide bonds – identify the
aa’s and proportions
Determine the amino acid sequence by partial
hydrolysis with enzymes and break specific
peptide bonds – deductively reconstruct from
fragments
Now automated sequencing 
18. Describe the two types of secondary protein
structure, and explain the role of hydrogen bonds
in maintaining the structure.
•
•
Coiling & folding of polypeptide backbone
H bonds between peptide linkages in the
protein’s backbone help stabilize
1.
•
Alpha helix
Helical coil stabilized by H bond every 4th
peptide bond
Found in fibrous protein – collagen/elastin

•
18. Continued…Beta pleated sheet
2. Beta pleated sheet
• Sheet of antiparallel
chains are folded into
accordion pleats
• Held together by H
bonds
• Dense core of globular
proteins & some
fibrous protein 
19. Explain how weak interactions and
disulfide bridges contribute to tertiary
protein structure.
Weak Interactions
• Hydrogen bonding
between polar side
chains
• Ionic bonds between
charged side chains
• Hydrophobic
interactions between
nonpolar in interior
Covalent linkage
• Disulfide bridges
between 2 cysteine
monomers brought
together by folding
• Reinforces
conformation 
20. Using collagen and hemoglobin as
examples, describe quaternary protein
structure.
Collagen
• Fibrous protein
with 3 helical
polypeptides
supercoiled into a
triple helix
Hemoglobin
• Four subunits
grouped together
(2 α chains and 2 β
chains) 
21. Define denaturation and explain how
proteins may be denatured.
• Is the process that alters a protein’s
native conformation and biological activity
Causes:
• Transfer to an organic solvent-hydrophobic
insides go out and vice versa
• Chemical agents that disrupt hydrogen,
ionic, and disulfide bonds
• Excessive heat – thermal agitation disrupts
the weak interactions 
22. Describe the characteristics that
distinguish nucleic acids from the other
major groups of macromolecules.
Nucleic acids –
• Contain phosphorus
• Store and transmit hereditary information
• Are polymers of nucleotides
• Determine protein structure, function, etc.
Examples –
• RNA (ribonucleic acid)
• DNA (deoxyribonucleic acid) 
23. Summarize the functions of nucleic
acids.
• To store and transmit hereditary
information
- directions for replication
- information to run all cell activity
- make up the genes for protein
synthesis
(the ‘brain’ for making anything) 
24. List the 3 major components of a
nucleotide, and describe how these
monomers are linked together to form a
nucleic acid.
1.
Pentose (5 carbon sugar)
- ribose, deoxyribose
2. Phosphate – attached to the 5th carbon of
the sugar
3. Nitrogenous base – pyrimidines & purines
• Covalent bonds called phosphodiester
linkages bond (between the phosphate of
one sugar and the sugar of another) 
25. Distinguish between a pyrimidine and a
purine.
Pyrimidine
Purine
- six-membered ring
made up of carbon and
nitrogen atoms
Ex: cytosine (C)
thymine (T) – DNA
uracil (U) – RNA
- five-membered ring
fused to a sixmembered ring
Ex: Adenine (A)
Guanine (G)

26. List the functions of nucleotides.
• Monomers for nucleic acids
• Transfer chemical energy from one
molecule to another (ex: ATP )
• Are electron acceptors in enzymecontrolled redox reactions of the cell
(ex: NAD+) 
27. Briefly describe the three-dimensional
structure of DNA.
•
•
•
•
•
•
Consists of 2 nucleotide
chains wound in a double
helix
Sugar-phosphate backbones
on the outside
2 strands held together by
hydrogen bonds between the
paired nitrogenous bases
Van der waals attraction
between stacked bases
2 DNA strands are
complementary and serve as
templates for new strands
Long – 1000’s or millions of
base pairs 