Download d. nucleic acids

Cells make a huge number of large molecules from a
small set of small molecules
• The four main classes of biological molecules
–
Are carbohydrates, lipids, proteins, and nucleic
acids
• Many of the molecules are gigantic
–
And are called macromolecules
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• Cells make most of their large molecules
–
By joining smaller organic molecules into
chains called polymers
• Cells link monomers to form polymers
–
By dehydration synthesis
H
OH
OH
OH
Short polymer
Unlinked monomer
Dehydration
Dehydratio
reaction
n reaction
H2O
OH
O
H
H
H
Longer polymer
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
H
H
• Polymers are broken down to monomers
–
By the reverse process, hydrolysis
Animation:
Hydrolysis of sucrose
H2O
H
OH
Hydrolysis
H
OH
OH
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
H
VI. Molecules of Life
A. Carbohydrates- main source of energy for cells
Monosaccharides are the simplest carbohydrates
• The carbohydrate monomers are monosaccharides
• A monosaccharide has a formula that is a multiple
of CH2O ( the ratio 1:2:1)
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• Monosaccharides can join to form disaccharides
–
Such as sucrose (table sugar) and maltose
(brewing sugar)
–
Polysaccharides are long chains of sugar units
• Polysaccharides are polymers of monosaccharides
–
CH2OH
CH2OH
O
O
H
HO
H
H
H
OH
Linked together by dehydration synthesis
H
H
OH
HO
OH
H
H
H
OH
Glucose
OH
H
OH
Glucose
H2O
CH2OH
H
HO
CH2OH
O
H
OH
H
H
OH
H
H
O
O
H
OH
H
H
OH
H
OH
Maltose
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• Starch and glycogen are polysaccharides
–
That store sugar for later use
• Cellulose is a polysaccharide found in plant cell walls
– provides structure
O
Cellulose fibrils in
a plant cell wall
O
O
O
O
O
O
O
O
O
O
O
O
O
CELLULOSE
OO
OO
O OH
OO
O OH
OO
O
OO
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O
GLYCOGEN
O O
Figure 3.7
O
O O
O
Cellulose
molecules
O
O
O
Glycogen
granules in
muscle
tissue
Glucose
monomer
STARCH
Starch granules in
potato tuber cells
OO
OO
O O
O
O O
O
B. LIPIDS
Fats are lipids that are mostly energy-storage
molecules
• Lipids are diverse compounds
–
That consist mainly of carbon and hydrogen
atoms
–
Hydrophobic –water fearing
Insulation- thermal & electrical
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• Fats, also called triglycerides
–
Are lipids whose main function is energy storage
–
Consist of glycerol linked to three fatty acids
–
Saturated – no double bonds (solid room temp.)
–
Unsaturated - has double bonds (liquid room
temp.)
H2O
Fatty acid
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CH2
CH3
CH2
CH3
CH3
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH
CH2
CH2
CH
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
O
O C
O C
C
O
O
O
C
C
H
H
H
C
H
H
Unsaturated Fat
CH2
HO
C O
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH3
C H
OH
H C
C
OH OH
H
H
H
Glycerol
Phospholipids, waxes, and steroids are lipids with a
variety of functions
• Phospholipids are a major component of cell
membranes (phospholipid bilayer)
• Waxes form waterproof coatings (cuticle on leaf)
• Steroids are often hormones (anabolic steroids synthetic)
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What are trans fats and why are they such a big deal?
• Twinkie Video
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
C. PROTEINS
Proteins are essential to the structures and
activities of life
• A protein
– Is a polymer constructed from amino acid
monomers
– Transport substances and fight disease
(antibodies)
– As enzymes they regulate chemical
reactions
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A protein’s specific shape determines its function
• A protein consists of one or more polypeptide
chains
–
Folded into a unique shape that determines
the protein’s function
Groove
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Groove
D. NUCLEIC ACIDS
• Examples of nucleic acids include deoxyribonucleic acid
(DNA) and ribonucleic (RNA)
–
Serve as the blueprints for building proteins and thus
control the life of a cell
• The monomers of nucleic acids are nucleotides
–
Nucleotides are composed of a 5-carbon sugar,
phosphate group, and nitrogenous base
H
H
N
N
N
H
OH
O
P
N
O
CH2
O

O
Phosphate
group
H
H
H
H
OH
H
Sugar
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
H
N
Nitrogenous
base (A)
• EXIT SLIP 10/7
1. What type of organic molecule are
enzymes made out of?
2. Generally, where could we say
carbohydrates originate from?
3. What atoms make up carbohydrates?
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• EXIT SLIP 10/8
1. What are the monomers of
carbohydrates?
2. What chemical process typically
builds polymers?
3. What chemical process typically
breaks polymers apart?
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• Additional Laboratory Questions
1. Explain how amino acids relate to
proteins and draw an amino acid, be
sure to label the functional groups.
2. Explain why carbon is uniquely
suited to form organic molecules.
3. Look ahead to section 2.4 of your
text and explain what factors can
influence the function of an enzyme.
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings