2.3 Molecules of life
What organic molecules are found
in living organisms?
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids
Summary of the macromolecules
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Organic
molecules
Examples
Monomers
Functions
CH2OH
Monosaccharides,
Carbohydrates disaccharides,
polysaccharides
O
H
OH
Immediate
energy
and stored
energy;
structural
molecules
H
H
HO
OH
H
OH
Glucose
H
Lipids
Fats, oils,
phospholipids,
steroids
H
H
H
H
H
C C
C
C
C
C
H
H
H
H
H
O
H C OH
H C OH
HO
H C OH
R
Fatty acid
H
Glycerol
Proteins
Structural,
enzymatic,
carrier,
hormonal,
contractile
amino
group
H2N
H
C
acid
group
COOH
R
group
Long-term
energy
storage;
membrane
components
Support,
metabolic,
transport,
regulation,
motion
Amino acid
phosphate
P
Nucleic acids
DNA, RNA
base
C
O
S
Nucleotide
Storage of
genetic
information
2.4 Carbohydrates
1. What are carbohydrates?
• Made of subunits called monosaccharides
• Made of C, H and O in which the H and O
atoms are in a 2:1 ratio
• Function as short and long-term energy
storage
• Found as simple and complex forms
2.4 Carbohydrates
What are simple carbohydrates?
• Monosaccharide – 1
carbon ring as found
in glucose
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6 CH2OH
5C
CH2OH
O
O
O
H
H
H
H
H
4
C
C
1
OH
OH
H
OH
HO
C
H
HO
HO
C
2
3
OH
H
H
OH
C6H12O6
• Disaccharide – 2
carbon rings as
found in maltose
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CH2OH
CH2OH
O
O
O
maltose C12H22O11
2.4 Carbohydrates
What
are
complex
carbohydrates?
• Polysaccharides are made of many carbon rings
•
Glycogen is the storage form in animals
•
Starch is the storage form in plants
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CH2OH
H
O
CH2OH
O
H
OH
H
H
OH
H
H
O
CH2OH
O
H
OH
H
H
OH
H
H
O
CH2OH
O
H
OH
H
H
OH
H
O
H
O
H
OH
H
H
OH
H
O
branched
nonbranched
starch
granule
cell wall
potato cells
© Jeremy Burgess/SPL/ Photo Researchers, Inc.
2.5 Lipids
2. What are lipids?
• Molecules that do not dissolve in water
• Used as energy molecules
• Found in cell membranes
• Found as fats and oils, phospholipids and
steroids
2.5 Lipids
How are fats and oils different?
• Fats
• Usually animal origin
• Solid at room temperature
• Function as long-term energy storage, insulation from
heat loss and cushion for organs
• Oils
• Usually plant origin
• Liquid at room temperature
2.5 Lipids
What is the structure of fats and
oils?
• A glycerol molecule and 3 fatty acid tails
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H
H C
H C
O
OH
OH
HO
+
O
HO
O
H C
OH
HO
H
H
H
H
C C
C
C
C
H
H
H
H
H
H
H
H
H
H
C C
C
C
C
C
C H
H
H
H
H
H
H
H
H
H
H
H
C C
C
C
C
C
H
H
H
H C O
H
H
H
dehydration reaction
H C O
O H
H
H
H
C
C
C
C
C
H
H
H
H
O H
H
H
H
H
H
C
C
C
C
C
C
C
H
H
H
H
H
H
O H
H
H
H
H
C
C
C
C
C
H
H
hydrolysis reaction
H C O
H
C
H
H
H
+ 3 H2O
H
H
glycerol
3 fatty acids
fat molecule
3 water
molecules
2.5 Lipids
Understanding fats when reading a
nutrition label
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• Recommendation for total
amount of fat for a 2,000
calorie diet is 65g
Start here
• Be sure to know how
many servings there are
• A % DV of 5% or less is Limit these
low and 20% or more is nutrients
high
• Try to stay away from
Get enough
trans fats
these
• Would you eat the food of
nutrients
on the right? Why or why
not?
Nutrition Facts
Serving Size 1 cup (228g)
Servings Per Container 2
Amount Per Serving
Calories 250
Calories from Fat 110
% Daily Value
Total Fat 12g
Saturated Fat 3g
Trans Fat 1.5g
Cholesterol 30mg
Sodium 470mg
Total Carbohydrate 31g
Dietary Fiber 0g
Sugars 5g
Protein 5g
18%
15%
Vitamin A
Vitamin C
Calcium
Iron
4%
2%
20%
4%
10%
20%
10%
0%
2.5 Lipids
What are steroids?
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H 3C
• A lipid
CH3
CH3
H 3C
CH3
• Structure is four fused HO
a. Cholesterol
carbon rings
• Examples are
cholesterol and sex
hormones
OH
CH3
OH
CH3
CH3
HO
O
b. Testosterone
c. Estrogen
b: © Warren Toda/epa/Corbis; c: © Tony Marsh/Reuters/Corbis
2.6 Proteins
3. What are proteins?
• Made of subunits called amino acids
• Important for diverse functions in the body
including hormones, enzymes, antibodies
and transport
• Can denature, change in shape, that
causes loss of function
2.6 Proteins
What do amino acids look like?
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H
C
H
O
CH2
C
O
C
C
CH
H3C
C
O
C
H
O
CH2
CH2
CH2
CH2
CH3
valine (val)
(nonpolar)
glutamic acid (glu)
(ionized, polar)
H
C
lysine (lys)
(ionized, polar)
O
C
CH2
H
O
C
C
NH
C
CH2
O
C
CH2
C
O
tryptophan (trp)
(nonpolar)
H
aspartic acid (asp)
(ionized, polar)
SH
cysteine (cys)
(polar)
O
2.6 Proteins
What are the four levels of protein
organization?
• Primary – the linear order of amino acids
• Secondary – localized folding into pleated
sheets and helices
• Tertiary – the 3-D shape of the entire protein in
space
• Quaternary – combination of more than one
polypeptide
• All proteins have primary, secondary and tertiary
structure, while only a few have quaternary
structure
2.6 Proteins
What do the levels of organization
look like?
Primary Structure:
sequence of amino acids
amino acid
COO–
peptide bond
Secondary Structure:
alpha helix or a pleated sheet
hydrogen bond
C
CH
CH
CH
C N
R
C N
R
R
CH
C N
R
CH
C N
N R
C
hydrogen bond
C
CH
C N
R
CH
CH
N R
(alpha) helix
Tertiary Structure:
final shape of polypeptide
Quaternary Structure:
two or more associated
polypeptides
(beta) sheet =
pleated sheet
disulfide bond
2.7 Nucleic acids
4. What are nucleic acids?
• Made of nucleotide subunits
• Function in the cell to make proteins
• Includes RNA and DNA
2.7 Nucleic acids
What are the 3 parts of a nucleotide?
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phosphate
C
P
5'
Nucleotide
O
S
4'
1'
2'
3'
sugar
nitrogencontaining
base
2.7 Nucleic acids
What are the five bases found in
nucleotides?
• Adenine (A) and guanine (G) are double-ringed purines
• Cytosine (C), thymine (T) and uracil (U) are single-ringed
pyrimidines
• In DNA A pairs with T and G pairs with C
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Hydrogen bond
H
N
N
H
CH2
O
C
N
N
H
P
bases
N
N
O
Thymine (T)
(DNA only)
Adenine (A)
A
C
S
N
HN
C
P
O
S
T
backbone
H
C
C
A
N
H
O
P
N
S
G
N
N
H
N
N
P
N
N
H
Guanine (G)
a. DNA structure with base pairs: A with T and G with C
H
O
CH
N
H
Uracil (U)
(RN only)
A
G
T
CH
U
S
Cytosine (C)
b. RNA structure with bases G, U, A, C
2.7 Nucleic acids
Summary of DNA and RNA
structural differences?
• DNA
– Sugar is deoxyribose
– Bases include A, T, C
and G
– Double stranded
• RNA
– Sugar is ribose
– Bases include A, U, C
and G
– Single stranded