Nucleic Acids
● Include DNA and RNA
Information storage molecules
They provide the directions for building proteins
Gene
DNA
Nucleic acids
Amino acid
RNA
Protein
Nucleic Acids
●Nucleic acids are polymers of nucleotides
Nitrogenous base
(A,G,C, or T)
– DNA, deoxyribonucleic acid
– RNA, ribonucleic acid
Nitrogenous base
A, G, C, or U
Thymine (T)
Phosphate
group
Sugar
(deoxyribose)
Uracil U
Phosphate
Phosphate
group
Base
Sugar
Sugar ribose
Nucleic Acids
●Each nucleotide has one of the following bases:
Nucleic Acids
●Nucleic Acid Structure
Sugar-phosphate
backbone
Base
Nucleotide pair
Hydrogen
bond
Bases
a DNA strand
polynucleotide
b Double helix
two polynucleotide strands
Nucleic Acids
●Nucleic Acid Structure
Nucleic Acids
DNA Structure
Carbohydrates
• Carbohydrates include
– Small sugar molecules in soft drinks
• Monosaccharides & Disaccharides
– Long starch molecules in pasta and potatoes
• Polysaccharides
Monosaccharides
• Monosaccharides are simple sugars
– Glucose, found
in sports drinks
– Fructose, found
in fruit
• Honey contains
both glucose and
fructose
Glucose
Fructose
Isomers
Monosaccharides
• In aqueous solutions, monosaccharides form
rings
(b) Abbreviated ring
structure
Disaccharides
• A disaccharide is a double sugar
• Disaccharides are joined by the process of dehydration
synthesis
Glucose
Glucose
Maltose
Disaccharides
• The most common disaccharide is sucrose,
common table sugar
– It consists of a glucose
linked to a fructose
– Sucrose is extracted
from sugar cane and the
roots of sugar beets
Polysaccharides
– They are long chains of sugar units
– They are polymers of monosaccharides
Glucose
monomer
Starch granules in
potato tuber cells
(a) Starch
Glycogen
Granules
In muscle
tissue
(b) Glycogen
Cellulose fibril in
a plant cell wall
Cellulose molecules
(c) Cellulose
Lipids
●Lipids are:
Neither macromolecules nor polymers
Hydrophobic, unable to mix with water
Oil (hydrophobic)
Vinegar (hydrophilic)
Figure 3.10
Lipids
●FATS
● Dietary fat consists largely of the molecule triglyceride
– A combination of glycerol and three fatty acids
Fatty acid
Glycerol
(a) A dehydration reaction linking a fatty acid to glycerol
(b) A fat molecule with a glycerol “head” and three
energy-rich hydrocarbon fatty acid “tails”
Lipids (Fats)
●Unsaturated fatty acids
– Have less than the maximum number of hydrogens
bonded to the carbons
●Saturated fatty acids
– Have the maximum number of hydrogens bonded to
the carbons
Lipids (Fats)
TYPES OF FATS
Saturated Fats
Unsaturated Fats
Margarine
INGREDIENTS: SOYBEAN OIL, FULLY HYDROGENATED
COTTONSEED OIL, PARTIALLY HYDROGENATED
COTTONSEED OIL AND SOYBEAN OILS, MONO AND
DIGLYCERIDES, TBHO AND CITRIC ACID
Plant oils
Trans fats
ANTIOXIDANTS
Omega-3 fats
Lipids
Phospholipids
Steroids
Lipids
●STEROIDS
Steroids are very different from fats in structure and
function.
Cholesterol
Testosterone
A type of estrogen
Biological Molecules
Visual
Summary 3.2