2.5 Carbohydrates
2.5 Carbohydrates
• Some Functions:
– Quick fuel
– Short-term energy storage
– Structure of organisms
– Cell to cell recognition
2.5 Carbohydrates
• Simple Carbohydrates
2.5 Carbohydrates
• Simple Carbohydrates
– Monosaccharides are sugars with 3 - 7
carbon atoms
2.5 Carbohydrates
• Simple Carbohydrates
– Monosaccharides are sugars with 3 - 7
carbon atoms
– Pentose refers to a 5-carbon sugar
– Hexose refers to a 6-carbon sugar
2.5 Carbohydrates
Three ways to represent the structure of glucose.
2.5 Carbohydrates
• Disaccharides contain two monosaccharides.
2.5 Carbohydrates
• Polysaccharides are long polymers that
contain many glucose subunits.
2.5 Carbohydrates
• Polysaccharides are long polymers that contain
many glucose subunits.
– Starch is the storage form of glucose in plants.
2.5 Carbohydrates
• Polysaccharides are long polymers that contain
many glucose subunits.
– Starch is the storage form of glucose in plants.
– Glycogen is the storage form of glucose in animals.
2.5 Carbohydrates
• Polysaccharides are long polymers that contain
many glucose subunits.
– Starch is the storage form of glucose in plants.
– Glycogen is the storage form of glucose in animals.
– Cellulose can be found in the cell walls of plants.
2.5 Carbohydrates
2.6 Lipids
2.6 Lipids
• Some Functions:
– Energy Storage
– Found in the plasma membrane
– Component of steroid hormones
Lipids do not dissolve in water
2.6 Lipids
• Some Functions:
– Energy Storage
– Found in the plasma membrane
– Component of steroid hormones
Lipids do not dissolve in water
Lipids are electrically neutral
2.6 Lipids
• Fats and Oils
2.6 Lipids
• Fats and Oils
– Fats
• Usually of animal origin
• Solid at room temperature
2.6 Lipids
• Fats and Oils
– Fats
• Usually of animal origin
• Solid at room temperature
2.6 Lipids
• Fats and Oils
– Fats
• Usually of animal origin
• Solid at room temperature
– Oils
• Usually of plant origin
• Liquid at room temperature
2.6 Lipids
• Functions of Fats
2.6 Lipids
• Functions of Fats
– Long-term energy storage
– Insulation against heat loss
– Protection of major organs
2.6 Lipids
Synthesis and degradation of a fat molecule
2.6 Lipids
Emulsification
2.6 Lipids
• Saturated and Unsaturated Fatty Acids
2.6 Lipids
• Saturated and Unsaturated Fatty Acids
– Fatty acids are hydrocarbon chains that end
with -COOH.
2.6 Lipids
• Saturated and Unsaturated Fatty Acids
– Fatty acids are hydrocarbon chains that end
with -COOH.
• Saturated fatty acids: No double covalent
bonds between carbon atoms
• Unsaturated fatty acids: Double bonds
between carbon atoms
2.6 Lipids
Saturated Fatty Acid
Unsaturated Fatty Acid
2.6 Lipids
• Phospholipids
2.6 Lipids
• Phospholipids
– Comprised of 2 fatty acids + a phosphate group
– Primary components of cellular membranes
2.6 Lipids
2.6 Lipids
• Steroids
2.6 Lipids
• Steroids
– All steroids have four adjacent rings.
2.6 Lipids
• Steroids
– All steroids have four adjacent rings.
– Examples:
 Cholesterol
 Testosterone
 Estrogen
2.6 Lipids
2.7 Proteins
• Proteins have important functions in cells.
– Proteins such as keratin and collagen have
structural roles.
– Proteins are also enzymes that speed up the
chemical reactions of metabolism.
– Proteins such as hemoglobin are responsible
for the transport of substances within the
body.
– Proteins also transport substances across cell
membranes.
2.7 Proteins
• Proteins have important functions in cells.
– Proteins form the antibodies of the immune
system that defend the body from disease.
– Proteins such as insulin are hormones that
regulate cellular function.
– Contractile proteins such as actin and myosin
allow parts of cells to move and muscles to
contract.
2.7 Proteins
• Proteins are comprised of amino acids.
2.7 Proteins
• Amino acids
– Amino group (-NH2)
– Acidic group (-COOH)
– R group (remainder)
2.7 Proteins
2.7 Proteins
• Peptides
– A polypeptide is a single chain of amino acids.
– A peptide bond joins two amino acids.
2.7 Proteins
2.7 Proteins
• Levels of Protein Organization
– The structure of a protein has three or four
levels of organization.
– The final shape of a protein is very important
to its function.
2.7 Proteins
2.7 Proteins
2.7 Proteins
2.8 Nucleic Acids
• DNA (deoxyribonucleic acid)
2.8 Nucleic Acids
• DNA (deoxyribonucleic acid)
• RNA (ribonucleic acid)
2.8 Nucleic Acids
• DNA stores genetic information.
• DNA codes for the order of amino acids in
a protein.
• RNA is an intermediary in the sequencing
of amino acids into a protein.
2.8 Nucleic Acids
• Components of a
nucleotide
– Phosphate
– Pentose sugar
– Nitrogen-containing
base
2.8 Nucleic Acids
DNA Structure
2.8 Nucleic Acids
2.8 Nucleic Acids
• ATP (Adenosine Triphosphate)
2.8 Nucleic Acids
• ATP (Adenosine Triphosphate)
– A high energy molecule
– ATP undergoes hydrolysis and energy is
released
2.8 Nucleic Acids