Nucleotides / Lipids
Pyrimidines
Purines
Base | Ribonucleoside |
Ribonucleotide |
(Base + Ribose) | (Base + Ribose + Phos.) | |
Adenine(A) | Adenosine | Adenosine 5'-monophosphate(AMP) |
Guanine(G) | Guanosine | Guanosine 5'-monophosphate(GMP) |
Cytosine(C) | Cytidine | Cytidine 5'-monophosphate(CMP) |
Uracil(U) | Uridine |
Uridine 5'-monophosphate(UMP) |
Ribose:
A "Ribonucleoside", A "Deoxyribonucleoside", A "Ribonucletide"
AMP
ADP
ATP
Learning the Names and Structures of the Nucleic Acids
Ribonucleotides are the Monomeric Units of Nucleic Acids
Nucleotides (ribonucleotides) can be linked sequentially to form nucleic acids (store and transmit genetic information).
Nucleotide Derivatives:
Many biosynthetic reactions in carbohydrate metabolism require nucleotide derivatives.
i.e. Glucose-1-phosphate + ATP ----> ADP-glucose
Lipids:
Large group of biomolecules soluble only in hydrophobic (non-polar) solvents.
Can be subdivided into:
fatty acids.
phospholipids.
steroids.
Fatty Acids:
-have an acidic head group and a long hydrocarbon tail.
-saturated (no -C=C-), unsaturated (-C=C-), polyunsaturated
Some Common Fatty Acids:
Myristic CH3(CH2)12COOH
Palmitic CH3(CH2)14COOH
Oleic CH3(CH2)7CH=CH(CH2)7COOH
Linoleic CH3(CH2)3(CH2CH=CH)2(CH2)7COOH
Linolenic CH3(CH2CH=CH)3(CH2)7COOH
Arachidonic CH3(CH2)3(CH2CH=CH)4(CH2)3COOH
Triacylglycerol Formation: storage form of fatty acids
Glycerol + Palmitic Acid (x3)
Phospholipids:
Most prevalent class of lipids in membranes.
Variations.......
Phospholids can have one of their oxygens on the phosphate group attached to:
Choline -O-CH2CH2N(CH3)3
Ethanolamine -O-CH2CH2NH3
Serine -O-CH2CH(+NH3)(CO2-)
Inositol
Dipalmitoyl Phosphatidylcholine (DPPC), "Lecithin"
Steroids:
Cholesterol
Clinical Correlate: Infant Respiratory Distress Syndrome
-In utero, the developing fetus exists in a fluid environment, the lungs are collapsed (oxygenation occurs across the placenta).
-At birth the newborn is suddenly exposed to air, the lungs must expand and fill w/ air.
-Because of the high surface tension, caused by H-bonding of water molecules, this requires a significant amount of energy.
-The energy barrier is decreased with Lung Surfactant: phospholipids, primarily DPPC (Lecithin) and proteins. These amphiphilic compounds form "sheets" in an aqueous environment reducing the surface tension between water molecules and decreasing the energy barrier.
-This surfactant prevents lung collapse in newborns as well as adults.
-Premature infants are deficient in surfactant.
-Hyaline Membrane Disease is defined as progressive respiratory failure in premature infants caused by inadequate surfactant and structurally immature lungs.
-Survanta is an artificial surfactant comprised of bovine lung extract containing phospholipids and proteins, with added lecithin.
-When administered to premature infants it mimics the surface tension lowering properties of natural lung surfactant -----> allowing CO2to escape the lungs and oxygenation of the blood.
© Dr. Noel Sturm 2014