Preparation for Exam 2
Exam Date: Monday, October 27
The exam will cover nucleic acids, carbohydrates, lipids, and membranes. It will
emphasize problems dealing with major concepts taught in each of these sections.
Nucleic Acids
You will be expect to know the basic anatomy of nucleotides. You should be able to
draw the structure of all the purine and pyrimidine rings. Know the difference between a
nucleoside and a nucleotide. Know the structure of ATP, NAD, NADP, UDP-glucose,
CDP-choline. Know how nucleotides link together. The meaning of 5’ and 3’ when
discussing the ends of the chain. Know the structure of DNA: bases per turn, X-ray
diffraction pattern, H-bonding pairs, major and minor grooves, palindrome sequences.
Know what restriction nucleases are and how they act specifically on DNA. Be able to
draw the complementary strand a given DNA strand and be able to explain the principle
behind didexoy DNA sequencing analysis.
Carbohydrates
Much of carbohydrates deals with nomenclature. Study the terms and know what they
mean, not just spelling the words correctly. Know D from L sugars; alpha anomers from
beta anomers, pentoses from hexoses, ketoses from aldoses, furanose from pyranoses,
enantiomers from diastereoisomers, reducing from non-reducing, hemiacetals from
hemiketals, aldonic from uronic sugars. Be able to draw the structures of D-glucose, Dgalactose, D-mannose, D-fructose, D-ribose. Know how sugars link to one another.
Know the meaning of a glycoside, a glycosidic bond. Know the structures of maltose,
lactose, sucrose, cellobiose. Know the homopolysaccharides: the structure of amylose
and amylopectin, glycogen. Know dextrose, dextrin, limit dextrin. Know how
polysaccharides form branch chains, how debranching enzyme works, the action of
amylase. Know the heteropolysaccharides and give examples of the major repeating
disaccharides in hyaluronate, chondroitin sulfates, heparin sulfate, and keratin sulfate.
Know how sugars link to proteins, the structure of proteoglycans found in mucous
secretions and fluids. Know the difference between proteoglycans and glycoproteins,
how oligosaccharide chains attach to proteins, the basic structure of these chains
including sialic acid. .
Lipids
Know the definition of a lipid and its properties. Know a simple from a complex lipid, an
amphipathic from a non-polar molecule, hydrophobic from hydrophilic groups in lipids.
Know by structure and name C:14, C:16, C:18 and C:20 saturated fatty acids. Know by
structure and name C:18 unsaturated fatty acids and polyunsaturated fatty acids.
Compare melting points and physical appearance of saturated and unsaturated fatty acids
In complex lipids, distinguish by structure a triacylglycerol, diacylglycerol,
monoacylglycerol form a diacylglycerol phosphate. Know by name and by structure the
phospholipids: phosphatidate, phosphatidy-(ethanolamine, serine, choline, inositol).
Know the steroids, cholesterol, steroid hormones, vitamin D3. Know sphingolipids,
sphingomyelin, ceramide, cerebroside. Know the structure of glycolipids. Know the
basics of terpenes, the structure of vitamin A. Know the action of detergents. Know the
difference between micelles, mono- and bilayers. Know the importance of amphipathic
properties of lipids in forming membranes. Know membrane properties such as lateral
and transverse diffusion. Know what is meant by liquid crystal, phase transition and how
cholesterol modulates the properties of the cell membrane.
Membranes
Know the distinguishing features of the unit membrane and fluid mosaic models of the
cell membrane. Know transport across the membrane via simple diffusion, facilitated
diffusion, active transport, and endocytosis. . Know integral from peripheral proteins
using glycophorin as an example. . Know the meaning of and be able to solve problems
that deal with chemical potential, membrane potential, and electrochemical potential.
Know the mechanisms of mediated transport, examples of active transport as shown by
Ca-ATPases, Na/KATPases. Know the significance of mechanisms that use uniport,
symport, and antiport modes of transport. Know the action of ionophores as channels and
as carriers. Know the function of valinomycin and gramicidin A. Know the features that
give rise to density differences in blood lipids chylomicrons, VLDL, IDL, LDL and
HDL. Know the mechanism by which a cell absorbs cholesterol from LDL.