TIGER

Click on the title of a resource to view it. To save screen space, only the first 3 resources are shown. You can display more resources by scrolling down and clicking on “View all xx results”.

For the textbook, chapter, and section you specified we found
1 Assessment Questions
5 Molecular Structures
25 Journal Articles
25 Other Resources
Assessment Questions: 1 results
Biochemistry : BioElements (20 Variations)
Use the Web-Elements website to identify which of the following biologically important elements are important for nerve function.

(Once you have selected an element, you should scroll down the left frame until you see "element" around us and then select Biology. After you have selected biology once, that information will appear for all subsequent elements chosen.)


Bioinorganic Chemistry
Molecular Structures: First 3 results
Carbon Monoxide CO

3D Structure

Link to PubChem

VSEPR Theory |
Gases |
Toxicology |
Atmospheric Chemistry |
Bioinorganic Chemistry |
Biosignaling |
Organometallics

Hydrogen Peroxide H2O2

3D Structure

Link to PubChem

Oxidation / Reduction |
Nonmetals |
Molecular Properties / Structure |
Bioinorganic Chemistry

Hydrogen Cyanide HCN

3D Structure

Link to PubChem

Acids / Bases |
Nonmetals |
Toxicology |
Bioinorganic Chemistry |
Hydrogen Bonding

View all 5 results
Journal Articles: First 3 results.
Pedagogies:
The A1c Blood Test: An Illustration of Principles from General and Organic Chemistry  Robert C. Kerber
The glycated hemoglobin blood test is a key measure of the effectiveness of glucose control in diabetics. The chemistry of glucose in the bloodstream, which underlies the test and its impact, provides an illustration of the importance of chemical equilibrium and kinetics to a major health problem.
Kerber, Robert C. . J. Chem. Educ. 2007, 84, 1541.
Applications of Chemistry |
Bioinorganic Chemistry |
Carbohydrates |
Mechanisms of Reactions |
Proteins / Peptides |
Bioorganic Chemistry
The Fluorescence of Lignum nephriticum: A Flash Back to the Past and a Simple Demonstration of Natural Substance Fluorescence  Mark Muyskens
This article describes a simple but visually striking demonstration of fluorescence from the aqueous extract of the tropical hardwood Pterocarpus indicus.
Muyskens, Mark. J. Chem. Educ. 2006, 83, 765.
Acids / Bases |
Fluorescence Spectroscopy |
Natural Products |
pH |
Solutions / Solvents |
UV-Vis Spectroscopy
The Discovery and Development of Cisplatin  Rebecca A. Alderden, Matthew D. Hall, and Trevor W. Hambley
Cisplatin is currently one of the most widely used anticancer drugs in the world. The unlikely events surrounding the discovery of its anticancer activity, subsequent introduction into the clinic, and the continuing research into platinum compounds is the subject of this review.
Alderden, Rebecca A.; Hall, Matthew D.; Hambley, Trevor W. J. Chem. Educ. 2006, 83, 728.
Bioinorganic Chemistry |
Coordination Compounds |
Drugs / Pharmaceuticals |
Medicinal Chemistry |
Metallic Bonding |
Oxidation State |
Synthesis
View all 25 articles
Other Resources: First 3 results
Molecular Models of Resveratrol  William F. Coleman
The featured molecules this month are from the paper "Resveratrol Photoisomerization: An Integrative Guided-Inquiry Experiment" by Bernard, Gernigon, and Britz-McKibbin exploring trans to cis photoisomerization in resveratrol. Examination of Figure 1 in that paper, where the hydrogen atoms have been omitted, might lead one to conclude that the structures are relatively straightforward. These isomers provide students an excellent opportunity to test their ability to take a two-dimensional representation and envision the three-dimensional structure of the molecule and to consider the competing factors that might lead to the three-dimensional structures being non-planar. The two-dimensional models focus attention on the possibility of extended pi-electron delocalization. Addition of the hydrogen atoms clearly suggests that delocalization will compete with non-bonded H-H repulsions in the cis isomer. Further examination of the trans isomer shows that such non-bonded interactions are, in what one might call a first-order approximation, like those in biphenyl interactions that lead biphenyl to be non-planar in both the gas phase and in a variety of solvents. The backbone of the trans isomer of resveratrol, trans-stilbene, has been the subject of a number of theoretical and experimental investigations (1, 2). In general, Hartree-Fock calculations predict a non-planar geometry for this molecule while Density Functional Calculations, using the same basis sets, predict an essentially planar structure. Spectroscopic evidence supports a temperature-dependent structure for trans-stilbene with the molecule being planar at low temperature and non-planar at high temperatures. Our calculations on trans-resveratrol produce similar results. Hartree-Fock calculations using the 6-31G** (6- 31G(d,p)) basis set predict a dihedral angle of approximately 24 degrees between each ring and the central carbon-carbon double bond. This result is consistent with the reported value of 23 degrees using the 6-31G* basis set. We also find that DFT calculations using the B3LYP functional and the 6- 31G** basis set, lead to a planar configuration. We include several versions of trans-stilbene and trans-resveratrol in the molecule collection so that students can explore these structural questions in more detail. For each molecule, structures obtained from PM3, HF(6-31G**), and DFT(B3LYP/6-31G**) calculations are included, as well as planar and non-planar structures of biphenyl. Measurement of the various bond and torsion angles using Jmol will help students develop a sense of the distance dependence of the non-bonded interactions and their importance in determining the actual structure. They might also wish to consider what additional degree(s) of freedom resveratrol and stilbene have that biphenyl does not, allowing the trans-form of the former molecules to remain planar under certain conditions, while minimizing the effect of the non-bonded repulsions.
Plant Chemistry |
Natural Products
Molecular Models of Lycopene and Other Carotenoids  William F. Coleman
Over the past decade or so the phrase emerging research suggests has entered the argot of advertising, and that phrase has been applied to this month's Featured Molecule, lycopene, particularly with regard to potential health benefits of tomatoes. The paper by Jie Zhu, Mingjie Zhang, and Qingwei Liu (1) describes an extraction and purification of lycopene from tomato paste using an emulsion rather than the traditional solvent-based extraction. Lycopene is a member of the family of molecules called carotenoids, the most familiar of which is beta-carotene. This family of natural products includes more than 500 members that have been isolated and whose structures have been determined. Professor Hanspeter Pfander's research group at the University of Bern maintains a Web site with a significant amount of information on carotenoid structure, synthesis, and activity (2). Structurally one can think of carotenoids as consisting of three segments, a relatively rigid conjugated central portion with end groups. The end groups are, in general, flexible with respect to rotation about the bond connecting them to the central portion. For example, in beta-carotene, the dependence of total energy on the dihedral angle shown in Figure 1, displays a very broad range of essentially isoenergetic conformations (Figure 2). The energies shown in Figure 2 were calculated at the PM3 level using Hyperchem 7.5 (3). Calculations at the HF/631-G(d,p) level, with many fewer data points, show a similar trend. Many of the health benefits derived from various carotenoids are attributed to their antioxidant activities. Carotenoids react with singlet-oxygen in a physical, diffusion-controlled, quenching process that results in ground state triplet-oxygen and, following a non-radiative relaxation, ground state carotenoid. Of the various carotenoids that have been studied, lycopene and beta-carotene show the greatest quenching rate constants (4). The carotenoids provide us with countless explorations by students and teachers looking for connections between fundamental chemical concepts and real-world applications. Structure, reactivity, chemical synthesis, biosynthesis, and stereochemistry are just a few of the concepts involved in understanding the manifest important roles that these molecules play.
Plant Chemistry |
Natural Products
Molecular Models of Annatto Seed Components  William F. Coleman
In January 2008 the focus of this column was on the plant pigments lycopene and beta-carotene (1). Our attention this month returns to two papers discussing the pigments in annatto seeds (Figure 1), including direct precursors to lycopene. The paper by Teixeira, Dur�n, and Guterres describes the extraction and encapsulation of annatto seed components (2). The McCullagh and Ramos paper describes the separation of the pigment bixin from these seeds by TLC and column chromatography (3). These molecules could form the basis of interesting exercises across the chemistry curriculum. In courses designed for non-majors, students could choose a molecule from the table and search the literature for both scientific and non-scientific sources. Are the claims made in the latter sources regarding the health benefits of these molecules consistent with the scientific data? That discussion could be expanded to the more general question of how one tests the validity of statements made in what are essentially advertisements. Are any of these precursor molecules to lycopene considered to have anticancer properties (4)? In introductory or general chemistry courses, students could explore the various bond lengths and bond angles in the molecules to see whether they are consistent with their expectations based on simple bonding models. In introductory, organic, or biochemistry classes, the thermodynamics of hydrogenation and dehydrogenation could be examined. This might make an interesting alternative to the oft-discussed Haber Process. What conditions would one propose for a dehydrogenation process? Why are dehydrogenation reactions important? What enzymes catalyze the various dehydrogenation steps from phytoene to lycopene? These molecules could also be used in a variety of computational exercises in introductory and physical chemistry courses. Hartree�Fock calculations on a molecule such as phytoene may prove time-consuming depending on the nature of the computing system available. A good place to begin would be to perform semi-empirical calculations on the various molecules. Do the optimized structures match experimental results or the results of larger calculations? Does the HOMO�LUMO gap correlate with the observed electronic absorption spectra? Which is more important in determining the difference in absorption between phytoene and phytofluene, the total number of double bonds or the number of bonds in the region of conjugation? Of course the aspect of these molecules that is most likely to capture student attention is their color, and they provide nice examples of the origin of color, the relationship between color observed and color absorbed, and, in upper level courses, the more detailed relationships of the energies of the ground and excited states.
Plant Chemistry |
Natural Products
View all 25 results