Monday's Molecule #222

Last week's molecule was D-serine. (Not L-serine.) The winner is undergraduate Zhimeng Yu [Monday's Molecule #221].

I was reminded of this week's molecule by a discussion we are having in an evolution forum and by a comment from a student who took a MOOC on genetics. Does it depict something that should be taught in every introductory genetics course? Is it something that should be discussed in an evolution course? You need to name the structure formed by the blue, gray, and black strands. It has a specific name.

Email your answer to me at: Monday's Molecule #222. I'll hold off posting your answers for at least 24 hours. The first one with the correct answer wins. I will only post the names of people with mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

Monday's Molecule #215

Last week's molecule was malonate (propanedioic acid). A derivative of malonate called malonyl-CoA is a key intermediate in fatty acid synthesis. Bill Chaney was the first person to identify the molecule and describe its function [Monday's Molecule #214].

Recently I've been having a discussion with the Chair of my department about whether undergraduates in introductory biochemistry courses should memorize structures. He thinks they should. I wondered whether all the professors in my department could draw the structures of some important molecules. Here are a couple of molecules that you might be able to recognize. How many of you can identify them without checking a textbook?

How many of you can identify them even with a textbook? I'll need a fairly exact identification. Be sure to specify "top" and "bottom" molecules.

Email your answers to me at: Monday's Molecule #215. I'll hold off posting your answers for 24 hours. The first one with the correct answer wins. I will only post the names of people with mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

Monday's Molecule #234

Last week's molecules [Monday's Molecule #233] were oxaloacetate, ethanol, lactate, alanine, and acetyl-CoA. All of them can be synthesized in a reaction using pyruvate as a substrate (two steps to make ethanol). All of them are precursors to pyruvate and hence glucose. The winner is Jean-Marc Neuhaus. I will be buying him four meals next time I visit Switzerland. I'm thinking it will be two raclettes and two fondues with lots of wine.

This week's molecule (left) is probably not very familiar to most of you so I don't anticipate many correct answers. You can use the common name. Email your answer to me at: Monday's Molecule #234. I'll hold off posting your answers for at least 24 hours. The first one with the correct answer wins. I will only post the names of people with mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

Monday's Molecule #193

Last week's molecule was capsaicin, the molecule responsible for the "hot" sensation of chili peppers. There were two winners: Seth Kasowitz and Bill Gunn [Monday's Molecule #192].

This week's molecule is featured in an article that I will (hopefully) blog about in the next few days. There's a common name of sorts but you will need to supply the correct IUPAC name to win the free lunch.

Post your answer as a comment. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.)

Monday's Molecule #160

 

This is a very important molecule for some species. It's important to me, for example, because I worked with it in an undergraduate research project forty-nine many years ago.

UPDATE: The original structure was missing a methyl group at the bottom right. This has now been corrected.

Identify the molecule—the common name will do but make sure you get it right because there are quite a few similar molecules. You must also say why it's important for some species.

Post your answer in the comments. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post correct answers to avoid embarrassment.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.)

Some past winners are from distant lands so their chances of taking up my offer of a free lunch are slim. (That's why I can afford to do this!)

In order to win you must post your correct name. Anonymous and pseudoanonymous commenters can't win the free lunch.

Winners will have to contact me by email to arrange a lunch date.

Comments are invisable for 24 hours. Comments are now open.

UPDATE: The molecule is a gibberellin-like molecule. It was intended to be gibberellin GA1 but I left off a methyl group. This is similar to Monday's Molecule #102 (gibberellin GA3). Defects in one of the genes for gibberellin GA1 synthesis gave rise to the tall/short phenotype studied by Gregor Mendel [Mendel's Stem Length Gene (Le)]. Gibberellin GA1 was one of the molecules synthesized by Elias James Corey, winner of the Nobel Prize in Chemistry 1990. The winner this week is Albi Celaj.

Winners
Nov. 2009: Jason Oakley, Alex Ling
Oct. 17: Bill Chaney, Roger Fan
Oct. 24: DK
Oct. 31: Joseph C. Somody
Nov. 7: Jason Oakley
Nov. 15: Thomas Ferraro, Vipulan Vigneswaran
Nov. 21: Vipulan Vigneswaran (honorary mention to Raul A. Félix de Sousa)
Nov. 28: Philip Rodger
Dec. 5: 凌嘉誠 (Alex Ling)
Dec. 12: Bill Chaney
Dec. 19: Joseph C. Somody
Jan. 9: Dima Klenchin
Jan. 23: David Schuller
Jan. 30: Peter Monaghan
Feb. 7: Thomas Ferraro, Charles Motraghi
Feb. 13: Joseph C. Somody

---

Monday's Molecule #123: Winners

 
UPDATE: The "molecule" is a normal electrocardiograph (ECG) of a human heartbeat [see Wikipedia: Electrocardiography]. The Nobel Laureate is Willem Einthoven.

There were eight responses in the first hour. The winner is Òscar Reig of Barcelona! This is our first European winner in many months. I guess I'll have to start posting Monday's Molecule much earlier in the day to give Europe a chance. (Australia doesn't get a chance.)

The undergraduate winner is Maria Altshuler of the University of Toronto who just became eligible after winning last month. Congratulations to Òscar and Maria.

This week there were four Europeans and one South American in the hunt. Not only do my Canadian friends need to be worried, but the Americans are also being challenged! I even had a correct entry from Singapore. That presents a real challenge when I try to calculate the winning time. Why can't they use the same day we use?

---

You've probably noticed already that today's "molecule" isn't exactly a molecule. That's OK, you can still try to guess what it is. I want a fairly complete description of what you see here. This is supposed to be easy in order to encourage some new readers to enter the contest. There was no winner last week!!!

There's a Nobel Prize associated with this diagram.

The first person to describe the graph and identify the Nobel Laureate wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first won the prize.

There are five ineligible candidates for this week's reward: Laura Gerth of the University of Notre Dame, Stefan Tarnawsky of the University of Toronto, Dima Klenchin of the University of Wisconsin, Madison, Adam Santoro of the University of Toronto., and Michael Clarkson of Waltham MA (USA).

The Americans have pulled ahead of the Canadians and the rest of the world is being shut out. Where are the Europeans? Are they just stupid or don't any of them stay up late? BTW, I want to thank all those smart Canadians who have been holding back in order to give the rest of the world a chance.

I still have one extra free lunch donated by a previous winner (Michael Clarkson) to a deserving undergraduate so I'm going to continue to award an additional free lunch to the first undergraduate student who can accept it. Please indicate in your email message whether you are an undergraduate and whether you can make it for lunch.

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Prizes so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.

Correct responses will be posted tomorrow.

Comments will be blocked for 24 hours.

---

Monday's Molecule #22

 
Name this molecule. This is very easy for any student who's ever taken a biochemistry course. The goal here is to show everyone else just how important this molecule is for understanding basic biochemistry.

As usual, there's a connection between Monday's molecule and this Wednesday's Nobel Laureate. This one's hard because the connection isn't obvious. (Hint: It's related to last week's molecule and Nobel Laureate.) The prize (free lunch) goes to the person who correctly identifies both the molecule and the Nobel Laureate. (Previous free lunch winners are ineligible for one month from the time they first won.)

Comments will be blocked for 24 hours. Comments are now open.

Monday's Molecule #29

 

Today's molecule is my first example of a protein. I've given you two different views of the molecule showing most of it as a ribbon model. A small stretch of the polypeptide is displayed as a stick model. You have enough information to identify the protein provided you have taken the appropriate courses in high school or college. All we need is the name of the protein but if you can identify the species and the PDB file that would be an impressive feat of detective work.

As usual, there's a connection between Monday's molecule and this Wednesday's Nobel Laureate(s). This one is an direct connection. Once you have identified the molecule the Nobel Laureate(s) are obvious.

The reward (free lunch) goes to the person who correctly identifies both the molecule and the Nobel Laureate(s). Previous free lunch winners are ineligible for one month from the time they first collected the prize. There are no ineligible candidates for this Wednesday's reward since recent winners have declined the prize on the grounds that they live in another country and can't make it for lunch on Thursday. There was no winner last week although several people were close.

Comments will be blocked for 24 hours. Comments are now open.

Monday's Molecule #37

 
Today's molecule looks complicated but it has a very simple name. The short common name of this molecule is not sufficient—you have to supply the correct biochemical name that distinguishes this molecule from similar ones found inside all cells. You're more than welcome to supply the complete IUPAC name if you know it.

There's an indirect connection between this Monday's Molecule and Wednesday's Nobel Laureate(s).

The reward (free lunch) goes to the person who correctly identifies the molecule and the Nobel Laureate(s). Previous free lunch winners are ineligible for one month from the time they first collected the prize. There's only one (Marc) ineligible candidates for this Wednesday's reward since many recent winners haven't collected their prize. The prize is a free lunch at the Faculty Club.

Comments will be blocked for 24 hours. Comments are now open.

Monday's Molecule #195

Last week's molecule was allantoin, the breakdown product of uric acid that's found in the urine of mammals. Other animals can degrade allantoin to more simple compounds but mammals have lost the genes for this pathway. The winners were Paul Clapham and Jacob Troth [Monday's Molecule #194]. They should contact me by email.

This week's molecule is a ubiquitous and essential molecule in all species. Give the common name but be sure you don't confuse it with other, very similar, molecules.

Post your answer as a comment. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.)

Monday's Molecule #105

 
Monday's molecule is on Tuesday this week. Sorry for the delay, I've been busy with a mid-term test in my introductory biochemistry course.

You have to identify this molecule. The role of this molecule in a particular species was elucidated by a Nobel Laureate in the second half of the 20th century. We need the name of the Nobel Laureate who first isolated and characterized the protein.

Your task is to correctly identify the molecule and the species from which it was purified. You also need to name the Nobel Laureate. The first one to do so wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first collected the prize.

There are five ineligible candidates for this week's reward: Dima Klenchin of the University of Wisconsin, Bill Chaney of the University of Nebraska, Maria Altshuler of the university of Toronto, Ramon, address unknown, and Jason Oakley of the University of Toronto.

Dima and Bill have offered to donate their free lunch to a deserving undergraduate so the next two undergraduates to win and collect a free lunch can also invite a friend. Since undergraduates from the Toronto region are doing better in this contest, I'm going to continue to award an additional free lunch to the first undergraduate student who can accept a free lunch. Please indicate in your email message whether you are an undergraduate and whether you came make it for your free lunch (with a friend).

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Laureate(s) so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.

Correct responses will be posted tomorrow. I reserve the right to select multiple winners if several people get it right.

Comments will be blocked for 24 hours.

---

Ethidium Bromide Binds to DNA

 
Last Monday's Molecule was ethidium, better known by the name of its common salt, ethidium bromide [Monday's Molecule #35]. Ethidium is a large planer molecule that binds tightly to DNA. It is often used in biochemistry laboratories to visualize fragments of DNA that have been separated on gels. The ethidium molecule is fluorescent—when illuminated with ultraviolet light it shines in the visible range. Here's a picture (below right) of DNA fragments that are illuminated by ethidium binding. It's from an old paper of mine (Moran et al. 1979)—these days you usually can't publish simple experiments like this.

Ethidium binds by inserting itself bewteen the stacked bases in double-stranded DNA. Note that the ring structure of ethidium is hydrophobic and resembles the rings of the bases in DNA. Ethidium is capable of forming close van der Walls contacts with the base pairs and that's why it binds to the hydrophobic interior of the DNA molecule.

Molecules that bind in this manner are called intercalating agents because they intercalate into the compact array of stacked bases. In doing so, they distort the double helix and interfere with DNA replication, transcription, DNA repair, and recombination. This is why intercalating agents are often potent mutagens.

The cartoon below shows the distortion of the sugar-phosphate backbone when an intercalating agent bind and it also shows that the DNA is lengthened when intercalating agents bind. This changes the properties of DNA considerably. One of the tricks in separating closed circular molecules of DNA from linear fragments (such as genomic DNA) is to treat the DNA with ethidium bromide. The intercalating agent doesn't bind to closed circular molecules because they can't be lengthened enough to allow insertion of the chemical between the bases. The normal circular plasmid DNA can then be separated from linear DNA with bound ethidium because binding of ethidium changes the overall density of DNA.



The structure shown above (right) is from Reha et al. (2002). It shows a molecule of ethidium lying between two A/T base pairs.

---

Moran,L., Mirault, M-E., Tissières, A., Lis, J., Schedl, P., Artavanis-Tsakonas, S., and Gehring, W. (1979) Physical Map of Two D. melanogaster DNA Segments Containing Sequences Coding for the 70,000 Dalton Heat Shock Protein. Cell 17:1-8.

Reha, D., Kabelác, M., Ryjácek, F., Sponer, J., Sponer, J.E., Elstner, M., Suhai, S., and Hobza, P. (2003) Intercalators. 1. Nature of stacking interactions between intercalators (ethidium, daunomycin, ellipticine, and 4',6-diaminide-2-phenylindole) and DNA base pairs. Ab initio quantum chemical, density functional theory, and empirical potential study. J. Am. Chem. Soc. 124:3366-76.

Monday's Molecule #81

 
Today's molecule is not a specific molecule but rather a type of molecule. You have to identify the type of molecule shown here.

There's a connection between today's molecule and a Nobel Prize. The clue is the red "P" atom in the molecule. The Nobel Prize was awarded for discovering where that red "P" came from and how quickly this type of molecule was produced. Similar studies were done with many other "P"-containing molecules. This was the beginning of a whole new field of study in biochemistry.

The first person to correctly identify the type of molecule and name the Nobel Laureate(s), wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first collected the prize. There are four ineligible candidates for this week's reward. You know who you are.

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Laureate(s) so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.

Correct responses will be posted tomorrow. I may select multiple winners if several people get it right.

Comments will be blocked for 24 hours. Comments are now open.

UPDATE: The molecule is a phosphatidate. It's an intermediate in the synthesis of triacylglycerols or glycerophospholipids. The R₁ and R₂ groups represent strings of -CH₂- groups, usually sixteen or eighteen carbons.

The phosphorus (P) atom is derived indirectly from inorganic phosphate and the incorporation of radioactive phosphorus as phosphate (³²PO₄^2-) into phosphatides was first studied by George de Hevesy. He received the Nobel Prize in 1943 for his work on using radioisotopes to study the synthesis of biological molecules such as phosphatides.

Lots of people knew that the molecule was a phosphatidate but nobody got the Nobel Laureate so there are no winners this week.

---

Monday's Molecule #194

Last week's molecule was N-(2-aminoethyl)glycine, a molecule that has been used to build artificial DNA molecules. The winner was Michael Rasmussen [Monday's Molecule #193].

This week's molecule is a real pisser. You'll have to give the complete, unambiguous, formal name AND explain why we don't make it.

Post your answer as a comment. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.)

Monday's Molecule #219

Last week's molecule was cobalamin or vitamin B12. The structure was solved by Dorothy Crowfoot Hodgkin who won the Nobel Prize in Chemistry in 1964. There have been ten Nobel Prizes for work on vitamins and coenzymes. There were a lot of people who got this one right. The winner is Piotr Gasiorowski. The undergraduate winner is Jacob Toth [Monday's Molecule #218]. That makes four lunches that I owe Jacob. Right now, he's far away (British Columbia) but he may be coming to Toronto to collect. That may cut down on his chances of winning!

Today's molecule is a very common enzyme found in all species (I don't know of any exceptions). It's part of a pathway that's familiar to all biochemistry students. The figure illustrates a classic "induced fit" mechanism of substrate binding where the binding of one substrate creates the binding pocket for the second substrate. In this case, it's the homodimeric animal version of the enzyme showing rotation of the small domain of one of the subunits. Name the enzyme and the reaction it catalyzes.

There's more. In order to win a free lunch you have to explain something else. It's related to the fundamental concepts that all biochemistry students should know. The standard Gibbs free energy change for the reaction catalyzed by this enzyme is ΔG°′ = -31.5 kJ mol^-1. What does that mean if you are trying to understand the reaction that takes place inside the cell? Is there a reason why this reaction isn't coupled to synthesis of ATP? I'm interested in seeing how most Sandwalk readers understand the fundamental concept of reaction thermodynamics.

Email your answers to me at: Monday's Molecule #219. I'll hold off posting your answers for at least 24 hours. The first one with the correct answer wins. I will only post the names of people with mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

Monday's Molecule #216

Last week's molecules were guanine and adenine. Everyone should have known these structures but only undergraduate Zhimeng Yu got it right! [Monday's Molecule #215].

You probably didn't memorize the structure of this week's molecule but you should be able to recognize it and check your answer in a textbook or on the web. What it is it? (I don't know why it has a gray background. Can anyone help? Fixed.)

Email your answers to me at: Monday's Molecule #216. I'll hold off posting your answers for at least 24 hours. The first one with the correct answer wins. I will only post the names of people with mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

Monday's Molecule #58

 
This is one example of a very common molecule found in every cell. You have to give us the common name of this molecule and identify the species. You'll be pleased to know that I don't need the systematic IUPAC name for this one.

There's a direct connection between this molecule and Wednesday's Nobel Laureate. Your task is to figure out the significance of today's molecule and identify the Nobel Laureate who studied its function. (Hint: The Nobel Laureate is a Canadian—there aren't very many Canadian Nobel Laureates so this is a very big hint.)

The reward goes to the person who correctly identifies the molecule and the Nobel Laureate. Previous winners are ineligible for one month from the time they first collected the prize. There is one ineligible candidates for this week's reward because Sandwalk readers were not very successful in December. The prize is a free lunch at the Faculty Club.

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk(at)bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and the Nobel Laureate. Note that I'm not going to repeat Nobel Laureates so you might want to check the list of previous Sandwalk postings.

Correct responses will be posted tomorrow along with the time that the message was received on my server. I may select multiple winners if several people get it right.

Comments will be blocked for 24 hours. Comments are now open.

UPDATE: We have a winner! This one proved to be far more difficult than I imagined. Everyone got the Nobel Laureate (Sidney Altman) but very few people got the molecule correct. Some people failed to identify the species correctly even though I specifically asked for the species. Most people said that the molecule is RNase P but that isn't quite correct.

The molecule is the M1 RNA subunit of RNase P from E. coli. The other subunit is a small protein called the C5 protein cofactor. This RNA is sometimes called RNA P and that would have been an acceptable answer.

Only one person got everything right and that response just arrived a few minutes ago. Congratulations to PonderingFool for knowing that the molecule was the M1 RNA component of E, coli RNase P and the Nobel Laureate is Sidney Altman.

---

Monday's Molecule #236

Last week's molecule [Monday's Molecule #235] was N-formylmethionyl-tRNA_f^Met (fMet-tRNA_f^Met). The polynucleotide has to be specifically identified as the initiator tRNA (tRNA_f^Met, in bacteria). The winner is Jon Binkley. As I expected, there were very few people who got the right answer—in fact, there was only one other correct answer.

This week's molecules (below) may look very familiar but don't be fooled. You'll have to be very careful in identifying and naming each one of the stereoisomers. (Use common names.)

Email your answer to me at: Monday's Molecule #236. The first one with the correct answer wins. I will only post the names of winners to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

Monday's Molecule #233

Last week's molecules [Monday's Molecule #232] were all-trans and 13-cis retinal. Retinal is the active protein donor/acceptor in bacteriorhodopsin. The all-trans form is shifted to the 13-cis form when a photon of light is absorbed. The retinal molecules are arranged within the membrane-bound bacteriorhodpsin in a way that binding and release of a proton results in transport from the cytoplasm to the exterior. The creation of a proton gradient drives ATP synthesis.

The winner is Philip Johnson from Switzerland.

This week's molecule (left) is actually a collection of molecules. Name all five molecules and tell me what they have in common from a biochemical perspective. Common names will do.

Email your answer to me at: Monday's Molecule #233. I'll hold off posting your answers for at least 24 hours. The first one with the correct answer wins. I will only post the names of people with mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

Monday's Molecule #107: Winners

 
The red arrow points to a lysosome and the blue arrows identify peroxisomes. The man who discovered and characterized these organelles is Christian de Duve (1974)

This week's winners are regulars: Dima Klenchin of the University of Wisconsin and undergraduate Alex Ling of the University of Toronto.

---

This Monday's "molecule" looks a lot like an electron micrograph of a cell instead of a molecule. That's because it's hard to connect a specific molecule with some Nobel Laureates. Your task today is to identify the two things identified by the red and blue arrows.

There's one Nobel Laureate who is closely identified with the discovery of these two things. Name this Nobel Laurete.

The first person to identify the images and the Nobel Laureate wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first won the prize.

There are eight ineligible candidates for this week's reward: Bill Chaney of the University of Nebraska, Maria Altshuler of the University of Toronto, Ramon, address unknown, Jason Oakley of the University of Toronto, John Bothwell from the Marine Biological Association of the UK, in Plymouth (UK), Wesley Butt of the University of Toronto, David Schuller of Cornell University, and Nova Syed of the University of Toronto.

Bill, John, and David have offered to donate their free lunch to a deserving undergraduate so the next two undergraduates to win and collect a free lunch can also invite a friend. Since undergraduates from the Toronto region are doing better in this contest, I'm going to continue to award an additional free lunch to the first undergraduate student who can accept a free lunch. Please indicate in your email message whether you are an undergraduate and whether you came make it for your free lunch (with a friend).

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Laureate(s) so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.

Correct responses will be posted tomorrow. I reserve the right to select multiple winners if several people get it right.

Comments will be blocked for 24 hours. Comments are now open.

---