Student’s Corner
Enigma
Eight riddles with the answers shut. Hints and answers open without sending anything to a server.
These are not trick questions dressed up as wisdom. Each one has a definite answer on this site. Write yours down before you open the panel. The hint is allowed. The answer is a last resort, and then you should be able to say where on the site the fuller story lives.
Enigma 1
I am three RNA letters. I start most protein stories a ribosome tells, and I am also the name of an amino acid. What am I?
Show a hint
In DNA spelling I begin with A and end with G, and the middle letter is the one DNA uses where RNA uses U.
Show the answer
AUG, methionine. It is the usual start codon and the only standard codon for methionine. On the codes bench it is marked as the start.
Enigma 2
I killed the idea that life appears in a nutritious soup by itself. My neck was bent so that dust would settle and air could still pass. What am I?
Show a hint
The liquid inside me had been boiled. I stayed clear until someone tipped the dust back in.
Show the answer
Pasteur’s swan-neck flask. The experiment is written out on the experiments page.
Enigma 3
I am a photograph of a fibre, number 51. The model builders were not the people who took me. What am I, and who held the camera?
Show a hint
I was published in Nature on 25 April 1953, beside two other papers.
Show the answer
Photo 51, the X-ray diffraction image of DNA made by Rosalind Franklin and Raymond Gosling. See landmark discoveries.
Enigma 4
A letter from the Malay Archipelago forced another naturalist to publish a theory he had been sitting on for years. Who sent the letter?
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He had the same mechanism, from a fever in the islands, not from a voyage on the Beagle.
Show the answer
Alfred Russel Wallace. The joint announcement with Darwin was in 1858. Both names are kept on the world contributions page.
Enigma 5
I was a halo on a plate of staphylococci, left by a mould that was not invited. The observation is famous. The medicine took other people more than a decade. What molecule began there?
Show a hint
The mould is a Penicillium. Oxford, not the first observer, made the therapy.
Show the answer
Penicillin. Fleming saw the halo in 1928. Florey, Chain, Heatley, and colleagues made it a drug. The fuller caution is under serendipities.
Enigma 6
I am not a bacterium, though I was filed with them for years. A small ribosomal RNA gave me away as a separate domain of life. What am I called now?
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The 1977 paper is by Carl Woese and George Fox. Hot springs and salt lakes are full of my relatives, and so are ordinary places.
Show the answer
Archaea. The discovery is in the code and sequence era and under Woese.
Enigma 7
Cattle ate spoiled sweet clover and their blood would not clot. The molecule that explained the deaths later became both a rat poison and a carefully dosed medicine. Name the molecule or the medicine.
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The laboratory was Karl Paul Link’s, in Wisconsin. Vitamin K is the pathway I block.
Show the answer
Dicoumarol, and its more potent relative warfarin. The story is under serendipities.
Enigma 8
I am a bacterial memory of viruses, written as odd repeats long before anyone wanted to edit a gene. What system am I?
Show a hint
Ishino reported the repeats without a function in 1987. A programmable cut came much later, and this site does not teach you how to make one.
Show the answer
CRISPR–Cas, an adaptive immune system. The chain of names is under serendipities.