Packet 3: Bonus 9
When used for protein expression, IPTG is often added to a liquid culture of this bacteria in a shaking incubator. For 10 points each:
[10e] Name this common gram-negative rod-shaped bacteria used as a model organism. The lac operon was discovered in this bacteria.
ANSWER: E. coli [or Escherischa coli]
[10m] Giuseppe Bertani and this scientist name a rich liquid medium for bacterial culture containing tryptone and yeast extract. This scientist and an alphabetically-earlier collaborator conducted an experiment showing mutations arise spontaneously and not in response to pressure.
ANSWER: Salvador Edward Luria [accept Luria-Bertani medium; accept Luria-Delbruck experiment]
[10h] The progress of liquid bacterial cultures is most commonly quantified by measuring optical density at this wavelength, often abbreviated as “OD” followed by the value. Express your answer in nanometers.
ANSWER: 600 nanometers [accept OD600]
<Editors, Biology> | C. Prelims 3 - Cambridge + UCLA + Stanford B + Virginia
| Heard | PPB | E % | M % | H % |
|---|---|---|---|---|
| 21 | 15.71 | 91% | 57% | 10% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| Brown | NYU A | 10 | 10 | 0 | 20 | EM |
| Chicago A | Georgia Tech A | 0 | 10 | 0 | 10 | M |
| Chicago B | Toronto B | 10 | 0 | 0 | 10 | E |
| Columbia A | North Carolina | 10 | 10 | 10 | 30 | EMH |
| Georgetown | Texas | 10 | 0 | 0 | 10 | E |
| Georgia Tech C | Bruin | 10 | 0 | 0 | 10 | E |
| Harvard | Swarthmore | 10 | 10 | 0 | 20 | EM |
| Illinois B | Northwestern A | 0 | 10 | 0 | 10 | M |
| Indiana | Columbia B | 10 | 10 | 0 | 20 | EM |
| Johns Hopkins | Vanderbilt | 10 | 10 | 0 | 20 | EM |
| MIT | Maryland A | 10 | 10 | 10 | 30 | EMH |
| Michigan | Stanford A | 10 | 10 | 0 | 20 | EM |
| NYU B | Pittsburgh | 10 | 0 | 0 | 10 | E |
| Penn State | Minnesota | 10 | 0 | 0 | 10 | E |
| Toronto A | Purdue | 10 | 10 | 0 | 20 | EM |
| UC Berkeley A | British Columbia | 10 | 0 | 0 | 10 | E |
| UC Berkeley B | Northwestern B | 10 | 10 | 0 | 20 | EM |
| UCF | Rutgers | 10 | 0 | 0 | 10 | E |
| Virginia Tech | Georgia Tech B | 10 | 10 | 0 | 20 | EM |
| WashU | Ohio State | 10 | 0 | 0 | 10 | E |
| Waterloo | Cornell | 10 | 0 | 0 | 10 | E |
Summary
| Tournament | Edition | Match | Heard | PPB | E % | M % | H % |
|---|---|---|---|---|---|---|---|
| Main Site | 2026-04-17 | ✓ | 21 | 15.71 | 91% | 57% | 10% |