nitrogen fixation - 2025 ACF Winter

Question

A glutamine-dependent signaling cascade that initiates this process begins with de-uridylation of P-II and GlnK, culminating in the transcription of nif genes. For 10 points each:

[10m] Name this process. An enzyme central to this process uses 16 ATP molecules in tandem with molybdenum-iron or vanadium-iron cofactors to reduce its triply-bonded substrate.

ANSWER: nitrogen fixation [prompt on nitrogen assimilation; prompt on assimilation or fixation]

[10h] Low nitrogen triggers rhizobia to secrete signaling lipochitooligosaccharides (“lipo-kite-oh-oligo-saccharides”), which are factors named for stimulating and forming these structures. These structures are mutualistic interaction sites between plants and nitrogen-fixing bacteria.

ANSWER: nodules [prompt on nod factors or nodulation]

[10e] Nodules are affixed to these plant organs, which are responsible for uptake of inorganic nutrients and water from soil.

ANSWER: roots

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Summary


California	Main	Y	3	16.67	100%	33%	33%
Canada	Main	Y	5	16.00	100%	40%	20%
Florida	Main	Y	7	14.29	100%	43%	0%
Great Lakes	Main	Y	2	10.00	100%	0%	0%
Lower Mid-Atlantic	Main	Y	3	13.33	100%	0%	33%
Midwest	Main	Y	5	18.00	100%	40%	40%
North	Main	Y	7	18.57	100%	43%	43%
Northeast	Main	Y	2	15.00	100%	50%	0%
Overflow	Main	Y	4	20.00	100%	75%	25%
Pacific Northwest	Main	Y	8	16.25	100%	25%	38%
South Central	Main	Y	1	10.00	100%	0%	0%
Southeast	Main	Y	8	11.25	100%	13%	0%
UK	Main	Y	3	16.67	100%	33%	33%
Upstate NY	Main	Y	5	14.00	100%	0%	40%
2025 ACF Nationals	2025-08-09	Y	7	15.71	100%	14%	43%
2024 ARCADIA at UC Berkeley	04/19/2025	Y	1	10.00	100%	0%	0%

Data


Berkeley A	Berkeley B	0	10	10	20
Berkeley D	Berkeley C	10	0	10	20
Stanford A	Stanford B	0	0	10	10
UCI	UCLA A	0	0	10	10
UCLA B	UCSD What Hath God Wrought	10	10	10	30
UCLA C	UCLA D	0	0	10	10
Claremont Pitzer	UCSB	0	0	10	10
USC	UCSD Two Running Violet V Forms	10	0	10	20
McMaster C	Carleton	0	0	10	10
Guelph A	Toronto C	0	0	10	10
McMaster A	McGill A	10	0	10	20
Toronto A	Ottawa	10	0	10	20
UF E	FSU	0	0	10	10
Melbourne B	UCF A	0	0	10	10
OSU D	CWRU A	0	0	10	10
OSU A	Pitt A	0	0	10	10
OSU B	MSU A	0	10	10	20
McGill B	Toronto I	0	0	10	10
Toronto J	Toronto G	0	0	10	10
Clemson A	Virginia B	0	10	10	20
South Carolina B	NC State	0	0	10	10
North Carolina A	Liberty B	10	0	10	20
North Carolina B	North Carolina C	0	10	10	20
Virginia A	Tennessee A	10	0	10	20
Toronto B	Toronto D	10	0	10	20
George Mason A	Maryland D	0	0	10	10
Penn A	George Mason B	10	0	10	20
Georgetown B	Catholic University	0	0	10	10
Maryland A	Georgetown A	0	10	10	20
Maryland B	Johns Hopkins C	10	10	10	30
NYU A	Johns Hopkins A	0	0	10	10
NYU B	UMBC A	10	10	10	30
Columbia B	Princeton A	10	0	10	20
Swarthmore A	Rutgers C	0	0	10	10
Missouri B	Truman State	0	0	10	10
WashU A	William Woods	10	10	10	30
Missouri A	WashU B	10	0	10	20
SIUE	WashU C	10	0	10	20
Chicago B	Purdue A	10	10	10	30
Kentucky	Chicago C	0	0	10	10
Notre Dame C	Chicago D	0	0	10	10
Illinois C	Indiana A	10	0	10	20
Illinois A	Michigan A	0	0	10	10
Louisville A	Michigan C	0	10	10	20
Indiana B	Michigan D	0	0	10	10
Michigan B	Chicago A	0	10	10	20
Macalester B	Iowa State	0	0	10	10
BC B	Brandeis Wilson	0	0	10	10
Brown A	BU	0	0	10	10
Brandeis Clemenceau	MIT A	0	0	10	10
Harvard	Brown C	0	0	10	10
Amherst A	MIT B	0	0	10	10
Brandeis Lloyd George	Tufts B	0	0	10	10
Dartmouth	Williams	0	0	10	10
Yale A	Cornell-UG	10	0	10	20
Simon Fraser	Washington A	0	0	10	10
British Columbia A	British Columbia D	10	10	10	30
British Columbia C	British Columbia B	0	0	10	10
Auburn A	Vanderbilt A	0	0	10	10
Georgia Tech A	Georgia Tech D	0	10	10	20
Georgia Tech C	Huntsville A	0	0	10	10
Auburn B	Vanderbilt B	0	0	10	10
Birmingham A	Cambridge B	0	0	10	10
Cambridge C	Edinburgh A	0	10	10	20
Sheffield A	Cambridge D	0	0	10	10
City St George's A	Imperial A	0	0	10	10
Sheffield C	Oxford A	0	10	10	20
Southampton A	Durham B	0	0	10	10
Warwick A	Oxford B	10	10	10	30
ESF	RIT B	0	0	10	10
Alabama A	Bruin A	0	10	10	20