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Flashcards in Third Exam Deck (51):
1

photorespiration

breakdown of ribulose-1,5-P2 into 3P-glycerate and phosphoglycolate (then glyoxylate)
causes eventual shutdown of Calvin Cycle, runs dry

2

reductive TCA

used to fix CO2 for gluconeogenesis
chlorobii, hyperthermophilic archaea
uses 3 NADPH, 3 CO2, 2 ATP, 2 FDH2 --> 1 pyruvate

3

pyruvate synthase

acetyl-CoA + NADPH + CO2 ---> pyruvate
reverse reaction of pyruvate dehydrogenase
used in reductive TCA

4

PEP synthase

pyruvate + ATP ---> PEP + AMP + Pi

5

3-hydroxypropionate pathway

fixes 2 CO2 into glyoxylate, then 1 more to make pyruvate
uses 3 NADPH, 4 ATP, 3 CO2 ---> 1 pyruvate
acidophilic bacteria, mesophiles, chloroflexi

6

best sources of nitrogen

proteins/AAs
NH4+
N2
NO3-
last 2 go thru NH4+

7

anammox

ammonia to N2

8

denitrification

nitrate to N2

9

nitrification

ammonia to nitrate/nitrite
ammonia oxidation

10

glutamate dehydrogenase

2-ketoglutarate + NH4+ + NADPH ---> glutamate
GDH
low affinity
only used in high NH4+

11

glutamine synthase

glutamate + NH4+ + ATP ---> glutamine
GS
high affinity
only used in low NH4+ with GOGAT

12

glutamate synthase

glutamine + 2-ketoglutarate + NADPH ---> 2 glutamate
GOGAT
only used in low NH4+

13

low ammonia enzymes

GS and GOGAT

14

high ammonia enzymes

GDH, use ammonia directly

15

transaminase

2-ketoglutarate + amino acid glutamate + ketoacid

16

regulation of phosphoribulokinase

-: AMP, PEP
+: NAD(P)H

17

regulation of rubisco

-: PEP
+: NADPH

18

cyanobacteria

use PSI and PSII
obligate photoautotrophs
H2O as electron donor
use Calvin cycle for CO2 fixation

19

calvin cycle

begins with rubisco
3PG kinase
GAP DH
regeneration
phosphoribulokinase
fixes CO2 for gluconeogenesis

20

purple bacteria

sulfur and non-sulfur are the same
only PSII = cyclic electron transport
H2S, H2, organic C as electron donor
calvin cycle for C fixation
bacteriochlorophyll a,b

21

chloroflexi

green non-sulfur bacteria
only PSII = cyclic electron transport
chemoheterotroph
H2S, H2 as electron donor
Calvin cycle
bacteriochlorophyll a, c, d

22

chlorobium

green sulfur bacteria
obligate photoautotrophs
only PSI, non-cyclic electron transport
bacteriochlorophyll a,c,d,e
H2S and H2 as electron donor
reductive TCA to fix C

23

CO2 transporters

low affinity constitutive transporter CO2 --> HCO3-
high affinity inducible CO2 --> HCO3-
high A symporter, uses Na motive force, HCO3- + Na+ --> HCO3- + Na+
high A ATPase, uses ATP inside cell to move HCO3- in

24

carboxysomes

densely packed protein structures with high levels of rubisco for carbon fixation
can use .037% CO2, need at least 5% without

25

carbonic anhydrase

HCO3- --> CO2

26

assimilatory nitrate reduction and enzymes

using nitrate for biomass
NO3- + XH2 ---> NO2- + X (nitrate reductase)
NO2- + 3 NADH + 4 H+ ----> NH3 + 3 NAD+ (nitrite reductase)

27

haber process

chemical method of fixing nitrogen into ammonia, increases overall nitrogen bioavailability
N2 + 3 H2 + 2 H+ ---> 2 NH4+
exergonic but requires high activation energy

28

nitrogenase reaction

N2 + 8 H+ + 8 e- + 16 ATP ----> 2 NH3 + H2 + 16 ADP+Pi
4 ATP used to free e- from FdH2
electrons continuously added to N2 to yield 2 NH3
2 H+ ---> H2

29

anammoxasome

membrane structure containing ladderanes for ammonia oxidation to N2

30

ladderane

fatty acid structure present in anammoxasomes, stabilizes intermediates like hydrazine

31

hydrazine synthase

NO + NH4+ + 1 e- ---> N2H4

32

hydrazine dehydrogenase

N2H4 ----> 4 e- + N2 + 4H+
1 e- goes to hydrazine synthase
2 e- go to ETC
1 e- goes to nitrite reductase

33

nitrite reductase

NO + 1 e- ---> NO2- + 2H+

34

leghemoglobin

in root nodules of legumes
regulate O2 levels for nitrogen-fixing bacteria

35

heterocysts

specialized cyanobacteria cells for nitrogen fixation
fix nitrogen to ammonia, then put it into glutamate and send to regular cells
regular cells do photosynthesis and send carbohydrates to heterocyst for energy, make NADH then FdH2 for nitrogenase
cyclic electron transport

36

regulation of nitrogen fixation

NtrB phosphorylated by ATP in low NH4+
NtrB passes P to NtrC, which activates transcription of nifL and nifA and glutamine synthase (glnA)
NifL inactivates NifA in high O2, NifA active in low O2
NifA activates transcription of nitrogen fixation (nif) genes

37

cyclic amino acids

tryptophan, phenylalanine, tyrosine

38

regulation of cyclic amino acid synthesis

first product after chorismate inhibits its own enzyme to prevent overproduction

39

making chorismate

erythrose-4P + PEP + NADPH + ATP -->-->--> shikimate
shikimate + PEP --> chorismate

40

tryptophan biosynthesis

chorismate -->-->--> tryptophan
uses serine, PRPP, glutamine
produces GAP, PP, pyruvate, glutamate

41

tyrosine biosynthesis

chorismate -->-->--> tyrosine
uses glutamate
makes 2-ketoglutarate

42

phenylalanine biosynthesis

chorismate -->-->--> phenylalanine
glutamate --> 2-ketoglutarate

43

making PRPP

ribose-5P + ATP ---> 5P-ribosyl-1PPi + AMP

44

UTP synthesis

aspartate + carbonoyl-P + PRPP -->-->--> UTP

45

CTP synthesis

UTP --> CTP

46

TTP synthesis

UTP --> dUTP --> dUMP --> dTTP

47

AMP and GMP synthesis

PRPP + glutamine + glycine + aspartate --> IMP (inosimic acid) + fumarate
IMP --> AMP or GMP

48

ribonucleotide reductase

reduces ribonucleotides to deoxyribonucleotides using thioredoxin
XTP + TR (red.) ---> dXTP + TR (ox)
TR reduced by NADH/thioredoxin reductase

49

thioredoxin reductase

TR (ox) + NADH --> TR (red.) + NAD+

50

desaturase

palimityl-ACP + NADPH + O2 ---> palmitoyl-ACP + NADP+ + H2O

51

elongase

palmitate ---> long FA