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Flashcards in Third Exam Deck (51)
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1
Q

photorespiration

A

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

2
Q

reductive TCA

A

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

3
Q

pyruvate synthase

A

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

4
Q

PEP synthase

A

pyruvate + ATP —> PEP + AMP + Pi

5
Q

3-hydroxypropionate pathway

A

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
Q

best sources of nitrogen

A
proteins/AAs
NH4+
N2
NO3-
last 2 go thru NH4+
7
Q

anammox

A

ammonia to N2

8
Q

denitrification

A

nitrate to N2

9
Q

nitrification

A

ammonia to nitrate/nitrite

ammonia oxidation

10
Q

glutamate dehydrogenase

A

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

11
Q

glutamine synthase

A

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

12
Q

glutamate synthase

A

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

13
Q

low ammonia enzymes

A

GS and GOGAT

14
Q

high ammonia enzymes

A

GDH, use ammonia directly

15
Q

transaminase

A

2-ketoglutarate + amino acid glutamate + ketoacid

16
Q

regulation of phosphoribulokinase

A

-: AMP, PEP

+: NAD(P)H

17
Q

regulation of rubisco

A

-: PEP

+: NADPH

18
Q

cyanobacteria

A

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

19
Q

calvin cycle

A
begins with rubisco
3PG kinase
GAP DH
regeneration
phosphoribulokinase
fixes CO2 for gluconeogenesis
20
Q

purple bacteria

A
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
Q

chloroflexi

A
green non-sulfur bacteria
only PSII = cyclic electron transport
chemoheterotroph
H2S, H2 as electron donor
Calvin cycle
bacteriochlorophyll a, c, d
22
Q

chlorobium

A
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
Q

CO2 transporters

A

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
Q

carboxysomes

A

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

25
Q

carbonic anhydrase

A

HCO3- –> CO2

26
Q

assimilatory nitrate reduction and enzymes

A

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

27
Q

haber process

A

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
Q

nitrogenase reaction

A

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
Q

anammoxasome

A

membrane structure containing ladderanes for ammonia oxidation to N2

30
Q

ladderane

A

fatty acid structure present in anammoxasomes, stabilizes intermediates like hydrazine

31
Q

hydrazine synthase

A

NO + NH4+ + 1 e- —> N2H4

32
Q

hydrazine dehydrogenase

A

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

33
Q

nitrite reductase

A

NO + 1 e- —> NO2- + 2H+

34
Q

leghemoglobin

A

in root nodules of legumes

regulate O2 levels for nitrogen-fixing bacteria

35
Q

heterocysts

A

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
Q

regulation of nitrogen fixation

A

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
Q

cyclic amino acids

A

tryptophan, phenylalanine, tyrosine

38
Q

regulation of cyclic amino acid synthesis

A

first product after chorismate inhibits its own enzyme to prevent overproduction

39
Q

making chorismate

A

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

shikimate + PEP –> chorismate

40
Q

tryptophan biosynthesis

A

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

41
Q

tyrosine biosynthesis

A

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

42
Q

phenylalanine biosynthesis

A

chorismate –>–>–> phenylalanine

glutamate –> 2-ketoglutarate

43
Q

making PRPP

A

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

44
Q

UTP synthesis

A

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

45
Q

CTP synthesis

A

UTP –> CTP

46
Q

TTP synthesis

A

UTP –> dUTP –> dUMP –> dTTP

47
Q

AMP and GMP synthesis

A

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

48
Q

ribonucleotide reductase

A

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

49
Q

thioredoxin reductase

A

TR (ox) + NADH –> TR (red.) + NAD+

50
Q

desaturase

A

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

51
Q

elongase

A

palmitate —> long FA