Final (ch 18) Flashcards

1
Q

This is the only nitrogen that is available to living systems

A

NH3

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2
Q

Nitrogen fixation converts N2 to this, with this enzyme

A

NH4+, nitrogenase

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3
Q

This is an example of an inducible enzyme that is only made when needed

A

nitrate reductase

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4
Q

NH4+ to NO2- is this process using this enzyme

A

nitrification

nitrate reductase

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5
Q

NO2- to NO3- is this process using this enzyme

A

nitrification

nitrite reductase

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6
Q

This is a metalloprotein containing Fe-S clusters and Fe-Mo cofactor

A

nitrogenase

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7
Q

this many electrons are required for nitrogen fixation

A

8

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8
Q

bacteria produce nitrate via

A

nitrification

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9
Q

some organisms convert nitrate back to N2 via

A

denitrification

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10
Q

produces glutamine from glutamate

A

glutamine synthetase (basic)

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11
Q

produces glutamate from glutamine

A

glutamate synthase (acidic)

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12
Q

N2 to NH4+

A

nitrogen fixation

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13
Q

Synthetase uses this, synthase does not

A

ATP

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14
Q

During glutamine synthetase reaction this happens

A

Glu is phosphorylated

ammonium ion displaces inorganic phosphate

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15
Q

During glutamate synthase reaction this happens

A

nirtogen is assimilated into citric acid cycle intermediate to produce Glu
Gln is deaminated to produce a second Glu

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16
Q

The conversion of alpha kg to glutamate is this type of reaction

A

transamination

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17
Q

Transaminases use this as a cofactor

A

pyridoxal-5’-phosphate

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18
Q

PLP is derived from this essential nutrient

A

pyridoxine (B6)

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19
Q

What ammino acid is attached to the PLP in a typical transaminase

A

lysine

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20
Q

This is the key to the mechansim behind transaminases

A

schiff base formation

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21
Q

what coenzyme is required for the conversion of serine to glycine

A

tetrahydrofolate

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22
Q

phenylketonuria results from a deficiency of this enzyme

A

phenylalanine hydroxylase

23
Q

what is the amino acid that is a precursor for the neurotransmitters epinephrine and norepinephrine

A

tyrosine

24
Q

denitrification is the conversion of this to this

A

nitrate to nitrogen gas

25
Q

AA with any of these three things are more difficult to synthesize

A

sulfur
branched chains
aromatic groups

26
Q

in plants and pacteria synthesis of aromatic AA involves formation of this

A

chorismate

27
Q

Tyr is produced from PhE via this

A

hydroxylation

28
Q

a compound diffusing directly from one active site to the other without entering the surrounding solven is called

A

channeling

29
Q

this process increases the rate of metabolic processes by preventing the lose of intermediate

A

channeling

30
Q

This is used in Trp synth

A

channeling

31
Q

This is not formed from carbohydrate metabolites

A

histidine

32
Q

Amino acids are the precursors of some of these, including

A

signaling molecules

GABA

33
Q

Catecholamines are derived from

A

amino acids

34
Q

this is the precursor of melatonin

A

serotonin

35
Q

giving rise to gluconeogenic precursors, citric acid cycle intermediates are an example

A

glucogenic

36
Q

giving rise to acetyl-CoA, used for ketogenesis or fatty acid synthesis, not used for gluconeogenesis

A

ketogenic

37
Q

These aa have ketogenic fates

A

leucine

lysine

38
Q

these aa have glucogenic and ketogenic fates

A
isoleucine
phenylalanine
threonine
pryptophan
tyrosine
39
Q

Some AA are converted to this via transamination

A

gluconeogenic substrates

40
Q

This is convered to pyruvate by a process that releases ammonia and sulfur

A

cysteine

41
Q

Enzyme that is lacking in people with phenylketonuria

A

phynylalanine hydroxylase

42
Q

phenylketonuria is the result of the buildup of these to substances

A

Phe

phenylpyruvate

43
Q

alkaptonuria

A

black urine disease

44
Q

approximately 80% of excess nitrogen is excretes as this

A

urea

45
Q

deposits of uric acid in the joints and extremities cause this

A

gout

46
Q

The urea cycle is linked to TCA by

A

fumarate

47
Q

review the urea cycle on pg 13

A

okay

48
Q

bacteria, fungi and some other organisms use this to breakdown urea

A

urease

49
Q

a coenzyme frequently encounted in transamination reactions is

A

pyridoxal phosphate

50
Q

This is not a glucogenic aa

A

leucine

51
Q

a molecule cynthesized in the mitochondrial matrix and transported to the cytosol for subsequent reaction is

A

citrulline

52
Q

how many atp equivalents are required to produce one molecule of urea from ammonia and aspartate

A

3

53
Q

These are three excreted forms of nitrogen

A

ammonia
urea
uric acid