Lecture 29-30 Flashcards
1
Q
do plants use amino cids for energy
A
no
2
Q
how do plants get nitrogen
A
nitrogen fixing bacteria (N2 to NH3)
3
Q
where does degradation occur of dietary proteins
A
gastrointestinal tract
4
Q
hormone secreted when dietary protein enters the stomach
A
gastrin
5
Q
what does gastrin stimulate the release of
A
HCl and pepsinogen
6
Q
zymogen that is converted to active pepsin by autocatalytic cleavage at low pH
A
pepsinogen
7
Q
cleaves long polypeptide chains into a mixture of smaller peptides
A
pepsin
8
Q
hormone secreted into the blood in response to low pH in the small intestine
A
secretin
9
Q
where is secretin secreted
A
into the blood
10
Q
what does secretin stimulate
A
pancreas to secrete carbonate into the small intestine
11
Q
hormone secreted into the blood in response to the arrival of peptides in the duodenum
A
choleccystokinin
12
Q
zymogens are secreted by what
A
exocrine cells of the pancreas
13
Q
what does cholecystokinin stimulate secretion of
A
trypsinogen, chymotrypsinogen, procarboxypeptidase A and B
14
Q
zymogen of trypsin
A
trypsinogen
15
Q
zymogen of chymotrypsin
A
chymotrypsinogen
16
Q
zymogen of carboxpeptidases A and B
A
procarbboxypeptidases A and B
17
Q
proteolytic enzyme that converts trypsinogen to trypsin
A
enteropeptidase
18
Q
eteropeptidase converts what to what
A
trypsinogen to trypsin
19
Q
activates additional trypsinogen, chymotrypsinogen, procarboxypeptidase, and proelastase
A
trypsin
20
Q
protein inhibitor that further protects the pancreas against self digestion
A
pancreatic trypsin inhibitor
21
Q
what is the first thing to break down proteins
A
pepsin
22
Q
what is used as a marker for protein degradation
A
ubiquitin
23
Q
what are proteins degraded by
A
28S proteasome
24
Q
what is structure of 26S
A
hollow
25
ubiquitin protein enters where
26S core,
26
what happens to protein in 26S core
is broken to free amino acids
27
what are the free amino acids made during protein degradation used for
new proteins
28
wehre does most of amino acid catabolism and syn take place
liver
29
what amino acids enter liver
ones you consume (via blood vessels)
30
why can't ammonia be transported in blood
increase in blood pH
31
due to not being able to transport ammonia, what does this mean
we cannot just deaminate Amino acids
32
how is NH4 transported safely
certain amino acids
33
first step of transporting NH4
transamination
34
what is the accepting amino acid for NH4
alpha ketoglutarate
35
what is cofactor for transamination
vitamin b6
36
transfer alpha amino group to a carbon atom of alpha
transamination rxn
37
catalyze the removal of the alpha amino groups
aminotransferases
38
are transamination reactions irreversible or reversible
reversible
39
what does ammonia compete with
K+
40
why does ammonia compete with K+
for transport into astrocyte cells
41
1 urea molecule = what
2 molecules of nitrogen
42
what accepts an amino group
PLP (aldehyde form)
43
donates its amino group to an alpha keto acid
pyridoxamine phosphate (aminated form)
44
what does Nh4 and K+ competition result in
elevated extracellular (K+)
45
symporter that transports Na, K. Cl
Na2+-K+-2Cl- cotransporter 1 (NKCC1)
46
excess Cl- from the excess K+ alters what
neuronal response to the neurotransmitter GABA
47
what transports N from muscle to liver
alanine
48
what else can be used to transport N
glutamine
49
how is glutamine made
glutamine synthesis, requires ATP
50
organism that excretes N2 in the form of ammonia
ammonotelic
51
organism that excretes urea
ureotelic
52
organism that excretes uric acid
uricotelic
53
what are the ammonotelic animals
most aquatic vertebrates
54
uricotelic anomals
birds, reptiles
55
ureotelic animals
many terrestrial vertebrates, also sharks
56
glutamate releases its amino group as
ammonia in the liver
57
NH4+ in the mitochondria comes form many different alpha amino acids in the form of -
amino group of l-glutamate, amide nitrogen of glutamine
58
pathway by which alanine carries ammonia and the carbon skeleton from pyruvate to liver
glucose alanine cycle
59
catalyzes the oxidative deamincation of glutamate to produce NH4+ and alpha ketoglutarate
l-glutamate dehydrogenase
60
where is l-glutamate dehydrogenase present
mitochondrial matrix
61
alpha ketoglutartate product can be...
oxidized as fuel, or serve as a glucose precursor in gluconeogenesis
62
glutamate dehydrogenase is positively modulated by..
ADP (signals low glucose levels)
63
glutamate dehydrogenase dehydrogenase is negatively modulated by..
GTP (signals high levels of alpha ketoglutarate)
64
skeletal muscles produce what
pyruvate, lactate ammonia
65
interconverts pyruvate and alanine via transamination with glutamate
allanine aminotransferase
66
interconverts pyruvate and alanine via transamination with glutamate
alanine aminotransferase
67
catalyzes combination of free ammonia with glutamate to yield glutamine
glutamate synthetase
68
critical to transport toxic ammonia to liver
glutamine synthetase
69
does glutamine synthetase require ATP
yes
70
glutaminase
catalyzes conversion of glutamine to glutamate and NH4+
71
used to syn other N containing compounds, transport N from extra haptic tissues to liver
glutamine
72
is glutamine regulated
yes, highly
73
glutamine synthetase is active when
deadenylylated
74
glutamine synthetase inactive when
adenylylated
75
is AMP on active or inactive version of glutamine synthetase
inactive
76
glutamine synthetase converts what to what
glutamate to glutamine
77
product of glutamine are...
inhibitors of glutamine snthetase
78
adding AMP
adenylation
79
glutamate dehydrogenase deaminates what to what
Glutamate to alpha keto gluturate
80
glutaaminase deaminates what to what
glutamine to glutamate
81
how is uridylylation regulated
allosteric regulation
82
where does urea cycle take place
cytosol and mitochondria
83
bicarbonate activated by phosphorylation , what enzyme
carbamoyl phosphate synthetase 1
84
what does carbamoyl phosphate synthetase 1 switch
swaps phosphate for ammonia
85
does Carbamoyl phosphate synthetase 1 use ATP
yes
86
how many ATP is required to make a carbamoyl phosphate
2
87
urea cycle step 1
ornithine + carbamoyl phosphate -> citruline
88
urea cycle step 1 enzyme
ornithine transcarbamoylase
89
urea cycle step 2
citruline -> argininosuccinate
90
enzyme for step 2
argininosuccinate synthetase
91
two cofactors of step 2
ATP + aspartate -> PPi + AMP
92
urea cycle step 3
argininosuccinate -> arginine
93
what leaves in step 3
fumarate
94
step 3 enzyme
argininosuccinase
95
step 4
arginine -> ornithine
96
enzyme step 4
arginase
97
what's used and released in step 4
h2o in, urea out
98
how many amino groups = 1 urea
2
99
how many ATP are used for urea cycle
2 atp (+2ATP for carbamoyl phosphate)
100
what is the 1 thing you get from urea cycle
1 fumarate
101
what can fumarate be converted to
malate
102
what can be used to form malate
fumarate
103
functions to regenerate NADH in the mitochondria
malate aspartate shuttle
104
2 ways urea cycle is regulated
level of enzyme synthesis, allosteric regulation of carbamoyl phosphate synthetase 1
105
catalyzes formation of N-acetyl glutamate from acetyl CoA and glutamate
N-acetylglutamate synthase
106
allosterically activates carbamoyl phosphate synthetase 1
n-acetylglutamate
107
too much protein = what
buildup of nitrogen in body
108
essentail amino acids are what
amino acids that cannot be synthesized by humans and must be obtained in the diet
109
albinism defective enzyme
tyrosine 3-monooxygenase (tyrosinase)
110
carbamoyl phosphate synthetase 1 deficiency defective enzyme
carbamoyl phosphate synthetase 1
111
maple syrup urine disease other name
branched chain ketoaciduria
112
maple syrup urine disease enzyme
branched chain alpha keto acid dehydrogenase complex
113
phenylkeoturia defective enzyme
phenylalanine hydroxylase
114
tyrosin 3-monooxygenase medical conditon
albinism
115
carbamoyl phosphate synthetase 1 medical condition
carbamoyl phosphate synthetase 1 deficiency
116
branched chain alpha keto acid dehydrogenase complex medical condition
maple syrup urine disease
117
phenylalanine hydroxylase medical condition
phenylketonuria
118
if issue with urea cycle enzymes, can treat with what
benzoate and/or phenylbutyrate
119
valine, leucine, isoleucine go to alpha keto acids
male syrup urine disease
120
3 amino acids involved in maple syrup urine disease
leucine, isoleucine, valine
121
what is inhibited in maple syrup urine disease
branch chain alpha keto acid dehydrogenase complex
122
what can maple syrup urine disease cause
mental degradation
123
in phenylketonuria, what can't be made
tyrosine
124
what enzyme does PKU block
phenylalanine hydroxylase
125
what does phenylalanine hydroxylase normally do
phenylalanine to tyrosine
126
PKU results in what
accumulation of keto acids
127
PKU makes what an essential amino acids
tyrosine, bc its production is blocked
128
dipeptide absorbed and broken down to phenylalanine and something else
aspartane
129
what can plants do that we can't do (amino acids)
they can put N groups on C skeletons to form amino acids
130
lightning and UV makes up what percent of Nitrogen cycle
15%
131
industrial makes up what percent of nitrogen cycle
25%
132
microorganisms make up what percent of nitrogen cycle
60%
133
nitrogen fixation main enzyme
dinitrogenase
134
most abundant gas in our atmosphere
molecular nitrogen
135
electrons in nitrogen fixation
extensive e transfer
136
how many ATP required per N2
16
137
involves extensive transfer of e- eventually transferred
nitrogen fixation
138
in amino acid synthesis, what is made first
carbon skeleton
139
in amino acid synthesis, what happens second
transamination reaction to add amino group
140
animals cannot synthesize what
EAA
141
how many biosynthetic families are there
6
142
when we synthesize AA, we use what as donors
glutamate and glutamine
143
2 universal AA donors
glutamate and glutamine
144
key in degradation and AA syn
transamination
145
remove amino group from 1 AA to a keto acid, forms new AA
transamination
