Week 5 Flashcards
1
Q
Pyrimidine pathway begins with what?
A
glutamine, CO2, 2 ATP
2
Q
Describe what occurs in Complex III
A
contains cavern, electrons picked up by cytochrome C and taken to IV, pumps 4 protons to intermembrane space
3
Q
Cytochromes contain _____ cofactors that can be reduced or oxidized
A
heme
4
Q
How is the X chromosome inactivated?
A
packaged into transcriptionally inactive heterochromatin. Heterochromatin coats inactive X DNA and prevents its transcriptional expression –> forms Barr body. Xist gene encodes RNA responsible for mediating this silencing.
5
Q
When non-equal concentrations are known, which equation should be used for delta G?
A
Delta G = Delta G naught + RTln[y]/[x]
6
Q
Purine biosynthesis starts with what molecule?
A
ribose-5-P
7
Q
Describe the enrgy required to convert oxaloacetate to citrate
A
-9 kcal/mol
8
Q
In sperm, all imprints are erased and rewritten with _______ pattern; in eggs, rewritten with _______ pattern; even in genes that come from opposite sex parent
A
paternal, maternal
9
Q
Describe how acetylcholine promotes the synthesis of NO
A
Acetylcholine binds to GPCR on endothelial cell –> IP3 generated –> increases Ca++ –> activates NO synthase –> NO produced from arginine
10
Q
Isocitrate to alpha-ketoglutarate to succinyl coA - both steps are promoted by this cofactor
A
Calcium
11
Q
What is the wobble base on tRNA?
A
3rd position in codon not totally required to match by all tRNAs (sometimes you get an I matching)
12
Q
In Huntington’s Disease, there is greater expansion in _______ parent transmission than in ______
A
male, female (gametogenesis)
13
Q
_________ genes are susceptibility targets for numerous human pathologies such as Angelman and Prader WIlli Syndrome
A
imprinted genes
14
Q
A positive feedback mechanism that results in ______________ would be an NZ that is activated by a signaling molecule but is then further stimulated by products that bind back to the NZ/signal complex and further stimulate it.
A
switchlike behavior
15
Q
Nucleoside monophosphate kinases convert ATP and NDP to
A
ADP and NDP
16
Q
What are the three tissues most dependent on oxidative phosphorylation?
A
heart, skeletal muscle, central nervous system
17
Q
TCA cycle enzymes are found in what part of the mitochondria?
A
Matrix
18
Q
Describe how the COX2 pathway can result in neoplasia (4 factors)
A
promotes tumor angiogenesis, induces tumor cell growth, inhibits apoptosis, dec immunosurveillance
19
Q
Describe the four step process of tRNA binding
A
1) aminoacyl tRNA binds to vacant “A” site
2) a new peptide bond is formed at “P” site
3) mRNA moves 3 nucleotide positions through ribosomal subunit to E site
4) spent tRNA is ejected and the ribosome is reset
20
Q
When a hormone secreted from a cell travels through the blood stream and binds to receptor on target cell, what signaling system is occurring? (encounter lots of cells during travel)
A
endocrine
21
Q
Describe the age and conflict of the child in the oral stage.
A
birth-1 yr, primary conflict - weaning, fixation can lead to excess reliance and vulnerability to overconsumption of food or alcohol. Frustrations can lead to pessimism, envy and aggression.
22
Q
__________ is usually the first AUG from 5’ cap site
A
kozak sequence
23
Q
During pyrimidine synthesis, _____ is added halfway through the cycle to produce orotidine (OMP)
A
PRPP, catalyzed by orotic acid transferase
24
Q
DNA methyltransferases can be indirectly repressed by _________
A
mir-29b
25
Modified ________ ensure that a differentiated cell stays differentiated
histones
26
Describe how NO causes rapid relaxation of smooth muscle cell
NO binds to guanylyl cyclase and converts GTP to cyclic GMP which causes rapid relaxation
27
How do ROCK and PKC activation inhibit MLCP activity?
ROCK phosphorylates MYPt1 inhibitory protein and PKC phosphorylates CPI-17 inhibitory protein, which leads to inactivation of MLCP
28
How do macrolides (such as erythromycin) inhibit protein synthesis?
prevent the Movement of ribosomes(translocation)
29
Non-specific NSAIDS also block the inducible COX2 pathway. Normally, the COX2 pathway can lead to ________ and _______ via PGE2. Why are these dangerous?
inflammation, neoplasia
| causes ulcers
30
How is phosphate transported to the matrix to provide substrate for ATP synthase?
Through the phosphate translocase (symporter), moves protons and phosphate in
31
In Fragile X, there is ____% penetrance in females with one full mutation and ____% penetrance in males with one full mutation
50%, 100%
32
In addition to thymine degradation, B12 plays an important part in conversion of __________ to methionine (catalyzed by methione synthase)
homocysteine
33
In a group of identical signaling cells, each cell receives a strong ________ signal . (also affects cells in the immediate enviro of the signaling cells)
autocrine
34
In the cytosine uracil degradation pathway, what are the compounds eventually degraded to?
acetyl SCoa
35
Describe miRNA therapy in asthma
decreases immune response
36
Progressive loss of motor control and psychiatric problems including dementia and affective disorder characterize this repeat expansion disorder that usually presents between ages 30 and 50
Huntington's Disease
37
Describe initiative vs guilt stage of Erikson
3-5 years, corresponds with phallic stage, interpersonal skills develop, too much control will lead to sense of guilt and inhibition and tendency to follow
38
Describe the attachment theory
emotional and physical attachment gives greater sense of stability in infants and toddlers, however if primary caretakers are overly anxious and depressed can have profound effect on kids
39
Pyrimidine pathway is activated by _____ and ATP
PRPP
40
Name 5 mechanisms of desensitization or negative feedback
- receptor sequestration (receptor returned to membrane, LDL is an example)
- receptor down regulation (receptor degraded, EGF receptor)
- inactivation of signaling protein (phosphorylation)
- receptor inactivation (examp GRK)
- production of inhibitory protein (examp arrestin)
41
Name two compounds that act in an autocrine manner (FADs of arachadonic acid)
eicosanoids
| prostaglandins
42
_________ both inhibit electron transport by inhibiting cytochrome oxidase
cyanide, carbon monoxide
43
The nitrogens in purine biosynthesis come from which compounds
Aspartate, Glycine, Amide N of glutamine
44
What happens in folic acid deficiency?
Cannot synthesize THF, slows down step in purine synthesis process
45
How does ChloramPhenicol inhibit protein synthesis?
inhibits Peptide bond formation (via peptidyl transferases)
46
True or false: A decreased delta G for a reaction makes the reaction proceed faster
FALSE
47
The most common form of inherited neurodevelopmental disorder is _________
Fragile X
48
In thymine degradation, ____ is required to break down methyl malonyl semialdehyde (MMSA) to succinyl sCoA [last step]
B12
49
In an abrupt response, as the number of activator molecules that must be bound simultaneously to effector proteins to activate them increases, the slope of the activation curve _____ as does the ________________
activation curve, response start time
50
Describe the limiting step in the Krebs Cycle
Oxaloacetate levels
51
Describe what occurs in complex IV
Contains 3 subunits. Subunit I contains two heme groups and a Cu. Subunit II contains two Cu ions. Electrons get picked up by Cu on subunit II and travel through Subunit I which causes 2 protons to get pumped through
52
The mRNA transcript associates with ______ at 5' cap and 3' poly A tail then mRNA positioned in the small ribosomal subunit
eukaryotic initiation factors (eif-2 important)
53
______ inhibits ATP synthase by inhibiting Fo subunit
oligomycin
54
True or false: Delta G naught depends on substrate and production reactions
FALSE DELTA G. Delta G naught is a CONSTANT
55
What three inputs turn Cak Kinase activity on?
phosphate removed from specific region, phosphate added to another specific region, cyclin is present
56
SSRI's are prescribed to treat anxiety disorders, OCD, premature ejaculation, eating disorders and sometimes _____
IBS
57
During _________, each cell contains a population of different mitochondria that are randomly distributed throughout the cell. When the daughter cells form, they randomly inherit a variable number of mitochondria.
mitotic segregation
58
GTP-binding proteins are in active state when _____ is bound and inactive when _____ is bound
GTP, GDP
59
Tetracyclines (TTC) inhibit protein synthesis by ____
TRNA Tries but Can't (prevents aminoacyl tRNA from attaching to A site of ribosomes)
60
Mitochondrial disorders normally manifest as what three types of disorders?
myopathies, neuropathies, encephalopathies (also linked to DM)
61
________ both prevent electron transfer from FE-S center to ubiquinone
Rotenone, Arigtal
62
Name 4 clinical consequences of B12 deficiency
1) pernicious anemia
2) megaloblastic anemia
3) neuro dysfunction
4) folate deficiency
63
Describe the steps of the Krebs cycle and where energy is produced.
Acetyl CoA enters the Krebs cycle.
Citrate --> IsoCitrate --> Alpha-Ketoglutarate --> Succinyl-Coa --> Succinate --> Fumarate --> Malate --> Oxaloacetate. Isocitrate, Alpha-Ketoglutarate, and Malate conversions yield NADH. Succinyl Coa to Succinate yields GTP. Succinate --> Fumarate yields FADH2.
64
In _______ signaling, a signaling cell releases local mediator to nearby target cells (affects only cells in immediate environment of signaling cell)
paracrine
65
In valine, isoleucine and threonine degradation, B12 is required for conversion of which compound to succinyl CoA?
methylmalonyl-CoA (catalyzed by methylmalonyl CoA mutase)
66
What drug inhibits DHFR and stops cancer cells from synthesizing nucleotides?
Methotrexate
67
How does clindamycin inhibit protein synthesis?
makes ribosomes Cling to mRNA (prevents translocation)
68
_____ and ____ are two flavoproteins that tightly associated with proteins and can accept one or two electrons
FADH2 and FMNH2
69
Describe the age and conflict of child in latency.
6-puberty. Ego and super ego develop and sexual impulses are repressed. Struggles can cause impairment in social skills and self confidence
70
Although SSRIs are just as effective as anticyclic antidepressants, what is a benefit of using them?
much higher toxic dose and fewer or milder side effects
71
When protons are pumped across membrane it creates a proton gradient, a charge gradient, and through mass action a __________ which drives ATP synthesis
proton motive force
72
Describe the energy required to convert malate to oxaloacetate in the Krebs cycle and how this moves forward
+7 kcal/mol, high malate concentrations
73
MELAS, mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes, sometimes only manifests as ____
DM
74
Describe the age and conflict of the child in anal stage.
1-3 years, conflict over toilet training, leads to anal retentive (too strict of parents) or repulsive personalities (too lenient)
75
Where do the nitrogens come from in pyrimidines?
glutamine, ribose-5-phosphate (comes from aspartic acid)
76
How is ATP transferred to the intermembrane space (and eventually cytosol)?
Through adenine nucleotide translocase (antiporter, ATP out of matrix, ADP into matrix)
77
In pyrimidine synthesis, what is required?
UMP
78
True or false: even normal alleles change every generation
TRUE - alleles are unstable af
79
Describe the effect of mi26 on liver cancer in rats
suppressed tumorigenesis
80
Stored nutrients and ingested foods get converted into energy sources via _________ reactions then _________ reactions reactions take that energy and use it to do osmotic work, mechanical work, and other cell work
catabolic, anabolic
81
Regulation of histone modification and heterochromatin formation, DNA methylation, Genomic imprinting, gene silencing and X chromosome inactivation are all examples of _____________
epigenetic processes
82
Conversion of energy from NADH to ATP is about 40% efficiency. Combined reaction free energy has -33 kcal/mol which generates ___ ATP
3
83
The carbons in purine biosynthesis come from which compounds
THF, glycine
84
What types of mutations would resemble mitochondrial disorders?
mutations in nuclear genes responsible for either Ox-phos components or for mitochondrial regulation
85
If enthalpy is greater than 0, reaction can still be spontaneous even if entropy is ______
greater than 0
86
Huntington disease results from repeat expansion that creates a _____________ mutation
gain of function
87
Probenecid inhibits uric acid ______ while colchine is an inflammatory drug, both used to treat gout
excretion
88
Describe the salvage pathway, also known as the degradation pathway of nucleotides.
Begins with RNA & DNA --> nuclease NZ breaks down to nucleotides --> phosphatase breaks down to nucleosides --> nucleosides undergo phosphorylation rxns --> bases --> PRPP added via enzyme --> NMP
89
Describe the function of Prozac and Lexapro that allow them to be SSRI
Block the reuptake transporters located on the membrane of the transmitting neuron (at synaptic cleft)
90
In repeat expansion disorders, congenital form is seen only in infants of affected _________
mothers
91
Describe the mechanism of how insulin receptor (RTK) activates Ras protein
It phosphorylates itself once activated, then these phosphorylated tryrosines recruit IRS1 via a PTB domain. IRS1 phosphorylated on tyrosines, which binds SH2 domain on Frb2. Fb2 binds Sos and Sos acts as GEF to activate Ras. Other phosphorylated tyrosines on IRS1 recruit add'l signaling protein that have SH2 domains.
92
Describe miRNA mediated gene silencing
Drosha is a dsRNAse that will breakdown pri-miRNA to precursor miRNA. After GTP-dependent export from nucleus, dicer chops miRNA. miRNA then bound to RISC with Argonaut 2. RISC guided to target DNA and degrades if perfect complimentary
93
In myotonic dystrophy, a man who is a premutation carrier for a repeat expansion disorder has a ____ risk of having a severely affected child. This man's daughters would have a ___ risk of having a severely affected child.
low, variable but could be high
94
____________ inhibits thymidylate synthase
5-fluorouracil
95
What is required to make purines?
IMP
96
True or false: Each individual has same two alleles in all somatic cells but during gametogenesis, each allele varies in every gamete
TRUE
97
In mitochondrial disorders, affected females transmit disease to _____ of their children whereas males transmit disease to ____.
all, none
98
Adenylosuccinate lyase is involved with converting aspartate to __________
fumarate
99
Cortisol, thyroxine, estradiol, testosterone, vitamin d3 and retinoic acid all are _____________
steroid hormones
100
____________________ associates with 5' cap of mRNA and then shorterns the poly A tail in the 3' to 5' direction
deadenylation nuclease (DAN)
101
Describe the FMR related disorders
FXTAS - fragile X associated tremor/ataxia syndrome (late onset), males (and some females) with FMR1 premutation
FMR1-related POI - ovarian insufficiency, 20% of females with FMR1 premutation
102
Molecular switches fall into two categories. In both categories what determines whether protein is inactive or active? What are two classes?
gain or loss of phosphate groups
| two classes are inactivated/activated by phosphorylation and GTP-binding proteins
103
Why can't thermogenin be used for weight loss?
Great way to burn energy but energy needs somewhere to go so converts to heat and temperature gets very elevated
104
How are signaling systems defined? (3 characteristics)
distances over which they operate, effective concentration of signaling molecule req to elicit a response and affinity of receptor for its ligand
105
Myotonic dystrophy results from a repeat expansion in _____________ RNA that decreases RNA stability (3' untranslated region)
protein kinase
106
What is the equation that relates delta G, H, and S
Delta G = Delta H - T* Delta S
107
What is the key regulatory step in pyrimidine synthesis catalyzed by?
aspartate transcarbamyolase
108
_________ play an important role in pain, fever and inflammation and thus the synthetic pathways for these compounds play an important role in pain
eicosanoids
109
NSAIDs such as ASA and ibuprofen block the first _________ step in catalyzed by _______ and ________ and thus inhibit prostaglandin, prostacycline and thromboxane synthesis
oxidation, COX1 and COX2
110
Folate derivatives, THF, are carbon carriers involved in what two things?
amino acid metabolism and nucleotide synthesis
111
Protons go around F0 subunit which causes the stalk to turn and conformational changes of alpha beta subunits in F1. This allows ADP and phosphate to bind in one conformation, then when the stalk turns what happens?
ATP is synthesized and kicked out
112
On what part of tRNA does amino acid bind
3' end, CCA tail
113
_____ can target heart disease at many different places
miR21
114
In endocrine signaling, hormones are greatly diluted in the blood stream so receptors are _________ whereas in synaptic signaling, neurotransmitters are released into the synapse which is only 100 nm wide and receptors are _______
high affinity, low affinity
115
In _________ signaling, a membrane bound signal molecule on the signaling cell makes contact with the target cell
contact-dependent
116
Folate deficiency decreases purine and dTMP synthesis while arrests cycle in the ________ and results in ___________________
S-phase, megaloblastic anemia
117
In MERFF (myoclonic epilepsy with ragged red fibers), heteroplasmy is seen. Describe heteroplasmy.
Mosacisim caused by variable number of mutant mitochondria per cell
118
Describe the industry vs inferiority stage of Erikson
5-12 years, corresponds with latency, peers and teachers become more important, self-explanatory
119
Ick, PI3K, PLC-gamma, IP3, Ca++, Src , JAK-STATs and NF-KB all fall under what class of receptors?
NZ linked
120
_________ leads to impaired dTMP synthesis, megaloblastic anemia, hyperhomocystenemia with increase risk for CVD, and neutral tube defects in pregnancy
Folate deficiency
121
The ________ is method by which NADH moves from cytosol into mitochondrial matrix in the liver, kidney and heart
malate-aspartate shuttle (oxaloacetate to malate occurs in cytosol producing NAD+ then reversal of reaction occurs in matrix producing NADH)
122
Arachadonic acid yields ______ and ______
COX1 and COX2
123
________ acts as an energy shuttle for phosphorylation of ADP --> ATP
creatine phosphate
124
What activates purine biosynthesis? How many ATPs are used?
presence of PRPP, 2 ATPs used to begin and then 3 more used later (total 5)
125
True or false: Mitochondria disorders are often progressive or do not manifest until adulthood because function is sufficient at birth but then deteriorates with age and accumulation of add'l mutations
TRUE
126
Where do the carbons come from in pyrimidines?
aspartate, CO2
127
Angelman Syndrome and Prader-Willi both the same loci on which chromosome?
chormosome 15 - q arm of 13th loci
128
True or False: Heme B contained within complex II plays a vital role in electron transport chain
FALSE, NOT INVOLVED
129
When delta H is less than 0, reaction is ______ whereas when delta H is greater than 0, reaction is ______
exothermic, endothermic
130
Describe the age and conflict of the child in phallic stage.
3-6 years old, primary conflict - Oedipal. Fixation leads to self-centered and narcissistic personality, commitment issues. Freud thought that this may cause homosexuality.
131
Name 5 factors that can induce the COX2 pathway
mitogens, growth factors, oncogenes, carcinogens, cytokines
132
What activates deoxy synthesis?
ATP presence
133
Describe the irreversible steps in the Krebs cycle
Alpha-ketoglutarate to succinyl-Coa, and oxaloacetate to citrate
134
Protein phosphatase _________ while protein kinase __________
dephosphorylates, phosphorylates
135
Huntington's Disease is a ______ penetrant _____ disease: normally results in death within 15 years of diagnosis
100%, protracted disease
136
Describe the generativity vs stagnation stage of Erikson
40-65 years, "big picture" and our place in it, giving back to society, failure would lead to feeling stuck, midlife crisis
137
What is delta G naught equal to at equilibrium (Delta G equal 0)
-RT*ln*Keq or -RT*ln[y]/ln[x] @ equilibrium
138
How do aminoglycosides (streptomycin) inhibit protein synthesiS?
A is first letter, thus aminoglycosides inhibit initiation (first step of translation) by preventing formation of initiation complex
139
Describe the autonomy vs shame and doubt stage of Erikson
18m-3 years, corresponds with anal stage, toilet training, this is where children develop independence
140
Describe sx of Angelman syndrome
speech difficulties, speech problems, seizures, jerky movements, and an unusually happy disposition
141
Nucleotide diphosphate kinases convert ATP and NDP unto
ADP and NTP
142
Describe equation for delta G including Reduction potential (deltaE)
Delta G = -nF*deltaE; n is number of e-s transferred, F is Faraday's constant
143
The ___________ synthesis pathway is targeted by several different cancer drugs, involves dUMP
thymidylate
144
The ________ is method by which NADH from cytosol gets into the mitochondria matrix in the skeletal muscle and brain
Glycerol-3-phosphate shuttle
145
What causes Angelman Syndrome?
individuals missing gene activity that normally comes from mom - mom's copy either defective or missing OR there are two paternal copies
146
In myotonic dystrophy, when does expansion occur and in which sex?
gametogenesis in females
147
Thermogenin is found in brown fat. What is its action?
It uncouples phosphorylation from electron transfer (ox phosphorylation)
148
Under chromatin remodeling, miRNAs can affect positioning of ________ by promoters
nucleosomes
149
What do patients with pyruvate dehydrogenase deficiency exhibit?
High serum levels of lactate --> acidotic
150
Describe acetylcholine's action on
a) heart pacemaker
b) salivary gland
c) skeletal muscle cell
a) decreased rate of firing (GPCR)
b) inc secretion (GPCR)
c) contraction (ion channel)
151
Elongation factors help enhance translation and control accuracy by _________
proofreading, incorrectly based paired tRNA preferentially dissociate
152
Adenylate kinase converts ATP and AMP into
2 ADP
153
When delta G is less than 0, reaction is ______ whereas when delta G is greater than 0, reaction is ______
exergonic, endergonic
154
Describe identity vs role confusion stage of Erikson
12-18 years, struggle to find place and identity, failure may lead to experimentation
155
Fragile X mental retardation results from an expansion on FMR1 ____________ (5' untranslated region) which inhibits transcription due to hypermethylation
RNA binding protein
156
Allopurinol inhibits uric acid formation by inhibiting the enzyme that forms it ___________
xanthine oxidase
157
What are the four "canonical" features of MERFF?
myoclonus, generalized epilepsy, ataxia, ragged-red-fibers in muscle biopsy
158
In ATP Synthase, ___ is a transmembrane protein and ___ contains a stalk that turns
F0, F1
159
Skeletal muscle deterioration (starting with the face), cardiac and smooth muscle defects, an inability to relax muscles, cataracts and mild mental retardation are all seen in _______________. (Which are "subclinical?")
myotonic dystrophy, cataracts and abnormal electromyogram
160
Describe the ego integrity vs despair stage of Erikson
65+, success leads to sense of closure, don't fear death. Seeing lives as unproductive and being haunted by past mistakes leads to despair.
161
What are the three sites on ribosomes?
P (peptidyl) site, A (amino acyl tRNA site), E (exit)
| also mRNA binding site
162
What is RT*lnKeq equal to in cal/mol?
-1364*logKeq cal/mol
163
When active, what does MLCP do?
cause relaxation of muscle
164
______, referred to as coenzyme Q or just Q, can accept one or two electrons
ubiquinone
165
What is needed for purine biosynthesis that is not needed for pyrimidine biosynthesis?
THF and Glycine
166
What causes Prader-Willi syndrome?
syndromic obesity, learning difficulties, short stature, compulsive eating (missing dad's copy or there are two maternal copies)
167
GMP and AMP degradation produces _______as a by-product. A build up in this chemical causes ______
uric acid, gout
168
Non-specific NSAIDs block the constitutive pathway of COX1. Normally, COX1 produces _________ that promote the production of mucus lining protecting the inner stomach and _______ which induces platelet aggregation
prostaglandins, thromboxane 2
169
Lesch-Nyhan syndrome, a self-mutilation disease, is caused by a defect in the ________________ step of the salvage pathway
G/HX-PRT
170
In Fragile X syndrome, repeats are located ______ of _____ site, and expansion causes hypermethylation which _____________
upstream, AUG start, inhibition of transcription
171
```
List the following in order of delta G naught from least negative to most negative:
Anhydrides (ATP)
Guanidium Phosphate (CEP)
Enoyl Phosphate (PED)
Esters (Amides)
Thiolesters (acetyl Coa)
```
esters (amide), thiol esters (acetyl Coa), anhydrides (ATP), guanidium phosphate (CEP), enoyl phosphate (PED)
172
Class V PDE inhibitors include Levitra, Cialis, Viagra and Sildenafil. How do these increase relaxation of smooth muscle?
PDE breaks down cGMP normally, if inhibited no breakdown of cGMP --> more relaxation
(arteries dilated but veins constricted)
173
Describe the age and conflict of a child in the genital stage
puberty-death, previous struggles may lead to more repression and add'l defenses against conscious sexuality
174
Name 4 common SSRI's
Lexapro, Prozac, Paxil, Zoloft
175
Name four sources of folate
yeast, liver, fruits, green veggies
176
Electron carriers NADH and FADH2 both have oxidation energies equal to delta G naught =
-15 kcal/mol
177
In smooth muscles, when Ca++ increases, ______ is activated which causes phosphorylation of LC50 and increase in contraction
MLCK
178
Describe the trust vs mistrust stage of Erikson
B-18 months, corresponds to oral phase of Freud, if consistent and stable caregiver than child will have hope and self confidence
179
Summarize the differences between purine and pyrimidine synthesis
Purine starts with PRPP then built around it; pyrimidine has PRPP added to NMP (in salvage pathway) or added to orotate (in UMP synthesis)
180
True or false : Highly methylated areas tend to be more transcriptional active
FALSE, less active, DNA methylation patterns are faithfully inherited
181
True or false: A decreased delta G for a reaction lowers Ea barrier
FALSE
182
Glutamine-PRPP amidotransferase is involved in converting glutamine + PRPP to ___________
glutamate
183
Describe the intimacy vs isolation stage of Erikson
18-40 years, love and work compete, avoiding intimacy can lead to isolation, loneliness and depression
184
Describe anticipation
Some dominant disorders manifest at an early age of onset and with increased severity in successive generations. Due to repeat expansion mutation.
185
What enzyme is required to form dNDP from NDP? (deoxy form)
ribonucleotide reductase, disulfide bond has to be reduced after dNDP is synthesized
186
In _______________, rapid loss of central vision due to death of the optic nerve occurs due to 1 of three missense mutations in a mitochondrial protein
Leber's hereditary optic neuropathy (LHON)
187
In the salvage pathway, adenine can be synthesized from bases + PRPP using the enzyme ___________
adenine phospho ribosyl transferase (A-PRT)
188
In the salvage pathway, guanine/hypoxanthine can be synthesized from bases + PRPP using the enzyme ________________
guanine/hypoxanthine phospho ribosyl transferase (G/HX-PRT)
189
______ can act as acceptors or donors in electron transfer. Contains at least 8 iron sulfur proteins.
Iron Sulfur Centers
190
In repeat expansion disorders, what are premutations?
Repeat expansions that are unstable and have dynamic increase in # of repeats in succeeding generations (eventually result in full mutation)
191
___________ inhibits phospholipase A2, which is the __________ in eicosanoid synthesis, an is widely used clinically to treat noninfectious inflammatory diseases
cortisone, first step
192
AMP is synthesized from IMP using _____ wheras GMP synthesized from IMP using ______ (later also produces NADH)
GTP, ATP
193
____________ is essential for proper embryonic development, imprinting, and X inactivation
DNA methyltransferases
194
What are three factors that play a role in targeting mRNA for degradation?
length of poly A tail, binding sites, and types of proteins that bind to it
195
Through ATP synthase, protons are delivered from the ______________ to the ___________ in a process that creates water
intermembrane space, matrix
196
In hydrolytic editing, when an incorrect AA binds to _______ site on tRNA synthetase, the tRNA detects its incorrect and removes it
editing
197
Cytidylate synthetase converts UTP to
CTP
198
Describe what occurs in Complex I of the Electron Transport Chain AKA NADH Dehydrogenase
NADH --> NAD+, 4 H+s are pumped to intermembrane space, FMN serve as electron carriers that transfer e- to Fe-S then Q
199
Describe pernicious anemia
Autoimmune disease that destroys parietal cells
200
What causes Prader-Willi syndrome?
syndromic obesity, learning difficulties, short stature, compulsive eating
201
Describe what occurs in Complex II AKA succinate dehydrogenase
Bound to inner mitochondria membrane, converts succinate to fumarate, produces FADH2, contains binding site for ubiquinone, heme B
202
How is NADH converted to ATP?
oxidative phosphorylation
203
Pyruvate dehydrogenase catalyzes the formation of acetyl CoA from pyruvate and produces NADH. What are the cofactors of this enzyme?
thymine pyrophosphate, lipoic acid, FAD
204
dUMP requires _______ to convert to dTMP and produces DHF as a product. DHF is resynthesized to methylene THF using __________________
methylene THF, dihydrofolate reductase
205
In Fragile X, an unstable trinucleotide repeat ______ will expand only in _______
CGG, mother
206
In the salvage pathway, pyrimidines are synthesized from bases + PRPP using the enzyme _______________
orotic acid transferase
207
Steroid hormones act as ______________ by causing inhibitory proteins on inactive receptors to dissociate thus activating receptors
transcription factors
208
What happens when histones are methylated?
bound very tight, you have silencing or repression
209
What can be used to analyze the severity of disease in repeat expansion disorders (correlates with number of repeats)?
Southern Blot analysis
210
Celebrex is a COX-2 inhibitor used for arthritis pain and inflammation. What is an issue with celebrex?
increase in major vascular events such as nonfatal MI, nonfatal stroke or death from a blood vessel related cause. Upper GI complications such as bleeding, obstructions, perforations
211
True or false: Delta G, Delta H, and/or Delta S give determine reaction rates
FALSE - high activation barrier dictates reaction rates
