quiz 3.2 NO and Nucleic acids Flashcards
reason why NO can reach the targets before degradation
high diffu rate
low solubility in water
NO was formerly called
endotelium-derived relaxing factor
NO is produced via action of
nitric oxide synthase
NO raeecting witth moclecular oxygens forms
N2O3
NO reacting with superoxide forms
peroxynitrite
the physiologic functions of NO are mediated through activation of soluble ______ to produce ______
guanylate cyclase
cGMP
how does NO activate guanylate cyclase
NO binds the sixth ligand and breaks the heme-histidine bond
what inactivates cGMP and stops the signal
phosphodiesterase 5
the heme moiety of NO resembles
cytochrome p450
2 functional domains of NO
oxygenase
reducatse
the substrate binding site in the oxygenase domain is the site for
arginine
parts of the oxygenase domain
heme moiety
substrate-binding site
tetrahydrobiopterin
tetra-coordinated zinc atom
which part of the oxygenase domain is the binding site for electron transfer
tetrahydrobiopterin
part of the oxygenase domain taht is for strucutural itnegrity
tetra-coordinated zinc atom
the domain of NO that structurally resembles p450 reducatse
reductase domain
connects the two domains and serves as the site for calmodulin attachment required for electron transfer from the reductase to te oxygenase domain
calmodulin-binding site
the elctron donor in the enzymatic reaction of NOS
NADPH
NADPH donated 2 electrons to ____ and reduces _____
FAD
FMN
____ reduces heme iron to ferrous form to which oxygen can bind to
FMN
source of nitrogen in NO
guanido group of arginine
source of oxygen in NO
molecular oxygen
synthesis of NO requires
2 O2
1.5 NADPH
in the synth of NO, arignine is
oxidized to N-hydroxy-L-arginine
in the 2nd step of NO, N-hydroxy-L-arginine is
oxidized to NO and citrulline
NO synth is inhibited by
CO
calmodulin-binding requires
influx of calcium to increase calcium conc.
______ binds to and activates NOS
calcium-calmodulin complex
when released ang potentially destructive reactiev oxygen species kapag NO synth
when no substrate but NOS is active
three major isoforms of NOS
neuronal
inducible
endothelial
the inducible isoform of NOS
iNOS/NOS 2
the membrane bound NOS isoform
eNOS/NOS 3
the indepedent NOS isoform
iNOS/NOS2
action of NOS 2
cytotoxicity
action of NOS 3
vasodilation
action of NOS 1
neurotransmission
NOS1 in skel msuces serves as
mediator of contractile force
nNOS is not normally induced at the transcirptional level therefore it is
constitively expressed
NO synth sis timulated by calcium influx through receptor-dependent channels following postsynaptic of ___________ receptors by _____-
N-methyl-D-aspartate
glutamate
is NO removed via deactivation
no
how is NO terminated
interaction with their target
NO is produced by NOS1 in myenteric neurons of the _______
gastrointestinal
pulmonary
vascular
urogenital systems
NO in the PNS causes
smooth muscle relaxation
what happens when no nNOS in GI tract
pyloric stenosis
in the GI system, nNOS is involved in
gut motility and sphincter control
in the pulmo system, NO mediates
bronchodil
in the vacular system, NO is invovled in the neural control of the vascular system especially in the ________
control of cerebral blood flow
in the urogenital system, NO is involved in
urethra and bladder control and penile erection
NOS1 is associated with ___ in the skel system
alpha-syntrophin
NO2: is calmodulin bound at basal physiologic conditions?
yes
overstimulation of NOS2 may lead to
spetic shock
how is NOS3 antithrombotic and anit-inflamm
inhibits platelets and leukocytes
this NO isoform has unique terminals where myristoylation and palmitoylation occur
NOS3
inhibits NOS3
caveolin
if ________, NOS3 is not found in the caveolae so no NO synth
palmitoylation
involved in uotake of L-arginine to ensure a supply of substrate for NO synthesis
cationic amino acid transporter 1`
action of EDRF can be prevented by
superoxide
hgb + NO
analogues of arg
endothelial cells cannot produce EDRF without ____
arginine
explain the anti-atherosclerotic properties of NO
prevents adhesion to endothel
inhibit prolif and migration
dec. permeability of endothel
used for angina tx
nitroglycerin
potent inhib of PDE5
sildenafi;
side effect of sildenafil
cyanopsis
central dogma of molec biology
dna determines rna determines proteins
named that the transforming substance is DNA
Avery, McCarty, McLeod
father of modern genetics
francis galton
stated the transforming principle in pneumococcus/streptococcus (genetic role of DNA)
Frederick Griffith
identified parts of the DNA RNA
Lavene
identified the base pairings
Chargaff
identified the double helix
Watso, Crick, Wilkins
helped Watson, Crick and Wilkins in the study of the double helix with her xray diffraction
Franklin
showed that the DNA was the genetic material of the phage T2 by labeling DNA or proteins
Hershey and Chase
Hershey and Chase’s experiment showed that
the protein does not infect, the DNA does
a nucleic acid has ____ ___ vdsnjghslfnva sbub
4 kinds of bases linked to a sugar-phosphate backbone
__ is the tranformation of DNA info into functional molecules
gene expression
most _______ genes are mosaics of introns and extrons
eukaryotic
a conjugated protein where the the prosthetic group is a class of organic compound known as nucleic acids
nucleotides
proesthetic group of nucleotides
nucleic acid
nonprotein group combined with a protein
prosthetic group
an example of nucleotides for carrying chemical energy
ATP
nucleotides are also components of enzyme cofactors such as
FAD
NAD
NADP
co A
an example of nucleotides serving as molecular mesengers
cAMP
an example of nucleotides serving as intermediate
SAM
the polymer strands of DNA are arranged in what manner
antiparallel
the Wtason-Crick model of DNA is in what form
B
the strandsa re held together and stabilized by
hydrogen bonds
base-stacking interaction
which bonds have higher melting point
G-C pair
why higher melting temp ang G-C pair
coz more hydrogen bonds
nucleotides with phosphate removed
nucleoside
components of ribosomes playing a role in protein synth
rRNA
carry gngetic info from gene to the ribosome
mRNA
translate info in mRNA into an amino acid
tRNA
three components of nucleotides
nitrogenous base (purine or pyrimidine)
pentose (D-ribose or 2-deoxyribose)
phosphate group
Pyrimidines in DNA and RNA
Uracil
Cytosine
thymine
Each phrimidine is linked to the sugar through the ___ position
n1
Common purine
Adenine guanine
Purines are attached to sugar at ___ position
N9
Nucleoside is a nitrogenous base covanlently bound in an ________
N-beta-glycosidic linkage to the 1’-carbon of a pentose sugar
A nu leotide is a nucleoside with at least one phosphate group attached to
5’ carbon of the sugar
Nucleotides are linked through their ____ in _____ linkages between the _____ and _____ of the next one
phosphate groups
Phosphodiester
5’ hydroxyl of one pentose to the 3’ hyxdroxyl of the next
Strands of nucleic acid containinh <50 nucleotides are called
Oligonucleotides
Stands with >50 nucleotides are called
Polynucleotides
Nucleobase glycosylated with either pentose sugar is called
Nucleoside
Ribonuclosides seen in RNA
A
G
C
U
Doexyribonucleosides found in DNA
dA
dG
dC
dT
Aling nitrogenous base ung 6 sided
Pyrimidine
Aling nitrogenous bases ung 9 sided
Purine
Adenine is aka
6-aminopurine
cytosine is aka
2-oxy-4 aminopyrimidine
Uracil is aka
2,4-dioxypyrimidine
Eukaryotic cells contain DNA combined with what protein
Histone
Beadlike structures with MW of 10k-20k
Histones
Classes of histones
Histone 1 H2A 2B 3 4
How are histones classified
Accdg to arg and lys content
Which histone bidns to the outside of the DNA
H1
each histone cluster is conposed of
2 moclecules each of 2B 2A 3 4
Ilang turns kpag nagwrap around ung DNA sa histone cluster
2
2 classes of nu leic acid
DNA RNA
histone with highest lys content
H1
Histone with highest arg conc
H4
Bases can exist in what orientations about the N-glycosidic bond
Syn
Anti
two isomer forms of purines and pyrimidines
lactam-lactim
keto enol
for those with amino groups, tautomers formed may be ______
amine-imine
phosphorylation of nucleotides will inc or dec solubility?
increase
nucleoside or base: which is more soluble?
nucleoside
which is resistant to acid treatment
pyrimidines
charge of nucleosides at biological pH
neutral
which are stable over a wide range of pHs
nucleotide and side
under strongly basic conditions, what happens to the nucleic acid
hydrolysis of phosphate esters
in which condtion is the N-glycosidic bonds more labile
acidic
when ang protonation of purine, kpag
high temp
maximum absoprtion of light by nuecleic acids occurs at
260nm
the absorbance property of nucleic acids is due to its
nitrogenous bases
purine or pyrimidine: which has higher abrsobranc
purine
what ha[[ens to absorbance when nucleic acid is hydrolyzed with free bases (?)
hyperchromicity
synthesis of strands go in what direction
5’ - 3-‘
how do you write/read the the nucleotide sequence
5’ - 3’
the bases in the interior of the helix are aligned at nearly
90deg relative to the axis
A-T or G-C: which has more hydrogen bonds
G-C 3 H bonds
A-T 2 H bonds
A-T easier to destroy
helices rich in ____ can exist as left-handed conformation in Z-DNA
G-C dinucleotides
Watson and Crick’s DNA model is in what conformation
B
this is a prat of a strand caused by asymmetry
grooves
the longer groove
major
the major groove in the B-form is
wide and deep
deanturation of the DNA causes what effects
hyperchromic effect and inc. UV absorption
when the 2 strands are separated, the indiv strands assume what conformation
random coil
factors determining stability and Tm of DNA
nature of solvent
pH
conc of ions
point where 50% of the DNA exists as single strands
Tm
process where the melted DNA is cooled and reforms its base pairs again
annealing or hybridization
common affinity matrixx for HPLC of DNA
hydroxyapatite
material of chpoice for electrophoresis
agarose
in eelctrophoresis, the DNA will migrate to which electrode
anode
features of tRNA
cloverleaf like 5' terminal PO4 3' terminal OH dihydrouridine in D arm anticodon arm pseudouridine variable arm
the T arm or TyC arm in the tRNA contains
pseudouridine
the 3’ terminal OH group of the tRNA is found in where
amino acid arm
the bases found in the 3’ end
CCA
amino acids are attracted to and activated when attached ro
3’ end
posttranscriptional events
capping
polyadeny.lic tail
splicing
seen in the 5’ end of mRNAs
7-methyl guanylic acid
gthe 7-methyl guanylic acid in the 5’ end of mRNA is attached via
5’-5’ triphosphate linkage
common rRNA in eukaryotes
80s
common rRNA in prokaryote
70s
rRNA is ___ and _____
35% protein
65% RNA
snRNA form small complexes called
small nuclear ribonucleoproteins
process where the noncoding parts are taken out of the DNA
splicing
the template strand
3’5’
the nontemplate/coding strand
5’3’
postranscriptional capping is for
better recognition of whatever blabla
the poattranscriptional polyadenylate tail is for
stability
