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144 Cards in this Set

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Protein malnutrition
Kwashiorkor
will see in kwashiorkor patient
"MEALS":
malabsorption
edema
anemia
liver (fatty)
skin lesions
*clinical picture = small child with swollen belly
energy malnutrition
Marasmus
see in Marasmus patient
tissue/msucle wasting
loss of subcutaneous fat
variable edema
nucleosome core
H2A, H2B, H3, H4
2 each of these + charged histones
charge of dna
-
nucleosome bead
- charged DNA loops twice around nucleosome core
only histone not in nucleosome core
H1
less condensed: heterochromatin or euchromatin
euchromatin -
heterochromatin is more condensed
transciptionally active: heterochromatin or euchromatin
euchromatin -
heterochromatin is transcriptionally inactive
anti-histone ab
drug-induced sle
purines
A,G
"pure as gold"
pyrimidines
C,U,T
"cut the py"
# of rings of purines
2
# of rings of pyrimidines
1
nucleotide with a ketone
Guanine
nucleotide with a methyl group
thymine
formation of uracil
from deamination of cytosine
unique nucleotide to rna
uracil
unique nucleotide to dna
thymine
nucleotide bond
3'-5' phosphodiester bond
pairs with highest melting point
G-C
with 3 H bonds
A-T bonds
A=T, 2 H bonds
amino acids necessary for purine synthesis
Gly
Asp
Gln
nucleotide =
base pair + ribose + phosphate
subsitute a purine for a purine or pyrimidine for a pyrimidine
transition
subsitute a purine for a pyrimidine or vise versa
transversion
each codon specifies only one amino acid
unambiguous
more than one codon may code for the same amino acid
degenerate/redundant
a.a. encoded by only 1 codon
methionine
read from a fixed starting point as a continuous sequence of bases
commaless, nonoverlapping
may not be commaless or nonoverlapping
some viruses
genetic code is conserved through evolution
universal
exceptions to being UNIVERSAL (4)
mitochondria
archaebacteria
mycoplasma
some yeasts
*universal means genetic code is conserved throughout evolution
mutation results in same aa
silent
serverity of damage of mutations: silent, nonsense, missense
nonsense > missense > silent
mutation results in changed aa
missense
mutation results in changed aa that is similar in chemical structure to mutated aa
conservative
mutation results in early stop codon
nonsense
mutation results in misreading of all nucleotides downstream
frameshift
*causes early disease
what mutation often results in a truncated protein
frameshift
where replication beigins in eukaryotes
A-T rich base pairs
nascent strand
strand to be replicated
daughter strand
new strand to be made as a result of replication
multiple origins of replication: eukaryote or prokaryote
eukaryote
single origin of replication: eukaryote or prokaryote
prokaryote
continuous dna synthesis on which strand
leading
discontinuous dna synthesis on which strand
lagging (ogazaki)
creates nicks in helix to relieve supercoils in dna replication
dna topoisomerase
denatures A-T bonds at beginning of dna replication
dna-a
unwinds dna (breaks helix)
helicase
phase of mitosis where dna replication occurs
S phase
enzyme of dna replication that makes an rna primer on which dnapIII can initiate replication
primase
5'->3' synthesis with
3'->5' exonuclease
enzyme in dna replication
dnapIII
enzyme that "proofreads" in dna synthesis
exonuclease
dna synthesis enzyme that degrades RNA primer and replaces with correct dna
dnapI
dna polymerase uses this to excise primers
5'->3' exonuclease
seals dna in dna synthesis
dna ligase
which enzyme forms the replication fork
helicase
stabilizes unwound helix
SSB and DNA topoisomerase (creates nick in helix to relieve supercoils)
steps in dna replication
1. helicase unwinds
stabilized by ssb and
dna topoisomerase
2. leading strand synthesized continuously via DNAPIII
3. lagging strand synthesized discontinuously in ogasaki fragments
4. dnapI removes rna primer and replaces with correct dna
5. dna ligase seals break at ogasaki fragments to make continuous
5' end of dna
with phosphate group
3' end of dna
with hydroxyl group
dna stabilization
via H bonds and hydrophobic interactions
diseases with imparied dna repair (5)
1. ataxia-telangiectasia
2. xeroderma pigmentosa
3. fanconi anemia
4. bloom syndrome
5. hnpcc
specific endonucleases release the oligonucleotide-containing damaged bases; while dna polymerase and ligase fill and reseal the gap, respectively
nucleotide excision repair
mutated nucleotide excision repair
xeroderma pigmentosa
dry skin with melanoma and other ca's; defective dna repair
xeroderma pigmentosa
glycosylases recognize and remove damaged bases, AP endonuclease cuts dna at apyrimidinic site, empty sugar is removed, and the gap is filled and resealed
base excision repair
unmethylated, newly synthesized string is recognized, mismatched nucleotides are removed, and the gap is filled and resealed
mismatch repair
mutation in hereditary nonpolyposis colon cancer
mismatch repair
brings together 2 ends of dna fragments
nonhomologous end joining
direction of synthesis
5' to 3'
largest rna
mrna
most abundant rna
rrna
smallest rna
trna
rna polymerase I
rrna
rna polymerase II
mrna
rna polymerase III
trna
B,B,alpha
zinc fingers
opens dna at promoter site in transcription
rna polymerase II
inhibits rna polymerase
alpha-amantin
source of alpha-amantin
cap mushrooms
mRna initiation codons
AUG
GUC (rarely)
codes for methionine in eukaryotes
AUG - start codon
start codon in prokaryotes codes for....
formyl-methionine (f-met)
mrna stop codons
UGA, UAA, UAG
binds promoter sequence of dna in transcription
rnapII
intial steps of transcription (3)
1. ranpII binds promoter sequence of dna (tata and caat box)
2. dna unwinds and forms "transcription bubble"
3. rnapII moves along "sense" strand, adding ribonucleotides to growing strand of mrna
site where rna polymerase and other transcription factors bind to DNA upstream from gene locus
promoter
site of promoter
A-T rich upstream sequence with TATA and CAAT box
mutation resulting in dramatic decline in amount of gene transcribed
promoter mutation
stretch of dna that alters gene expression by binding transcription factors
enhancer
operator
site where negative regulators (repressors) bind
contain the actual genetic information coding for a protein
exons
intervening noncoding segments of dna
introns
different exons can be combined to make unique proteins in different tissues
alternative splicing
primary transcript combines with snRNP's to form.....
spliceosome
intermediate formed to spliceosome
lariat-shaped intermediate that is released to remove introns and join 2 exons
steps in splicing (3)
1. primary transcript combines with snRNPs to form spliceosome
2. lariat-shaped intermediate is generated
3. lariat is released to remove introns and join 2 exons
location of rna processing
at nucleus
process after transcription
rna processing -
1. capping at 5' end
2. poly a tail at 3' end
3. splice out introns
capped and tailed transcript
mRNA
initial transcript before rna processing is called....
hnRNA (heterogeneous nuclear RNA)
only step of rna processing that does not occur at the nucleus (instead at the cytoplasm)
capping on 5' end
added during capping
7-methyl-G
add methyl group on c7
and add guanesine
end that is capped
5'
end with poly-a tail
3'
function of poly-a tail
protects genes from degradation
guides rna to 30s to read 3' end
how many A's in the poly-A tail
~200 A's added to 3' end
# of nucleotides in trna
75 - 90
cloverleaf shaped rna
trna
sequence at 3' end of trna
CCA
location of anticodon
in middle loop - opposite 3' end
end of amino acid covalent bond in trna
3' end of trna
attaches aa to 3' end of trna
aminoacyl-trna synthetase
scrutinizes aa before and after it binds to trna
aa-trna synthetase
if aa bound to trna is incorrect, bond is hydrolyzed by
synthetase (aa-trna synthetase)
aa-trna bond has this for formation of peptide bond
energy
mischarged trna
reads usual codon
interts wrong amino acid
ACC at 3' end of trna codes for......
Met
"wobble" position
3rd nucleotide of an mrna codon
says that accurate base pairing is required only in the first 2 nucleotide positions of an mRNA codon
"wobble" theory
3 main steps of protein synthesis
1. initiation
2. elongation
3. termination
location of protein synthesis
ribosome
occupies A site
trna of next aa to be added to the growing polypeptide
occupies P site
trna containing growing peptide chain
helps assemble the 30s ribosomeal subunit with the initiator tRNA
IF initiation factor
released when mrna and ribosomal subunit assemble with the complex
IF initiation factor
codon recognized by initiator trna
AUG
occurs during Initiation of protein synthesis
IF's help assemble the 30s ribosomal subunit with the initiator tRNA. then if's are released when mRNA and ribosomal subunit assemble with the complex
during elongation, aminoacyl trna binds to.....
A site
during elongation, catalyzes peptide bond formation, transfering growing polypeptide to amino acid in A site
peptidyl transferase
energy needed for tRNA activation
ATP (charging)
energy needed for tRNA translocation
GTP
ribosome advances 3 nucleotides toward 3' end of rna
during elongation, to move peptidyl RNA to p site
completed protein is released from ribosome when stop codon enters a site
TERMINATION step of protein synthesis
holds Empty tRNA as protein exits
E site
3 steps of elongation
1. aminoacyl tRNA binds A site
2. peptidyltransferase catalyzes peptide bond formation, transfers growing popypeptide to amino acid in A site
3. ribosome advances 3 nucleotides toward 3' end of RNA, moving peptidyl RNA to P site
Termination
stop codon enters a site. complete protein is released from ribosome. protein is dislocated. empty trna occupies E site
posttranslational modifications (3)
trimming
covalent alteration
proteasomal degradation
removal of N- or C- terminal pro-peptides from zymogens to generate mature proteins
trimming
phosphoylation, glycosylation, and hydroxylation
covalent alterations
attachment of ubiquitin to defective proteins to tag them for breakdown
proteosomal degradation