Shared Flashcard Set

Details

Biochemistry Block I Exam (Tulane SOM 2015)
Biochemistry from Block I Set 2/2
79
Medical
Professional
09/05/2011

Additional Medical Flashcards

 


 

Cards

Term
GLUT-2
Definition
Transports glucose in plasma via facilitated diffusion
Term
GLUT-5
Definition
Transports fructose into intestinal epithelial cells via facilitated diffusion
Term
SGLT-1
Definition
Transports 2Na+, glucose into intestinal epithelial cells via secondary active symport
Term
p-ATPases (phosphorylation) in eukaryotes
Definition
Ca++-ATPase
H+/K+-ATPase
Na+/K+-ATPase
Term
buffer
Definition
weak acid + conjugate weak base; accept or donate protons to maintain stable pH
Term
what stereoisomeric form of amino acids is most common biologically?
Definition
L form
Term
phosphorylation by kinases can occur on which amino acids?
Definition
those with hydroxyl groups: threonine, tyrosine, serine
Term
bond between N and alpha-C
Definition
circle slash angle of freedom
Term
bond between alpha-C and C
Definition
psi angle of freedom
Term
in an alpha-helix...
Definition
right-handed turn
H bonds between n and n+4 amino acids
maximal intrastrand H bonding
R groups face outward
Term
in beta-sheets...
Definition
participating strands can be parallel or antiparallel (strongest H bond)
R groups alternate above and below plane of sheet
backbone zigzags
Term
beta-turns
Definition
1. proline is 2nd AA
2. glycine is 3rd AA
Term
super secondary structures
Definition
beta-barrel
beta-alpha-beta loop
alpha-alpha corner
Term
nomenclature: endings for nucelosides
Definition
purines: -sine, pyrimidines: -dine
Term
nomenclature: endings for nucleotides
Definition
purines/pyrimidines: -ylate
Term
nucleosome
Definition
AKA "beads on a string" or 11 nm fiber; transcriptionally active; stabilized by phosphate - charges and histone + charges (Arg, Lys)
Term
euchromatin
Definition
dispersed, trascriptionally-active DNA
Term
heterochromatin
Definition
condensed, transcriptionally-inactive DNA
Term
what causes DNA condensation?
Definition
deacetylation (HDACs)
methylation (prevents acetylation)
repressor proteins ie. H1 (Histone)
Term
what causes DNA decondensation?
Definition
acetylation (HATs)
phosphorylation
activator proteins ie SWI, SNF
Term
gene families...
Definition
may be widespread on multiple chromosomes or clustered together
may arise by tandem gene amplification
Term
histone genes...
Definition
contain to introns
multigene compound clusters on multiple chr.
highly evolutionarily conserved, except H1
genes are duplicated
Term
methods of verifying a cloned insert:
Definition
1. PCR
2. RE digestion pattern
3. DNA sequencing
4. radioactive screen
Term
cloning vectors
Definition
1. plasmid <10
2. bacteriophage <23
3. cosmid 30-45
4. BAC 100-300
5. YAC 200-2000
Term
ciproflaxin
Definition
antibiotic topoisomerase (relegation) inhibitor
Term
DNA Polymerase I
Definition
bacterial
removes primers
repairs
matures Okazaki fragments
Term
DNA Polymerase III
Definition
bacterial
main replication polymerase
Term
DNA Polymerase alpha
Definition
eukaryotic
primes
first DNA synthesis
Term
DNA Polymerase delta
Definition
some leading strand synthesis
primarily lagging strand synthesis
Term
DNA Polymerase epsilon
Definition
some lagging strand sythesis
primarily leading strand synthesis
Term
DNA Polymerase beta
Definition
DNA repair
Term
DNA Polymerase epsilon complex components
Definition
1. DNA Polymerase epsilon
2. Rfc (reloader)
3. PCNA (clamp)
Term
base excision repair
Definition
1. most common transition 5MeC -> T
2.DNA glycosylase removes base (T)
3. apurinic (AP)endonuclease cuts backbone
4. DNA lyase removes Pi, ribose
5. repair/ seal w/ DNA Pol beta + ligase
Term
homologous recombination
Definition
reciprocal exchange of DNA between homologous chromosomes
Term
site-specific recombination
Definition
requires specific sequences from both segments; bacteriophage DNA insertion into bacterial genome
Term
antibiotic resistance
Definition
may be caused by transpositions
Term
meiotic recombination model
Definition
1. gap created by RecB,C,D complex
2. branch migrates and displaces homologous strand -> extension, additional branch migration (RecA, DNA Pol) -> formation of Holliday Intermediate (RecA) -> cleavage by Ruv proteins
Term
homologous recombination + DNA lesion
Definition
bypasses lesion during replication
1. fork collapse (RecA, RecFOR)
2. lagging strand serves as template
3. reverse branch mirgation reestablishes bubble, bypasses lesion
4. lesion repaired later
Term
homologous recombination + DNA nick
Definition
repairs nick during replication
1. leading strand stalled at nick
2. strand invasion by lagging strand (RecA, RecBCD)
3. lagging strand serves as template
4. branch migration forms Holliday Int.
5. Ruv proteins cleave
Term
antibody diversity
Definition
afforded by transposition
1. RSS (Recombo Signal Sequences)cleaved by RAG1 and RAG2 protein
2. this removal of intervening DNA sequences (+ differential mRNA splicing) produces variable light chains
Term
UP Element
Definition
TA-rich sequence in prokaryotic DNA that stimulates transcription
Term
TATAAT and TTGACAT regions
Definition
sequences in prokaryotic DNA that help define transcription start (+1)
Term
speciality factor sigma
Definition
factor in prokaryotic transcription that brings RNA Pol to start sequences
Term
operon
Definition
prokaryotes; group of polycistronic genes that shares the same start sequences
Term
TATA box
Definition
recruits TBPs (TATA Binding Proteins) which bind MINOR GROOVE of TATA Box, binding site for PIC, -30 from +1 start site
Term
Initiator Region
Definition
Inr, sequence on eukaryotic DNA within or near +1 site; where DNA is initially unwound
Term
Transcriptional Activators
Definition
DNA binding regions and activation domains; can be located near or far from transcribed sequence; chromatin remodeling and mediator effected by
Term
helix-turn-helix motif
Definition
repressor motif that binds to 2 adjacent DNA major grooves in a sequence-specific manner; bends DNA slightly
Term
Leucine zipper motif
Definition
transcription factor; binds to DNA via basic residues (Arg, Lys); 2 proteins assoc. via hydrophobic interactions of Leu (looks like zipper); ex: fos-jun TF
Term
basic helix-loop-helix motif
Definition
2 such molecules interact via 1 leucine; interact w/ DNA via basic residues (Arg, Lys)
Term
zinc finger motif
Definition
2 loop structures wrap around major grooves; loops formed by 2 cysteine molecules assoc. w/ zinc ion
Term
enhancers in eukaryotic DNA sequences
Definition
usu. far from TATA Box; may be upstream, downstream, or in an intron; do not interact directly with the PIC
Term
TFIIB
Definition
Binds after TBPS, interacts w/ TBPs, TATA Box; recruits RNA Pol II/ TFIIF complex
Term
TFIIE
Definition
docking site for TFIIH, which completes PIC assembly
Term
TFIIH
Definition
helicase activity powered by ATP hydrolysis, phosphorylates serines of CTD of RNA Pol II, starting transcription; also recruits nucleotide excision repair proteins
Term
TBP
Definition
TATA Binding Protein- locate TATA Box
Term
TFIIA
Definition
stabilizes TBPs and TFIIB
Term
TFIID
Definition
initiates PIC assembly in absence of TATA Box
Term
what does RNA Pol I do?
Definition
transcribes pre-rRNA; does not require ATP to start; has own TFs; uses specific polymerase terminator sequence
Term
what does RNA Pol II do?
Definition
transcribes mRNA, snRNA, and miRNA; requires ATP to start; termination somewhere after polyA signal site
Term
what does RNA Pol III do?
Definition
transcribes tRNA, 5S rRNA; does not require ATP to start; has own TFs; uses Box A, B, and C as promoter; termination after poly U sequence (A-U combo unstable-released)
Term
HIV and CTD
Definition
Tat, Cyclin T activate CDK9, phosphorylates CTD to prevent termination
Term
hnRNA
Definition
"heterogenous nuclear RNA" contains introns and exons
Term
splice donor site
Definition
site of intron splicing during hnRNA processing; starts with "GT"
Term
splice acceptor site
Definition
end of intron to be spliced during hnRNA processing; "AG"
Term
eIF1A
Definition
binds to 40S subunit
Term
eIF3
Definition
binds to 40S subunit first
Term
eIF6
Definition
binds to 60S subunit
Term
eIF2
Definition
w/ GTP binds to Met-tRNAi, brings it to 40S subunit during initiation
Term
eIF4E
Definition
binds to 5' cap of mRNA
Term
PABs
Definition
Poly-A Binding Proteins; bind to poly A tail of mRNA during formation of initiation complex
Term
eIF4G
Definition
binds eIF4E/PABS to bring 5' and 3' ends of mRNA together
Term
eIF4A
Definition
has helicase activity towards mRNA
Term
eIF4B
Definition
finds AUG start codon
Term
eIF4F
Definition
complex that includes eIF4A,B,E,and G; binds to 40S subunit to bring mRNA over to it
Term
eEF1alpha
Definition
elongation factor; binds GTP to aa-tRNA to allow for paptide bond formation
Term
eEF1betagamma
Definition
exchanges GDP for GTP on eEF1alpha, recharging it for use in elongation
Term
eEF2
Definition
AKA "translocase"; eEF2 + GTP moves ribosome one codon towards 3' end of mRNA, shifting contents of various sites
Term
eRF
Definition
release factors bind to stop codon in A site -> activate ribosome to hydrolyze polypeptide -> results in ribosome disassembly
Supporting users have an ad free experience!