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BCH 361 4th Test Study Cards
BCH 361 ASU Frome 4th Test Study Guide
145
Biochemistry
Undergraduate 3
05/05/2011

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Term
Sticky Ends
Definition
Result of Restriction endonucleases that cleave double-stranded DNA
Term
Methylation of endogenous DNA
Definition
How bacteria protect their own DNA from degradation.
Term
What needs to happen in order for eukaryotic proteins to be expressed in E.coli?
Definition
Removal of introns, addition of the Shine-Dalgarno sequence to mRNA, post-translational modifications, chaperones need to be added
Term
Expression vector
Definition
Plasmid that contains gene of interest
Term
DNA Library
Definition
Contains whole genome
Term
cDNA library
Definition
mRNAs expressed in a cell, used as cDNA templates
Term
ex vivo
Definition
cells are removed, altered, and given back
Term
in vivo
Definition
virus infect tissue directly
Term
SCID
Definition
Disease that makes the immune system non functional
Term
Processing of long dsRNA to siRNA
Definition
dsRNA is cleaved by RNAse to produce 21-25bp dsRNA
Term
Assembly of RNA-induces silencing complex (RISC)
Definition
one strand of siRNA (guide strand) is assembled into a RNA-induced silencing complex (RISC) that cleaves target mRNA
Term
Dicer
Definition
produces small RNA from longer precoursors
Term
Argonaute
Definition
Core component of all silencing complexes (RISC)
Term
DNA replication takes place only
Definition
Once each generation in each cell
Term
Errors in replication occur spontaneously only once in ever
Definition
10^9 to 10^10 base pairs
Term
DNA replication takes place only once
Definition
each generation in each cells
Term
Errors in replication occur spontaneously
Definition
only once in every 10^9 to 10^10 BP
Term
Errors in hydrogen bonding
Definition
lead to errors in a growing DNA chain once very 10^4 to 10^5 BP
Term
DNA Pol I exonuclease activity
Definition
3'-5'
Term
DNA Pol I blue domain
Definition
Polymerase-domain
Term
DNA pol I yellow
Definition
3'-5' exonuclease
Term
Why does DNA contain thymine instead of uracil
Definition
More stable, uracil leads to higher levels of mutation during replication
Term
Thymine Dimers
Definition
Are created by UV radiation damage to DNA
Term
Mutagenic lesions are the result of
Definition
small changes to the basepairing region of DNA bases
Term
Small changes to the basepairing region of DNA bases includes
Definition
spontaneous deaminations, depurinations, oxidised bases
Term
What are cytotoxic lesions?
Definition
Chemically diverse group of DNA lesions
Term
Cytotoxic lesions can be
Definition
Double-strand breaks, UV-induced bulky adducts, DNA interstrand crosslinks (ICL's), uncapped telomeres, certain oxidised bases
Term
Unrepaired cytotoxic lesions can
Definition
block vital DNA metabolic processes, such as gene transcription, DNA replication, or chromosome segregation
Term
Unrepaired cytotoxic lesions can lead to
Definition
Proliferative arrest or cell death
Term
Repair process in E.coli (mutagenic, one strand)
Definition
Base-excision repair (BER)
Term
First step in base-excision repair
Definition
Damaged base is excised from the backbone by DNA glycosylase
Term
Second step in Base-Excision Repair
Definition
Apurinic/apyrimidinic endonuclease searches the DNA strand for missing bases, when it finds missing base, it cleaves the sugar-phosphate backbone
Term
Third step in Base-Excision Repair
Definition
Excision nuclease removes the AP site and several further nucleotides
Term
Fourth step of Base-Excision Repair
Definition
DNA polymerase adds the missing bases
Term
Fifth and final step in Base-Excision Repair
Definition
Ligase connects the sugar-phosphate backbone
Term
Repair process for mutations that affect one strand (cytotoxic)
Definition
Nucleotide-excision repair, Transcriptional coupled repair, global genome repair
Term
Repair process for mutations that affect both strands (cytotoxic and mutagen)
Definition
Interstrand crosslink repair, homologous recombination, end jointing
Term
Responsible for longevity assurance
Definition
Transcription coupled repair and interstrand crosslink repair
Term
DNA damage occurring anywhere in the genome is repaired by
Definition
GG-NER subpathway of Nucleotide excision repair, Base Excision Repair, and Interstrand Crosslink Repair
Term
XPC-hHR23B
Definition
This protein dimer detects classic NER lesions
Term
For some types of damage, these dimers may assist XPC-hHR23B
Definition
XPE heterodimer (DDB1 and p48)
Term
First step of General Genome nucleotide excision repair
Definition
NER lesions are detected by the protein dimer XPC-hHR23B
Term
Second step of GG-NER
Definition
Next, the basal transcription factor TFIIH, which includes two DNA helicases with opposite polarities (XPB and XPD), is recruited. The endonuclease XPG is recruited simultaneously, or shortly thereafter.
Term
Third step of GG-NER
Definition
Once the DNA is unwound around the site of the lesion, RPA is required to bind the single-stranded DNA and stabilise the open complex. The XPC–hHR23B duplex is replaced by XPA, which is believed to contribute by verifying the presence of a lesion. Finally, a third protein dimer, the endonuclease ERCC1–XPF, is recruited. Dual incisions are made in one strand flanking the lesion
Term
Fourth step of GG-NER
Definition
The damaged oligonucleotide is released and the gap filled via template-dependent DNA polymerisation by the replication machinery.
Term
Xeroderma pigmentosum
Definition
Human disorder that is characterized by defects in DNA repair
Term
Transcription Coupled Repair
Definition
Site of DNA damage can be identified during transcription when the lesion causes RNA pol II to stall.
Term
TFIIH, XPG, CSA and CSB
Definition
Protein complex that is responsible for removing the stalled polymerase from the transcribed strand so that repair of the lesion can occur
Term
Cockayne syndrome
Definition
Human disorder that is characterized by defects in DNA repair.
Term
p53
Definition
Is a chemical activated in response to several malignancy-associated stress signals, resulting in tumor-cell inhibition
Term
Cockayne syndrome
Definition
Human disorder that is characterized by defects in DNA repair.
Term
p53 and MDM2
Definition
Form an Auto-regulatory feedback loop
Term
MDM2
Definition
What p53 stimulates the expression of
Term
MDM2 binds to p53 thereby
Definition
Inhibiting transcriptional activity, favoring nuclear export, stimulation degradation.
Term
Super p53 mice exhibit
Definition
Enhanced DNA damage response, tumor resistant, age normally
Term
Viron
Definition
Complete virus particle
Term
Capside
Definition
Where the genetic information in a virus is stored
Term
SV40
Definition
One of the smallest viruses, codes for five proteins
Term
Oncogene
Definition
Gene that induces cancer
Term
HIV p10 (GAG/Pol protease)
Definition
Proteolytic cuts the large precursor protein to form the virus proteins
Term
HIV p17 Matrix protein MA
Definition
Protects virus RNA
Term
HIV p24 Capsid protein CA:
Definition
Builds the structure of the caspid
Term
HIV gp41 Transmembrane protein
Definition
Transmembrane anchor for the docking protein gp120
Term
HIV gp120
Definition
external protein responsible for docking to the cell
Term
p34 Integrase
Definition
Integrates the double stranded virus DNA into human DNA
Term
Long terminal repeats (LTRs)
Definition
Used for regulation and initiation of transcription
Term
Replication is
Definition
Semi-conservative
Term
Semi-conservative
Definition
Each daughter strand contains one template strand and a newly synthesized strand
Term
Meselson and Stahl
Definition
Established in the 1950's that replication is semi-conservative
Term
Origin of Replication (Ori)
Definition
DNA double helix unwinds at this point
Term
Replication forks
Definition
Where new polynucleotide chains are formed
Term
Direction of replication (DNA)
Definition
Bidirectional
Term
One origin of replication
Definition
Prokaryotes
Term
Several origins of replication in
Definition
Eukaryotes
Term
Leading strand in Prokaryotes
Definition
Synthesized continuously in the 5'-3' direction toward the replication fork on the exposed 3'-5' template strand
Term
E.coli Pol III
Definition
Synthesizes the leading strand and okasaki fragments
Term
E.coli Pol II
Definition
Repair enzyme
Term
Pol I
Definition
Removes primers, synthesizes DNA gaps between okasaki fragments
Term
DNA ligase
Definition
Seals the backbone in replication
Term
Origin Recognition Complex
Definition
Bound to the origin site, inactive.
Term
Replication Activation Protein
Definition
Binds to the Origin Recognition Complex
Term
Replication Licensing Factors
Definition
These bind to the DNA
Term
Telomeres
Definition
Repeated DNA sequences 5'TTAGGG3', protects the end of the chromosome from deterioration or from fusion with neighbouring chromosomes
Term
Telomere shortening
Definition
Leads to programmed aging/death of cells
Term
Telomerase
Definition
Resynthesizes telomeres after replication has occurred, preventing cell death/aging
Term
Aminoacyl-tRNA synthase
Definition
Loads tRNA's with amino acids
Term
First step in activation of amino acids
Definition
Phosphodiester bond is formed between the carboxyl group of the amino acid and the phosphate group of AMP
Term
Step two of Activation of Amino Acids (Class II Enzymes)
Definition
nucleophilic attack of the free electron pair at 3’OH of last nucleotide of tRNA (adenine) to the carboxyl-C of the amino acid
Term
Step two of activation of amino acids (Class I Enzymes)
Definition
Nucleophilic attack of the free electron pair at 2’OH of last nucleotide of tRNA to the Carboxyl C of the amino acid
Term
Step three of activation of amino acids (Class I enzymes)
Definition
transfer of the ester bond between the amino acid and the tRNA from 2’ to 3’ position (transesterfication)
Term
Ester bond
Definition
This is hydrolyzed when the wrong amino acid is bound to the tRNA
Term
fMet-tRNA
Definition
The first tRNA that binds to the ribosome in Prokaryotes
Term
First step of initiation of translation in Prokaryotes
Definition
30S subunit of Ribosome, loaded with fMet-tRNA binds to Shine-Dalgano sequence of the mRNA
Term
Second step of initiation of translation in Prokaryotes
Definition
GTP is hydrolyzed , 50S subunit of Ribosome binds, IF-1, IF-2 and IF3 are released
Term
Suppressor tRNAs in Eukaryotes
Definition
Recognize STOP codons and allow continuation of translation
Term
Nonsense mutations
Definition
Introduce stop codons in a sequence due to a single mutation
Term
Specific proteases of the endoplasmic reticulum
Definition
Removes leader sequences
Term
Golgi apparatus
Definition
Directs finished proteins to their final destination
Term
Ribosomes associated with the membranes of the Rough ER
Definition
Synthesizes membrane/secretion bound proteins
Term
N-terminus is also known as a
Definition
signal sequence
Term
Signal recognition particle (SRP)
Definition
Recognizes the signal peptide
Term
Signal peptidase
Definition
Removes the signal peptide following passage through the ER membrane
Term
Preproteins
Definition
Proteins that contain a signal peptide
Term
Preproproteins
Definition
Proteins destined for secretion that are further proteolyzed following secretion; contains pro sequences
Term
These engage the ER membrane through interaction of the SRP receptor in the ER membrane
Definition
Ribosomes
Term
Kozak Sequence
Definition
-3 ACCAUGG +4, Surrounds the AUG codon for recognition
Term
poly-A binding protein (Pab1p)
Definition
Links the polyA tail to the 4g and pre-initiation complex
Term
Scanning mechanism driven by ATP-Hydrolysis
Definition
5'cap orients the ribosome to the correct AUG codon
Term
Initial amino acid in initiation
Definition
Methionine
Term
Phosphodiester bonds
Definition
Bond DNA and RNA to form a sugar phosphate backbone
Term
H bonds in G-C
Definition
Three
Term
H-bonds in A-T
Definition
Two
Term
Base stacking
Definition
Hydrophobic interactions of the ring systems of the bases
Term
B-DNA
Definition
Most common DNA form in nature, right handed
Term
A-DNA
Definition
Present in DNA/RNA hybrids, right handed
Term
Z-DNA
Definition
Present in dCGCGCGCG sequences, left handed
Term
Rotation of the base pairs can form
Definition
A Z-DNA section in the middle of a B-DNA
Term
Topoisomerase
Definition
Enzymes that supercoil DNA
Term
Type I Topoisomerases
Definition
Cut and seal the phosphodiesterbond of one DNA strand
Term
Type II Topoisomerases
Definition
cut and seal the phosphodiester bond of both DNA strands
Term
mRNA
Definition
Brings genetic information from DNA to the protein
Term
sn-RNAs
Definition
Help processing of mRNA to its mature form in Eukaryotes
Term
tRNA
Definition
brings the amino acids to the site of protein biosynthesis
Term
rRNA
Definition
constituent of ribosomes (site of protein biosynthesis)
Term
small interferring RNA si-RNA
Definition
are involved in silencing of genes. They contain antisense RNA and block translation by interaction with the mRNA
Term
Amino acid binding site
Definition
3' end
Term
A ribosome consists of
Definition
2 large subunits, containing RNA and protein
Term
Reason why DNA contains Thymine instead of Uracil
Definition
Cytosine can be deaminated to Uracil, Thymine is a methylated Uracil, all uracil that occurs in DNA is caused by this deamination. DNA repair enzymes can detect this and replace it with cytosine
Term
Chemical Structure of DNA
Definition
H at the 2' position
Term
Chemical structure of RNA
Definition
OH at the 2' position
Term
TATA box (-10) and -35 Box
Definition
Elements of the promoter region for transcription in Prokaryotes
Term
Pol I in Eukaryotes synthesizes
Definition
rRNA
Term
Pol II in Eukaryotes synthesizes
Definition
mRNA
Term
Pol III in Eukaryotes synthesizes
Definition
tRNA
Term
Glycosylation and Cofactor Binding
Definition
Protein modification that occurs after translation
Term
Premature aging
Definition
The result of Cockayne Syndrome
Term
DNA viruses cause
Definition
Influenza, Chicken Pox and Herpes
Term
RNA viruses cause
Definition
AIDS, Polio
Term
Adhesion and Injection
Definition
How prokaryotic viruses enter the cell
Term
Incorporation by endocytosis
Definition
How viruses enter Eukaryotic cells
Term
Gene silencing
Definition
Hinders the translation of mRNA by the use of siRNA, inhibiting translation in the cytosol of eukaryotic cells
Term
DNA glycosylase in base excision repair
Definition
Excises damaged bases from the backbone, 1st step in BER
Term
Excision Nuclease in Base Excision Repair
Definition
Removes the AP site and several further nucleotides, third step in BER
Term
DNA Pol in Base Excision Repair
Definition
Adds missing bases, fourth step of BER
Term
Ligase in Base Excision Repair
Definition
Connects the sugar-phosphate backbone, fifth and final step in BER
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