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Biochem- Sands- Ross University
Biochem- Sands- Ross University
58
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Professional
09/22/2009

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Term
Campothecin
Definition
Top. 1 inhibior- used to treat cancer, chemotherapeutic agent
Term
Gyrase
Definition
Top. II, induces negative supercoils for easier unwinding of DNA
Term
Ciprofloxacin
Definition
Inhibits Gyrase (Top. II)
Term
Etoposide
Definition
Top. II Inhibitor
Term
Doxorubicin
Definition
Top. II Inhibitor
Term
Transcription- Prokayrotic Pol. I does what?
Definition
Removes RNA primer and fills in gap with DNA on lagging strand
Term

Eukaryotic Transcription- RNase H and/or Fen1

(flap endonuclease)

Definition
remove RNA primer
Term
How is telomeric DNA replication different from that of other chromosomal regions?
Definition
The DNA polymerase contains an RNA molecule that serves as template for DNA synthesis.
Term
Transcription- Eukaryotic Polymerases B & E?
Definition
Involved in repair of nuclear DNA
Term
What is sensitive to  a-amanitin?
Definition
Translation- RNA pol. II- (mRNA)
Term
Affect of Ricin?
Definition
Depurinates adenine in the 28S rRNA thereby inactivating the large ribosomal subunit.  alters the ability of the ribosome to interact with translation elongation factors
Term
Affect of  Rifampicin?
Definition
 inhibits RNA polymerase in bacterial cells by binding to the b-subunit of RNA polymerase.  Rifampicin "makes the liver extremely active," hindering the effectiveness of other medications. Activates P450 enzymes thereby increasing the clearance of drugs from the body.
Term
Using one example, explain how mutations in mitochondrial tRNA can cause disease.
Definition
The mutated tRNA (leucine) reduces the amount of complex 1 that is made in the mitochondria, which affects the amount of ATP made. 
Term
Function of Shine-Delgarno sequence in Prokaryotic mRNA?
Definition

 

This sequence helps recruit the ribosome to the mRNA to initiate protein synthesis by aligning it with the start codon.

Term
Pribnow box?
Definition
The Pribnow box is an A-T rich sequence (TATAAT) located 10 base pairs upstream from the start site for transcription. This sequence is involved in the initial recognition of the promoter by RNA polymerase.
Term
A promoter region of a gene is best described as:
Definition
A site where RNA polymerases bind to DNA to initiate transcription
Term
Sigma factor?
Definition

 

Sigma factor functions to ensure that RNA polymerase binds

  stably to DNA only at promoters.

It increases the affinity of the RNA polymerase for the promoter.
Term
A-DNA?
Definition
DNA/RNA hybrid
Term
The closest equivalent to the σ (sigma) subunit of bacterial RNA polymerase in eukaryotes is:
Definition
A set of “general” transcription factors
Term
Proteins involved with RNA processing are attached to the what?

-Capping factors
-Splicing factors
-Polyadenylation factors
Definition
C-terminal Domain (CTD)
Term
What carries out splicing of Eukaryotic DNA?
Definition
A combination of snRNAs and proteins called spliceosomes
Term
The 5' cap and the 3' poly-A tail are added in the production of mature eukaryotic mRNA. The 5' cap and the 3' poly-A tail have which respective functions?
Definition
Translation initiation- cap
Transcript stability- tail
Term
Eukaryotic transcription termination requires...
Definition
A termination signal sequence
Term
Rat1?
Definition
It is a necessary protein from moving the mRNA from the nucleus to the cytoplasm. It is thought to act like a “torpedo” and knocks the polymerase off the DNA.
Term
Degenerancy of gentetic code means?
Definition
While each codon specifies one amino acid, each amino acid may have more than one triplet coding for it
Term
Mutations that do not change the amino acid for which the codon is coding is a
Definition
Silent mutation
Term
Mutations that change the amino acid for which the codon is coding is a
Definition
Missense Mutation
Term
Mutations that Change the codon to a stop codon are
Definition
Nonsense Mutations
Term
Name 2 stop Codons
Definition
UAG, UAA
Term
Huntington disease, Fragile X syndrome, Myotonic dystrophy are all caused by what?
Definition
Trinucleotide repeats in translation
Term
Frame Shift Mutations
Definition
The addition or subtraction of any nucleotides other than a multiple of three, causes a frame-shift.
Frame-shift create a protein that is usually “nonsensical” or “nonsensical and truncated”.
The amino acid sequence beyond the frame shift is always altered.
Term
Aminoacyl-tRNA synthetases role in translation?
Definition
Attaches amino acids to tRNAs
Term
ATP and GTP roles in translation?
Definition
ATP is needed to hook up tRNAs and amino acids; GTP is needed to translate the mRNA
Term
How many high energy bonds does it take to activate an amino acid?
Definition
Two.
Term
When an amino acid is attached to AMP it is called?
Definition
An activated amino acid.
Term
When an amino acid is attached to tRNA it is called?
Definition
A charged tRNA.
Term
Know this
Definition
Prokaryotic ribosomes
Are 70S in size
Large subunit is 50S
contains 23S and 5S rRNA
Small subunit is 30S
contains 16S rRNA
Eukaryotic ribosomes
Are 80S in size
Large subunit is 60S
Contains 28S, 5.8S and 5S rRNA
Small subunit is 40S
Contains 18S rRNA
Term
How many amino acids?
How many codons?
Definition
20 amino acids
61 codons that correspond to amino acids.
Term
Chloramphenicol
Definition
Antibiotic that inhibits the formation of a peptide bond in prokaryotes during translation
Term
Cyclohexamide
Definition
Antibiotic that inhibits the formation of a peptide bond in eukarytoes during translation
Term
Peptidyl transferase
Definition
Creates peptide bonds on ribosomes between amino acids at A and P sites during translation
Term
Translation energy??
Definition
GTP for everything except to charge RNA, which uses ATP
Term
Streptomycin
Definition
Binds to 30s subunit and distorts its structure, interfering with the iniation of protein synthesis.
Term
Tetracycline
Definition
Interacts with small ribosomal subunits, blocking acces of the amino-acyl-tRNA to the mRNA-ribosome complex, interfering with t-RNA anticodon reading of m-RNA codon
Term
Puromycin
Definition
Bears a structural resemblance to amino-acyl tRNA and becomes incorporated into the growing peptide chain, thus causing inhibition of further elongation in both prokaryotes and eukaryotes
Term
Clindamycin and Erythromycin
Definition
Bind irreversibly to a site on the 50S subunit of the bacterial ribosome, thus inhibiting translocation.
Term
Elongation factor-G
Definition
a cytoplasmic protein that transiently associates with the ribosome
Term
Does formation of the peptide bond during protein synthesis have an energy requirement?
Definition
No, it already obtained energy from attachment of an amino acid to its tRNA
Term
Translation is terminated by ....
Definition
a release factor (RF) and UGA, UAG, or UAA codons
Term
Polysomes
Definition
Most messages are translated by more than one ribosome at a time.
These multi-simultaneously translated mRNA are called polysomes.
Term
What is the complex of proteins called that binds to the cap structure in translation?
Definition
eIF4 initiation factors
Term
Ferritin
Definition
is a cytosolic iron binding protein expressed when iron is abundant in the cell..... Control of mRNAs translation by iron.
Term
Transferrin Receptor
Definition
is a plasma membrane receptor important for the import of iron into the cytosol.
They are coordinately regulated, in opposite directions, by control of protein synthesis. Control of
Term
One of the ways of controlling the synthesis of hemoglobin proteins is by the availability of heme. When heme is low a kinase called HCI is active. What translation initiation factor is phosphorylated by HCI thereby making it difficult to translate the globin mRNA in the cell?
Definition
eIF2
Term
Interferon control in translation
Definition
Regulation of translation can also be induced in virally infected cells.
It would benefit a virally infected cell to turn off protein synthesis to prevent propagation of the viruses.
This is done by interferon.
Term
eIF4G
Definition
functions as a bridge between the methyl cap binding subunit and the 40S subunit.
Term
Poliovirus stops cellular translation by
Definition
cleaving one of the cap binding proteins (eIF4G). The consequence of this cleavage is that translation of cellular mRNAs stops.
But…the viral RNA is still translated due to the presence of an internal ribosomal entry site (IRES).
This acts like a bacterial initiation site to allow Cap-independent initiation from internal AUG codons.
Term
Diptheria
Definition
stops translation by screwing up the translocation process.
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