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55 Cards in this Set

  • Front
  • Back
What is the Ras/Raf pathway
1. growth factor binds G protein
2. Ras binds GTP and becomes active
3. Ras activates Raf
4. Raf phosphyrlates MEK
5 MEK phosphoryaltes MAP kinase
6. MAP kinase phosphoylates other cytoplasmic and nuclear proteins
7. transcription of proto-oncogenes
burkitt's lymphoma
myc is translocated from chromosome 8 to 14 and comes under contrl of Ig heavy chain promoter and is over expressed
philadelphia chromosome
in bone marrow cells, part of ch9 inserts into ch22, causing increased tyrosine kinase activity promoting uncontrolled growth of lueukemic cells. causes chronic myelogenous leukemia
proto oncogenes
encode protiens involved in a cell's normal growth control pathway
tumor supressor genes
encode molecule that regulate (inhibit) cell proliferation and slow it down.
2. products of tumor suppressor genes often modulate pathwyas that are activated by the products of proto oncogenes
1. stops replication in cells that have dna damage and targets teh unrepaierd cells for apoptosis
2. p53 stimulates production of p21
3. p 21 inhibits cyclin/CDK complex and stops cell cycle progression
binds to Ras and holds it in the GDP form, which is the inactivated form
3 stages of apoptosis
1. initiation
2. signal integration
3. execution
("Icy" ISE. what an "ISE Death!")
mitochondrial integrity pathway to apoptosis
1. changes lead to release of cytochrome C from mitochondria
2. This initiates apoptosis
3. Cytochrome C binds a caspase and makes it active
4. execution
the death receptor
1. CTL binds a ligand and the death receptor
2. caspase 8 is activated
3. activates other caspases which kill the cell
sigma subunit
recognizes -10 and -35 sequences in pks. its found in rna pol
binds to pk rna pol
4 inhibitors of protein synthesis
1. Streptomycin
2. Tetracycline
3. Chloramphenicol
4. erythromycin
1. initiation and elongation
2. amionacyl trna binding to A site
1. peptidyltransferase
2. translocation
transcription enhancers
dna elements that increase the frequency of transcription
transcription silencers
dna elements that bind protiens which decrease the rate of transcription
blocks viral dna polymerase (reverse trnacriptase) activity by actin as a dna chain terminator.

no 3' OH for polymerization
5-FU (fluro uracil)
inhibits synthesis of thymine.

used to treat colon cancer
intercalates or slipls between stacked base paris of dna
2. when present, dna cannont act as a template for replication or transcription
used to treat solid malignancies like breast cancer
AA synthesis enzymes in bacterial growth
If you add the enzyme, it will act as a corepresor to stop AA synthesis
sugar utilazation enzymes during bacteria growth
When lactose is added, Beta galactosidase is produced.

lactose acts as an inducer to pull the repressor away from the dna so that beta galactosidase can be produced
chain elongation of dna
1. dntp binds w/ residue on template
2. 3' OH attacks phosphate
3. PPi leaves, providing energy for rxn
purpose of EK mrna cap?
Plays a role in initiation of translation

the initiation factors, eIF, bind to it
Termination of transcritption:
1. rho independent
2. rho dependent
1. GC hair pin loops make rna pol fall off
2. Rho protein gets on mrna and through an atp dependent process moves up the stand and makes the pol fall off
1. Poly A cleaveage thing
2. Sits down on mrna at AAUAAA sequence
3. endonuclease cuts down stream
4. poly A pol binds up to 250 A residues
introns and how splicing works
1. U1 binds to GU
2. U2 binds to A
3. U5 binds to AG
4. U4/U6 completes spliciesome
mutation in promoter result in ineffective transcriptoin

1. point mutation in TATA box
2. Problems w/ poly A cleaviage signal: AAUAAA
Abs made against snRPS
Activation of AAs in translation, ie, how they get bound to the tRNA
1. catalyzed by amino-acyl-tRNA synthetase
2. AA binds to ATP and PPi is released to provide energy
3. CCA region of tRNA, specifically the 3' OH of the terminal ribose, binds to the carbonyl group on the AA, and AMP is released
the start codon binds in which site of tRNA
P site
what helps bring in the tRNA in translation?
Elongation Factors:
1. EF (Eks)
2. EF-tu (Pks)
steps of translation
1. EF or EF-tu brings in tRNA into A site
2. Peptidyl transferase transfers the AA from P site to tRNA in A site. C-thr-N-C-met-N. thus, carboxy terminous binds to the amino terminous of new AA
3. translocation
4. termination by way of stop codon
stop codons
Molecular basis of sickle cell anemia
Val replaces a Glu.
Causes protein to fold poorly
what key molecule is the heme/globin pathway trying to regulate?
eIF2, an initiation factor. if phosphorylated, it will be inactive and mRNA for globin will not by translated
Diptheria toxin inhibits what??
cystic fibrosis
protein doesn't fold nomrally

Phe 508 was deleted
Where do proteins in free ribosomes go?
1. cytosol
2. mitochondria
signal peptidase
makes a true amino terminous of peptide in RER
What happens when the signal recognition particle binds to the signal sequence in a new polypeptide?
translation is stopped until peptide gets into the RER
benzapyrene does what
forms adducts w/ G interrupting G-C base pairs

produces distortions in the double helix
what can transposons do
1. viral transposons can code for Rna
2. Code for drug resistant markers
3. code for enzymes degrading toxic and carcinogenic compounds
telomorase acts similarily to which enzyme
reverse transcriptase
the use of leader peptides is important in what??
amino acid synthesis

1. If 2 and 3 pair, then AAs are made
2. If 3 and 4 pair, then transription is terminated
peptidyl transferase is located where?
large ribosomal subunit
2 component of regulatory system
1. sensor kinase
2. response regulator

This regulates gene expression from an enviromental factor outside of cell
cancer invasion
migration and penetratin by cancer cells into NEIGHBORING CELLS
cancer metastasis
penetrate into lymphatic and blood vessesls and circulete trhought the blood stream, and invade normal tissues ELSEWHERE IN THE BODY
genes in philadlephia chromosome
1. A portion of ABL (CH 9) inserts into BCR (CH 22)
2. Hybrid -BCR-ABL gene promotes uncontrolled growht of eukemic cells
tightly packed
mutations in nucleotide excision repair lead to the following

xeroderma pigmentosum

thymine dimeres
mutations in mismatch repair lead to the following
hereditary non polyposis colorectal cancer
exceptions to central dogm
1. rna can contain genetic info, like in viruses
2. proteins can transmit genetic info: prions
3. rna can have catalytic activity: bibozymes