Biochem Test 2

Front 1

What is the Ras/Raf pathway

Back 1

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

Front 2

burkitt's lymphoma

Back 2

myc is translocated from chromosome 8 to 14 and comes under contrl of Ig heavy chain promoter and is over expressed

Front 3

philadelphia chromosome

Back 3

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

Front 4

proto oncogenes

Back 4

encode protiens involved in a cell's normal growth control pathway

Front 5

tumor supressor genes

Back 5

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

Front 6

p53

Back 6

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

Front 7

NF-1

Back 7

binds to Ras and holds it in the GDP form, which is the inactivated form

Front 8

3 stages of apoptosis

Back 8

1. initiation
2. signal integration
3. execution
("Icy" ISE. what an "ISE Death!")

Front 9

mitochondrial integrity pathway to apoptosis

Back 9

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

Front 10

the death receptor

Back 10

1. CTL binds a ligand and the death receptor
2. caspase 8 is activated
3. activates other caspases which kill the cell

Front 11

sigma subunit

Back 11

recognizes -10 and -35 sequences in pks. its found in rna pol

Front 12

rifampin

Back 12

binds to pk rna pol

Front 13

4 inhibitors of protein synthesis

Back 13

1. Streptomycin
2. Tetracycline
3. Chloramphenicol
4. erythromycin

Front 14

streptomycin
tetracycline

Back 14

1. initiation and elongation
2. amionacyl trna binding to A site

Front 15

chloramphenicol
erythromycin

Back 15

1. peptidyltransferase
2. translocation

Front 16

transcription enhancers

Back 16

dna elements that increase the frequency of transcription

Front 17

transcription silencers

Back 17

dna elements that bind protiens which decrease the rate of transcription

Front 18

AZT

Back 18

blocks viral dna polymerase (reverse trnacriptase) activity by actin as a dna chain terminator.

no 3' OH for polymerization

Front 19

5-FU (fluro uracil)

Back 19

inhibits synthesis of thymine.

used to treat colon cancer

Front 20

Doxorubicin

Back 20

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

Front 21

AA synthesis enzymes in bacterial growth

Back 21

If you add the enzyme, it will act as a corepresor to stop AA synthesis

Front 22

sugar utilazation enzymes during bacteria growth

Back 22

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

Front 23

chain elongation of dna

Back 23

1. dntp binds w/ residue on template
2. 3' OH attacks phosphate
3. PPi leaves, providing energy for rxn

Front 24

purpose of EK mrna cap?

Back 24

Plays a role in initiation of translation

the initiation factors, eIF, bind to it

Front 25

Termination of transcritption:
1. rho independent
2. rho dependent

Back 25

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

Front 26

CPSF

Back 26

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

Front 27

introns and how splicing works

Back 27

1. U1 binds to GU
2. U2 binds to A
3. U5 binds to AG
4. U4/U6 completes spliciesome

Front 28

Thalesemia

Back 28

mutation in promoter result in ineffective transcriptoin

1. point mutation in TATA box
2. Problems w/ poly A cleaviage signal: AAUAAA

Front 29

Lupus

Back 29

Abs made against snRPS

Front 30

Activation of AAs in translation, ie, how they get bound to the tRNA

Back 30

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

Front 31

the start codon binds in which site of tRNA

Back 31

P site

Front 32

what helps bring in the tRNA in translation?

Back 32

Elongation Factors:
1. EF (Eks)
2. EF-tu (Pks)

Front 33

steps of translation

Back 33

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

Front 34

stop codons

Back 34

UAG, GUA, UAA

Front 35

Molecular basis of sickle cell anemia

Back 35

Val replaces a Glu.
Causes protein to fold poorly

Front 36

what key molecule is the heme/globin pathway trying to regulate?

Back 36

eIF2, an initiation factor. if phosphorylated, it will be inactive and mRNA for globin will not by translated

Front 37

Diptheria toxin inhibits what??

Back 37

translocation

Front 38

cystic fibrosis

Back 38

protein doesn't fold nomrally

Phe 508 was deleted

Front 39

Where do proteins in free ribosomes go?

Back 39

1. cytosol
2. mitochondria

Front 40

signal peptidase

Back 40

makes a true amino terminous of peptide in RER

Front 41

What happens when the signal recognition particle binds to the signal sequence in a new polypeptide?

Back 41

translation is stopped until peptide gets into the RER

Front 42

benzapyrene does what

Back 42

forms adducts w/ G interrupting G-C base pairs

produces distortions in the double helix

Front 43

what can transposons do

Back 43

1. viral transposons can code for Rna
2. Code for drug resistant markers
3. code for enzymes degrading toxic and carcinogenic compounds

Front 44

telomorase acts similarily to which enzyme

Back 44

reverse transcriptase

Front 45

the use of leader peptides is important in what??

Back 45

amino acid synthesis

1. If 2 and 3 pair, then AAs are made
2. If 3 and 4 pair, then transription is terminated

Front 46

peptidyl transferase is located where?

Back 46

large ribosomal subunit

Front 47

2 component of regulatory system

Back 47

1. sensor kinase
2. response regulator

This regulates gene expression from an enviromental factor outside of cell

Front 48

cancer invasion

Back 48

migration and penetratin by cancer cells into NEIGHBORING CELLS

Front 49

cancer metastasis

Back 49

penetrate into lymphatic and blood vessesls and circulete trhought the blood stream, and invade normal tissues ELSEWHERE IN THE BODY

Front 50

genes in philadlephia chromosome

Back 50

1. A portion of ABL (CH 9) inserts into BCR (CH 22)
2. Hybrid -BCR-ABL gene promotes uncontrolled growht of eukemic cells

Front 51

Euchromatin

Back 51

loose

Front 52

heterochromatin

Back 52

tightly packed

Front 53

mutations in nucleotide excision repair lead to the following

why?

Back 53

xeroderma pigmentosum

thymine dimeres

Front 54

mutations in mismatch repair lead to the following

Back 54

hereditary non polyposis colorectal cancer

Front 55

exceptions to central dogm

Back 55

1. rna can contain genetic info, like in viruses
2. proteins can transmit genetic info: prions
3. rna can have catalytic activity: bibozymes