6. Why do normal fibroblasts maintained at high densiy in outhre become A. Cells
ID: 214252 • Letter: 6
Question
6. Why do normal fibroblasts maintained at high densiy in outhre become A. Cells B. transarmed? arrested by contact inhibition have an increased mutation rate, which leads to cell transformation. Cells maintained at high density do not arrest upon contact with other cells. C. Cels dividing at high density have a higher mutation D. Cells that have acquired transforming mutations are selscted for under condions that arest cell drision. 17. The tumor promoting effects of phorbol esters are likely due to: A. Suppression of TGF- signals. B. The activation of PKC8. C. The damage to DNA (mutations). D. Elevated levels of diacylglycerol. 18. With the introduction in the early 80's of the mammogram, breast cancer incidence went up, but mortaity argely remained unchanged. What this mean? False positives. Early detection does not prevent metastasis. The spread of cancer celis occurs earlier than previously thought All of the above. A. B. C. D. 9. What are nerve and muscle cell almost never observed A. Ner B. Nerve and muscle cells are terminally differentiated. C. Nerve and muscle cells have short telomeres that get used up during development D. Nerve and muscle cells do not express telomerase. E. All of the above. ve and muscle cells have very wel developed DNA repair mechanisms that imit mutations in these cels 20. The transition from the cyclin D-CDK4 checkpoint to the Oycin E-COK2 checkopoints s dbe br A. Cyclin D levels are degraded by the proteasome,wrich prevents he inhblton drogdin E C B. Cyclin D-CDK4 suppresses TGF-B signals, which activates cycln E- CDI2d tinatay asots C. Cyclyn D levels increase and bind both p21 and p27, which are requized tor CDK4 all the p21 and p27, which are inhibitory for cyclin Cyclin E-CDK2 phosphorylates E-CDK2 cyclin D, which targets cyclin D for degradtation by the D.Explanation / Answer
16. A. Cells can be cultured for a long time if they are splited regularly as it avoids the senescence associated with prolonged high density.
17. D. Tumor promoting phorbol is similar to the sturture of DAG(diacylglycerol) which activates protien kinase C. This activation is brought by binding of phorbol ester where DAG normally occupies.
18. D. There was no change in the mortal rate of breast cancer even after introducing of mammograph just because the early detection doesnot prevent metastatis, spread of cancer is early than expected and the resultts are false positives.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.