tarina wrote:Telomerase is an enzyme that is produced only in cells that are actively dividing. For this reason it is generally absent from body tissues in adults. Bone marrow is an exception to this rule, however, since even in adults, bone marrow cells continually divide to replace old blood cells. Cancers are another exception, because their cells are rapidly dividing.
The information provided most strongly supports which of the following?
A. Telomerase is the only enzyme that is present in cancerous cells but absent from cells that are not actively dividing.
B. In children, the only body tissues from which telomerase is absent are those in which cells are not rapidly dividing.
C. The presence of telomerase in bone marrow is no indication of bone marrow cancer.
D. Cancer of the bone marrow develops more rapidly than cancer growing in any other kind of adult tissue.
E. The level of telomerase production is always higher in cancerous tissue than in noncancerous tissue.
Answer: C
Lets eliminate the wrong choices first, shall we?
A. Telomerase is the only enzyme that is present in cancerous cells but absent from cells that are not actively dividing.
To say 'T' is the ONLY enzyme is - going to an extreme conclusion that there are no other enzymes present. our premises don't state so.
B. In children, the only body tissues from which telomerase is absent are those in which cells are not rapidly dividing.
We are not talking about children in general, we are talking about adults. Cancer may be present in children as well, but that is a another topic altogether - not touched by this passage.
C. The presence of telomerase in bone marrow is no indication of bone marrow cancer. Hmm, lets keep this.
D. Cancer of the bone marrow develops more rapidly than cancer growing in any other kind of adult tissue. We are NOT comparing different types of cancer here. out of scope.
E. The level of telomerase production is always higher in cancerous tissue than in noncancerous tissue. Hmm, keep this in, too.
Comparing C and E:
Again eliminate first!
E) says level of T production in cancerous tissue > T production in NC Tissue
C) Presence of T in the BM isn't indication of BM Cancer.
If in doubt, go back to your framework:
Telomerase is an enzyme that is produced only in cells that are actively dividing. For this reason it is generally absent from body tissues in adults. Bone marrow is an exception to this rule, however, since even in adults, bone marrow cells continually divide to replace old blood cells. Cancers are another exception, because their cells are rapidly dividing.
T is an enzyme produced when cells are ACTIVELY DIVIDING ---> So, T is GENERALLY (not completely) absent from BT in adults ---> BM is an exception because BMC are continually dividing ---> Cancer is another exception as well.
Two examples of exception are shown. They are just stated. Not compared. It is NOT the case:
For C: If cancer has T ---> BM has T ---> BM Cancer is present (Ask yourself this: Is it true? you'll feel that No, I can't link these two with this analogy here)
Rather, Cancer has T (ok, fine) ---> BM has T ---> BM C is not necessarily present (ask yourself again, and you'll see, yea I can say that
)
For E: T is MORE present in C cells > than in NC Cells (Not necessarily true, because T levels may be same, maybe another factor or enzyme is triggering T, this MAY or MAY NOT be true -->Conclusion MUST be true from premises.
So E eliminated.
C is your answer
Hope this helps!
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