Genetic analysis indicates that an unknown organism contains a gene that codes for a defective form of telomerase. Based on this information alone, you can conclude that this organism

Question

A.  is prokaryotic.
B.  is eukaryotic.
C.  has unusually long telomeres.
D.  has an increased risk of developing cancer.

Clarify Question
· What is the key concept addressed by the question?
  · What type of thinking is required?
  · What key words does the question contain?
 
Gather Content
  · What do you already know about telomerase?
 
Consider Possibilities
  · Consider the different answer options. Which can you rule out?
 
Choose Answer   · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
 
Reflect on Process
  · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

B.  is eukaryotic.

Clarify Question
· What is the key concept addressed by the question?
    o This question addresses the function of telomerase.
  · What type of thinking is required?
    o Although you may not have seen this example before, you know enough about the concept to Apply your knowledge and understanding to this unfamiliar situation.
  · What key words does the question contain?
    o Telomerase is the enzyme that adds telomeres to the ends of chromosomes.
 
Gather Content
  · What do you already know about telomerase?
    o Telomerase is the enzyme that adds telomeres to the ends of chromosomes.
    o This solves the problem presented by linear chromosomes during DNA replication.  If not for telomeres, the chromosome ends would gradually get shorter and shorter with each replication event.
 
Consider Possibilities
  · Consider the different answer options. Which can you rule out?
    o Does a defective telomerase suggest long telomeres? No, the opposite. Telomerase is necessary to add the telomeres.
    o Does a defective telomerase suggest a risk of cancer? Well, without telomeres, DNA can become damaged. But in fact cancer cells upregulate telomerase, so that the cells can survive multiple rounds of replication and division. So no, defective telomerase would not increase cancer.
    o Does a defective telomerase indicate that the organism is prokaryotic? No, because prokaryotes do not have telomerase at all, and never did. They generally have circular chromosomes so they have no need for telomerase.
 
Choose Answer   · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
    o Does a defective telomerase indicate that the organism is eukaryotic? Well, yes! Only eukaryotes have telomerase. They will likely be hampered without a functional gene, but the presence of the gene does suggest that they must be a eukaryote.
 
Reflect on Process
  · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
    o This question required you to Apply your knowledge and understanding to this unfamiliar situation.
    o Did you remember that telomerase is necessary to add telomeres?
    o Did you recognize that only eukaryotes have telomerase?