All of the following statements regarding colobomas are true, EXCEPT
A. Coloboma iridis generally does not affect vision.
B. Coloboma iridis gives the iris a keyhole appearance.
C. Colobomas are caused by improper choroid fissure closure and may occur in the iris, retina, choroid, or sclera.
D. Renal Coloboma Syndrome describes colobomas which are linked to renal disease.
E. Renal Coloboma Syndrome is caused by a mutation in PAX2, a HOX gene.
Answer: C. Colobomas are caused by improper choroid fissure closure and may occur in the iris, retina, choroid, or sclera.
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Thanks to a novel recessive mutation, a certain plant species has begun to invade colder Arctic regions outside of its normal range. However, this cold-tolerant mutation has not yet become fixed in the population. A second mutation arises that promotes self-pollination. Do you predict that the self-pollination allele will be selected for in the Arctic regions? Why or why not?
A. Yes. The self-pollinated plant is more likely to maintain the cold-tolerant mutation, and plants in the Arctic are unlikely to be visited by pollinators. B. No. Outcrossing is always beneficial, since it enhances genetic diversity. C. No. Plants that produce flowers must be cross-pollinated for proper seed development. D. Cannot make a prediction from the information given. It depends on whether the plant is normally insect-pollinated or wind-pollinated. Clarify Question What is the key concept addressed by the question? What type of thinking is required? Gather Content What do you already know about pollination? What other information is related to the question? Choose Answer Given what you now know, what information 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?
Meiosis functions in _____
a. asexual reproduction of single-celled eukaryotes b. growth and tissue repair in multicelled species c. sexual reproduction d. asexual reproduction of single-celled eukaryotes and growth and tissue repair in multicelled species
In a certain population, the allele causing sickle cell anemia has an allele frequency of 0.2. If the
population is in genetic equilibrium for this allele, what fraction of the population would be carriers for the allele? a. 0.24 b. 0.32 c. 0.42 d. 0.48 e. 0.80
Which enzyme is responsible for adding complementary DNA bases to an exposed DNA strand?
A) DNA helicase B) DNA polymerase C) DNA ligase D) DNA peptidase