Sickle-cell anemia is a condition in which individuals produce defective red blood cells which cannot effectively transport oxygen to the tissues in the body. Homozygosity for this mutation is usually lethal, whereas heterozygosity is non-lethal and can even result in a resistance to malaria. This is an example of which of the following?
a) codominance
b) additive effects
c) a multigene trait
d) sexual selection
e) incomplete dominance
Ans: a) codominance
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Natural selection operates directly on
(a) the genotype. (b) individual alleles. (c) the phenotype. (d) color only.
The most likely explanation for the phenomenon where a protein may be found in different sub-cellular locations in different cells is
A. stabilization of the mRNA transcript B. alternative splicing C. RNA interference D. transport of mRNA from the nucleus to the cytoplasm
What is TRUE about the settlers of Easter Island?
a. The settlers traveled 2000 km across the ocean to arrive there. b. The population of the island peaked at 100,000 people. c. People were already living there when the settlers from Polynesia arrived. d. The island had been settled repeatedly over the years, but nobody stayed until the 1700s.
The discovery of RNA interference (RNAi) led to its use in biotechnology and medicine. All of the following are examples of how RNAi could be used in biotechnology or medicine, EXCEPT ________
A) to treat a disease characterized by the overexpression of a nonmutated gene B) to study loss-of-function phenotypes of specific genes in a model research organism C) to treat a disease characterized by a gene that is not expressed D) to treat a disease characterized by the normal expression of a mutated gene E) to treat a disease characterized by the buildup of a specific protein