Imagine a diploid sexually reproducing organism, Diploidus sexualis, that contains three pairs of chromosomes. This organism is unusual in that no recombination between homologous chromosomes occurs during meiosis
A. Assuming that the chromosomes are distributed independently during meiosis, how many different types of sperm or egg cells can a single individual of this species produce?
B. What is the likelihood that two siblings of this species will be genetically identical? You can assume that the homologous chromosomes of each parent are different from one another and from their counterparts in the other parent.
A. Eight different types. With respect to each of the three chromosomes, an individual can produce two kinds of gamete. The gamete can receive the copy that the individual received from "mom" or the copy from "dad." Thus, with three chromosomes, there are 2 × 2 × 2 = 8 possible gametes.
B. 1/64. The mother and father together can produce 8 × 8 = 64 different genetic combinations.
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A type of cofactor would be ________.
A. active sites B. substrates C. metallic ions D. vitamins E. ribozymes
What would happen if a mutation created a new allele that decreased fitness?
A) The new allele would spread through the population and decrease the fitness of that population. B) The new allele would decrease the fitness of the individual that possessed it, and that individual would have few or no offspring. C) The new allele would have to change back to an allele of higher fitness so the possessor of that allele could maintain its fitness. D) The individual with the new allele would wait for an environmental change so that its fitness would increase again.
Which of the following allow communication between the cells of the heart muscle tissue, resulting in the coordinated beating of the heart?
a. tight junctions b. anchoring junctions c. desmosomes d. gap junctions
Does the data on butterfly larval survival (shown below) by itself conclusively show that imperial blue but-terflies and Iridomyrmex ants engage in an overall mutualistic and not an antagonistic relationship?
a. Yes, the decreased mortality in the presence of ants provides a tremendous fitness gain for the ants. b. Yes, larvae need to survive in order to reproduce. c. No, the decrease in survival can be easily compensated by the high reproductive rate of the cat-erpillars. d. No, the gain in fitness through increased survival may be offset by a decrease in reproduction due to the secretion provided to the ants.