a) False. Mendel's data were actually very close to the predicted values, which is one of the reasons why his experiments are considered groundbreaking in the field of genetics. The use of pea plants did not limit the total number of progeny that could be examined, as Mendel was able to generate large numbers of offspring through controlled breeding.
b) True. If one mutant is able to grow on medium including nutrients A or B, and another mutant is able to grow on A but not B, it suggests that A is required for the biosynthesis of B. This implies that A comes before B in a biosynthetic pathway.
c) False. Since histidinol is the final intermediate in the histidine biosynthetic pathway, mutants that can grow on histidinol should also be able to grow on histidine. If a mutant can grow on histidinol but not on histidine, it suggests that there is another step in the pathway that is affected by the mutation.
d) False. The fact that monozygotic twins reared apart show remarkable similarities in certain behavioral traits implies that those traits are predominantly determined genetically, not environmentally. This is because monozygotic twins share the same genetic makeup, so any similarities in their behavior are likely due to their shared genes.
e) True. The frequency of double crossovers between two markers does indeed increase as the markers get farther apart. This is because the likelihood of a crossover event occurring between the two markers increases with the distance between them. As a result, the frequency of single crossovers, which involve only one marker, would decrease.
f) True. The behavior of any one pair of chromosomes is indeed independent of any other pair. During meiosis, the chromosomes segregate independently, meaning that each gamete receives only one member of each chromosome pair. This is known as Mendel's law of independent assortment.
g) True. One can indeed select for rare recombinants to map the positions of phage mutants that are very close together. By identifying and selecting for rare recombinant events, researchers can determine the relative positions of different mutations on a chromosome or genome.
h) False. A typical suppressor mutation does not alter a tRNA anticodon. Instead, it alters a different component of the translation machinery, such as a release factor or a ribosomal protein. This alteration allows the mutant tRNA to recognize and suppress a termination codon in the middle of a gene, allowing for the synthesis of a full-length protein.