Biology 8e Campbell Chapter 14 Mendel and the Gene Idea Multiple Choice Questions 1 A B C D E A B C D Answer D Topic Concept 14 1 Skill Knowledge Comprehension 2 Pea plants were particularly well suited for use in Mendel s breeding experiments for all of the following reasons except that peas show easily observed variations in a number of characters such as pea shape and flower color it is possible to control matings between different pea plants it is possible to obtain large numbers of progeny from any given cross peas have an unusually long generation time many of the observable characters that vary in pea plants are controlled by single genes What is the difference between a monohybrid cross and a dihybrid cross A monohybrid cross involves a single parent whereas a dihybrid cross involves two parents A monohybrid cross produces a single progeny whereas a dihybrid cross produces two progeny A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid only one A monohybrid cross is performed for one generation whereas a dihybrid cross is performed for two generations 1 A monohybrid cross results in a 9 3 3 1 ratio whereas a dihybrid cross gives a 3 1 ratio A cross between homozygous purple flowered and homozygous white flowered pea plants results in offspring with purple flowers This demonstrates E Answer C Topic Concept 14 1 Skill Knowledge Comprehension 3 A B D E true breeding C dominance a dihybrid cross the blending model of genetics the mistakes made by Mendel Answer C Topic Concept 14 1 Skill Knowledge Comprehension 2 4 The F1 offspring of Mendel s classic pea cross always looked like one of the two parental varieties because A B C D E A B C D E one phenotype was completely dominant over another each allele affected phenotypic expression the traits blended together during fertilization no genes interacted to produce the parental phenotype different genes interacted to produce the parental phenotype Answer A Topic Concept 14 1 Skill Knowledge Comprehension 5 What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants There is considerable genetic variation in garden peas Traits are inherited in discrete units and are not the results of blending Recessive genes occur more frequently in the F1 than do dominant ones An organism that is homozygous for many recessive traits is at a disadvantage Genes are composed of DNA Answer B Topic 3 How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE A Concept 14 1 Skill Knowledge Comprehension 6 4 8 16 32 64 B Answer Topic Concept 14 1 Skill Application Analysis 7 B C D E A B C D E Two plants are crossed resulting in offspring with a 3 1 ratio for a particular trait This suggests that the parents were true breeding for contrasting traits incomplete dominance that a blending of traits has occurred that the parents were both heterozygous that each offspring has the same alleles Answer 4 D Topic Concept 14 1 Skill Knowledge Comprehension 5 8 Two characters that appear in a 9 3 3 1 ratio in the F2 generation should have which of the following properties Each of the traits is controlled by single genes The genes controlling the characters obey the law of independent assortment Each of the genes controlling the characters has two alleles Four genes are involved E Sixteen different phenotypes are possible Answer A sexually reproducing animal has two unlinked genes one for head shape H and one for tail length T Its genotype is HhTt Which of the following genotypes is possible in a gamete from this organism A B C D A B C D E B Topic Concept 14 1 Skill Knowledge Comprehension 9 HT Hh HhTt T tt A Answer Topic 6 It was important that Mendel examined not just the F1 generation in his breeding experiments but the F2 generation as well because A he obtained very few F1 progeny making statistical analysis difficult parental traits that were not observed in the F1 reappeared in the F2 analysis of the F1 progeny would have allowed him to discover the law of segregation but not the law of independent assortment the dominant phenotypes were visible in the F2 generation but not in the F1 Concept 14 1 Skill Application Analysis 10 B C D E A B C D E many of the F1 progeny died Answer B Topic Concept 14 1 Skill Synthesis Evaluation 11 0 25 50 75 7 When crossing an organism that is homozygous recessive for a single trait with a heterozygote what is the chance of producing an offspring with the homozygous recessive phenotype 100 C Answer Topic Concept 14 1 Skill Application Analysis 8 Use Figure 14 1 and the following description to answer the questions below In a particular plant leaf color is controlled by gene locus D Plants with at least one allele D have dark green leaves and plants with the homozygous recessive dd genotype have light green leaves A true breeding dark leaved plant is crossed with a light leaved one and the F1 offspring is allowed to self pollinate The predicted outcome of the F2 is diagrammed in the Punnett square shown in Figure 14 1 where 1 2 3 and 4 represent the genotypes corresponding to each box within the square Figure 14 1 Which of the boxes marked 1 4 correspond to plants with dark leaves 12 1 only 1 and 2 2 and 3 4 only 1 2 and 3 Answer E Topic Concept 14 1 Skill Application Analysis 13 1 A B C D E A B Which of the boxes correspond to plants with a heterozygous genotype 9 Which of the plants will be true breeding 1 and 2 1 2 and 3 2 and 3 C D E 2 3 and 4 Answer D Topic Concept 14 1 Skill Application Analysis 14 A B C D E 1 and 4 2 and 3 1 4 1 only None Answer A Topic Concept 14 1 Skill Application Analysis 10 A B C D E A B C D E Answer C Topic Concept 14 1 Skill Knowledge Comprehension 16 15 Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that new mutations were frequently generated in the F2 progeny reinventing traits that had been lost in the F1 the mechanism controlling the appearance of traits was different between the F1 and the F2 plants traits can be dominant or recessive and the recessive traits were obscured by the dominant ones in the F1 the traits were lost in the F1 due to blending of the parental traits members of the F1 generation had only one allele for each character but members of the F2 had two alleles for each character Which of the following about the law of segregation is false It