Mendel and the Gene Idea

Campbell Biology Mendel and the Gene Idea Multiple Choice Questions 1) Which of the following statements correctly describes the terms monohybrid cross and dihybrid cross? A) A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. B) A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied. C) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. D) A monohybrid cross results in a 9:3:3:1 ratio, whereas a dihybrid cross gives a 3:1 ratio. Answer: B 2) Which of the following sentences state a significant conclusion that Gregor Mendel drew from his experiments with pea plants? A) There is considerable genetic variation in garden peas. B) Traits are inherited in discrete units and are not the result of "blending." C) Recessive genes occur more frequently in the F1 generation than do dominant ones. D) Genes are composed of DNA. Answer: B 3) How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE? A) 4 B) 8 C) 16 D) 64 Answer: B 4) Which of the following best describes how an individual with genotype AaBbCCDdEE can make haploid gametes with different genotypes? A) mutations during meiosis form new alleles that are incorporated into the gametes B) crossing over during prophase I leads to increased genetic diversity C) the inheritance of a particular copy of one chromosome does not affect the inheritance of a different chromosome D) dominant alleles tend to be inherited together Answer: C 5) Which of the following best describes how an individual with genotype AaBbCCDdEE can make gametes with eight different genotypes. A) mutations during meiosis form new alleles that are incorporated into the gametes B) crossing over during prophase I leads to increased genetic diversity C) the inheritance of a particular copy of one chromosome does not affect the inheritance of a different chromosome D) dominant alleles tend to be inherited together Answer: C 6) Which of the following describes why Mendel continued some of his experiments into the F2 or F3 generation? A) Collecting data from more generations allowed him to obtain a larger number of offspring. B) Following multiple generations allowed him to determine whether a recessive trait would reappear. C) Determining whether a dominant trait would reappear required multiple dihybrid crosses. D) Data from the F1 generation did not allow him to distinguish which alleles were segregating Answer: B 7) Which of the following statements about the law of independent assortment is correct? A) It describes the inheritance of different genes relative to one another. B) It describes the inheritance of different alleles relative to one another. C) It is the consequence of having two copies of each chromosome in somatic cells and one copy in gametes. D) It is the reason that dominant alleles are visible in the organism's phenotype. Answer: A 8) Which of the following statements about the law of segregation is correct? A) It describes the inheritance of different alleles relative to one another. B) It describes the inheritance of different chromosomes relative to one another. C) It explains how codominant alleles each affect the phenotype in separate ways. D) It describes situations where either genotype or environment affect phenotype, but not both. Answer: B 9) A diploid animal is dihybrid at the Head shape (H) and Tail length (T) loci. Which of the following gamete genotypes can it produce? A) Hh B) HhTt C) HHTT D) Ht Answer: D 10) Which of the following statements correctly describes how Mendel explained why traits disappeared in the F1 generation and then reappeared in the F2 generation? A) New mutations were frequently generated in the cross that generated F 2 offspring, causing traits that had been lost in the F1 to reappear in the F2. B) The mechanisms controlling the appearance of traits in the F 1 and F2 plants were different. C) Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F1. D) Members of the F1 generation had only one allele for each trait, but members of the F 2 had two alleles for each trait. Answer: C 11) When Mendel set up a Parental (P) cross between true breeding purple and white flowered plants to generate the F1 and then allowed the F1 to self-pollinate to generate the F2 he saw a dominant to recessive ratio of 3:1. What phenotypic ratio would be expected if he crossed the F 1 with the original purple parent? A) 4:0 B) 1:1 C) 3:1 D) 9:3:3:1 Answer: A 12) Which of the following statements correctly explains the fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment? A) None of the traits obeyed the law of segregation. B) The diploid number of chromosomes in the pea plants was seven. C) All of the genes controlling the traits had only two different alleles. D) All of the genes controlling the traits were on different chromosomes. Answer: D