Bio 101 EXAM 4 Questions With Verified Solutions

Bio 101 EXAM 4 Questions With Verified Solutions What results if a fragment of a chromosome breaks off and then reattaches to the original chromosome at the same place but in the reverse direction? - answerAn inversion A couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child's condition? - answerNondisjunction occurred in one member of the couple during gamete production. In a typical animal, mitosis produces ____________ while meiosis produces _____________. - answertwo diploid daughter cells ... four haploid daughter cells Which of the following phases of cell division confirms Mendel's observation of the segregation of alleles in gamete formation? - answeranaphase I of meiosis You cross a true-breeding red-flowered snapdragon with a true-breeding white-flowered one. All of the F1 are pink. What does this say about the parental traits? - answerRed shows incomplete dominance over white. One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this alteration called? - answertranslocation Why did Mendel continue some of his experiments to the F2 generation? - answerto observe whether or not a recessive trait would reappear Labrador retrievers have black, brown, or yellow fur. Fur color is controlled by two genes, one of which exhibits epistasis. Black (B) is dominant over brown (b) in one gene, and (E) is dominant over (e) in the other gene. The (E) gene is epistatic to the (B) gene. In a cross of a black female with a brown male, results can be all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. In one cross of black × black, the results were as follows: 9/16 black, 4/16 yellow, 3/16 brown. The genotype eebb must result in which of the following? - answeryellow What number and types of chromosomes are found in a human somatic cell? - answer44 autosomes and 2 sex chromosomes Which of the following statements best describes the SRY gene? - answerIt is a gene region present on the Y chromosome that triggers male development. Asexual reproduction __________. - answerproduces offspring genetically identical to the parent Which of the following describes the ability of a single gene to have multiple phenotypic effects? - answerpleiotropy Which of the following do you expect if an individual is heterozygous for the sickle-cell trait? - answerHe or she will show some symptoms of the disease. Consider pea plants with the genotypes GgTt and ggtt. How many types of gametes can be produced by each of these two plants? - answerfour ... one What is an allele? - answeran alternative version of a gene The chromatids move toward the opposite poles of a dividing cell during ______. - answeranaphase II In certain plants, the tall trait is dominant to the short trait. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short? - answer0 What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants? - answerTraits are inherited in discrete units and are not the results of the "blending" of traits. Which of the following is a situation in which the chromosome number is either 2n + 1 or 2n − 1? - answeraneuploidy Height in humans generally shows a normal (bell-shaped) distribution. What type of inheritance most likely determines height? - answera combination of polygenic inheritance and environmental fact