Gregor Mendel used pea plants to study 1. flowering. 2. gamete formation. 3. the inheritance of traits. 4. cross-pollination. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Offspring that result from crosses between parents with different traits 1. are true-breeding. 2. make up the F2 generation. 3. make up the parental generation. 4. are called hybrids. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Gregor Mendel removed the male parts from the flowers of some plants in order to 1. prevent hybrids from forming. prevent crosspollination. stimulate selfpollination. make controlled crosses between plants. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 The chemical factors that determine traits are called 1. 2. 3. 4. 1 alleles. traits. genes. characters. 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Gregor Mendel concluded that traits are 1. not inherited by offspring. inherited through the passing of factors from parents to offspring. determined by dominant factors only. determined by recessive factors only. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 When Gregor Mendel crossed a tall plant with a short plant, the F1 plants inherited 1. 2. an allele for tallness from each parent. an allele for tallness from the tall parent and an allele for shortness from the short parent. an allele for shortness from each parent. an allele from only the tall parent. 3. 4. 25% 1 1 2 3 4 5 25% 25% 2 3 25% 4 The principle of dominance states that 1. 2. 3. all alleles are dominant. all alleles are recessive. some alleles are dominant and others are recessive. alleles are neither dominant nor recessive. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 When Gregor Mendel crossed true-breeding tall plants with true-breeding short plants, all the offspring were tall because 1. the allele for tall plants is recessive. the allele for short plants is dominant. the allele for tall plants is dominant. they were true-breeding like their parents. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 If a pea plant has a recessive allele for green peas, it will produce 1. green peas if it also has a dominant allele for yellow peas. both green peas and yellow peas if it also has a dominant allele for yellow peas. green peas if it does not also have a dominant allele for yellow peas. yellow peas if it does not also have a dominant allele for green peas. 2. 3. 4. 25% 1 1 2 3 4 5 25% 2 25% 3 25% 4 A tall plant is crossed with a short plant. If the tall F1 pea plants are allowed to selfpollinate, 1. the offspring will be of medium height. all of the offspring will be tall. all of the offspring will be short. some of the offspring will be tall, and some will be short. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 In the P generation, a tall plant was crossed with a short plant. Short plants reappeared in the F2 generation because 1. some of the F2 plants produced gametes that carried the allele for shortness. the allele for shortness is dominant. the allele for shortness and the allele for tallness segregated when the F1 plants produced gametes. they inherited an allele for shortness from one parent and an allele for tallness from the other parent. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 In the P generation, a tall plant was crossed with a short plant. If alleles did not segregate during gamete formation, 1. all of the F1 plants would be short. some of the F1 plants would be tall and some would be short. all of the F2 would be short. all of the F2 plants would be tall. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 When you flip a coin, what is the probability that it will come up tails? 1. 2. 3. 4. 1 1/2 1/4 1/8 1 2 3 25% 4 5 1 25% 25% 2 3 25% 4 The principles of probability can be used to 1. predict the traits of the offspring produced by genetic crosses. determine the actual outcomes of genetic crosses. predict the traits of the parents used in genetic crosses. decide which organisms are best to use in genetic crosses. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 In the P generation, a tall plant is crossed with a short plant. The probability that an F2 plant will be tall is 25% 25% 25% 25% 1. 25%. 2. 50%. 3. 75% 4. 100%. 1 2 3 4 5 1 2 3 4 Organisms that have two identical alleles for a particular trait are said to be 1. 2. 3. 4. 1 hybrid. homozygous. heterozygous. dominant. 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Figure 11–1 In the Punnett square shown in Figure 11–1, which of the following is true about the offspring resulting from the cross? 1. About half are expected to be short. All are expected to be short. About half are expected to be tall. All are expected to be tall. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 A Punnett square shows all of the following EXCEPT 1. all possible results of a genetic cross. the genotypes of the offspring. the alleles in the gametes of each parent. the actual results of a genetic cross. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 If you made a Punnett square showing Gregor Mendel’s cross between true-breeding tall plants and true-breeding short plants, the square would show that the offspring had 1. the genotype of one of the parents. a phenotype that was different from that of both parents. a genotype that was different from that of both parents. the genotype of both parents. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 What principle states that during gamete formation genes for different traits separate without influencing each other’s inheritance? 1. 2. principle of dominance principle of independent assortment principle of probabilities principle of segregation 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Figure 11–2 The Punnett square in Figure 11–2 shows that the gene for pea shape and the gene for pea color 25% 25% 25% 25% 1. assort independently. 2. are linked. 3. have the same alleles. 4. are always homozygous. 1 2 3 4 5 1 2 3 4 How many different allele combinations would be found in the gametes produced by a pea plant whose genotype was RrYY? 25% 25% 25% 25% 1. 2 2. 4 3. 8 4. 16 1 2 3 4 5 1 2 3 4 If a pea plant that is heterozygous for round, yellow peas (RrYy) is crossed with a pea plant that is homozygous for round peas but heterozygous for yellow peas (RRYy), how many different phenotypes are their offspring expected to show? 25% 1. 2. 3. 4. 1 2 25% 25% 25% 2 4 8 16 3 4 5 1 2 3 4 Situations in which one allele for a gene is not completely dominant over another allele for that gene are called 25% 25% 25% 25% 1. multiple alleles. 2. incomplete dominance. 3. polygenic inheritance. 4. multiple genes. 1 2 3 4 5 1 2 3 4 A cross of a black chicken (BB) with a white chicken (WW) produces all speckled offspring (BBWW). This type of inheritance is known as 1. incomplete dominance. 2. polygenic inheritance. 3. codominance. 4. multiple alleles. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Variation in human skin color is an example of 1. incomplete dominance. 2. codominance. 3. polygenic traits. 4. multiple alleles. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Gregor Mendel’s principles of genetics apply to 1. 2. 3. 4. 1 plants only. animals only. pea plants only. all organisms. 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Why did Thomas Hunt Morgan use fruit flies in his studies? 1. Fruit flies produce a large number of offspring. Fruit flies take a long time to produce offspring. Fruit flies share certain characteristics with pea plants. Fruit flies have a long lifespan. 2. 3. 4. 1 2 3 4 5 25% 1 25% 2 25% 3 25% 4 A male and female bison that are both heterozygous for normal skin pigmentation (Aa) produce an albino offspring (aa). Which of Mendel’s principles explain(s) why the offspring is albino? 1. dominance only 2. independent assortment only 3. dominance and segregation 4. segregation only 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 The number of chromosomes in a gamete is represented by the symbol 1. 2. 3. 4. 1 Z. X. N. Y. 2 3 25% 4 5 1 25% 25% 2 3 25% 4 If an organism’s diploid number is 12, its haploid number is 1. 2. 3. 4. 1 12. 6. 24. 3. 2 3 25% 4 5 1 25% 25% 2 3 25% 4 Gametes have 1. homologous chromosomes. twice the number of chromosomes found in body cells. two sets of chromosomes. one allele for each gene. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Gametes are produced by the process of 1. 2. 3. 4. 1 mitosis. meiosis. crossing-over. replication. 2 3 4 5 25% 1 25% 25% 2 3 25% 4 What is shown in this figure? 1. 2. 3. 4. independent assortment anaphase I of meiosis crossing-over replication 25% 1 1 2 3 4 5 25% 2 25% 3 25% 4 Chromosomes form tetrads during 1. prophase I of meiosis. 2. metaphase I of meiosis. 3. interphase. 4. anaphase II of meiosis. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 What happens between meiosis I and meiosis II that reduces the number of chromosomes? 1. Crossing-over occurs. 2. Metaphase occurs. 3. Replication occurs twice. 4. Replication does not occur. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Unlike mitosis, meiosis results in the formation of 1. 2. 3. 4. 1 diploid cells. haploid cells. 2N daughter cells. body cells. 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Unlike mitosis, meiosis results in the formation of 1. two genetically identical cells. 2. four genetically different cells. 3. four genetically identical cells. 4. two genetically different cells. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Crossing-over rarely occurs in mitosis, unlike meiosis. Which of the following is the likely reason? 1. Chromatids are not involved in mitosis. Tetrads rarely form during mitosis. A cell undergoing mitosis does not have homologous chromosomes. There is no prophase during mitosis. 2. 3. 4. 25% 1 1 2 3 4 5 25% 25% 2 3 25% 4 Which of the following assort independently? 1. chromosomes 2. genes on the same chromosome 3. multiple alleles 4. codominant alleles 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Linked genes 1. are never separated. 2. assort independently. 3. are on the same chromosome. 4. are always recessive. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 If the gene for seed color and the gene for seed shape in pea plants were linked, all of Mendel’s F1 plants would have produced wrinkled, green peas. Mendel’s F2 plants would have exhibited a different phenotype ratio for seed color and seed shape. Mendel’s F1 plants would have exhibited a different phenotype ratio for seed color and seed shape. all of Mendel’s P plants would have produced wrinkled, green peas. 1. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 Gene maps are based on 1. the frequencies of crossing-over between genes. 2. independent assortment. 3. genetic diversity. 4. the number of genes in a cell. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 If two genes are on the same chromosome and rarely assort independently, 1. crossing-over never occurs between the genes. crossing-over always occurs between the genes. the genes are probably located far apart from each other. the genes are probably located close to each other. 2. 3. 4. 1 2 3 4 5 25% 1 25% 25% 2 3 25% 4 The farther apart two genes are located on a chromosome, the 1. less likely they are to be inherited together. more likely they are to be linked. less likely they are to assort independently. less likely they are to be separated by a crossover during meiosis. 2. 3. 4. 1 2 3 4 5 25% 25% 25% 25% 1 2 3 4 A trait is a specific characteristic that varies from one individual to another. _________________________ 1. True 50% 50% 2. False 1 2 3 4 5 1 2 Gregor Mendel concluded that the tall plants in the P generation passed the factor for tallness to the F1 generation. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 An organism with a dominant allele for a particular form of a trait will sometimes exhibit that trait. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 True-breeding plants that produced axial flowers were crossed with true-breeding plants that produced terminal flowers. The resulting offspring produced terminal flowers because the allele for terminal flowers is recessive. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 When alleles segregate from each other, they join. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 If the alleles for a trait did not segregate during gamete formation, offspring would always show the trait of at least one of the parents. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 The principles of probability can explain the numerical results of Mendel’s experiments. _________________________ 1. True 50% 50% 2. False 1 2 3 4 5 1 2 The probability that a gamete produced by a pea plant heterozygous for stem height (Tt) will contain the recessive allele is 100%. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 If two speckled chickens are mated, according to the principle of codominance, 25% of the offspring are expected to be speckled. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 Coat color in rabbits is determined by a single gene that has multiple alleles. _________________________ 1. True 50% 50% 2. False 1 2 3 4 5 1 2 If an organism has 16 chromosomes in each of its egg cells, the organism’s diploid number is 32. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 If an organism is heterozygous for a particular gene, the two different alleles will be separated during anaphase II of meiosis, assuming that no crossing-over has occurred. _________________________ 1. True 2. False 1 2 3 4 50% 5 1 50% 2 Mitosis results in two cells, whereas meiosis results in one cell. _________________________ 1. True 50% 50% 2. False 1 2 3 4 5 1 2 If an organism has four linkage groups, it has eight chromosomes. _________________________ 1. True 50% 50% 2. False 1 2 3 4 5 1 2 Genes in the same linkage group are usually inherited separately. _________________________ 1. True 50% 50% 2. False 1 2 3 4 5 1 2 The plants that Gregor Mendel crossed to produce the F1 generation made up the ____________________ generation. 1 2 3 4 5 0 of 5 The different forms of a gene are called ____________________. 1 2 3 4 5 0 of 5 If the allele for shortness in pea plants were dominant, all the pea plants in Mendel’s F1 generation would have been ____________________. 1 2 3 4 5 0 of 5 If the alleles for traits in pea plants did not segregate during gamete formation, offspring that were recessive for a trait could be produced only by crossing two plants that were ____________________ for that trait. 1 2 3 4 5 0 of 5 ____________________ is the likelihood that a particular event will occur. 1 2 3 4 5 0 of 5 If you flip a coin five times and it comes up heads each time, the probability that it will come up heads the next time is ____________________. 1 2 3 4 5 0 of 5 Figure 11–1 In the Punnett square shown in Figure 11–1, the genotypes of the offspring are ____________________. 1 2 3 4 5 0 of 5 Pea plants that are TT, ____________________, or tt have different genotypes. 1 2 3 4 5 0 of 5 When two heterozygous tall pea plants are crossed, the expected genotype ratio of the offspring is _________________________. 1 2 3 4 5 0 of 5 The principle of independent assortment states that ____________________ for different traits can segregate independently during the formation of gametes. 1 2 3 4 5 0 of 5 If pea plants that are homozygous for round, yellow seeds (RRYY) were crossed with pea plants that are heterozygous for round, yellow seeds (RrYy), the expected phenotype(s) of the offspring would be _________________________. 1 2 3 4 5 0 of 5 Crossing a pink-flowered four o’clock with a white-flowered four o’clock will produce pink-flowered offspring and ____________________-flowered offspring. 1 2 3 4 5 0 of 5 An organism’s gametes have ____________________ the number of chromosomes found in the organism’s body cells. 1 2 3 4 5 0 of 5 Crossing-over occurs during the stage of meiosis called ____________________. 1 2 3 4 5 0 of 5 The relative locations of each known gene can be shown on a ____________________ map. 1 2 3 4 5 0 of 5 Define genetics. 1 2 3 4 5 0 of 5 What attributes of the garden pea plant made it an excellent organism for Gregor Mendel’s genetic studies? 1 2 3 4 5 0 of 5 What might have caused Gregor Mendel NOT to conclude that biological inheritance is determined by factors that are passed from one generation to the next? 1 2 3 4 5 0 of 5 How many recessive alleles for a trait must an organism inherit in order to exhibit that trait? 1 2 3 4 5 0 of 5 Figure 11–2 What is the phenotype ratio of the offspring in the Punnett square shown in Figure 11–2? 1 2 3 4 5 0 of 5 A pea plant heterozygous for height and seed color (TtYy) is crossed with a pea plant heterozygous for height but homozygous recessive for seed color (Ttyy). If 80 offspring are produced, how many are expected to be tall and have yellow seeds? 1 2 3 4 5 0 of 5 What might happen if the gametes of a species had the same number of chromosomes as the species’ body cells? 1 2 3 4 5 0 of 5 How many sets of chromosomes are in a diploid cell? 1 2 3 4 5 0 of 5 Define homologous chromosomes. 1 2 3 4 5 0 of 5 What happens to the number of chromosomes per cell during meiosis? 1 2 3 4 5 0 of 5 Contrast the cells produced by mitosis with those produced by meiosis. 1 2 3 4 5 0 of 5 Why did Gregor Mendel not observe gene linkage during his experiments with pea plants? 1 2 3 4 5 0 of 5 What is a linkage group? 1 2 3 4 5 0 of 5 What does a gene map show? 1 2 3 4 5 0 of 5 The gene map of a fruit fly’s chromosome 2 shows the relative locations of the star eye, dumpy wing, and black body genes to be 1.3, 13.0, and 48.5, respectively. Between which two genes does crossingover occur most frequently? 1 2 3 4 5 0 of 5 A pea plant with yellow seeds was crossed with a plant with green seeds. The F1 generation produced plants with yellow seeds. Explain why green seeds reappeared in the F2 generation. 1 2 3 4 5 0 of 5 You wish to determine whether a tall pea plant is homozygous or heterozygous for tallness. What cross should you perform to arrive at your answer? Explain your choice of cross 1 2 3 4 5 0 of 5 Why are the results of genetic crosses shown in Punnett squares interpreted as probabilities, not certainties? Give some specific reasons 1 2 3 4 5 0 of 5 A cross between two organisms heterozygous for two different genes (AaBb) results in a 9 : 3 : 3 : 1 phenotype ratio among the offspring. Is the offspring’s genotype ratio the same? Explain your answer 1 2 3 4 5 0 of 5 Explain the difference between incomplete dominance and codominance. 1 2 3 4 5 0 of 5 A florist wants to guarantee that the seeds she sells will produce only pink-flowered four o’clock plants. How should she obtain the seeds? 1 2 3 4 5 0 of 5 The stages of meiosis are classified into two divisions: meiosis I and meiosis II. Compare and contrast these two divisions. 1 2 3 4 5 0 of 5 Suppose the homologous chromosomes that make up a tetrad fail to separate during anaphase I of meiosis. Predict the results of this event. 1 2 3 4 5 0 of 5 Explain why the daughter cells produced by meiosis are genetically different from each other, whereas the daughter cells produced by mitosis are not. 1 2 3 4 5 0 of 5 Define linkage, and explain how linkage is used to make gene maps. 1 2 3 4 5 0 of 5