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What process is responsible for the independent assortment of alleles?
What process is responsible for the independent assortment of alleles?
Meiosis
How do cells acquire homologous chromosome pairs that carry the alleles that are independently assorted?
How do cells acquire homologous chromosome pairs that carry the alleles that are independently assorted?
Fusion of gametes
Which of the following statements most accurately describes the process of independent assortment?
Which of the following statements most accurately describes the process of independent assortment?
Alleles of different genes segregate from one another in a random manner.
The principle of independent assortment is best illustrated by events that take place during metaphase II, during which sister chromatids segregate independently of each other.
The principle of independent assortment is best illustrated by events that take place during metaphase II, during which sister chromatids segregate independently of each other.
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How many genetically unique types of gametes could be produced by an individual with the genotype RrYY?
How many genetically unique types of gametes could be produced by an individual with the genotype RrYY?
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Which of the following parental genotypes would yield a 1:1:1:1 phenotypic ratio in the offspring?
Which of the following parental genotypes would yield a 1:1:1:1 phenotypic ratio in the offspring?
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In his breeding experiments, Mendel first crossed true-breeding plants to produce a second generation, which were then allowed to self-pollinate to generate the offspring. How do we name these three generations?
In his breeding experiments, Mendel first crossed true-breeding plants to produce a second generation, which were then allowed to self-pollinate to generate the offspring. How do we name these three generations?
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Which of the following is true about a plant with the genotype AABbcc?
Which of the following is true about a plant with the genotype AABbcc?
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What is an allele?
What is an allele?
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What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?
What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?
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The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?
The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?
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Why did Mendel continue some of his experiments to the F2 or F3 generation?
Why did Mendel continue some of his experiments to the F2 or F3 generation?
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Which of the following differentiates between independent assortment and segregation?
Which of the following differentiates between independent assortment and segregation?
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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 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?
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Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that
Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that
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Which of the boxes marked 1-4 correspond to plants with dark leaves?
Which of the boxes marked 1-4 correspond to plants with dark leaves?
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Which of the boxes correspond to plants with a heterozygous genotype?
Which of the boxes correspond to plants with a heterozygous genotype?
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Which of the plants will be true-breeding?
Which of the plants will be true-breeding?
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Mendel worked
Mendel worked
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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?
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?
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Height in humans generally shows a normal (bell-shaped) distribution. What type of inheritance most likely determines height?
Height in humans generally shows a normal (bell-shaped) distribution. What type of inheritance most likely determines height?
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In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?
In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?
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Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?
Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?
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Which of the following is an example of polygenic inheritance?
Which of the following is an example of polygenic inheritance?
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Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. The flower color trait in radishes is an example of which of the following?
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. The flower color trait in radishes is an example of which of the following?
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Skin color in a certain species of fish is inherited via a single gene with four different alleles. How many different types of gametes would be possible in this system?
Skin color in a certain species of fish is inherited via a single gene with four different alleles. How many different types of gametes would be possible in this system?
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Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color is incompletely dominant to white (r). The heterozygous condition results in pink (Rr) flower color. If snapdragons are heterozygous for height as well as for flower color, a mating between them will result in what ratio?
Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color is incompletely dominant to white (r). The heterozygous condition results in pink (Rr) flower color. If snapdragons are heterozygous for height as well as for flower color, a mating between them will result in what ratio?
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Which of the following provides an example of epistasis?
Which of the following provides an example of epistasis?
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Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce
Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce
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A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible partial genotype for the son?
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible partial genotype for the son?
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A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible genotype for the mother?
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible genotype for the mother?
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A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible phenotype for the father?
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible phenotype for the father?
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Folk singer Woody Guthrie died of Huntington's disease, an autosomal dominant disorder. Which statement below must be true?
Folk singer Woody Guthrie died of Huntington's disease, an autosomal dominant disorder. Which statement below must be true?
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Various procedures can be used to detect genetic disorders before birth. Among the tests discussed in this chapter, which is the least invasive (list first), and which two allow the chromosomes of the fetus to be examined?
Various procedures can be used to detect genetic disorders before birth. Among the tests discussed in this chapter, which is the least invasive (list first), and which two allow the chromosomes of the fetus to be examined?
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Which of the following do you expect if an individual is heterozygous for the sickle-cell trait?
Which of the following do you expect if an individual is heterozygous for the sickle-cell trait?
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An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient?
An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient?
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The frequency of heterozygosity for the sickle-cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following?
The frequency of heterozygosity for the sickle-cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following?
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Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize the amino acid phenylalanine. This amino acid is not naturally produced by humans. Therefore, the most efficient and effective treatment is which of the following?
Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize the amino acid phenylalanine. This amino acid is not naturally produced by humans. Therefore, the most efficient and effective treatment is which of the following?
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One of two major forms of a human condition called neurofibromatosis (NF 1) is inherited as a dominant gene, although it may range from mildly to very severely expressed. If a young child is the first in her family to be diagnosed, which of the following is the best explanation?
One of two major forms of a human condition called neurofibromatosis (NF 1) is inherited as a dominant gene, although it may range from mildly to very severely expressed. If a young child is the first in her family to be diagnosed, which of the following is the best explanation?
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In each generation of this family after generation I, the age at diagnosis is significantly lower than would be found in nonfamilial (sporadic) cases of this cancer (~ 63 years). What is the most likely reason?
In each generation of this family after generation I, the age at diagnosis is significantly lower than would be found in nonfamilial (sporadic) cases of this cancer (~ 63 years). What is the most likely reason?
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Quantitative characters vary in a population along a continuum. How do such characters differ from the characters investigated by Mendel in his experiments on peas?
Quantitative characters vary in a population along a continuum. How do such characters differ from the characters investigated by Mendel in his experiments on peas?
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Look at the Punnett square, which shows the predicted offspring of the F2 generation from a cross between a plant with yellow-round seeds (YYRR) and a plant with green-wrinkled seeds (yyrr). Select the correct statement about wrinkled yellow seeds in the F2 generation.
Look at the Punnett square, which shows the predicted offspring of the F2 generation from a cross between a plant with yellow-round seeds (YYRR) and a plant with green-wrinkled seeds (yyrr). Select the correct statement about wrinkled yellow seeds in the F2 generation.
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Each chromosome in this homologous pair possesses a different allele for flower color. Which statement about this homologous pair of chromosomes is correct?
Each chromosome in this homologous pair possesses a different allele for flower color. Which statement about this homologous pair of chromosomes is correct?
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The pattern of inheritance (monohybrid, dihybrid, sex-linked, and genes linked on the same chromosomes) can be predicted from data if one is given the parent or offspring genotypes or phenotypes. Two organisms, with genotypes BbDD and BBDd, are mated. Assuming independent assortment of the B/b and D/d genes, determine the genotypic ratios in offspring that would occur.
The pattern of inheritance (monohybrid, dihybrid, sex-linked, and genes linked on the same chromosomes) can be predicted from data if one is given the parent or offspring genotypes or phenotypes. Two organisms, with genotypes BbDD and BBDd, are mated. Assuming independent assortment of the B/b and D/d genes, determine the genotypic ratios in offspring that would occur.
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Study Notes
Meiosis and Independent Assortment
- Meiosis is the process responsible for the independent assortment of alleles.
- Homologous chromosome pairs are acquired through the fusion of gametes.
Mendel's Experiments
- The principle of independent assortment states that alleles of different genes segregate randomly.
- Mendel's experiments involved true-breeding plants labeled as P (parental), F1 (first generation), and F2 (second generation).
- Traits are inherited in discrete units, not through blending.
- A plant with genotype AABbcc is homozygous at two loci.
Gametes and Genetic Variation
- An individual with genotype RrYY can produce two genetically unique types of gametes.
- Parental genotypes AaBb and aabb yield a 1:1:1:1 phenotypic ratio in offspring.
- Genotype AaBbCCDdEE allows for numerous gametes due to different chromosome assortments.
Dominance and Recessive Traits
- Recessive traits can reappear in F2 generation due to their obscured presence in the F1 generation.
- Incomplete dominance exemplified by red and white snapdragons resulting in pink flowers.
Polygenic Inheritance and Pleiotropy
- Height in humans is influenced by polygenic inheritance and environmental factors.
- Cystic fibrosis is an example of pleiotropy, affecting multiple organs and exhibiting varied symptoms.
Genetic Concepts
- Alleles are alternative versions of a gene.
- Polygenic inheritance is seen in traits like skin pigmentation.
- Incomplete dominance occurs when red and white radish flowers cross to yield purple offspring.
Genetic Crosses and Ratios
- Heterozygous snapdragons produce a phenotypic ratio of 6:3:3:2:1.
- The cross of roan cattle produces offspring in the ratio of 1 red:2 roan:1 white.
- Epistasis is illustrated when one genotype prevents the expression of another.
Blood Types and Inheritance
- Blood type inheritance involves multiple alleles and genes with dominance relationships.
- Possible genotypes for a mother with blood type A could include IAi.
- The father of a type B son could be B positive.
Genetic Disorders and Inheritance Patterns
- Huntington's disease is autosomal dominant, suggesting a parent likely carried the allele.
- Phenylketonuria (PKU) requires dietary regulation as an effective treatment.
- Sickle-cell trait may cause some symptoms, and heterozygosity can provide malaria resistance.
Prenatal Genetic Testing
- Ultrasound imaging is a non-invasive technique, while chorionic villus sampling (CVS) and amniocentesis allow chromosome examination.
- Genetic disorders can often be detected before birth.
Quantitative Traits
- Quantitative characters differ from Mendelian traits due to polygenic inheritance, affecting traits along a continuum.
- F2 generation results, derived from specific crosses, can be predicted using Punnett squares.
Homologous Chromosomes
- Each chromosome in a homologous pair contains different alleles, representing maternal and paternal contributions.
- Homologous chromosomes are essential for understanding inheritance patterns and genetic variation.
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Description
Explore the fundamentals of meiosis, independent assortment, and Mendel's genetic experiments. This quiz covers key concepts such as gamete formation, genotype analysis, and the principles of inheritance. Test your understanding of dominant and recessive traits in genetic variations.
