You conduct a dihybrid cross. a ________ ratio would make you suspect that the genes are linked.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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Chapter 10: Patterns of Inheritance, Mendel Laws

Multiple-Choice Questions

2) Which of the following statements best represents the theory of pangenesis developed by Hippocrates? A) Pregnancy is a spontaneous event, and the characteristics of the offspring are determined by the gods. B) Particles called pangenes, which originate in each part of an organism's body, collect in the sperm or eggs and are passed on to the next generation. C) Offspring inherit the traits of either the mother or the father, but not both. D) Fertilization of plants is dependent on an animal. E) Heritable traits are influenced by the environment and the behaviors of the parents. 3) Which of the following statements regarding hypotheses about inheritance is false? A) The theory of pangenesis incorrectly suggests that reproductive cells receive particles from somatic cells. B) Contrary to the theory of pangenesis, somatic cells do not influence eggs or sperm. C) The blending hypothesis does not explain how traits that disappear in one generation can reappear in later generations. D) The blending hypothesis suggests that all of the traits of the offspring come from either the mother or the father. E) Aristotle suggested that inheritance is the potential to produce body features. 4) Mendel conducted his most memorable experiments on A) peas. B) roses. C) guinea pigs. D) fruit flies. E) clones. 5) Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as A) hybrids. B) the F2 generation. C) monohybrid crosses. D) independent crosses. E) true-breeding. 6) Which of the following statements regarding cross-breeding and hybridization is false? A) The offspring of two different varieties are called hybrids. B) Hybridization is also called a cross. C) The parental plants of a cross are the P generation. D) The hybrid offspring of a cross are the P1 generation. E) The hybrid offspring of an F1 cross are the F2 generation. 7) A monohybrid cross is A) the second generation of a self-fertilized plant. B) a breeding experiment in which the parental varieties have only one trait in common. C) a breeding experiment in which the parental varieties differ in only one character. D) a triploid plant that results from breeding two very different plants. E) a breeding experiment in which the parental varieties have only one prominent trait. 8) Which of the following statements regarding genotypes and phenotypes is false? A) The genetic makeup of an organism constitutes its genotype. B) An organism with two different alleles for a single trait is said to be heterozygous for that trait. C) Alleles are alternate forms of a gene. D) An allele that is fully expressed is referred to as recessive. E) The expressed physical traits of an organism are called its phenotype.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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9) Research since Mendel's time has established that the law of the segregation of genes during gamete formation A) applies to all forms of life. B) applies to all sexually reproducing organisms. C) applies to all asexually reproducing organisms. D) applies only to unicellular organisms. E) is invalid. 10) All the offspring of a cross between a black-eyed mendelien and an orange-eyed mendelien have black eyes. This means that the allele for black eyes is ________ the allele for orange eyes. A) codominant to B) recessive to C) more aggressive than D) dominant to E) better than 11) All the offspring of a cross between a black-eyed mendelien and an orange-eyed mendelien have black eyes. What is the expected phenotypic ratio of a cross between two orange-eyed mendeliens? A) 3 black-eyed:1 orange-eyed B) 0 black-eyed:1 orange-eyed C) 1 black-eyed:3 orange-eyed D) 1 black-eyed:0 orange-eyed E) 1 black-eyed:1 orange-eyed 12) The alleles of a gene are found at ________ chromosomes. A) the same locus on homologous mitochondrial B) the same locus on heterologous C) different loci on homologous D) different loci on heterologous E) the same locus on homologous 13) The phenotypic ratio resulting from a dihybrid cross showing independent assortment is expected to be A) 1:2:1. B) 3:1. C) 9:1:1:3. D) 3:9:9:1. E) 9:3:3:1. 14) If A is dominant to a and B is dominant to b, what is the expected phenotypic ratio of the cross: AaBb × AaBb? A) 16:0:0:0 B) 8:4:2:2 C) 4:4:4:4 D) 1:1:1:1 E) 9:3:3:1 15) Mendel's law of independent assortment states that A) chromosomes sort independently of each other during mitosis and meiosis. B) genes sort independently of each other in animals but not in plants. C) independent sorting of genes produces polyploid plants under some circumstances. D) each pair of alleles segregates independently of the other pairs of alleles during gamete formation. E) genes are sorted concurrently during gamete formation. 16) Imagine that we mate two black Labrador dogs with normal vision and find that three of the puppies are like the parents, but one puppy is chocolate with normal vision and another is black with PRA (progressive retinal atrophy, a serious disease of vision).

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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We can conclude that A) both of the parents are homozygous for both traits. B) one of the parents is homozygous for both traits. C) the same alleles that control coat color can also cause PRA. D) the alleles for color and vision segregate independently during gamete formation. E) the alleles for color and vision segregate dependently during gamete formation. 17) A testcross is A) a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest. B) a mating between an individual of unknown genotype and an individual heterozygous for the trait of interest. C) a mating between an individual of unknown genotype and an individual homozygous dominant for the trait of interest. D) a mating between two individuals heterozygous for the trait of interest. E) a mating between two individuals of unknown genotype. 18) Using a six-sided die, what is the probability of rolling either a 5 or a 6? A) 1/6 × 1/6 = 1/36 B) 1/6 + 1/6 = 1/3 C) 1/6 + 1/6 = 2/3 D) 1/6 + 1/6 = 1/12 E) 1/6 19) Assuming that the probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couple's first-born child will be female and that their second-born child will be male? A) 20% B) 25% C) 50% D) 75% E) 100% 20) A carrier of a genetic disorder who does not show symptoms is most likely to be ________ to transmit it to offspring. A) heterozygous for the trait and able B) heterozygous for the trait and unable C) homozygous for the trait and able D) homozygous for the trait and unable E) heterozygous for the trait and unlikely 21) Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes? A) DD and dd B) dd and dd C) Dd and Dd D) DD and DD E) Dd and DD 22) Most genetic disorders of humans are caused by A) multiple alleles. B) recessive alleles. C) drinking during pregnancy. D) a mutation that occurs in the egg, sperm, or zygote. E) dominant alleles.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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23) The vast majority of people afflicted with recessive disorders are born to parents who were A) both affected by the disease. B) not affected at all by the disease. C) slightly affected by the disease, showing some but not all of the symptoms. D) subjected to some environmental toxin that caused the disease in their children. E) affected by the disease but had subclinical symptoms. 24) Which of the following statements best explains why dominant alleles that cause lethal disorders are less common than recessive alleles that cause lethal disorders? A) Lethal disorders caused by dominant alleles are usually more severe than lethal disorders caused by recessive alleles. B) Unlike lethal disorders caused by recessive alleles, lethal disorders caused by dominant alleles usually cause the death of the embryo. C) Most individuals carrying a lethal dominant allele have the disorder and die before they reproduce, whereas individuals carrying a lethal recessive allele are more likely to be healthy and reproduce. D) The presence of a lethal dominant allele causes sterility. E) Many lethal recessive alleles cause enhanced disease resistance when they are present in the heterozygous state, and carriers of these alleles have more children, on average, than other people. 25) Amniocentesis and chorionic villus sampling allow for ________ and ________ of the fetus so that it can be tested for abnormalities. A) imaging . . . biochemical testing B) imaging . . . karyotyping C) sexing . . . imaging D) karyotyping . . . biochemical testing E) direct observation . . . biochemical testing 26) Which of the following statements regarding prenatal testing is false? A) Results from chorionic villus sampling come faster than from amniocentesis. B) Chorionic villus sampling is typically performed later in the pregnancy than amniocentesis. C) Ultrasound imaging has no known risk. D) The complication rate for chorionic villus sampling is about 2% and for amniocentesis is about 1%. E) Chorionic villus sampling and amniocentesis are usually reserved for pregnancies with higher than usual risks of complications. 27) Which of the following statements regarding genetic testing is false? A) Genetic testing before birth requires the collection of fetal cells. B) Carrier testing helps determine if a person carries a potentially harmful disorder. C) Most children with recessive disorders are born to healthy parents. D) The screening of newborns can catch inherited disorders right after birth. E) Most human genetic diseases are treatable if caught early. 28) For most sexually reproducing organisms, Mendel's laws A) cannot strictly account for most patterns of inheritance. B) explain the reasons why certain genes are dominant. C) help us understand the global geographic patterns of genetic disease. D) indicate if a particular genotype will cause a certain phenotype. E) clarify the phenomenon of incomplete dominance. 29) Which of the following statements is false? A) Incomplete dominance supports the blending hypothesis. B) Heterozygotes for hypercholesterolemia have blood cholesterols about twice normal. C) The four blood types result from various combinations of the three different ABO alleles. D) ABO blood groups can provide evidence of paternity. E) The impact of a single gene on more than one character is called pleiotropy.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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30) All the offspring of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is ________ to the allele for white flowers. A) dominant B) codominant C) pleiotropic D) incompletely dominant E) recessive 31) Imagine that beak color in a finch species is controlled by a single gene. You mate a finch homozygous for orange (pigmented) beak with a finch homozygous for ivory (unpigmented) beak and get numerous offspring, all of which have a pale, ivory-orange beak. This pattern of color expression is most likely to be an example of A) incomplete dominance. B) codominance. C) pleiotropy. D) polygenic inheritance. E) crossing over. 32) Which of the following is an example of incomplete dominance in humans? A) sickle-cell disease B) hypercholesterolemia C) skin color D) ABO blood groups E) phenylketonuria 33) The expression of both alleles for a trait in a heterozygous individual illustrates A) incomplete dominance. B) codominance. C) pleiotropy. D) polygenic inheritance. E) blending inheritance. 34) A person with AB blood illustrates the principle of A) incomplete dominance. B) codominance. C) pleiotropy. D) polygenic inheritance. E) blending inheritance. 35) Which of the following statements regarding sickle-cell disease is false? A) Sickle-cell disease is common in tropical Africa. B) Persons who are heterozygous for sickle-cell disease are also resistant to malaria. C) Sickle-cell disease causes white blood cells to be sickle-shaped. D) All of the symptoms of sickle-cell disease result from the actions of just one allele. E) About one in ten African-Americans is a carrier of sickle-cell disease. 36) Sickle-cell disease is an example of A) codominance and pleiotropy. B) codominance and blended inheritance. C) multiple alleles, pleiotropy, and blended inheritance. D) codominance and multiple alleles. E) multiple alleles and pleiotropy.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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37) Which of the following terms refers to a situation where a single phenotypic character is determined by the additive effects of two or more genes? A) incomplete dominance B) codominance C) pleiotropy D) polygenic inheritance E) blending inheritance 38) Which of the following is essentially the opposite of pleiotropy? A) incomplete dominance B) codominance C) multiple alleles D) polygenic inheritance E) blending inheritance 39) The individual features of all organisms are the result of A) genetics. B) the environment. C) genetics and cytoplasmic determinants. D) the environment and individual needs. E) genetics and the environment. 40) The chromosome theory of inheritance states that A) chromosomes that exhibit mutations are the source of genetic variation. B) the behavior of chromosomes during meiosis and fertilization accounts for patterns of inheritance. C) the behavior of chromosomes during mitosis accounts for inheritance patterns. D) humans have 46 chromosomes. E) the inheritance pattern of humans is predetermined from chromosomes. 41) Genes located close together on the same chromosomes are referred to as ________ genes and generally ________. A) associated . . . sort independently during meiosis B) linked . . . sort independently during meiosis C) homologous . . . are inherited together D) linked . . . do not sort independently during meiosis E) codependent . . . do not sort independently during meiosis 42) Linked genes generally A) follow the laws of independent assortment. B) do not follow the laws of independent assortment. C) show incomplete dominance. D) reflect a pattern of codominance. E) show pleiotropy. 43) You conduct a dihybrid cross and then testcross the generation. A ________ ratio would make you suspect that the genes are linked. A) 3:1 B) 1:2:1 C) 1:1:1:1 D) 7:7:1:1 E) 9:3:3:1

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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44) Crossing over ________ genes into assortments of ________ not found in the parents. A) recombines unlinked . . . genes B) recombines linked . . . alleles C) combines unlinked . . . alleles D) combines linked . . . genes E) recombines unlinked . . . chromosomes 45) The mechanism that "breaks" the linkage between linked genes is A) incomplete dominance. B) pleiotropy. C) codominance. D) independent assortment. E) crossing over. 46) Which of the following kinds of data could be used to map the relative position of three genes on a chromosome? A) the frequencies with which the genes exhibit incomplete dominance over each other B) the frequencies of mutations in the genes C) the frequencies with which the genes are inherited from the mother and from the father D) the frequencies with which the genes are heterozygous E) the frequencies with which the corresponding traits occur together in offspring 47) What is the normal complement of sex chromosomes in a human male? A) two X chromosomes B) two Y chromosomes C) two X chromosomes and one Y chromosome D) one X chromosome and one Y chromosome E) one Y chromosome 48) The sex chromosome complement of a normal human male is A) XO. B) XX. C) XY. D) YY. E) YO. 49) How many sex chromosomes are in a human gamete? A) one B) two C) three D) four E) five 50) How is sex determined in most ants and bees? A) by the X-Y system B) by the Z-W system C) by the number of chromosomes D) by the size of the sex chromosome E) by the X-O system

BSC1005 Biology General Chapter 11

Molecular Biology of the Gene

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Chapter 11: Molecular Biology of the Gene Multiple-Choice Questions 1) Which of the following statements regarding viruses is false? A) A virus is generally considered to be alive because it is cellular and can reproduce on its own. B) The host cell provides most of the tools and raw materials for viral multiplication. C) Once a person is infected with the herpes virus, the virus remains permanently latent in the body. D) Viruses can enter a host cell when the protein molecules on the outside of the virus fit into receptor molecules on the outside of the cell. E) Herpesviruses and the virus that causes AIDS can remain latent inside our cells for long periods of time. 2) Which of the following people conducted the experiments that demonstrated that DNA is the genetic material of bacteriophages? A) Watson and Crick B) Hershey and Chase C) Franklin D) Griffith E) Pauling 3) One type of virus that infects bacteria is called a A) phage. B) mage. C) rhinovirus. D) filovirus. E) coronavirus. 4) When a T2 bacteriophage infects an Escherichia coli cell, which part of the phage enters the bacterial cytoplasm? A) the whole phage B) only the RNA C) only the DNA D) the protein "headpiece" and its enclosed nucleic acid E) the tail fibers 5) The way that genetic material of a bacteriophage enters a bacterium is most like the way that A) a drug is injected with a hypodermic needle. B) a person swallows a pill. C) skin lotion is rubbed onto the hands. D) sugar dissolves in water. E) water soaks into a sponge. 6) The monomers of DNA and RNA are A) amino acids. B) monosaccharides. C) nucleotides. D) fatty acids. E) nucleic acids. 7) Which of the following statements regarding DNA is false? A) DNA uses the sugar deoxyribose. B) DNA uses the nitrogenous base uracil. C) DNA is a nucleic acid. D) One DNA molecule can include four different nucleotides in its structure. E) DNA molecules have a sugar-phosphate backbone.