BIO_Chapter 7 – Flashcards
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What is the purpose of a test-cross? a) A test-cross is just another term for an experimental cross between two unknown organisms. b) A test-cross allows a breeder to see how quickly it takes to go from generation to generation for a particular organism. c) A test-cross can demonstrate the efficiency of breeding. d) A test-cross can reveal an unknown genotype. e) A test-cross can reveal an unknown internal phenotype.
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d) A test-cross can reveal an unknown genotype.
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Which of the following statements about the Rh marker allele is most accurate? a) The Rh marker results from a single gene with two alleles. b) An individual's red blood cells carry the Rh cell surface marker if they have one or two copies of the dominant Rh marker allele. c) If a person has one or two copies of the dominant Rh marker allele then their blood type is noted as "positive", that is, B+ or B positive. d) If an individual has two copies of the recessive allele for the gene, they do not have any Rh markers, and are therefore are described as "negative", that is, B- or B negative. e) All of the above
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e) All of the above
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Which of the following did NOT contribute to the success of Mendel's research? a) He chose a good organism to study, i.e. pea plants, which had clear-cut phenotypes. b) He chose to focus on easily categorized traits, such as round or wrinkled c) He began his studies by first repeatedly breeding together similar plants until he had many distinct populations, each of which was unvarying for a certain trait d) He did not utilize any true-breeding organisms in order to study various types of traits e) None of the above contributed to Mendel's research success.
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d) He did not utilize any true-breeding organisms in order to study various types of traits
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Sex-linked traits: a) are only controlled by genes on the Y chromosome. b) are controlled by genes on the X and Y chromosomes. c) appear more frequently in females if they are recessive. d) are only inherited from the father. cannot be visualized using a pedigree.
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b) are controlled by genes on the X and Y chromosomes.
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The impact of a single gene on more than one characteristic is called: a) codominance. b) homozygosity. c) polygenic inheritance. d) pleiotropy. e) epistasis.
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d) pleiotropy.
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Which of the following is NOT included in the definition of a phenotype? a) all the genes an individual carries b) chemicals an individual produces, such as in digesting lactose c) features visible to the naked eye, i.e. height d) certain behaviors an individual exhibits e) outward appearance
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a) all the genes an individual carries
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What is a pedigree? a) A cross between animals other than humans b) A type of genetic test to determine probability of inheritance c) A tool to document harmful traits only d) A way of following genotypes that are the same as the phenotype e) A type of family tree that can help answer questions about genes and their inheritance patterns
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e) A type of family tree that can help answer questions about genes and their inheritance patterns
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Which of the following statements is FALSE? a) Type AB blood cells produce A and B antigens but neither A nor B antibodies b) Type A blood cells produce A antigens and B antibodies c) Type B blood cells produce B antigens and A antibodies d) Type O blood cells produce neither A nor B antigens and produce no antibodies e) Type AB blood cells produce A and B antigens and A and B antibodies
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e) Type AB blood cells produce A and B antigens and A and B antibodies
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Traits that are determined by a single gene: a) must occur on the X chromosome because males have only a single X, so the gene must be able to function in the absence of its homologous allele. b) occur in single-celled organisms, but not in humans. c) can have only two alleles. d) are common in humans. e) include eye color and skin color.
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d) are common in humans.
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Sickle-cell anemia is a genetic disease caused by the presence of a faulty hemoglobin gene (HbS). The normal version of this gene is HbA. Which of the following is TRUE about HbS and HbA? a) It is impossible for a person to carry two HbS genes. b) They're both alleles for the same trait. c) A person with two HbS genes would be a silent carrier. d) Hemoglobin genes are always inherited from one's mother. e) People carrying two HbS genes smell like rotten fish.
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b) They're both alleles for the same trait.
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Which of the following blood types is incorrectly matched with its potential recipient? a) Type AB can only receive from type A, B, or AB. b) Type A can only receive from type A or type O. c) Type B can only receive from type B or type O. d) Type O can only receive from type O. e) All of the answer options are correct.
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a) Type AB can only receive from type A, B, or AB.
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Which of the following is INCORRECTLY matched regarding the Punnett Square and a one-factor cross (e.g. BB x Bb)? a) Inside the square: genotypes of actual offspring b) There are no rules to setting up a Punnett square; just do it in a way that you understand. c) Top of the square: lists the two alleles that one of the parents produces d) Left side of the square: lists the two alleles that the other parent produces e) Inside the square: genotypes of potential offspring
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a) Inside the square: genotypes of actual offspring
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What is a linked gene? a) The situation where two different genes are found on the same chromosome b) An abnormality where two chromosomes are connected due to some sort of mutation c) Any gene that exhibits an outward effect; in fact, all genes are linked. d) A gene that suppresses the effects of another gene e) A gene that causes mutations, such as trisomy 21
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a) The situation where two different genes are found on the same chromosome
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How can an individual carry a defective gene but not exhibit the defective phenotype? a) An individual may not have that defective gene in every cell, and so appear normal. b) Individuals carry two copies of gene instructions, and one dominant allele could mask the presence of a recessive defective allele. c) Individuals are always homozygous. d) Both choices A and C are true. e) None of the above
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b) Individuals carry two copies of gene instructions, and one dominant allele could mask the presence of a recessive defective allele.
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Which of the following statements is true regarding pedigree analysis? a) Darkened shapes always represent individuals with the trait being traced. b) Squares represent females, while circles represent males. c) The length of the vertical lines is dependent on the relatedness coefficient between two individuals. d) Pedigree charts always enable you to predict the characteristics of the offspring. e) Horizontal lines connect siblings.
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a) Darkened shapes always represent individuals with the trait being traced.
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A diploid individual with two identical alleles for a particular gene is said to be: a) homozygous for every gene. b) heterozygous for that gene. c) homozygous for that gene. d) isogenous. e) heterozygous for every gene.
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c) homozygous for that gene.
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In certain plants, red flowers are dominant to white flowers. If a heterozygous plant is crossed with a homozygous red-flowered plant, what is the probability that the offspring will be white-flowered? a) 25% b) 50% c) 0% d) 75% e) It depends on whether the traits are linked.
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c) 0%
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The phenotype of an organism is: a) a hypothesis of its evolutionary origins. b) the form it achieves as an adult. c) the embryonic expression of its genes. d) its genetic make-up. e) its physical characteristics.
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e) its physical characteristics.
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In snapdragons, there is an allele for flower color, CW, that produces no pigment. A plant with the genotype CWCW will produce _____________ flowers. a) no b) black c) pink d) red e) white
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e) white
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In the figure shown, which are the recessive traits? a) green and wrinkled b) wrinkled and smooth c) yellow and smooth d) green and short e) yellow and short
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a) green and wrinkled
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A cross between homozygous red-eyed flies and homozygous white-eyed flies results in progeny that all have red-eyes. This result demonstrates: a) a dihybrid cross. b) the norm of reaction. c) a blending of alleles. d) the law of independent assortment. e) dominance.
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e) dominance.
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A person with the genotype AB can receive blood of what type? a) type B blood b) type O blood c) type A blood d) All of the above blood types would work fine. e) None of the above blood types would work.
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d) All of the above blood types would work fine.
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Which of the following pairings, indicated by letters referring to blood type phenotypes, CANNOT produce a child with type B blood? a) B x O b) A x B c) O x AB d) AO x AO e) All of the above could produce a child with type B blood.
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d) AO x AO
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Jay has type O blood, and his brother Alon has type AB blood. What are the genotypes of these boys' parents? a) IAi and IBi b) ii and IBi c) IAi and IBIB d) IAIA and IBi e) It is not possible to determine the phenotype of the boys' parents from the information provided.
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a) IAi and IBi
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Most genes come in alternative forms called: a) heterozygotes. b) homozygotes. c) gametes. d) chromosomes. e) alleles.
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e) alleles.
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The same genetic condition that causes sickle-cell anemia can also protect against: a) yellow fever. b) hemophilia. c) tuberculosis. d) malaria. e) HIV-AIDS.
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d) malaria.
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In pea plants, purple flower color is dominant to white flower color. If two pea plants that are true-breeding for purple flowers are crossed, in the offspring: a) all of the flowers will be purple. b) three-quarters of the flowers will be purple and one-quarter will be white. c) half of the flowers will be purple and one-quarter will be white. d) one-quarter of the flowers will be purple and three-quarters will be white. e) all of the flowers will be white.
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e) all of the flowers will be white.
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A woman with type B blood and a man with type A blood could have children with which of the following phenotypes? a) A, B, AB, or O b) O only c) AB only d) AB or O e) A, B, or O
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a) A, B, AB, or O
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How can an individual carry a defective gene but not exhibit the defective phenotype? a) An individual may not have that defective gene in every cell, and so appear normal b) Individuals carry two copies of gene instructions, and one dominant allele could mask the presence of a recessive defective allele c) Individuals are always homozygous d) Both a) and c) are true e) None of the above is true
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b) Individuals carry two copies of gene instructions, and one dominant allele could mask the presence of a recessive defective allele
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A phenotype:
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consists of the observable properties of an individual.
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In pea plants, purple flower color is dominant to white flower color. If two pea plants that are true-breeding for purple flowers are crossed, in the offspring:
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all of the flowers will be purple.
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How can two pea plants that have different genotypes for seed color be identical in phenotype?How can two pea plants that have different genotypes for seed color be identical in phenotype? a) Genotype has no relation to phenotype. b) One of the two plants could be homozygous for the dominant allele while the other could be heterozygous. c) One of the two plants could be homozygous for the recessive allele while the other could be heterozygous. d) Both of them have the dominant gene, but it is not being expressed. e) One of the two plants could be homozygous for the dominant allele while the other could be homozygous for the recessive allele.
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One of the two plants could be homozygous for the dominant allele while the other could be heterozygous.
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The impact of a single gene on more than one characteristic is called: a) epistasis. b) pleiotropy. c) homozygousity. d) codominance. e) polygenic inheritance.
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b) pleiotropy
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Cystic fibrosis, which is usually lethal before reproductive ages, is a homozygous recessive disease. Why do cases continue to arise, even though people with the disease rarely live to reproduce? a) Individuals can pass on the alleles in non-genetic ways, including through the sharing of needles. b) The harmful allele can reside in heterozygous individuals with few to no negative effects. c) Cystic fibrosis is a multifactorial disorder, and is probably controlled by the action of many genes. d) Mosquitoes can transfer the disease from person to person. e) Occassionally an individual does reproduce and passes on both of their alleles.
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b) The harmful allele can reside in heterozygous individuals with few to no negative effects.
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If a baby has "his father's nose," it's because: a) the baby has not inherited the "suppress father's nose allele" from his mother. b) the father's nose is not a heritable trait, it is just a chance event that the baby has a similar nose. c) the baby has inherited many alleles from his father that work together to shape the baby's nose. d) the baby has inherited the "father's nose" allele from his father. e) the baby has inherited the "father's nose" allele from his mother.
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c) the baby has inherited many alleles from his father that work together to shape the baby's nose.
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If you have blood type A, which of the following is true about you? a) you produce antibodies to attack A antigens b) you can donate blood to Type B and Type AB only c) you have A antigens d) you are the universal donor e) you can receive blood from Type B and Type O only
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c) you have A antigens
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The phenotype of an organism can best be determined by: a) a reciprocal cross. b) true-breeding. c) inbreeding. d) observing the organism. e) sequencing its genes.
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d) observing the organism.
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The sickle-cell allele is considered to be pleiotropic because: a) it is involved in a continuously varying trait: the amount of resistance to malaria. b) it has at least two effects: disrupting oxygen delivery and protecting against malaria. c) it is codominant, in that heterozygotes have both circular and sickled red blood cells. d) it has at least two effects: promoting oxygen delivery and protecting against malaria. e) in the dominant form it disrupts oxygen and in the recessive form in protects against malaria.
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d) it has at least two effects: promoting oxygen delivery and protecting against malaria.
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The test-cross: a) makes it possible to determine the genotype of an individual of unknown genotype who exhibits the dominant version of a trait. b) is a cross of an individual whose genotype for a trait is not known with an individual homozygous recessive for the trait. c) only takes one offspring to reveal the genotype of an individual whose genotype is unknown. d) a) and b) are both correct. e) a), b), and c) are correct.
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d) a) and b) are both correct.
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The law of segregation states that: a) the number of chromosomes in a cell is always divisible by 2. b) Eggs and sperm separate before fertilization occurs. c) gametes cannot be separate and equal. d) an allele on one chromosome will always segregate from an allele on a different chromosome. e) each of two alleles for a given trait segregate into different gametes.
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e) each of two alleles for a given trait segregate into different gametes.
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A plant with pink flowers is allowed to self-pollinate. Generation after generation, it produces pink flowers. This is an example of: a) the law of independent assortment. b) a true-breeding plant. c) allopolyploidy. d) interbreeding. e) codominance.
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b) a true-breeding plant.
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The failure of a seedling to turn green if grown in the dark is an example of: a) a lack of the chroloplast gene. b) incomplete dominance. c) interaction between codominant alleles. d) pleiotropy. e) interaction between genotype and environment.
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e) interaction between genotype and environment.
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Flower color in snapdragons is an example of incomplete dominance. When a red-flowered plant is crossed with a white-flowered plant, the offspring have pink flowers. If a pink-flowered plant is crossed with another pink-flowered plant, their offspring will be: a) all white. b) all pink. c) 50% pink and 50% red. d) 25% white and 75% red. e) 25% red, 50% pink, and 25% white.
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e) 25% red, 50% pink, and 25% white.
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Monterey cypress trees grow along the coast of California with most of their branches clustered on one side of the tree, pointing away from the sea. If a monterey cypress seed is germinated beyond 50 miles from the coastline, the tree grows up with a symmetric distribution of branches, just like other evergreens. This scenario demonstrates which statement about genetics? a) The "windblown" shape seen in coastal trees is obviously caused by a polygenic inheritance. b) The "windblown" shape seen in coastal trees is obviously determined by their genotypes. c) The "windblown" shape seen in coastal trees is a result of environmental conditions, not their genes. d) Both a) and b) are true. e) None of the above are true.
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c) The "windblown" shape seen in coastal trees is a result of environmental conditions, not their genes.
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If two giraffes were crossed, where one is heterozygous for albinism (a) and the other has a homozygous dominant genotype, what would be the expected genotypic and phenotypic ratios? a) 0 AA: 0 Aa: 1 aa; all albino b) 1 AA: 2Aa: 1aa; 3 pigmented: 2 albino c) 2 AA: 2 Aa: 0 aa; all pigmented d) 2 AA: 0 Aa: 0 aa; all pigmented e) 2 AA: 2 Aa: 0 aa; 4 pigmented: 2 albino
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c) 2 AA: 2 Aa: 0 aa; all pigmented
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In the ABO blood type system in humans, there are _________ different alleles, ____________ different phenotypes, and ____________ different genotypes. a) four; three; six b) four; six; four c) four; six; three d) three; four; six e) four; four; three
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d) three; four; six
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If you have blood type A, which of the following is true about you? a) you can donate blood to Type B and Type AB only b) you have A antigens c) you produce antibodies to attack A antigens d) you are the universal donor e) you can receive blood from Type B and Type O only
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b) you have A antigens
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A woman with type B blood and a man with type A blood could have children with which of the following phenotypes? a) AB or O b) AB only c) A, B, AB, or O d) A, B, or O e) The answer cannot be determined from the information provided.
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c) A, B, AB, or O
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When genetically based traits are inherited independently from each other, this is known as: a) pleitropy. b) Law of Segregation. c) linkage. d) multi-allelism. e) Mendel's law of independent assortment.
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e) Mendel's law of independent assortment.
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Which of the following is NOT a continuously varying trait? a) eye color b) height c) blood type d) skin color e) geekiness
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c) blood type
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If you crossed a snapdragon that had the CWCW genotype at the flower color gene with a snapdragon that had the CRCR genotype: a) all of the offspring would have the CRCR genotype. b) one-quarter of the offspring would have the CWCW genotype; one-half the offspring would have the CWCR genotype, and one-quarter of the offspring would have the CRCR genotype. c) three-quarters of the offspring would have white flowers. d) all of the offspring would have the CWCR genotype. e) all of the offspring would have the CWCW genotype.
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d) all of the offspring would have the CWCR genotype.
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In peas, tall plants are dominant to short plants. A heterozygous plant is crossed with a homozygous recessive plant. What fraction of the offspring would you expect to have the short phenotype? a) none b) all of the offspring c) 1/4 d) 1/2 e) 3/4
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d) 1/2
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Gregor Mendel performed his famous experiments on: a) finches. b) pigeons. c) green beans. d) humans. e) garden peas.
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e) garden peas.
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Which of the following did Gregor Mendel never see? a) a gene b) a pea c) a stamen d) an F2 generation e) the publication of his research on the genetics of pea plants
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a) a gene
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Albinism (lack of skin and hair pigmentation) is caused by a recessive autosomal allele. A woman and man, both normally pigmented, have an albino child together. For this trait, what is the genotype of the albino child? a) It depends on the environment that the child lives in. b) homozygous dominant c) heterozygous d) homozygous recessive e) It is unknown, because not enough information is provided.
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d) homozygous recessive
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Sickle-cell anemia is a genetic disease caused by the presence of a faulty hemoglobin gene (HbS). The normal version of this gene is HbA. Which of the following is TRUE about HbS and HbA? a) It is impossible for a person to carry two HbS genes. b) People carrying two HbS genes smell like rotten fish. c) A person with two HbS genes would be a silent carrier. d) They're both alleles for the same trait. e) Hemoglobin genes are always inherited from one's mother.
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d) They're both alleles for the same trait.
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We say that genes are linked when: a) they are located near each other on a single chromosome. b) they are responsible for producing the same protein. c) they are located in the same spot on two different chromosomes. d) they produce a balanced polymorphism. e) they are responsible for producing different proteins that act together in the same biochemical reaction.
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a) they are located near each other on a single chromosome.
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What was the MOST important scientific advance gained from Gregor Mendel's experiments with pea plants? a) Darwin's theory of evolution by natural selection was confirmed. b) We learned that recessive alleles occur more frequently in the F2 generation than do dominant ones. c) We learned that there is considerable genetic variation in garden peas. d) We learned that chromosomes are composed of DNA. e) We learned that many traits are inherited in discrete units, and are not the result of blending.
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e) We learned that many traits are inherited in discrete units, and are not the result of blending.
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An individual's blood-type alleles carry instructions that direct construction of a specfic set of chemicals which protrude from every red blood cell. These chemicals are called: a) cell proteins b) antibodies c) antigens d) hemoglobins e) sickled cells
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c) antigens
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In ABO blood group inheritance, what is the relationship between the alleles A and B (sometimes written as IA and IB)? a) They are polygenic to each other. b) They are incompletely dominant to each other. c) They are pleiotropic to each other. d) They are codominant to each other. e) None of the above is correct about alleles A and B.
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d) They are codominant to each other.
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The difference between incomplete dominance and codominance is: a) that in incomplete dominance, the offspring exhibit the traits of both parents, while in codominance, the offspring do not exhibit the traits of either parent. b) that in incomplete dominance, the offspring do not exhibit the traits of either parent, while in codominance, the offspring exhibit the traits of both parents. c) that in incomplete dominance, the trait under observation is produced by the a single allele, while in codominance, the trait is produced by a combination of multiple alleles. d) that in incomplete dominance, the trait under observation is produced by the combination of multiple alleles, while in codominance, the trait is produced by a single allele. e) There is no difference, incomplete dominance and codominance mean the same thing.
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b) that in incomplete dominance, the offspring do not exhibit the traits of either parent, while in codominance, the offspring exhibit the traits of both parents.
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The ABO blood type system in humans is a system that contains ________ alleles that produce __________ different phenotypes. a) four; three b) three; four c) six; three d) three; six e) three; three
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b) three; four
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A male with an X-linked recessive disorder mates with a female that is a carrier for this same X-linked recessive disorder. Which of the following is the correct expected frequency of this disorder in their children? a) 50% frequency in the daughters b) 50% frequency in the sons c) 50% frequency in both the sons and the daughters d) 75% frequency in the sons e) 75% frequency in the daughters
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c) 50% frequency in both the sons and the daughters
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Phenylketonuria is a genetic disorder that: a) causes the inability to convert phenylalanine to tyrosine. b) causes the inability to convert tyrosine to phenylalanine. c) causes a build up of lipid in the neurons. d) causes too many copies of phenylalanine to be added to protein chains. e) causes too few copies of tyrosine to be added to protein chains.
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a) causes the inability to convert phenylalanine to tyrosine.
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Which of the following is true of an individual with blood type AB? a) They have red blood cells with A and B antigens. b) They are classified as the "universal donor" and can donate blood to anyone. c) They produce A and B antibodies. d) They can receive blood from blood type O individuals only. e) They have red blood cells with A antigens only.
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c)
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Tay-Sachs, which is a recessive lethal disease, results only when individuals possess two copies of the disease-causing allele. Which of the following statements is true about this disease? a) Heterozygous individuals only pass on the dominant copy of the allele to offspring. b) Heterozygous individuals may pass on their copy of the disease-causing allele to offspring. c) Heterozygous individuals are more fit than homozygous dominant individuals, so eventually, there will only be heterozygotes in the population. d) All cases of this disease must be caused by new mutations. e) A homozygous individual can pass on both of the recessive genes for Tay-Sachs.
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b)Heterozygous individuals may pass on their copy of the disease-causing allele to offspring.
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A man who is a silent carrier of the FMO3 "fish odor syndrome" has children by a woman who is "normal." Which of the following would best explain how a child born from these parents could have fish odor syndrome? a) FMO3 is x-linked. b) The child inherits two copies of defective FMO3 alleles from its father. c) The mother is also a silent carrier of the defective FMO3 allele. d) The child has a mutation in one of its cells, making the FMO3 genes defective in those cells. e) The child inherits two copies of defective FMO3 alleles from its mother.
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c) The mother is also a silent carrier of the defective FMO3 allele.
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Peas (Pisum sativum) were well suited for Mendel's breeding experiments for all of the following reasons except: a) the pea plant is rather prolific in seed production. b) peas exhibit variations in a number of observable characteristics, such as flower color and seed shape. c) Mendel and his staff could control the pollination between different pea plants. d) many of the characteristics that vary in pea plants are controlled by single genes. e) peas have a particularly long generation time.
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e) peas have a particularly long generation time.
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The SRY gene is considered pleiotropic because: a) it is a single gene that influences multiple traits: development of fetal gonads, secretion of testosterone, and more. b) it is one gene involved in continuously varying traits, in this instance, height. c) it is part of a multi-allelic system that determines the sex of a growing fetus. d) it is part of a multi-allelic system that determines blood type. e) it is one gene involved in continuously varying traits, in this instance, eye color.
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it is a single gene that influences multiple traits: development of fetal gonads, secretion of testosterone, and more.
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Which of the following did Gregor Mendel never see?
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a chromosome
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Virtually everyone __________________ has a parent that exhibits the same trait. a) with unattached earlobes b) with albinism c) with Tay-Sachs disease d) over six feet tall e) under five feet tall
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a) with unattached earlobes
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Which of the following was NOT true of Gregor Mendel? a) He developed the first theory about how traits are inherited. b) He lived in the 19th century. c) His primary research system was the pea plant. d) He was an Austrian monk. e) He understood basic concepts about DNA replication.
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e) He understood basic concepts about DNA replication.
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If a male with color blindness (sex-related variety) and a female with normal vision have a color blind son, what can you infer about the parents? a) The mother was a carrier for color blindness. b) The mother was homozygous for color blindness. c) The son inherited a gene for color blindness from his mother and one from his father. d) The mother's father was color blind. e) The son inherited the gene for color blindness from his father.
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a) The mother was a carrier for color blindness.
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Genes that are _____________ do not assort independently, but they may recombine by crossing over. a) epistatic b) polygenic c) pleiotropic d) linked e) dominant
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d) linked
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Phenotypes are generally a product of: a) pleitropic effects of a single gene. b) multiple alleles at the same gene locus. c) two or more genes in combination with each other. d) the genotype in combination with the environment. e) incomplete dominance.
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d) the genotype in combination with the environment.
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In pea plants, tall stem length is dominant to short and round seed shape is dominant to wrinkled seed shape. If a plant that is homozygous for tall stem and homozygous for wrinkled seeds is allowed to self-fertilize, what proportion of the offspring will have wrinkled seeds and a tall stem? a) None of the offspring will have wrinkled seeds and a tall stem. b) 3/16 c) 1/2 d) All of the offspring will have wrinkled seeds and a tall stem. e) 3/4
answer
d) All of the offspring will have wrinkled seeds and a tall stem.
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Pedram and Monica are both heterozygous for the widow's peak trait. Individuals who have two copies of the widow's peak allele exhibit a sharp, pointed hairline. What is the probability that the couple's first three children will all have widow's peaks? a) 1/64 b) 1/8 c) 3/4 d) 1/4 e) 1/12
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a) 1/64
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Four traits that Mendel studied extensively in pea plants were flower position, seed color, stem length, and pod shape. For flower position, the axial (A) allele is dominant over terminal (a); for seed color, the yellow allele (Y) is dominant over green (y); for stem length, the tall (T) allele is dominant over dwarf (t); and for pod shape, the inflated (I) allele is dominant over constricted (i). Imagine a tetrahybrid cross between two AaYyTtIi plants. What is the probability of observing an individual with the AaYYttIi genotype in the next generation? a) 1/16 b) 1/4 c) 1/128 d) 1/64 e) 1/2
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d) 1/64
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The fact that freckles tend to be inherited with red hair is counter to which of Mendel's assertions? a) Genes for different traits sort independently of each other. b) There are only two alleles possible for a trait. c) One allele is always fully dominant over another. d) Two copies of genetic instructions are carried per cell for a given characteristic. e) A single phenotype is dictated by two genes carried in each cell.
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a) Genes for different traits sort independently of each other.
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Which of the following traits shows a polygenic method of inheritance? a) flower color in snapdragons b) seed color in peas c) sickle-cell disease in humans d) skin color in humans e) blood type in humans
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d) skin color in humans
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An individual's blood-type alleles carry instructions that direct construction of a specfic set of chemicals which protrude from every red blood cell. These chemicals are called antigens. If you have A antigens, which antibodies will you produce? a) neither A nor B b) O c) A d) both A and B e) B
answer
B
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An individual who has the genotype HbSHbA has the phenotype of: a) hemophilia. b) blood type O. c) having both normal, circular red blood cells and sickle-shaped red blood cells in his or her circulatory system. d) having red blood cells that are intermediate in shape between circular and sickle-shaped. e) blood type A.
answer
c) having both normal, circular red blood cells and sickle-shaped red blood cells in his or her circulatory system.
question
A situation in which the heterozygote offspring of two homozygotes show an phenotype intermediate between those of the parents is called: a) multiple allelism. b) heterozygote superiority. c) pleiotropy. d) polygenic traits. e) incomplete dominance.
answer
e) incomplete dominance
question
How can an individual whose parents did not have the "fish odor syndrome" trait inherit that trait? a) Under the circumstances outlined above, the "fish odor syndrome" cannot be inherited. b) If each parent were a silent carrier of the "fish odor syndrome," then their offspring would have a 50% chance of having the syndrome. c) If each parent were a silent carrier of the "fish odor syndrome," then their offspring would have a 100% chance of having the syndrome. d) Only one parent needs to pass on the gene in order for the offspring to have the "fish odor syndrome. e) If each parent were a silent carrier of the "fish odor syndrome," then their offspring would have a 25% chance of having the syndrome.
answer
e) If each parent were a silent carrier of the "fish odor syndrome," then their offspring would have a 25% chance of having the syndrome.
question
Without knowing the genetic basis, humans have selectively bred for: a) increased body size in cattle. b) transgenic tomatoes. c) increased milk production. d) both a) and b). e) both a) and c).
answer
e) both a) and c).
question
Phenylketonuria (PKU) is a disease characterized by the buildup of phenylalanine. The enzyme phenylalanine hydroxylase, which catalyzes the conversion of _________ to __________, is mutated and non-functional. a) phenylalanine; tyrosine b) phenylalanine; trypsin c) phenylalanine; arginine d) tyrosine; phenylalanine e) None of the above is correct.
answer
a) phenylalanine; tyrosine
question
Individuals carrying two non-functioning alleles for the gene producing the enzyme that converts phenylalanine into tyrosine: a) will develop phenylketonuria (PKU). b) will develop both PKU and Tay-Sachs disease, because one pleiotropic gene influences both traits. c) may or may not develop phenylketonuria, because the environment (diet, in this case) also plays a role in determining their phenotype. d) will develop both PKU and Tay-Sachs disease, because the genes causing the two traits are on the same chromosome. e) do not need to worry about their phenylalanine consumption, because PKU depends on both genes and the environment.
answer
c) may or may not develop phenylketonuria, because the environment (diet, in this case) also plays a
question
The ABO blood type system in humans is an example of: a) multiple alleles and codominance. b) codominance but not multiple alleles. c) multiple alleles but not codominance. d) balanced polymorphism and codominance. e) balanced polymorphism and dominant alleles.
answer
a) multiple alleles and codominance.
question
A man with the autosomal recessive disorder phenylketonuria (PKU) and a woman without PKU have a son named Peter, who does not have PKU. Peter is curious about whether his mother is a carrier for PKU. Which of the following facts would allow him to know? a) Neither of Peter's maternal grandparents have PKU. b) Peter's own daughter has PKU. c) Peter submits his own blood sample to a local genotyping lab, which establishes that he is a carrier for PKU. d) Peter's maternal grandfather has PKU. e) Peter's sister does not have PKU.
answer
d) Peter's maternal grandfather has PKU.
question
In the case of Mendel's peas, a single gene determined the height of the plant. However, in humans, adult height is influenced by many genes. A trait such as human height is said to be:
answer
polygenic.
question
All of the offspring of a black hen and a white rooster are gray. The simplest explanation for this pattern of inheritance is: a) sex linkage. b) incomplete dominance. c) codominance. d) multiple alleles. e) incomplete heterozygosity.
answer
b) incomplete dominance.
question
Pea flowers may be purple (P) or white (p). Pea seeds may be round (R) or wrinkled(r). What proportion of the offspring from a cross between heterozygous purple-flowered, round-seeded individuals will have both white flowers and round seeds? a) 1/16 b) 3/4 c) 9/16 d) 1/2 e) 3/16 The SRY gene is considered pleiotropic bec
answer
e) 3/16
question
Heart disease is thought to be a polygenic disorder in humans. Knowing this, what would you expect to see if you screened 100 people for heart disease? a) Those with heart disease should carry two of three or four different alleles for a single heart disease gene. b) Those heterozygous for heart disease should be normal. c) Those with heart disease should exhibit three levels of disease: mild, intermediate, and intense. d) Those with heart disease should show a continuous range of symptoms, from very mild to very intense. e) They should either have no heart disease or suffer full, debilitating effects from the disease.
answer
d) Those with heart disease should show a continuous range of symptoms, from very mild to very intense.
question
Which of the following is NOT a continuously varying trait? a) height b) weight c) skin color d) sickle cell disease e) eye color
answer
d) sickle cell disease
question
How many human traits are controlled by single gene? a) over a 100,000 b) 2 c) 0 d) about a 100 e) over 9,000
answer
b) 2
