Q&A Hero

Q: ColchicineChoose the most appropriate answer for each.a. 3n; generally sterileb. a chromosome segment is permanently transferred to a nonhomologous chromosomec. (2n - 1); a zygote deprived of a chromosomed. a repeat of a particular DNA sequence in the same chromosome or in nonhomologous onese. (2n + 1); three chromosomes of the same kind are present in a set of chromosomesf. a piece of the chromosome is inadvertently left out during the repair processg. inhibits microtubule assembly; used in karyotypingh. a chromosome segment that has been cut out and rejoined at the same place, but backward

Q: It is now possible to analyze the genetics of the new generation by a. fetoscopy. b. amniocentesis. c. chorionic villi sampling. d. preimplantation diagnosis. e. all of these.

Q: A prenatal diagnosis procedure that has recently come into wide use can be performed earlier than amniocentesis, and it involves sampling the a. yolk sac material. b. allantois. c. chorion. d. yolk sac. e. umbilical cord.

Q: Amniocentesis is a. a surgical means of repairing deformities. b. a form of chemotherapy that modifies or inhibits gene expression or the function of gene products. c. used in prenatal diagnosis to detect chromosomal mutations and metabolic disorders in embryos. d. a form of gene replacement therapy. e. all of these.

Q: Amniocentesis involves sampling a. the fetus directly. b. the fetal cells floating in the amniotic fluid. c. sperm. d. blood cells. e. placental cells.

Q: Symptoms of phenylketonuria (PKU) may be minimized or suppressed by a diet low in a. serine. b. glycine. c. phenylalanine. d. proline. e. glutamic acid.

Q: PKU can be detected by a. prenatal karyotyping. b. urine analysis at birth. c. blood tests at birth. d. saliva tests. e. both urine analysis and blood tests at birth.

Q: Males that tend to be taller than average and show mild mental impairment may have a. XXY chromosomes. b. XYY chromosomes. c. Turner syndrome. d. Down syndrome. e. none of these.

Q: The sex chromosome composition of a person with Klinefelter syndrome is a. XXX. b. XO. c. XXY. d. XYY. e. none of these.

Q: The sex chromosome composition of a person with Turner syndrome is a. XXX. b. XO. c. XXY. d. XYY. e. none of these.

Q: Which of the following syndromes is characterized by a karyotype with 45 chromosomes? a. Turner b. Down c. androgen insensitivity d. Klinefelter e. cri-du-chat

Q: Down syndrome involves trisomy a. 3. b. 5. c. 15. d. 19. e. 21.

Q: The failure of chromosomes to separate during mitosis or meiosis is called a. genetic displacement. b. trisomy. c. crossing over. d. nondisjunction. e. disjunction.

Q: The above figure represents which of the following: a. a male with trisomy 21 b. a female with trisomy 21 c. a result caused by the use of colchicine d. a gorilla globin gene spread e. none of these

Q: Polyploidy a. can occur naturally. b. occurs when there are more than two sets of chromosomes. c. can be artificially induced by colchicine. d. is responsible for some of our major foods. e. is all of these.

Q: Which of the following is a transfer of genes between non-homologous chromosomes? a. crossing over b. aneuploidy c. trisomy d. translocation e. duplication

Q: A chromosome's gene sequence that was ABCDEFG before damage and ABFEDCG after is an example of a. inversion. b. deletion. c. duplication. d. translocation. e. aneuploidy.

Q: A chromosome's gene sequence that was ABCDEFG before modification and ABCDCDEFG afterward is an example of a. inversion. b. deletion. c. duplication. d. translocation. e. aneuploidy.

Q: The above figure represents which of the following chromosomal changes: a. inversion b. deletion c. duplication d. translocation e. aneuploidy

Q: The above figure represents which of the following chromosomal changes: a. inversion b. deletion c. duplication d. translocation e. aneuploidy

Q: The above figure represents which of the following chromosomal changes: a. inversion b. deletion c. duplication d. translocation e. aneuploidy

Q: Chromosomal aberrations can be produced by exposure to a. viruses. b. radiation. c. various chemicals. d. viruses and radiation only. e. viruses, radiation, and various chemicals.

Q: If a daughter expresses an X-linked recessive gene, she inherited the trait from a. her mother. b. her father. c. both parents. d. neither parent. e. her grandmother.

Q: A woman heterozygous for color blindness (an X-linked recessive allele) marries a man with normal color vision. What is the probability that their first child will be color blind? a. 25% b. 50% c. 75% d. 100% e. none of these

Q: Males tend to be affected in greater numbers by X-linked recessive genetic disorders than are females because a. females have two dominant genes for the disorder. b. males have only one X chromosome. c. males have a double dose of the gene. d. Y chromosomes are not as strong as X chromosomes. e. none of these.

Q: A human X-linked gene is a. found only in males. b. more frequently expressed in females. c. found on the Y chromosome. d. transmitted from father to son. e. found on the X chromosome.

Q: An X-linked carrier is a a. homozygous dominant female. b. heterozygous female. c. homozygous recessive female. d. homozygous male. e. heterozygous male.

Q: Concerning the sex chromosomes, which of the following is correct? a. The Y chromosome carries a greater number of genes for nonsexual traits than does the X. b. X and Y are different in size but carry nearly equal numbers of genes. c. The X chromosome carries more genes for nonsexual traits than does the Y. d. The X chromosome carries only gender-related genes. e. The X chromosome carries the SRY gene.

Q: The Punnett square illustration above shows that theoretically a. half of human sperm carry a Y chromosome. b. half of human zygotes are XY. c. all zygotes carry an X chromosome. d. gender depends upon which type of sperm fertilizes the egg. e. all of these are true.

Q: The probability of producing a normal child by two parents who are carriers for an autosomal recessive disorder is a. 0%. b. 25%. c. 50%. d. 75%. e. 100%.

Q: Achondroplasia a. is inherited as an autosomal recessive condition. b. affects about one in one million people. c. affects only homozygotes. d. is characterized by abnormally short arms and legs. e. is all of these.

Q: Which of the following is the genetic condition observed in the middle person from the above figure? a. Huntington disease b. acondroplasia c. triple recessive condition d. galactosemia e. all of these

Q: Which of the following is most logical from a health perspective? a. Light skin and little exposure to sun. b. Light skin and extensive exposure to sun. c. Dark skin and little exposure to sun. d. Dark skin and lots of exposure to sun. e. Light skin and little sun, or dark skin and lots of sun.

Q: How many genes are involved in determining skin color? a. 1. b. 2. c. 10. d. 20. e. >100.

Q: In sweet peas, genes C and P are necessary for colored flowers. In the absence of either (__ pp or cc __) or both (cc pp), the flowers are white. Give the probable genotype of a plant with colored flowers and a plant with white flowers that produced 38 plants with colored flowers and 42 plants with white flowers.

Q: In sweet peas, genes C and P are necessary for colored flowers. In the absence of either (__ pp or cc __) or both (cc pp), the flowers are white. What will be the color of the offspring of the crosses listed below and in what proportions?(a) Cc Pp x cc pp(b) Cc Pp x Cc Pp(c) Cc PP x Cc pp(d) Cc pp x cc Pp

Q: In summer squash, spherical-shaped fruit has been shown to be dominant to elongated fruit. On one occasion two different spherical varieties were crossed and produced all disk-shaped fruits. When these hybrid disk-shaped fruits were crossed, they produced 75 disk-shaped fruits, 48 spherical fruits, and 9 elongated fruits. Explain these results.

Q: In cultivated stocks, the cross of a variety of white flower plants produced all red flowers in the F1 generation, but the F2 generation produced 87 red, 31 cream, and 39 white. Explain these results by giving the genotypes possible for each phenotype.

Q: White fruit color in summer squash is influenced by a dominant allele W, whereas colored fruit must be ww. In the presence of ww, a dominant gene G results in yellow fruit, and if the individual had both recessive genes in the homozygous condition, it would be green. Give the F2 phenotypic ratios resulting from a cross of a pure-breeding white of genotype WW GG with a green.

Q: Congenital deafness in humans is due to the homozygous condition of either of the recessive genes d or e, or both of these genes. Both dominant D and E are necessary for normal hearing. Gene D/d affects the middle ear, while gene E/e affects the inner ear. It does not matter how good the normal inner ear (as indicated by E__) is; if there is something wrong in the middle ear, the individual is unable to hear. The same applies for the other gene. Give the phenotypic results of the following crosses:(a) Dd EE x Dd EE(b) Dd Ee x Dd Ee(c) dd EE x DD ee(d) Dd EE x Dd ee(e) Dd EE x DD Ee

Q: In poultry, the genes for rose comb (R) and pea comb (P) produce walnut whenever they occur together (R__ P__); single-combed individuals have the homozygous condition for both genes (rr pp).(a) Give the F1 and F2 phenotypic results of a cross of a pure-breeding rose comb (RR pp) with a pure-breeding pea comb (rr PP).(b) Give the phenotypic results of a cross of Rr Pp x rr Pp.(c) Give the phenotypic results of a cross of RR Pp x rr Pp.(d) Give the phenotypic results of a cross of Rr pp x rr Pp.(e) Give the phenotypic results of a cross of Rr Pp x rr pp.

Q: In the late 1920s, a mutation occurred in many silver fox farms around the world. The fox farms that sold expensive furs were proud of the quality of their furs, and each advertised that it had the best, purest breed of all the fox farms. The new mutations produced a "platinum" coat pattern that was commercially desirable, so the farms crossed them to get more. The results of their breeding experiments were as follows: (1) silver x silver >>> all silver offspring; (2) silver x platinum >>> equal numbers of silver and platinum; (3) platinum x platinum >>> two platinum for each silver offspring. Explain.

Q: A cross of two Kerry horses always produces Kerry. A cross of a Kerry with a Dexter produces 1/2 and 1/2. Crosses of two Dexters produce two Dexters for every Kerry. Explain.

Q: In rabbits, there are four alleles at the c locus. Arranged in dominance sequence they are: C (agouti), cch(chinchilla), ch(Himalayan), and c (albino) (a) Is it possible to cross two agouti rabbits and produce both chinchilla and Himalayan offspring? (b) Is it possible to cross two chinchillas and produce 1/2 chinchilla and 1/2 Himalayan?

Q: In horses, there are four alleles at the A locus. Arranged in dominance sequence they are:A (wild), ab (bay), ac (brown), ad (black)If you bred several bay mares whose sires were brown to a brown stallion whose sire was black, what are the genotypes of the parents; what type of offspring would be produced; and in what proportion?

Q: There are three alleles controlling the ABO blood types. IA and IB are codominant genes so that the combination IAIB produces the AB blood type. The third allele, IO, is recessive to the other two alleles. Indicate which of these parents could produce the given child: ParentsChildYes or No(a)A x ABB (b)A x OA (c)A x BO (d)A x ABO (e)A x ABB (f)B x BO (g)AB x ABA

Q: In a certain breed of chicken, an incomplete dominant gene controls color. The homozygous black, when crossed with the homozygous splashed-white, produces an intermediate gray color pattern referred to as blue. A second gene controls the shape of the comb. The dominant allele (R) produces rose, whereas the recessive allele (r) produces single. Give the F1 and F2 genotypic and phenotypic ratios of a cross between a pure-breeding black single and a pure-breeding splashed-white rose.

Q: In radishes, two incompletely dominant genes control color and shape. Red and white radishes are homozygous, whereas the hybrid is purple. Long and round are homozygous and, if crossed, will produce an oval hybrid. Give the F2 genotypic and phenotypic ratio produced by crossing pure-breed red long radishes with white round varieties.

Q: A breeder of cattle has a herd of white cows and a roan bull. Hair color in this breed is controlled by an incompletely dominant gene. The two homozygous forms are either red or white, and the heterozygous is roan.(a)What colors of calves are expected and in what proportions?(b)Outline a procedure to develop an all-red herd.

Q: If long or round are homozygous forms of an incompletely dominant gene, and oval is the phenotype of the heterozygote, give the F2 ratio of the cross between long and round (both genotype and phenotype).

Q: Assume that red plants crossed with white plants give rise to pink plants. Explain how to eliminate red plants if you start with two pinks.

Q: Crosses between a yellow rat with a yellow rat always produce yellow. Crosses between a white rat with a white rat always produce white. The alleles affect the same aspect of coat color. The crosses of a white with a yellow produce a cream. What happens if you cross two creams?

Q: In horses, black coat color is influenced by the dominant allele (B), and chestnut coat color by the recessive allele (b). Trotting gait is due to a dominant gene (T), pacing gait to the recessive allele (t). What color horse would you use to find out the genotype of a black trotter? Give the genotype and phenotype.

Q: In horses, black coat color is influenced by the dominant allele (B), and chestnut coat color is influenced by the recessive allele (b). Trotting gait is due to a dominant gene (T), pacing gait to the recessive allele (t). If a homozygous black trotter is crossed to a chestnut pacer, (a) what will be the appearance of the F1 and F2 generations? (b) which phenotype will be the most common? (c) which genotype will be the most common? (d) which of the potential offspring will be certain to breed true?

Q: In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall purple crossed with a tall purple produces 3/4 tall purple and 1/4 tall white. What is the genotype of the parents?

Q: In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall plant with purple flowers crossed with a tall plant with white flowers produces 3/8 tall purple, 1/8 tall white, 3/8 dwarf purple, and 1/8 dwarf white. What is the genotype of the parents?

Q: In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall plant with white flowers crossed with a dwarf plant with purple flowers produces 1/4 tall purple, 1/4 tall white, 1/4 dwarf purple, and 1/4 dwarf white. What is the genotype of the parents?

Q: In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall plant with purple flowers crossed with a dwarf plant with white flowers produces 1/4 tall purple, 1/4 tall white, 1/4 dwarf purple, and 1/4 dwarf white. What is the genotype of the parents?

Q: In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall plant with white flowers crossed with a dwarf plant with purple flowers produces all tall offspring with purple flowers. What is the genotype of the parents?

Q: In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall plant with purple flowers crossed with a dwarf plant with white flowers produces 1/2 tall with purple flowers and 1/2 tall with white flowers. What is the genotype of the parents?

Q: The allele for albinism (c) is recessive to the allele for normal pigmentation (C). A normally pigmented woman whose father is an albino marries an albino man whose parents are normal. They have three children, two normal and one albino. Give the genotypes for each person listed.

Q: In humans, normal skin pigmentation is influenced by a dominant gene (C), which allows pigmentation to develop. All individuals who are homozygous for the recessive allele (c) are unable to produce an enzyme needed for melanin formation and are therefore referred to as albino. Two normal parents produce an albino child. What are the chances that the next child will be an albino?

Q: If 2 spot (S) is dominant to 4 spot (s), give the genotypes for the parents in the following crosses:(a) 2 spot x 2 spot yields 2 spot and 4 spot(b) 2 spot x 4 spot yields only 2 spot(c) 2 spot x 4 spot yields 2 spot and 4 spot(d) 2 spot x 2 spot yields only 2 spot(e) 4 spot x 4 spot yields only 4 spot

Q: If black fur color is controlled by a dominant allele (B) and brown by its recessive allele (b), give the genotypes of the parents and offspring of a cross of a black male with a brown female that produces 1/2 black offspring and 1/2 brown offspring.

Q: In poultry, rose comb is controlled by a dominant allele, and its recessive allele controls single comb.(a)Give the genotype and phenotype produced from crossing a pure-breeding rose comb chicken with a pure-breeding single comb chicken.(b)Give the results of the backcross of the F1 hybrid with both pure-breeding parents.

Q: If wire hair (W) is dominant to smooth hair (w), and you find a wire-haired puppy, how would you determine its genotype by a genetic breeding experiment? Give both the genotype and phenotype involved with the cross with the unknown.

Q: Tall (D) is dominant to dwarf (d). Give the F2 genotypic and phenotypic ratios of a cross between a pure-breeding tall plant and a pure-breeding dwarf plant.

Q: Which is easier to establish in a pure-breeding population, a dominant or a recessive gene?

Q: In a certain plant, when individuals with blue flowers are crossed with individuals with blue flowers, only blue flowers are produced. Plants with red flowers crossed with plants with red flowers sometimes produce only red flowers, although other times they produce either red or blue flowers. When plants with red flowers are crossed with plants with blue flowers, sometimes only red flowers are produced; other times either red or blue flowers are produced. Which gene is dominant?

Q: Which eye color has the gene combination to deposit the most melanin in the iris? a. blue. b. gray. c. brown. d. green. e. all are the same.

Q: Unexpected phenotypes can be the result of a. altered metabolic pathways. b. a gene mutating in different ways in different individuals. c. an environmental effect during development. d. a post-developmental environmental effect. e. any of these.

Q: Height, weight, and eye color are examples of phenotypes that illustrate all BUT a. polygenic inheritance. b. continuous variation. c. pleiotropy. d. the action of several gene pairs each with additive effects. e. the cumulative effect of several gene products acting to determine phenotype.

Q: Which of the following is FALSE about camptodactyly? a. Not all individuals who inherit the allele do express the allele. b. The condition affects the shape and mobility of fingers. c. Some individuals have abnormal fingers on only one hand. d. It is caused by a multiple allele system. e. Individual differences in the expression of this gene may stem from a variety of causes.

Q: A graph of phenotypic variation similar to the illustration above strongly suggests a. incomplete dominance. b. codominance. c. epistasis. d. polygenic inheritance. e. environmental effects on phenotype.

Q: A bell-shaped curve of phenotypic variation is indicative of a. incomplete dominance. b. continuous variation. c. multiple alleles. d. epistasis. e. environmental variables on phenotypes.

Q: Which of the following has been correlated with the ability of rats to cope with stress as adults? a. A nurturing mother. b. The number of siblings they have. c. The temperature they are raised in. d. The altitude they are born at. e. All of these.

Q: In which of the following does environment not play a role? a. depression. b. bipolar disorder. c. schizophrenia. d. depression and schizophrenia. e. it plays a role in all these.

Q: Yarrow will not alter its phenotype in response to: a. temperature. b. soil conditions. c. being produced by sexual versus asexual reproduction. d. water conditions. e. changing altitude.

Q: Which of the following can impact methylation patterns? a. drugs. b. exercise. c. stress. d. diet. e. all of these.

Q: Which of the following does not stimulate the production of males in water fleas? a. spring. b. warm water. c. salty water. d. high competition for resources. e. crowding.