Heredity Exam 1

Chapters 13-15

80 points

Name ______

Block ______

Multiple Choice (1 point each)

  1. If the liver cells of an animal have 24 chromosomes, the sperm cells would have how many chromosomes?
  1. 12
  2. 24
  3. 48
  4. twice the diploid number
  5. half the haploid number
  1. How does the sexual life cycle increase the genetic variation in a species?
  1. by producing gametes with different combinations of parental chromosomes
  2. by allowing the combination of chromosomes from two different individuals
  3. by allowing recombination of alleles on a chromosome
  4. Both A and B are correct.
  5. A, B, and C are correct.
  1. Which of the following events occurs during prophase I of meiosis?
  1. reduction in chromosome number
  2. segregation of alleles of unlinked genes
  3. synapsis and crossing over
  4. duplication of chromatids
  5. segregation of alleles of linked genes
  1. Which of the following is true of a species that has a chromosome number of 2n = 16?
  1. The species is diploid with 32 chromosomes.
  2. The species has 16 different types of chromosomes.
  3. There are 16 homologous pairs.
  4. During the S phase of the cell cycle there will be 32 separate chromosomes.
  5. A gamete from this species has 8 chromosomes.
  1. What is a karyotype?
  1. the phenotype of an individual
  2. the genotype of an individual
  3. a unique combination of chromosomes found in a gamete
  4. the kind of nucleus a cell has
  5. a method of organizing the homologous chromosomes of a cell in relation to their number, size, and type.
  1. Which of the following is the term for a human cell that contains 22 pairs of autosomes and two X chromosomes?
  1. an unfertilized egg cell
  2. a sperm cell
  3. a male somatic cell
  4. a female somatic cell
  5. Both A and D are correct.
  1. Crossing over occurs during which phase of meiosis?
  1. prophase I
  2. anaphase I
  3. telophase I
  4. prophase II
  5. metaphase II

Use the following key to answer questions 8 – 11. Each answer may be used once, more than once, or not at all.

  1. The statement is true for mitosis only
  2. The statement is true for meiosis I only
  3. The statement is true for meiosis II only
  4. The statement is true for mitosis and meiosis I
  5. The statement is true for mitosis and meiosisII
  1. Homologous chromosomes synapse and crossing over occurs.

Answer _____

  1. This occurs when a cell divides to form two cells that are genetically identical.

Answer _____

  1. The events during this process cause the majority of genetic recombinations.

Answer _____

  1. The process(es) is (are) preceded by a copying (replication) of the DNA.

Answer _____

------

  1. What is a genetic cross called between an individual of unknown genotype and homozygous recessive genotype.
  1. a self-cross
  2. a testcross
  3. a hybrid cross
  4. an F1 cross
  5. a dihybrid cross
  1. In crossing a homozygous recessive with a heterozygote, what is the chance of getting an offspring with the homozygous recessive phenotype?
  1. 0%
  2. 25%
  3. 50%
  4. 75%
  5. 99%
  1. Black fur in mice (B) is dominant to brown fur (b). Short tails (T) is dominant to long tails (t). What proportion of the progeny of the cross BbTt x BBtt will have black fur and long tails?
  1. 1/16
  2. 3/16
  3. 6/16
  4. 8/16
  5. 9/16

Use the information given here to answer the following questions 15-17. Feather color in budgies is determined by two different genes that affect the pigmentation of the outer feather and its core Y_B_ is green; yyB _ is blue; Y_bb is yellow; and yybb is white.

  1. A green budgie is crossed with a blue budgie. Which of the following results is NOT possible?
  1. all green offspring
  2. all blue offspring
  3. all white offspring
  4. all yellow offspring
  5. All of the above are possible, but with different probabilities.
  1. Two blue budgies were crossed. Over the years, they produced 22 offspring, 5 of which were white. What are the most likely genotypes for the two blue budgies?
  1. yyBB and yyBB
  2. yyBB and yyBb
  3. yyBb and yyBb
  4. yyBB and yybb
  5. yyBb and yybb
  1. The inheritance of color in budgies is an example of what genetic phenomenon?
  1. pleitropy
  2. penetrance
  3. polygenic inheritance
  4. dominance
  5. epistasis

------

  1. A couple has three children, all of whom have brown eyes and blond hair. Both parents are homozygous for brown eyes (BB), but one is a blond (rr) and the other is a redhead (Rr). What is the probability that their next child will be a brown-eyed redhead?
  1. 1/16
  2. 1/8
  3. ¼
  4. ½
  5. 1

Use the following information to answer questions 19-21. A woman and her husband both show the normal phenotype for pigmentation, but both had one parent who was an albino. Albinism is an autosomal recessive trait.

  1. What is the probability that their first child will be an albino?
  1. 0%
  2. 25%
  3. 50%
  4. 75%
  5. 100%
  1. If their first two children have normal pigmentation, what is the chance that their third child will be an albino?
  1. 0%
  2. 25%
  3. 50%
  4. 75%
  5. 100%
  1. What is the chance that their fourth child will have a homozygous genotype?
  1. 0%
  2. 25%
  3. 50%
  4. 75%
  5. 100%

------

  1. Given the parents AABBCc x AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?
  1. ¼
  2. 1/8
  3. ¾
  4. 3/8
  5. 1
  1. Which of the following is an example of polygenic inheritance?
  1. pink flowers in snapdragons
  2. the ABO blood groups in humans
  3. sex-linkage in humans
  4. white and purple color in sweet peas
  5. skin pigmentation in humans
  1. A 9:3:3:1 phenotypic ratio is characteristic of the
  1. F1 generation of a monohybrid cross.
  2. F2 generation of a monohybrid cross.
  3. F1 generation of a dihybrid cross.
  4. F2 generation of a trihybrid cross.
  1. A 1:2:1 phenotypic ratio in the F2 generation of a monohybrid cross is a sign of
  1. complete dominance.
  2. multiple alleles.
  3. incomplete dominance.
  4. polygenic inheritance.
  5. pleiotropy.
  1. A 1:1:1:1 ratio of offspring from a dihybrid testcross indicates that
  1. the genes are linked
  2. the dominant organism was homozygous
  3. crossing over has occurred
  4. the genes are 25 map units apart.
  5. The genes are not linked.
  1. A color-blind son inherited his trait from his
  1. mother
  2. father
  3. mother, only if she is color-blind
  4. father, only if he is color-blind
  5. mother, only if she is not color-blind
  1. Which of the following chromosomal alterations does not alter genic balance but may alter phenotype because of difference in gene expression?
  1. deletion
  2. inversion
  3. duplication
  4. nondisjunction
  5. genomic imprinting
  1. In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW, a lethal recessive allele that causes death of the embryo occurs on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male heterozygous for the lethal allele and a normal female?
  1. 2:1 male to female
  2. 1:2 male to female
  3. 1:1 male to female
  4. 4:3 male to female
  5. 3:1 male to female
  1. The finding that defective genes behave differently in offspring depending on whether they belong to the maternal or paternal chromosomes is implicated in which of the following?
  1. Prader-Willi syndrome
  2. Fragile X syndrome
  3. Angelman syndrome
  4. Only A and C are correct
  5. A,B, and C are all correct
  1. A mammalian zygote with which of the following chromosomal abnormalities will never develop into a viable embryo?
  1. YO
  2. XO
  3. XXX
  4. XXY
  5. XXXY
  1. What does independent assortment refer to?
  1. The separation of alleles in anaphase I
  2. The random arrangement of chromosomal tetrads at metaphase I
  3. The separation of chromotids at anaphase 1
  4. The random arrangement of gene loci on a chromosome
  5. The fact that any pair of chromatids in a tetrad can cross over.
  1. The particular position of a gene on a chromosome is known as a(n)
  1. Allele
  2. Tetrad
  3. chiasma
  4. locus
  5. map distance
  1. The frequency of crossing over between any two linked genes is
  1. higher if they are recessive
  2. difficult to predict
  3. determined by their relative distance
  4. the same as if they were not linked,
  5. proportional to the distance between them.
  1. A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color-blind marries a color-blind male. What is the probability that this couple’s son will be color-blind?
  1. 0%
  2. 25%
  3. 50%
  4. 75%
  5. 100%

Use the following pedigree to answer questions 36-39

Europe’s Royal Families


  1. The above pedigree could demonstrate which of the following genetic disorders?
  1. Tay Sachs
  2. Huntington’s Disease
  3. Color-blindness
  4. Hemophilia
  5. Both C and D
  1. What is the method of inheritance of the genetic disorder?
  1. recessive
  2. dominant
  3. sex-linked recessive
  4. sex-linked dominant
  5. none of the above
  1. What is the genotype of the male that died at age 23 in column V?
  1. XiX
  2. XY
  3. XiY
  4. XX
  5. XYY
  1. What is the genotype of that individual's mother?
  1. XiX
  2. XY
  3. XiY
  4. XX
  5. XYY

------

  1. The statement, “The X and Y chromosomes determine sex” is inaccurate and misleading. Which of the following statements is most accurate?
  1. Genes on the X and Y chromosomes determine sex.
  2. Genes on the X chromosome that are not present on the Y determine sex.
  3. Genes on the Y chromosome that are not present on the X determine sex.
  4. A variety of genes on other chromosomes play various roles in determining sex, and the activity of those genes is controlled by a small number of genes on the X and/or Y chromosome.
  5. A variety of genes on the X and/or the Y chromosomes play various roles in determining sex, and the activity of those genes is controlled by a small number of genes on other chromosomes.

______

Essay questions (20 points each.)

Answer two of the three questions.

1. C. 13- Compare and contrast the division process of a somatic cell and a gamete cell. Be sure to explain the nearly unlimited variation that gametic cell division allows.

2- C. 14- Explain Mendel’s quantitative approach, that led to his discoveries, in the principles of genetics. Describe the law of segregation, independent assortment and Mendelian rules for inheritance.

3-C. 15- Morgan was able to relate Mendelian inheritance patterns to chromosomes. How did he achieve this? Additionally, explain the following, linked genes, sex-linked inheritance and aneuploidy.