NAME ______2009
AP BIOLOGY GENETICS TEST
- If red hair, blue eyes, and freckles were consistently inherited together, the best explanation would be that
(A)these traits are recessive characteristics
(B)both parents have red hair, blue eyes, and freckles
(C)the genes for these traits are linked on the same chromosome
(D)gene duplications have occurred
(E)these traits are dominant to others1986 AP Exam
- Human identical twins develop when
(A)two identical eggs are fertilized by two different sperm
(B)a single egg is fertilized by two sperm
(C)two different eggs are fertilized by two different sperm
(D)the embryo splits and each portion continues to develop
(E)a diploid egg is fertilized by a diploid ovum 1986 AP Exam
- A human genetic defect that affects the ability to metabolize a particular amino acid is
(A)phenylketonuria
(B)hemophilia
(C)sickle cell anemia
(D)Down's syndrome
(E)Turner's syndrome1986 AP Exam
4. A represents the dominant allele and a represents the recessive allele of a pair. If, in 1,000 offspring, 500 are aa and 500 are of some other genotype, which of the following are most probably the genotypes of the two parents?
(A)Aa and Aa
(B)Aa and aa
(C)AA and Aa
(D)AA and aa
(E)aa and aa1990 AP Exam
5. The primary value of a specific type of backcross known as a testcross is to
(A)determine whether a trait is really hereditary
(B)permit detection of recessive genes
(C)reveal cases of blending inheritance
(D)reveal remote ancestors
(E)reveal sex-linked inheritance1990 AP Exam
6. A diploid cell has three pairs of homologous chromosomes designated J1/J2, K1/K2and L1/L2. Which of the
following represents a probable chromosome complement in a haploid cell formed by meiosis?
(A)J1 and K1
(B)J1 and J2
(C)J2, K1, and L2
(D)J1, J1, K2, and K2
(E)J1, J2, K1, K2, L1, and L21990 AP Exam
7. The replacement of glutamic acid by valine at a specific position in the beta chains of hemoglobin leads to sickle cell anemia. This change represents which of the following mutational events?
(A)DNA base-pair substitution
(B)DNA base-pair deletion
(C)DNA base-pair addition
(D)Chromosomal deletion
(E)Frame-shift mutation1990 AP Exam
8. In corn, the trait for tall plants (T) is dominant to the trait for dwarf plants (t) and the trait for colored kernels (C) is dominant to the trait for white kernels (c). In a particular cross of corn plants, the probability of an offspring being tall is 1/2 and the probability of a kernel being colored is 3/4. Which of the following most probably represents the parental genotypes?
(A)TtCcxttCc
(B)TtCcxTtCc
(C)TtCc xttcc
(D)TTCcxttCc
(E)TTCcxTtCC1990 AP Exam
9. A form of vitamin D-resistant rickets, known as hypophosphatemia, is inherited as an X-linked dominant trait. If a male with hypophosphatemia marries a normal female, which of the following predictions concerning their potential progeny would be true?
(A)All of their sons would inherit the disease.
(B)All of their daughters would inherit the disease.
(C)About 50% of their sons would inherit the disease.
(D)About 50% of their daughters would inherit the disease.
(E)None of their daughters would inherit the disease.1990 AP Exam
10. The relative location of four genes on a chromosome can be mapped from the following data on crossover frequencies. .
GenesFrequency of Crossover
B and D5%
C and A15%
A and B30%
C and B45%
C and D50%
Which of the following represents the relative positions of these four genes on the chromosome?
(A)ABCD
(B)ADCB
(C)CABD
(D)CBAD
(E)DBCA1990 AP EXAM
11. In fruit flies, vermilion eyes are a sex-linked recessive characteristic. If a vermilion-eyed female is crossed with a wild-type male, what proportion of the male offspring should have vermilion eyes?
(A)0%
(B)25%
(C)50%
(D)75%
(E)100%1990 AP Exam
12. Which of the following is a correct statement about mutations?
(A)They are a source of variation for evolution.
(B)They drive evolution by creating mutation pressures.
(C)They are irreversible.
(D)They occur in germ cells but not in somatic cells.
(E)They are most often beneficial to the organisms in which they occur.1994 AP Exam
13. In garden peas, a single gene controls stem length. The recessive allele (t) produces short stems when homozygous. The dominant allele (T) produces long stems. A short-stemmed plant is crossed with a heterozygous long-stemmed plant. Which of the following represents the expected phenotypes of the offspring and the ratio in which they will occur?
(A)3 long-stemmed plants : 1 short-stemmed plant
(B)1 long-stemmed plant : 1 short-stemmed plant
(C)1 long-stemmed plant : 3 short-stemmed plants
(D)Long-stemmed plants only
(E)Short-stemmed plants only1994 AP Exam
14. Assume that genes A and B are not linked. If the probability of allele A in a gamete is 1/2 and the probability of allele B in a gamete is 1/2, then the probability that both A and B are in the same gamete is
(A)1/2 x 1/2
(B)1/2 + l/2
(C)1/2 1/2
(D)½ 1999 AP Exam
15. A couple has 5 children, all sons. If the woman gives birth to a sixth child, what is the probability that the sixth child will be a son?
(A)5/6
(B)1/2
(C)1/5
(D)1/6
(E)1/641999 AP Exam
16. Which of the following best describes the parents in a testcross?
(A)One individual has the dominant phenotype and the other has the recessive phenotype.
(B)Both individuals are heterozygous.
(C)Both individuals have the dominant phenotype.
(D)Both individuals have the recessive phenotype.
(E)Both individuals have an unknown phenotype.1999 AP Exam
17. In sheep, eye color is controlled by a single gene with two alleles. When a homozygous brown-eyed sheep is crossed with a homozygous green-eyed sheep, blue-eyed offspring are produced. If the blue-eyed sheep are mated with each other, what percent of their offspring will most likely have brown eyes?
(A)0%
(B)25%
(C)50%
(D)75%
(E)100%1999 AP Exam
18. In peas the trait for tall plants is dominant (T) and the trait for short plants is recessive (t). The trait for yellow seed color is dominant (Y) and the trait for green seed color is recessive (y). A cross between two plants results in 296 tall yellow plants and 104 tall green plants. Which of the following are most likely to be the genotypes of the parents?
(A)TTYYxTTYY
(B)TTyyxTTYy
(C)TtYyxTtYy
(D)TtYyxTTYy
(E)TtYYxTtyy 1990 AP Exam
19. In humans, red-green color blindness is a sexlinked recessive trait. If a man and a woman produce a color-blind son, which of the following must be true?
(A)The father is color-blind.
(B)Both parents carry the allele for color blindness.
(C)Neither parent carries the allele for color blindness.
(D)The father carries the allele for color blindness.
(E)The mother carries the allele for color blindness.1999 AP Exam
20. A spermatocyte produces the following four sperm cells.
These cells are the result of nondisjunction during
which of the following phases?
(A)Interphase (G1 or G2)
(B)Interphase (S)
(C)Mitosis
(D)Meiosis I
(E)Meiosis II 2002 AP Exam
21. Coat color in mice is determined by genes at two loci. When black mice from a particular population mate, they produce offspring in the following ratios: 9 black: 3 brown: 4 white. These results suggest that white coat color is expressed as a result of
(A)dominance
(B)incomplete dominance
(C)codominance
(D)a sex-linked trait
(E)epistasis2002 AP Exam
22. Which of the following can be diagnosed by examining a karyotype of an individual’s white blood cells?
(A)Sickle cell anemia
(B)Alzheimer disease
(C)Down syndrome
(D)Cystic fibrosis
(E)Duchenne muscular dystrophy2002 AP Exam
23. In the pedigree below, squares represent males and circles represent females. Individuals who express a particular trait are represented by shaded figures. Which of the following patterns of inheritance best explains the transmission of the trait?
(A)Sexlinked dominant
(B)Sexlinked recessive
(C)Autosomal recessive
(D)Autosomal dominant
(E)Incompletely dominant 1999 AP Exam
24. A severe dose of x-ray radiation results in conditions such as anemia, atypical sperm production, and a depressed immune system because the cells affected
(A)are fully differentiated
(B)are the largest cells in the body
(C)are the most actively dividing cells in the body
(D)contain more protein than any other cells in the body
(E)contain pigments that reflect radiation1990 AP Exam
Questions 25-28 refer to the probabilities below.2002 AP Exam
(A)0
(B)1/16
(C)1/4
(D)1/2
(E)3/4
25. Probability that the genotype Aa will be produced by the parents AaxAa
26. Probability that the genotype ccdd will be produced by the parents CcDdxCcDd
27. Probability that the genotype Rr will be produced by the parents Rrxrr
28. Probability that the genotype TtSs will be produced by the parents TtSsxTtSS
Questions 29-30refer to the probabilities below
(A)1/l6
(B)1/4
(C)1/2
(D)9/161986 AP Exam
(E)1
Galactosemia is a simple, inherited, autosomal recessive trait. A normal couple has a child affected with galactosemia. For each of the following situations, select from the list above the appropriate probability.
29. The probability that the next two children will both be affected with galactosemia
30. The probability that the father of the galactosemic child is heterozygous for the recessive allele
Questions 31-32 refer to the birth of a child with blood type A to a mother with blood type B
31. The father must have which of the following blood types?
(A)AB only
(B)Either AB or B
(C)Either AB or O
(D)Either AB or A
(E)AB or A or O1999 AP Exam
32. If the father has blood type AB, which of the following statements is correct about the mother?
(A)She contributes an IB allele, which is recessive to the father's IAallele.
(B)She contributes an i allele which is recessive to the father's IA allele.
(C)She contributes an IB allele which is codominant to the father's IA allele.
(D)She contributes an allele that is codominant to the father's IB allele.
(E)She is homozygous for the IB allele.1999 AP Exam
Questions 33-35refer to the pedigree below in which females are indicated by circles and males are indicated by squares.
33. The genotype of the P1 male must be
(A)OO
(B)AO
(C)BO
(D)AB
(E)AA
34. The only other possible genotype for children of the F1AB male would be
(A)OO
(B)BO
(C)AO
(D)AA
(E)AB
35. The most likely genotype of the mate of the F1AO female is
(A)AB
(B)BB
(C)OO
(D)AA
(E)BO1986 AP Exam
Questions 36-39refer to the following pedigree that illustrates the inheritance of sickle cell anemia. Shading indicates the presence of sickle cell anemia.
36. The phenotype of individual C is best explained by the fact that this individual received an allele for sickle cell anemia from
(A)an autosomal chromosome of each parent
(B)the Y chromosome contributed by the father
(C)the X chromosome contributed by the mother
(D)the X chromosome contributed by the father
(E)the Y chromosome contributed by the mother
37. What is the probability that the next child of parents A and B would have had sickle cell anemia?
(A)0%
(B)25%
(C)60%
(D)75%
(E)100%
38. The most reasonable explanation for the fact that the offspring of C and D do not have sickle cell anemia is that each received a
(A)sickle allele from the mother
(B)normal allele from the father
(C)sickle allele from each parent
(D)normal allele from each parent
(E)pair of normal alleles from the father
39. Which of the following statements is correct about the four offspring of C and D?
(A)Only the females are carriers of the sickle cell trait.
(B)Only the males are carriers of the sickle cell trait.
(C)Only the females are heterozygous for the sickle cell trait.
(D)All are homozygous for the sickle cell trait.
(E)All are carriers of the sickle cell trait.
1990 AP Exam
Questions 40-42 refer to the following information.
Achondroplastic dwarfism is a dominant genetic trait that causes severe malformation of the skeleton. Homozygotes for this condition are spontaneously aborted (hence, the homozygous condition is lethal) but heterozygotes will develop to be dwarfed.
Matthew has a family history of the condition, although he does not express the trait. Jane is an achondroplastic dwarf. Matthew and Jane are planning a family of several children and want to know the chances of producing a child with achondroplastic dwarfism.
40. The genotypes of Matthew and Jane are best represented as
MatthewJane
(A)AAAa
(B)Aaaa
(C)aaaa
(D)aaAa
(E)AaAa
41.The probability that Matthew and Jane's first child will be an achondroplastic dwarf is
(A)0%
(B)25%
(C)50%
(D)75%
(E)100%
42. If three children are born to Matthew and Jane, what are the chances that the first two children will not express the trait but that the third child will be an achondroplastic dwarf?
(A)5/8
(B)4/8
(C)3/8
(D)1/8
(E)1/161994 AP Exam
Questions 43-45
A male fruit fly (Drosophila melanogaster) with red eyes and long wings was mated with a female with purple eyes and vestigial wings. All of the offspring in the F1, generation had red eyes and long wings.
These F1 flies were test crossed with purple-eyed, vestigial-winged flies. Their offspring, the F2 generation, appeared as indicated below.
F2 Generation:
125red eyes, long wings
124purple eyes, vestigial wings
18purple eyes, long wings
16red eyes, vestigial wings
283Total
43. If in the F1 and F2 generations the same characteristics appeared in both males and females, it would be safe to assume that these traits for eye color and wing length
(A)are sex-linked
(B)vary in dominance according to sex
(C)are sex-influenced characteristics
(D)are autosomal characteristics
(E) follow the Mendelian rule of independent assortment
44. In the F2 generation, the results are best explained by the fact that
(A)the test cross with the F1 flies resulted in sterile offspring
(B)these genes for eye color and wing shape do not pass through the F1 generation
(C)these genes for eye color and wing shape are found on the same chromosome
(D)crossing-over decreases variability
(E)the genes are sex-linked
45. If a single locus controls wing shape, then the alleles for this gene act as
(A)dominant-recessive alleles
(B)incomplete-dominance alleles
(C)codominant alleles
(D)multiple alleles
(E)variable alleles1994 AP Exam
Questions 46-48
A culture of white-eyed fruit flies (Drosophila melanogaster) was maintained for many generations. Females from the stock white-eyed culture were crossed with red-eyed (wild-type) males. The F1 females were crossed with the white-eyed males from the original culture. The resulting phenotypes of the progeny are summarized below.
Parental Generation CrossF1 Generation (at least 500 flies)
White-eyed females x red-eyed males100% of females are red-eyed
100% of males are white-eyed
F1 Generation CrossF2 Generation (at least 500 flies)
F1 red-eyed females x white-eyed males50% of females are red-eyed and 50% are white-eyed
50% of males are red-eyed and 50% are white-eyed
46. The best explanation for the red-eyed F1 females is
(A)mutation
(B)culture contamination
(C)dominance
(D)multiple loci
(E)sex-influenced traits
47. There are white-eyed females in the F2 generation because
(A)white is a dominant allele
(B)the white allele is autosomal
(C)a mutation has occurred
(D)these F2 females have two white alleles
(E)the white allele is located on the Y chromosome
48. Which of the following best describes the mode of inheritance of eye color in the white culture?
(A)Autosomal
(B)Dominant
(C)Located on the Y chromosome
(D)Sex-linked
(E)Lethal2002 AP Exam