AP Biology Genetics | COMPLETE QUESTIONS AND ANSWERS | 2025
LATEST UPDATED | ALREADY GRADED A+
Which of the following is true about a plant with the genotype AABbcc? - (answers)It is
homozygous at two loci.
Details: An organism having a pair of identical alleles at a given locus is said to be homozygous
for that locus. Here, the plant is homozygous at loci A and C.
What is an allele? - (answers)an alternative version of a gene
Details: A diploid organism carries two alleles for each autosomal gene. The two alleles are
found at comparable locations (loci) on homologous chromosomes. The alleles may be identical
or slightly different, but they affect the same genetic character.
You cross a true-breeding red-flowered snapdragon with a true-breeding white-flowered one. All
of the F1 are pink. What does this say about the parental traits? - (answers)Red shows
incomplete dominance over white, and the F1 is therefore pink.
Folk singer Woody Guthrie died of Huntington's disease, an autosomal dominant disorder.
Which statement below must be true? - (answers)It is very likely that at least one of Woody
Guthrie's parents also have had the allele for Huntington's disease.
Details: Unless the disease is caused by a new mutation, which is quite rare, individuals with a
dominant condition must have inherited the dominant allele from one of their parents. As it
happens, Guthrie's mother also died of Huntington's disease.
Various procedures can be used to detect genetic disorders before birth. Among the tests
discussed in this chapter, which is the least invasive (list first), and which two allow the
chromosomes of the fetus to be examined? - (answers)ultrasound imaging ... chorionic villus
sampling ... amniocentesis
Details: Both CVS and amniocentesis involve the preparation of a karyotype using fetal cells.
Which of the following do you expect if an individual is heterozygous for the sickle-cell trait? -
(answers)He or she will show some symptoms of the disease.
Details: A heterozygote will produce both normal and abnormal hemoglobin.
, How do cells acquire homologous chromosome pairs that carry the alleles that are independently
assorted? - (answers)Fusion of gametes.
Details: During fertilization, gametes bring together homologous chromosomes to generate a
diploid individual.
Which of the following statements most accurately describes the process of independent
assortment? - (answers)Alleles of different genes segregate from one another in a random
manner.
Details: The random distribution of alleles is required for independent assortment.
True or false? The principle of independent assortment is best illustrated by events that take
place during metaphase II, during which sister chromatids segregate independently of each other.
- (answers)False
Details: The principle of independent assortment is best illustrated by events that take place
during metaphase I, during which nonhomologous chromosomes segregate independently of
each other.
How many genetically unique types of gametes could be produced by an individual with the
genotype RrYY? - (answers)Two
What is nondisjunction? - (answers)An error in cell division that causes homologous
chromosomes or sister chromatids to move to the same side of the dividing cell.
Details: Nondisjunction refers to the failure of pairs of chromosomes or sister chormatids to
separate during meiosis or mitosis.
When can nondisjunction occur? - (answers)Nondisjunction errors can occur in meiosis I, when
homologous chromosomes fail to separate, or in either mitosis or meiosis II, when sister
chromatids fail to separate.
Which syndrome is characterized by the XO chromosome abnormality? - (answers)Turner
syndrome
Details: Turner syndrome is characterized by a chromosome pattern of XO, or one X
chromosome and no Y chromosome.
LATEST UPDATED | ALREADY GRADED A+
Which of the following is true about a plant with the genotype AABbcc? - (answers)It is
homozygous at two loci.
Details: An organism having a pair of identical alleles at a given locus is said to be homozygous
for that locus. Here, the plant is homozygous at loci A and C.
What is an allele? - (answers)an alternative version of a gene
Details: A diploid organism carries two alleles for each autosomal gene. The two alleles are
found at comparable locations (loci) on homologous chromosomes. The alleles may be identical
or slightly different, but they affect the same genetic character.
You cross a true-breeding red-flowered snapdragon with a true-breeding white-flowered one. All
of the F1 are pink. What does this say about the parental traits? - (answers)Red shows
incomplete dominance over white, and the F1 is therefore pink.
Folk singer Woody Guthrie died of Huntington's disease, an autosomal dominant disorder.
Which statement below must be true? - (answers)It is very likely that at least one of Woody
Guthrie's parents also have had the allele for Huntington's disease.
Details: Unless the disease is caused by a new mutation, which is quite rare, individuals with a
dominant condition must have inherited the dominant allele from one of their parents. As it
happens, Guthrie's mother also died of Huntington's disease.
Various procedures can be used to detect genetic disorders before birth. Among the tests
discussed in this chapter, which is the least invasive (list first), and which two allow the
chromosomes of the fetus to be examined? - (answers)ultrasound imaging ... chorionic villus
sampling ... amniocentesis
Details: Both CVS and amniocentesis involve the preparation of a karyotype using fetal cells.
Which of the following do you expect if an individual is heterozygous for the sickle-cell trait? -
(answers)He or she will show some symptoms of the disease.
Details: A heterozygote will produce both normal and abnormal hemoglobin.
, How do cells acquire homologous chromosome pairs that carry the alleles that are independently
assorted? - (answers)Fusion of gametes.
Details: During fertilization, gametes bring together homologous chromosomes to generate a
diploid individual.
Which of the following statements most accurately describes the process of independent
assortment? - (answers)Alleles of different genes segregate from one another in a random
manner.
Details: The random distribution of alleles is required for independent assortment.
True or false? The principle of independent assortment is best illustrated by events that take
place during metaphase II, during which sister chromatids segregate independently of each other.
- (answers)False
Details: The principle of independent assortment is best illustrated by events that take place
during metaphase I, during which nonhomologous chromosomes segregate independently of
each other.
How many genetically unique types of gametes could be produced by an individual with the
genotype RrYY? - (answers)Two
What is nondisjunction? - (answers)An error in cell division that causes homologous
chromosomes or sister chromatids to move to the same side of the dividing cell.
Details: Nondisjunction refers to the failure of pairs of chromosomes or sister chormatids to
separate during meiosis or mitosis.
When can nondisjunction occur? - (answers)Nondisjunction errors can occur in meiosis I, when
homologous chromosomes fail to separate, or in either mitosis or meiosis II, when sister
chromatids fail to separate.
Which syndrome is characterized by the XO chromosome abnormality? - (answers)Turner
syndrome
Details: Turner syndrome is characterized by a chromosome pattern of XO, or one X
chromosome and no Y chromosome.
