#1
What is the mode of inheritance for a trait that is determined by more than one gene?
Multifactorial
ExplanationMultifactorial inheritance involves the contribution of multiple genes to the expression of a trait.
#2
Which of the following statements about Mendel's laws is NOT true?
The law of dominance states that alleles for different traits segregate independently.
ExplanationThe law of dominance actually states that one allele may mask the expression of another in a heterozygous individual.
#3
If a pea plant with round seeds (RR) is crossed with a pea plant with wrinkled seeds (rr), what is the genotype of the F1 generation?
Rr
ExplanationThe F1 generation will be heterozygous (Rr) for seed shape.
#4
In a monohybrid cross, if one parent has the genotype Aa and the other parent has the genotype aa, what is the probability of the offspring having the genotype aa?
50%
ExplanationThere is a 50% chance of the offspring inheriting the aa genotype.
#5
What is the phenotype of an organism with the genotype AaBb?
Heterozygous
ExplanationThe organism with the genotype AaBb is heterozygous for both genes, exhibiting a combination of dominant and recessive traits.
#6
If a pea plant that is heterozygous for flower color is crossed with a homozygous recessive pea plant, what is the expected phenotypic ratio of their offspring?
1:1
ExplanationIn this monohybrid cross, the expected phenotypic ratio is 1:1, with equal chances for the dominant and recessive traits.
#7
In a dihybrid cross, what is the expected phenotypic ratio if the two genes are on different chromosomes and show independent assortment?
1:1:1:1
ExplanationIndependent assortment on different chromosomes results in a 1:1:1:1 phenotypic ratio for the possible combinations of traits.
#8
In a cross between two heterozygous individuals for a single gene, what is the expected phenotypic ratio?
3:1
ExplanationThe expected phenotypic ratio in a monohybrid cross between heterozygous individuals is 3:1, with three dominant to one recessive phenotype.
#9
In humans, what is the sex of a person with genotype XXY?
Male
ExplanationA person with XXY genotype has Klinefelter syndrome, which results in male development despite having an extra X chromosome.
#10
In a monohybrid cross between two heterozygous individuals, what is the expected phenotypic ratio?
3:1
ExplanationThe expected phenotypic ratio in a monohybrid cross between heterozygous individuals is 3:1.
#11
In humans, blood type is determined by a gene with three alleles: A, B, and O. If a person with blood type A (genotype AO) has a child with a person with blood type B (genotype BO), what is the probability that their child will have blood type O?
25%
ExplanationThe child has a 25% chance of inheriting the O allele from both parents, resulting in blood type O.
#12
A man with blood type AB (genotype IAIB) has a child with a woman with blood type O (genotype ii). What is the probability that their child will have blood type A?
25%
ExplanationThe child has a 25% chance of inheriting the A allele from the father and the O allele from the mother, resulting in blood type A.
#13
In a dihybrid cross, if two genes are on the same chromosome and show complete linkage, what is the expected phenotypic ratio?
3:1
ExplanationComplete linkage on the same chromosome leads to a 3:1 phenotypic ratio due to the lack of independent assortment.
#14
A woman with blood type O (genotype ii) has a child with a man with blood type AB (genotype IAIB). What is the probability that their child will have blood type B?
50%
ExplanationThe child has a 50% chance of inheriting the B allele from the father, resulting in blood type B.
#15
In a dihybrid cross, if two genes are on the same chromosome but show incomplete linkage, what is the expected phenotypic ratio?
9:3:3:1
ExplanationIncomplete linkage on the same chromosome leads to a 9:3:3:1 phenotypic ratio.