21) In Mendel’s pea plants, yellow seeds dominant to green : 1380791.
21) In Mendel’s pea plants, yellow seeds are dominant to green seeds. If a true-breeding green-seed-producing plant is crossed to a heterozygous yellow-seed-producing plant, what percentage of offspring produces green seeds?
A) 10 percent
B) 50 percent
C) 33 percent
D) 25 percent
E) 100 percent
22) In humans, “unattached” earlobes are dominant over “attached” earlobes. Widow’s-peak hairline is dominant over non-widow’s-peak hairline. Use E and e for the earlobe phenotype alleles and W and w for the hairline phenotype alleles. A woman and a man, both with genotype EeWw, have a child. What is the probability that the child will have attached earlobes and a widow’s peak?
A) 1/16
B) 9/16
C) 1/3
D) 3/4
E) 3/16
23) Which of the following represents a dihybrid cross?
A) YYyy x PPpp
B) YY x pp
C) YyPp x YyPp
D) YP x Yp
E) Yp x YY
24) In humans, “unattached” earlobes are dominant over “attached” earlobes. Widow’s-peak hairline is dominant over non-widow’s-peak hairline. Use E and e for the earlobe phenotype alleles and W and w for the hairline phenotype alleles. A woman with unattached earlobes and a widow’s peak and a man with attached earlobes and a widow’s peak have a child. The child has attached earlobes and a non-widow’s-peak hairline. What are the genotypes of the parents?
A) EEWW and eeww
B) EeWw and eeWw
C) EEWW and eeWw
D) EeWw and EeWW
E) EeWw and eeww
25) What is the physical basis for the independent assortment observation that Mendel made?
A) Male and female gametes are produced in separate organs in separate individuals.
B) Sister chromatids do not separate until meiosis II.
C) There are two chromosome divisions in meiosis.
D) Homologous chromosomes are randomly aligned and separated during meiosis.
E) Recombination (crossing over) occurs in meiosis.
26) The Law of Independent Assortment states that:
A) in meiosis, crossing over creates genetically diverse gametes.
B) in fertilization, the combining of sperm and eggs is random.
C) generation of male and female gametes must occur in separate organisms.
D) in any dihybrid cross, it is possible to get any combination of phenotypes.
E) in gamete formation, gene pairs are transmitted independently of each other.
27) When Mendel crossed plants and followed two traits (a dihybrid cross), he saw a 9:3:3:1 ratio of traits in the F2 generation. What did he conclude?
A) The two traits affect each other’s transmission.
B) Dominant traits are always more common than recessive ones.
C) In meiosis, one allele of each gene is passed to each gamete.
D) The transmission of one trait is unaffected by the other.
28) Let S = smooth pea and s = wrinkled pea; Y = yellow pea and y = green pea. What are the different possible genotypes of the gametes produced by a plant that is heterozygous for both characters?
A) All will be SsYy.
B) Ss, Yy
C) S, s, Y, y
D) SY, Sy, sY, sy
E) SY, sy
29) Let S = smooth pea and s = wrinkled pea; Y = yellow pea and y = green pea. What pea phenotype would be produced by the genotype SsYy?
A) smooth, yellow
B) smooth, green
C) wrinkled, yellow
D) wrinkled, green
30) In order to track the inheritance of a single character, you would need to do a:
A) monohybrid cross.
B) dihybrid cross.
C) trihybrid cross.
D) true-breeding cross.
21) In Mendel’s pea plants, yellow seeds dominant to green : 1380791
