Choose the correct statements about Mendel’s laws of inheritance:
A. A homozygous parent produces all gametes that are similar.
B. During gamete formation, the alleles of a pair segregate from each other such that a gamete receives both the factors.
C. The alleles do not show any blending, and both the characters are recovered as such in the F2 generation.
D. The law of dominance is used to explain the expression of both the parental characters in the F1 of a monohybrid cross.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A and C only
Mendel gave two laws from his monohybrid crosses. The Law of Dominance says that in a dissimilar pair of factors one dominates the other, which is why only one parental character shows in the F1. The Law of Segregation says that the two alleles of a pair separate during gamete formation, so each gamete gets one of them.
A. A homozygous parent produces all gametes that are similar. — True. A TT plant can give only T gametes and a tt plant only t gametes.
B. During gamete formation, the alleles of a pair segregate from each other such that a gamete receives both the factors. — False. The alleles segregate so that a gamete receives only one of the two factors, not both.
C. The alleles do not show any blending, and both the characters are recovered as such in the F2 generation. — True. This is the fact on which the Law of Segregation is based.
D. The law of dominance is used to explain the expression of both the parental characters in the F1 of a monohybrid cross. — False. The law of dominance explains why only one parental character is expressed in the F1; both are expressed in the F2.
The correct statements are A and C.
NCERT Extract:
Law of Dominance – “… The law of dominance is used to explain the expression of only one of the parental characters in a monohybrid cross in the F1 and the expression of both in the F2. It also explains the proportion of 3:1 obtained at the F2.”
Law of Segregation – “This law is based on the fact that the alleles do not show any blending and that both the characters are recovered as such in the F2 generation though one of these is not seen at the F1 stage. Though the parents contain two alleles during gamete formation, the factors or alleles of a pair segregate from each other such that a gamete receives only one of the two factors. Of course, a homozygous parent produces all gametes that are similar while a heterozygous one produces two kinds of gametes each having one allele with equal proportion.”