Phenotypic ratio of incomplete
dominance in Mirabilis jalapa.
a. 2 : 1 : 1 b. 1 : 2 : 1
c. 3 : 1 d. 2 : 2
2. In dihybrid cross, F2
generation offsprings
show four different phenotypes while the
genotypes are ................
a. six b. nine
c. eight d. sixteen
3. A cross between an individual with
unknown genotype for a trait with
recessive plant for that trait is ..............
a. back cross b. reciprocal cross
c. monohybrid cross d. test cross
4. When phenotypic and genotypic ratios
are the same, then it is an example of
............
a. incomplete dominance
b. complete dominance
c. Multiple alleles
d. cytoplasmic inheritance
5. If the centromere is situated near the end
of the chromosome, the chromosome is
called ................
a. Metacentric b. Acrocentric
c. Sub-Metacentric d. Telocentric
6. Chromosomal theory of inheritance was
proposed by ................
a. Sutton and Boveri
b. Watson and Crick
c. Miller and Urey
d. Oparin and Halden
7. If the genes are located in a chromosome
as p-q-r-s-t, which of the following gene
pairs will have least probability of being
inherited together?
a. p and q b. r and s
c. s and t d. p and s
8. Find the mis match pair :-
a. Down’s syndrome = 44 + XY
b. Turner’s syndrome = 44 + XO
c. Klinefelter syndrome = 44 + XXY
d. Super female = 44 + XXX
9. A colourblind man marries a woman,
who is homozygous for normal colour
vision ,the probability of their son being
colourblind is –
a. 0% b. 25%
c. 50% d. 100%
Answers
1. B. 1:2:1
2. B. Nine
3. D. Test cross
4. A. Incomplete dominance
5. B. Acrocentric
6. A. Sutton and boveri
7. D. P and s
8. A. Down syndrome
9. A. 0%
Explanation:
1. Mirabilis jalapa Plants have red and white flowers which when crossed with each other produce pink flowers in F1 generation. If F1 generation is crossed plants appear in a ratio of 1:2:1 having red, pink or white petals.
2. In dihybrid cross we get genotypic ratio of 1:2:2:1:4:1:2:2:1 which give us 9 genotypes.
3. A cross between an individual with unknown genotype for a trait with recessive plant for that trait is Called test cross.
4. When phenotypic and genotypic ratios are the same, then it is called incomplete dominance.
5.If the centromere is situated near the end of the chromosome, the chromosome is called Acrocentric chromosome. It is rod shaped.
6. Chromosomal theory of inheritance states that chromosomes are physical basis of heredity which was proposed by sutton and boveri.
7. there is high probability that two genes which are present side by side in a chromosome get inherited together.
9. Colour blindness is a recessive sex-linked trait and appears only when both sex chromosomes carry recessive gene