HEREDITY AND EVOLUTION
Frame the following crosses. Write the phenotypic and genotypic ratios ,where ever required(1)In African-violet plants, purple flowers are dominant to white flowers. You purchase an Africanviolet plant with white flowers. It's genotype could be represented as :
A). PP
B). Pp
C). pP
D). pp
(2)To discover whether an animal showing the dominant trait is homozygous or
heterozygous, it must be crossed with an animal that is:
A). homozygous dominant
C). heterozygous
B). homozygous recessive
D). choices B & C
(3) Two tall pea plants are crossed, producing 105 tall plants & 32 short plants. The genotypes of
the tall parent plants are:
A). Tt & Tt
B). TT & Tt
C). Tt & tt
D). tt & tt
(4 )A woman with Type O blood and a man who is Type AB have are expecting a child. What are the
possible blood types of the kid?
(5) What are the possible blood types of a child who's parents are both heterozygous for "B" blood
type?
(6) What are the chances of a woman with Type AB and a man with Type A having a child with Type
O?
(7) In a pea plant, round seeds are dominant over wrinkled .If a cross is carried between these two
plants, give answer to the following questions-.
a) Mention the genes for the traits?
b) State the trait of F₁ hybrids .
c) Write the ratio of F₂ PROGENY obtained from this cross. What is the name of the cross?
(8) A tall pea plant bearing violet flowers is crossed with short pea plant bearing white flowers. Work
out the F₁ and F₂ generations. Give F₂ ratio.
(9) In a cross between plants with purple flowers and plants with white flowers, the offsprings of F₁
generation ,all had purple flowers. When the F₁ generation was self-crossed, it was observed in
the F₂ generation that out of 100, 75 flowers were purple. Make a cross and answer the followinga) State the type of cross.
b) What are the genotypes of the F₂ progeny?
c) What is the ratio of purple:white flowers in the F₂ generations?
Q 10) A cross between a tall plant (TT) and short plant (tt) resulted in progeny that were all tall plants
becausei)
ii)
iii)
iv)
Shortness is the dominant trait.
Tallness is the recessive trait.
Tallness is the dominant trait
Height of the pea plant is not governed by gene “T” or “t”.
Q11) Given below is the experiment carried out by Mendel to study inheritance of two traits in garden
pea.
X
RRyy
rrYY
(round,green)
(wrinkled,yellow)
A
B
C
F₁
Round ,yellow
F₁
315,round yellow
D
108, round green
E
101, wrinkled yellow
F
32, wrinkled green
G
(a) What do A,B,C,D,E,F and G represent in these boxes?
(b) State the objective for which Mendel performed this experiment?
Q12) In human beings, blue eye colour is recessive to brown eye colour. If a brown-eyed man has a
blue –eyed mother ,then finda) What are the possible genotypes of his father?
b) What is the genotype of the man and his mother?
Q13) The genotype of green stemmed tomato plants is denoted as GG and that of purple stemmed
tomato plants is gg. When these two are crosseda) What colour of stem would you expect in their F₁ progeny?
b) Give the percentage of purple –stemmed plants if F₁ plants are self-pollinated?
c)What ratio would you find the genotypes GG and Gg in the F₂ progeny?
Q14) In the following crosses, write the characteristics of the progenyCROSSES
RRYY
x
Round ,yellow
RrYy
x
Round,yellow
rryy
x
wrinkled,green
RRYY
x
Round,yellow
RRYY
round, yellow
RrYy
round,yellow
rryy
wrinkled,green
rryy
wrinkled, green
PROGENY
AII -----------------------------------------
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Q15) In dogs, the barking trait is dominant over silent trait and erect ears are dominant over
drooping ears. Now ,find outa) Expected phenotypic ratio of offsprings when dogs, heterozygous for both the traits are crossed?
b) What are the different phenotypes observed?
c) What is this type of cross known as?
Q15) Guinea pig having black colour when crossed with guinea pig having same colour produced 80
offsprings ,out of which 60 were black and 20 were white. Now, find outa) What is the possible genotype of the guinea pigs?
b) Which trait is dominant and which trait is recessive?
c) What is this cross called as and what is its phenotypic ratio?
Q16) A woman having blood group B marries a man having blood group A and they have four
offsprings. Two children are having blood group O ,one having group B and the other having AB .
a)
b)
c)
d)
Which blood group is dominant?
Which blood is recessive?
What are the genotypes of parents?
Show the possible genotypes and phenotypes of offsprings .
Q17)
a) Trace the F₁ generation formed by crossing two plants with separate traits for shape and seed
colour – round ,green (RRyy) and wrinkled ,yellow (rrYY).
b) Mention the characteristic exhibited by it.
Q18) Problems of human blood groups:
1. A woman with Type O blood and a man who
is Type AB have are expecting a child. What
are the possible blood types of the kid?
2. What are the possible blood types of a child
who's parents are both heterozygous for "B"
blood type?
3. What are the chances of a woman with Type
AB and a man with Type A having a child
with Type O?