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WorksheetsPunnett Squares Practice
Total questions: 25
Worksheet time: 2hrs 5mins
Name
Class
Date
1.
Which of these Punnett squares represents a cross between a homozygous dominant parent and a heterozygous parent?
a)
b)
c)
d)
2.
If both parents have the genotype Aa, what is the chance their offspring will also have the genotype Aa?
a)
0%
b)
25%
c)
50%
d)
75%
e)
100%
3.
In pea plants, the tall allele is dominant to the short allele. What key would demonstrate this?
a)
Tall = T
Short = S
Short = S
b)
Tall = T
Short = t
Short = t
c)
Tall = t
Short = T
Short = T
d)
Tall = TT
Short = tt
Short = tt
4.
A heterozygous long-tusked elephant is crossed with a homozygous recessive short-tusked elephant. What is the probability of the offspring having short tusks?
a)
0%
b)
25%
c)
50%
d)
75%
5.
What is the probability of a purple-horned unicorn if a heterozygous pink-horned unicorn is crossed with a heterozygous pink-horned unicorn?
a)
0%
b)
25%
c)
50%
d)
75%
6.
Georgette wants to breed her pet phoenixes, but she isn't sure if the babies will burst into blue flames or red flames. Her documents show that her female phoenix is homozygous dominant for red flames, while her male phoenix is homozygous recessive for blue flames. What color flames will the babies have?
a)
Red
b)
Blue
c)
Purple
d)
50% Red, 50% Blue
7.
Leonardo bet his friend Olivet that two heterozygous green-eyed sea monsters could not have a recessive blue-eyed baby sea monster. Olivet said they can have a blue-eyed sea monster.
Who wins the bet?
Who wins the bet?
a)
Leonardo
b)
Olivet
c)
Both
d)
Neither
8.
A brown-furred ewok has 12 babies with a black-furred ewok. 9 ewok babies have black fur, while 3 ewok babies have brown fur. What are the probable genotypes of the parents?
a)
BB and bb
b)
BB and Bb
c)
Bb and Bb
d)
Bb and bb
9.
Jabba the Hutt has finally decided to settle down and have a family. He has undergone genetic testing and learned that he is heterozygous for Hutt Fungal Syndrome, which is caused by recessive alleles. He is worried that his children might suffer from this syndrome. His Hutt mate has undergone genetic testing and discovered she is homozygous dominant for the syndrome. Should Jabba be worried?
a)
Yes
b)
No
10.
Identify the homozygous dominant genotype:
a)
FF
b)
Ff
c)
ff
11.
What phenotype would result from crossing a homozygous dominant purple-flowered pea plant with a homozygous recessive white-flowered pea plant?
a)
Pp
b)
Purple
c)
White
d)
PP and pp
12.
Which of the following best describes the genotype "Rr"?
a)
recessive
b)
heterozygous
c)
purebred
d)
all of the above
13.
Which of the following genotypes is dominant?
a)
AA
b)
Aa
c)
aa
d)
both AA and Aa
14.
T - tall and t = short
In the punnett square below, what belongs in the missing square
In the punnett square below, what belongs in the missing square
a)
tt
b)
Tt
c)
Bb
d)
TT
15.
G = green, g = yellow
The genotype for a yellow plant is...
The genotype for a yellow plant is...
a)
GG
b)
Gg
c)
gg
d)
all of the choices result in yellow
16.
In plants, tall (T) is dominant to short (t). Perform the following cross: Tt x Tt. What is the probability of producing a short plant?
a)
0%
b)
25%
c)
50%
d)
75%
17.
Two brown eyed parents (Bb) have a baby. What is the chance the baby is blue eyed?
a)
0 %
b)
25%
c)
50%
d)
75%
18.
A man, who has red-green colorblindness, and his wife, who is a carrier for colorblindness, have a colorblind son. What is the probability that their next son will also be colorblind?
a)
0%
b)
25%
c)
50%
d)
100%
19.
A woman heterozygous for A blood marries a man heterozygous for B blood. What is the probability that they will produce offspring with AB blood?
a)
0%
b)
25%
c)
50%
d)
75%
20.
Black hair color is dominant to white hair color in mice. Determine the phenotypic ratio for the offpring of a heterozygous black mouse and a white mouse.
a)
4 Black: 0 White
b)
3 Black: 1 White
c)
2 Black: 2 White
d)
0 Black: 4 White
21.
Genetic crosses involving a particular type of flower exhibit complete dominance with respect to petal color. Red (R) is dominant to white (r). Using the Punnett square, what is the expected percentage of offspring that will have white flowers from a cross of parent flowers with a genotype of Rr.
a)
0%
b)
25%
c)
50%
d)
100%
22.
Tay-Sachs disease is a lethal, autosomal recessive genetic disorder. If both parents are heterozygous carriers of the disease, what are the chances of them having a child who is also a heterozygous carrier for Tay-Sachs?
a)
0%
b)
25%
c)
50%
d)
75%
23.
Biologists have found that a form of deafness is a recessive trait in dogs. If a female dog that is heterozygous for the trait mates with a male dog that is deaf, what percent of their offspring will be deaf?
a)
0%
b)
50%
c)
75%
d)
100%
24.
In certain species of plants, purple flowers (P) are dominant to white flowers (p). If two heterozygous plants are crossed, what will be the phenotype of the offspring?
a)
100% purple flowers
b)
100% white flowers
c)
75% white flowers, 25% purple flowers
d)
25% white flowers, 75% purple flowers
25.
What allele combination should go in the missing box?
a)
AA
b)
Aa
c)
aa
d)
none of these
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