Name: ( ) Class: Date:
Genetics - HKCEE MC
DNA and Gene
97 41
Which of the following statements about DNA are correct?
(1) It is made up of protein. (2) It is capable of replication.
(3) It controls protein synthesis.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
07 31
Which of the following statements about chromosomes are correct?
(1) It is made up of DNA and proteins. (2) It plays a role in protein synthesis.
(3) It is capable of replication.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
09 08
Which of the following descriptions about a gene are correct?
(1) It may undergo mutation
(2) It is made up of DNA and protein
(3) It determines the types of protein a cell makes.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
10 58.
Which of the following statements about DNA and chromosomes is correct?
A. DNA is absent from prokaryotes.
B. Chromosomes are made up of DNA and proteins.
C. A larger chromosome has a greater number of DNA molecules.
D. DNA regulates cellular activities through controlling the synthesis of carbohydrates.
Genetics past paper questions - 1
, Monohybrid cross
Example 1
The first child of two tongue-roller parents is a non-roller. What is the probability that their second child
is also a non-roller?
A. 3/4 B. 1/2 C. 1/4 D. 1/16
89 23 - 25 refer to the inheritance of coat colour in the wild fox which is determined by a pair of alleles.
Red coat colour is dominant over silver coat colour.
89 23
Suppose a hybrid red-coated fox produced 6 million sperms. The number of sperms carrying the genes for
silver coat colour would most likely be
A. 0. B. 3 million. C. 6 million. D. 12 million.
89 24
An embryo resulting from the mating of two silver-coated foxes is transplanted into the uterus of a
red-coated fox. The resulting offspring will be
A. red-coated. B. silver-coated.
C. red-coated with silver spots. D. silver-coated with red spots.
89 25
A hybrid red-coated fox was crossed with a silver-coated fox, and produced 3 silver-coated offspring and
1 red-coated offspring. This 3:1 ratio can be explained by the fact that
A. Mendel's law does not apply to this animal.
B. the silver coat colour is a dominant character.
C. the expression of the genes is affected by the environment.
D. a small number of offspring may not show the expected genetic ratio.
91 30
In the fruit fly, red eye is dominant to white eye. A homozygous red-eyed fruit fly is crossed with a
heterozygous red-eyed fruit fly. The expected phenotypic ratio among the offspring is
A. 1 red-eyed : 1 white-eyed B. 1 red-eyed : 3 white-eyed
C. 3 red-eyed : 1 white eyed D. 1 red-eyed : 0 white-eyed.
92 51
Two grey rats are mated. The female gives birth to 2 young grey and 6 young black rats. Which of the
following deductions is correct?
A. Grey is dominant to black because black offspring appear.
B. Black is dominant to grey because in the young rats the ratio of black to grey is 3 to 1.
C. Both grey and black are dominant because both kinds of young rats appear.
D. Both grey and black are recessive because both kinds of young rats appear.
Genetics past paper questions - 2
,94 39
Brown eye colour is dominant to blue eye colour in man. A brown-eyed father and a blue-eyed mother
have four children. Three of the children are blue-eyed and one is brown-eyed.
Which of the following statements is correct?
A. The father is homozygous for eye colour.
B. The phenotypic ratio of brown eyes to blue eyes in the children is 1 to 1.
C. The chance of a fifth child being brown-eyed is 1/2
D. The chance of a fifth child being blue-eyed is 3/4
01 55
The eye colour of Siamese cat is controlled by a pair of alleles. A cross between two brown-eyed cats
produced four offspring, of which three had green eyes and one had brown eyes. Which of the following
is correct?
Conclusion Evidence
A. Brown eye is dominant. The phenotypic ratio of the offspring is 3:1.
B. Brown eye is dominant. Two brown-eyed parents produce green-eyed offspring.
C. Green eye is dominant. The phenotypic ratio of the offspring is 3:1.
D. Green eye is dominant. Two brown-eyed parents produce green-eyed offspring.
05 16
A gardener pollinated a purple-flowered pea plant with the pollens from a white-flowered pea plant.
When the seeds obtained from this cross were germinated, he obtained 252 purple-flowered plants and
245 white-flowered plants. What conclusion can be drawn from the result of this cross?
A. Purple flower colour is dominant to white flower colour.
B. Neither purple nor white flower colour is dominant.
C. Both parent plants are heterozygous.
D. One parent plant is homozygous and the other is heterozygous.
06 13
Two homozygous parents with different phenotypes of the same traits are crossed to produce some
offspring. Which of the following correctly describes the offspring with respect to this trait?
A. The offspring may have two different phenotypes.
B. The offspring are similar to both parents.
C. The offspring only show one phenotype.
D. The offspring are homozygous.
09 12
The petal colour of pea plants is controlled by a pair of alleles. The allele for purple petals is dominant
while the allele for white petals is recessive. Which of the following combinations of cross and result can
confirm that a pea plant with purple petals is a homozygote?
Cross Result
A. cross with a pea plant with white petals ratio of offspring with purple petals to those with white
petals is around 1:1
B. cross with a pea plant with white petals all offspring have purple petals
C. cross with a pea plant with purple petals ratio of offspring with purple petals to those with white
petals is around 3:1
D. cross with a pea plant with purple petals all offspring have purple petals
Genetics past paper questions - 3
, 10 35.
The length of wings of a fruitfly is controlled by a pair of alleles. A fruitfly homozygous for long wings
was crossed with a fruitfly with short wings and all their offspring had long wings. The offspring were
then allowed to interbreed. Which of the following statements about the F2 generation are correct?
(1) 25% of the F2 generations would be homozygous.
(2) Some of the long-winged fruitflies would be heterozygous.
(3) The expected ratio of long-winged fruitflies to short-winged fruitflies would be 3:1.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
11 16.
Albinism (a condition in which pigment fails to develop in skin) in humans is caused by a recessive allele.
A normal man married an albino woman and their first child is an albino. What is the probability of their
second child being an albino?
A. 0 % B. 25 % C. 50 % D. 75 %
Genetics past paper questions - 4
Genetics - HKCEE MC
DNA and Gene
97 41
Which of the following statements about DNA are correct?
(1) It is made up of protein. (2) It is capable of replication.
(3) It controls protein synthesis.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
07 31
Which of the following statements about chromosomes are correct?
(1) It is made up of DNA and proteins. (2) It plays a role in protein synthesis.
(3) It is capable of replication.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
09 08
Which of the following descriptions about a gene are correct?
(1) It may undergo mutation
(2) It is made up of DNA and protein
(3) It determines the types of protein a cell makes.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
10 58.
Which of the following statements about DNA and chromosomes is correct?
A. DNA is absent from prokaryotes.
B. Chromosomes are made up of DNA and proteins.
C. A larger chromosome has a greater number of DNA molecules.
D. DNA regulates cellular activities through controlling the synthesis of carbohydrates.
Genetics past paper questions - 1
, Monohybrid cross
Example 1
The first child of two tongue-roller parents is a non-roller. What is the probability that their second child
is also a non-roller?
A. 3/4 B. 1/2 C. 1/4 D. 1/16
89 23 - 25 refer to the inheritance of coat colour in the wild fox which is determined by a pair of alleles.
Red coat colour is dominant over silver coat colour.
89 23
Suppose a hybrid red-coated fox produced 6 million sperms. The number of sperms carrying the genes for
silver coat colour would most likely be
A. 0. B. 3 million. C. 6 million. D. 12 million.
89 24
An embryo resulting from the mating of two silver-coated foxes is transplanted into the uterus of a
red-coated fox. The resulting offspring will be
A. red-coated. B. silver-coated.
C. red-coated with silver spots. D. silver-coated with red spots.
89 25
A hybrid red-coated fox was crossed with a silver-coated fox, and produced 3 silver-coated offspring and
1 red-coated offspring. This 3:1 ratio can be explained by the fact that
A. Mendel's law does not apply to this animal.
B. the silver coat colour is a dominant character.
C. the expression of the genes is affected by the environment.
D. a small number of offspring may not show the expected genetic ratio.
91 30
In the fruit fly, red eye is dominant to white eye. A homozygous red-eyed fruit fly is crossed with a
heterozygous red-eyed fruit fly. The expected phenotypic ratio among the offspring is
A. 1 red-eyed : 1 white-eyed B. 1 red-eyed : 3 white-eyed
C. 3 red-eyed : 1 white eyed D. 1 red-eyed : 0 white-eyed.
92 51
Two grey rats are mated. The female gives birth to 2 young grey and 6 young black rats. Which of the
following deductions is correct?
A. Grey is dominant to black because black offspring appear.
B. Black is dominant to grey because in the young rats the ratio of black to grey is 3 to 1.
C. Both grey and black are dominant because both kinds of young rats appear.
D. Both grey and black are recessive because both kinds of young rats appear.
Genetics past paper questions - 2
,94 39
Brown eye colour is dominant to blue eye colour in man. A brown-eyed father and a blue-eyed mother
have four children. Three of the children are blue-eyed and one is brown-eyed.
Which of the following statements is correct?
A. The father is homozygous for eye colour.
B. The phenotypic ratio of brown eyes to blue eyes in the children is 1 to 1.
C. The chance of a fifth child being brown-eyed is 1/2
D. The chance of a fifth child being blue-eyed is 3/4
01 55
The eye colour of Siamese cat is controlled by a pair of alleles. A cross between two brown-eyed cats
produced four offspring, of which three had green eyes and one had brown eyes. Which of the following
is correct?
Conclusion Evidence
A. Brown eye is dominant. The phenotypic ratio of the offspring is 3:1.
B. Brown eye is dominant. Two brown-eyed parents produce green-eyed offspring.
C. Green eye is dominant. The phenotypic ratio of the offspring is 3:1.
D. Green eye is dominant. Two brown-eyed parents produce green-eyed offspring.
05 16
A gardener pollinated a purple-flowered pea plant with the pollens from a white-flowered pea plant.
When the seeds obtained from this cross were germinated, he obtained 252 purple-flowered plants and
245 white-flowered plants. What conclusion can be drawn from the result of this cross?
A. Purple flower colour is dominant to white flower colour.
B. Neither purple nor white flower colour is dominant.
C. Both parent plants are heterozygous.
D. One parent plant is homozygous and the other is heterozygous.
06 13
Two homozygous parents with different phenotypes of the same traits are crossed to produce some
offspring. Which of the following correctly describes the offspring with respect to this trait?
A. The offspring may have two different phenotypes.
B. The offspring are similar to both parents.
C. The offspring only show one phenotype.
D. The offspring are homozygous.
09 12
The petal colour of pea plants is controlled by a pair of alleles. The allele for purple petals is dominant
while the allele for white petals is recessive. Which of the following combinations of cross and result can
confirm that a pea plant with purple petals is a homozygote?
Cross Result
A. cross with a pea plant with white petals ratio of offspring with purple petals to those with white
petals is around 1:1
B. cross with a pea plant with white petals all offspring have purple petals
C. cross with a pea plant with purple petals ratio of offspring with purple petals to those with white
petals is around 3:1
D. cross with a pea plant with purple petals all offspring have purple petals
Genetics past paper questions - 3
, 10 35.
The length of wings of a fruitfly is controlled by a pair of alleles. A fruitfly homozygous for long wings
was crossed with a fruitfly with short wings and all their offspring had long wings. The offspring were
then allowed to interbreed. Which of the following statements about the F2 generation are correct?
(1) 25% of the F2 generations would be homozygous.
(2) Some of the long-winged fruitflies would be heterozygous.
(3) The expected ratio of long-winged fruitflies to short-winged fruitflies would be 3:1.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
11 16.
Albinism (a condition in which pigment fails to develop in skin) in humans is caused by a recessive allele.
A normal man married an albino woman and their first child is an albino. What is the probability of their
second child being an albino?
A. 0 % B. 25 % C. 50 % D. 75 %
Genetics past paper questions - 4
