Codominance

Description: Codominance Quiz
Number of Questions: 15
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Tags: genetics codominance biology
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What is codominance?

  1. When two alleles of a gene are both expressed in the phenotype of a heterozygote

  2. When one allele of a gene is dominant over the other allele

  3. When two alleles of a gene are both recessive

  4. When two alleles of a gene are both incompletely dominant


Correct Option: A
Explanation:

Codominance is a type of inheritance in which both alleles of a gene are expressed in the phenotype of a heterozygote. This means that neither allele is dominant over the other, and both alleles contribute to the phenotype of the individual.

Which of the following is an example of codominance?

  1. Blood type AB

  2. Eye color in humans

  3. Height in humans

  4. Skin color in humans


Correct Option: A
Explanation:

Blood type AB is an example of codominance because both the A and B alleles are expressed in the phenotype of the individual. This results in the individual having type AB blood.

What is the genotype of an individual with codominant alleles?

  1. Homozygous dominant

  2. Homozygous recessive

  3. Heterozygous

  4. Incomplete dominant


Correct Option: C
Explanation:

An individual with codominant alleles has a heterozygous genotype. This means that they have one copy of the dominant allele and one copy of the recessive allele.

What is the phenotype of an individual with codominant alleles?

  1. A blend of the two phenotypes

  2. The dominant phenotype

  3. The recessive phenotype

  4. An intermediate phenotype


Correct Option: A
Explanation:

The phenotype of an individual with codominant alleles is a blend of the two phenotypes. This means that both alleles are expressed in the phenotype, and neither allele is dominant over the other.

Which of the following is not a characteristic of codominance?

  1. Both alleles are expressed in the phenotype

  2. Neither allele is dominant over the other

  3. The phenotype is a blend of the two phenotypes

  4. The genotype is homozygous dominant


Correct Option: D
Explanation:

Codominance is a type of inheritance in which both alleles of a gene are expressed in the phenotype of a heterozygote. This means that neither allele is dominant over the other, and both alleles contribute to the phenotype of the individual. Therefore, the genotype of an individual with codominant alleles cannot be homozygous dominant.

What is the probability of an offspring inheriting both dominant alleles from their parents?

  1. 0%

  2. 25%

  3. 50%

  4. 75%


Correct Option: B
Explanation:

The probability of an offspring inheriting both dominant alleles from their parents is 25%. This is because each parent has a 50% chance of passing on the dominant allele, and the offspring must inherit one dominant allele from each parent in order to express the dominant phenotype.

What is the probability of an offspring inheriting both recessive alleles from their parents?

  1. 0%

  2. 25%

  3. 50%

  4. 75%


Correct Option: B
Explanation:

The probability of an offspring inheriting both recessive alleles from their parents is 25%. This is because each parent has a 50% chance of passing on the recessive allele, and the offspring must inherit one recessive allele from each parent in order to express the recessive phenotype.

What is the probability of an offspring inheriting one dominant allele and one recessive allele from their parents?

  1. 0%

  2. 25%

  3. 50%

  4. 75%


Correct Option: C
Explanation:

The probability of an offspring inheriting one dominant allele and one recessive allele from their parents is 50%. This is because each parent has a 50% chance of passing on the dominant allele and a 50% chance of passing on the recessive allele, and the offspring can inherit either combination of alleles.

What is the genotype ratio of a cross between two heterozygous individuals?

  1. 1:2:1

  2. 3:1

  3. 1:1

  4. 2:1


Correct Option: A
Explanation:

The genotype ratio of a cross between two heterozygous individuals is 1:2:1. This means that there will be one offspring with the homozygous dominant genotype, two offspring with the heterozygous genotype, and one offspring with the homozygous recessive genotype.

What is the phenotype ratio of a cross between two heterozygous individuals?

  1. 3:1

  2. 1:2:1

  3. 1:1

  4. 2:1


Correct Option: A
Explanation:

The phenotype ratio of a cross between two heterozygous individuals is 3:1. This means that there will be three offspring with the dominant phenotype and one offspring with the recessive phenotype.

Which of the following is an example of incomplete dominance?

  1. Blood type AB

  2. Eye color in humans

  3. Height in humans

  4. Skin color in humans


Correct Option: B
Explanation:

Eye color in humans is an example of incomplete dominance because the heterozygous genotype results in an intermediate phenotype. This means that the offspring of parents with different eye colors will have an eye color that is a blend of the two parents' eye colors.

What is the genotype of an individual with incomplete dominant alleles?

  1. Homozygous dominant

  2. Homozygous recessive

  3. Heterozygous

  4. Incomplete dominant


Correct Option: C
Explanation:

An individual with incomplete dominant alleles has a heterozygous genotype. This means that they have one copy of the dominant allele and one copy of the recessive allele.

What is the phenotype of an individual with incomplete dominant alleles?

  1. A blend of the two phenotypes

  2. The dominant phenotype

  3. The recessive phenotype

  4. An intermediate phenotype


Correct Option: D
Explanation:

The phenotype of an individual with incomplete dominant alleles is an intermediate phenotype. This means that the phenotype is a blend of the two phenotypes, and neither allele is dominant over the other.

Which of the following is not a characteristic of incomplete dominance?

  1. Both alleles are expressed in the phenotype

  2. Neither allele is dominant over the other

  3. The phenotype is a blend of the two phenotypes

  4. The genotype is homozygous dominant


Correct Option: D
Explanation:

Incomplete dominance is a type of inheritance in which both alleles of a gene are expressed in the phenotype of a heterozygote. This means that neither allele is dominant over the other, and both alleles contribute to the phenotype of the individual. Therefore, the genotype of an individual with incomplete dominant alleles cannot be homozygous dominant.

What is the probability of an offspring inheriting both dominant alleles from their parents in a cross between two heterozygous individuals?

  1. 0%

  2. 25%

  3. 50%

  4. 75%


Correct Option: B
Explanation:

The probability of an offspring inheriting both dominant alleles from their parents in a cross between two heterozygous individuals is 25%. This is because each parent has a 50% chance of passing on the dominant allele, and the offspring must inherit one dominant allele from each parent in order to express the dominant phenotype.

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