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Quiz Chapter 11: Inheritance

10 questions ยท Form 5 Biology Bab 10: Inheritance

Question 1 of 10Score: 0

What term describes alternative forms of the same gene occupying the same locus on homologous chromosomes?

Full Question List & Answer Key

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1. What term describes alternative forms of the same gene occupying the same locus on homologous chromosomes?

  1. Autosomes
  2. Alleles
  3. Genotypes
  4. Phenotypes
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Answer: B

Alleles are alternative variations of a specific gene locus.

2. In a monohybrid cross between two heterozygous tall pea plants (Tt x Tt), what is the expected phenotypic ratio of the offspring?

  1. 1 Tall : 1 Dwarf
  2. 3 Tall : 1 Dwarf
  3. 1 TT : 2 Tt : 1 tt
  4. 9 Tall : 3 Dwarf
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Answer: B

Crossing two heterozygous individuals (Tt x Tt) yields a 3:1 ratio of dominant (Tall) to recessive (Dwarf) phenotypes.

3. What is the genotype of a female who is a carrier for red-green color blindness?

  1. X^C X^C
  2. X^C X^c
  3. X^c X^c
  4. X^c Y
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Answer: B

A female carrier is heterozygous, carrying one normal dominant allele (X^C) and one mutant recessive allele (X^c).

4. Why are sex-linked recessive conditions like haemophilia more common in human males than females?

  1. Males have two Y chromosomes
  2. Males possess only one X chromosome and lack a corresponding dominant allele to mask a recessive sex-linked gene
  3. The Y chromosome carries two copies of the defective gene
  4. Females cannot transmit sex-linked traits
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Answer: B

Males are heterogametic (XY) and possess only one X chromosome; therefore, a single recessive allele on the X chromosome causes the disorder.

5. Which tool is used in genetics to display family relationships and trace the pattern of inheritance of a genetic trait across generations?

  1. Karyotype chart
  2. Punnett square
  3. Pedigree chart
  4. Food web
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Answer: C

A pedigree chart visualizes phenotypic traits across multiple generations in a family history.

6. What is the probability of a couple having a female child in any single pregnancy?

  1. 25%
  2. 50%
  3. 75%
  4. 100%
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Answer: B

Each pregnancy has a 50% (1 in 2) probability of producing an XX (female) or XY (male) child.

7. In humans, how many autosomes are contained in a normal sperm cell?

  1. 46
  2. 44
  3. 23
  4. 22
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Answer: D

A human gamete contains 23 total chromosomes: 22 autosomes and 1 sex chromosome (X or Y).

8. A cross between a red flower and a white flower produces all pink flowers. What genetic phenomenon does this demonstrate?

  1. Complete Dominance
  2. Incomplete Dominance
  3. Codominance
  4. Multiple Alleles
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Answer: B

Incomplete dominance occurs when the heterozygous phenotype is an intermediate blend of the two homozygous phenotypes.

9. Which cross is used to determine whether an individual showing a dominant phenotype is homozygous dominant or heterozygous?

  1. Monohybrid cross
  2. Test cross
  3. Dihybrid cross
  4. Reciprocal cross
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Answer: B

A test cross involves crossing the dominant-phenotype individual with a homozygous recessive individual.

10. What phenotypic ratio is expected in the F2 generation of a classic dihybrid cross (RrYy x RrYy)?

  1. 3 : 1
  2. 1 : 2 : 1
  3. 9 : 3 : 3 : 1
  4. 1 : 1 : 1 : 1
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Answer: C

A dihybrid cross between two double-heterozygotes results in a 9:3:3:1 phenotypic ratio.

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