Biology Inheritance Test Online MCQs

Mustansar KhanLast Updated: October 14, 2025

Important Biology Inheritance Question and Answer

Total Questions:	48
Time Allowed:	25 Minutes
Total Marks:	48
How to Attempt Test:	Please choose the right Option in MCQ-type question.
Test Helpful For:	Biology Test MDCAT Test FPSC/PPSC/SPSC/KPPSC/BPSC/AJKPSC/NTS Biology Interview Question Answer Universities Entrance Test

Biology Inheritance Practice Test Online With Explanation

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1. Which process leads to genetic recombination?

Translation

Replication

Crossing over

Mitosis

2. Why can’t fathers pass X-linked traits to sons?

Sons reject X chromosomes

Sons don’t have X chromosomes

Fathers don’t carry defective genes

Fathers only pass the Y chromosome to sons

3. Which of the following is a result of gene linkage?

Greater genetic variation

Inherited traits appear together

Traits assort independently

Random recombination

4. What process can separate linked genes?

Transcription

Crossing over

Replication

Translation

5. In which sex is hemophilia most commonly expressed?

Both equally

Males

Only children

Females

6. What is the expected genotypic ratio of a monohybrid cross between two heterozygotes?

1:2:1

1:1

9:3:3:1

3:1

7. What does heterozygous mean?

Having two identical alleles

Having different alleles

Having a dominant trait only

Having one allele

8. Which term refers to different forms of a gene?

Chromatids

Traits

Alleles

Nucleotides

9. Which scientist is known as the father of genetics?

Watson

Darwin

Mendel

Lamarck

10. Which of the following terms best describes the physical appearance of an organism?

Genotype

Karyotype

Allele

Phenotype

11. Which of the following violates the law of independent assortment?

Codominance

Gene linkage

Mutation

Crossing over

12. The units of inheritance are:

Ribosomes

Chromosomes

Proteins

Genes

13. Which phase of meiosis does crossing over occur?

Anaphase II

Telophase I

Prophase I

Metaphase I

14. What is the significance of independent assortment?

It ensures mutation

It increases the number of cells

It maintains genetic stability

It increases genetic variation

15. What is the result of crossing TT (tall) with tt (short) pea plants?

All short

50% tall, 50% short

All medium

All tall

16. Which term describes genes located on the same chromosome and inherited together?

Alleles

Codominant genes

Recessive genes

Linked genes

17. A recessive allele is expressed only when:

It is dominant over another allele

It is on a heterozygous genotype

It is present on both homologous chromosomes

It is present on a Y chromosome

18. Which of the following diseases is caused by an X-linked recessive gene?

Hemophilia

Diabetes

Sickle-cell anemia

Cancer

19. How many alleles does a diploid organism have for each gene?

Four

One

Two

Three

20. What is gene mapping based on?

Shape of DNA

Location of traits

Physical size of chromosomes

Frequency of crossing over

21. What is the purpose of a Punnett square?

To predict the probability of genetic traits

To study chromosomes under a microscope

To identify dominant alleles

To determine the age of a gene

22. What is the probability that a carrier mother and a normal father will have a son with hemophilia?

100%

50%

25%

23. Which of the following best describes Mendel's Law of Segregation?

Alleles for a trait separate during gamete formation

Dominant traits are always expressed

Genes always blend in offspring

Traits are inherited in pairs

24. Which of the following best defines crossing over?

Exchange of segments between non-sister chromatids of homologous chromosomes

Segregation of alleles during mitosis

Exchange of genetic material between sister chromatids

Random mutation of DNA

25. Which of the following is a test cross?

TT × TT

Tt × tt

TT × Tt

Tt × Tt

Page 2 of 2

26. In hemophilia, a female must inherit:

One defective autosome

Two defective X chromosomes

One defective X

One defective Y

27. What is the condition in which an individual has two identical alleles for a trait?

Diploid

Homozygous

Hybrid

Heterozygous

28. What is the effect of crossing over on linked genes?

Ensures they always remain linked

Has no effect

Prevents their expression

May separate them, increasing variation

29. How many types of gametes can be produced by a heterozygous dihybrid individual (TtRr)?

30. Why are X-linked recessive traits more common in males?

Y chromosome protects them

Males have only one X chromosome

Males are more prone to mutations

Males have two X chromosomes

31. What does the Law of Independent Assortment explain?

Dominant traits hide recessive ones

Mutations occur randomly

Alleles always segregate together

Each pair of alleles segregates independently during gamete formation

32. Hemophilia primarily affects:

Nerve function

Digestive system

Blood clotting

Muscle strength

33. If T is dominant for tall and t for dwarf, what is the phenotype of Tt?

Recessive

Dwarf

Tall

Medium height

34. A hemophilic male and a carrier female have how many chances of passing on the disease?

25%

50%

75%

100%

35. In Mendel’s experiments, which trait was dominant?

Short stem

Wrinkled seeds

White flower

Tall stem

36. A female with normal genes for clotting marries a hemophilic man. What is the chance their son will have hemophilia?

25%

100%

50%

37. Gene linkage occurs when:

Genes are located on different chromosomes

Genes code for the same protein

Genes are located close together on the same chromosome

Genes are silenced

38. If two carriers of a recessive disorder marry, what is the chance their child will be affected?

25%

100%

50%

39. In X-linked inheritance, who can be carriers of the trait?

Only females

Neither

Both males and females

Only males

40. A male inherits his X chromosome from:

Both parents

His mother

Only from autosomes

His father

41. In a Punnett square of an XʰX × XY cross, what is the chance of a daughter being a carrier?

50%

100%

25%

42. Sex-linked genes are mostly located on:

Y chromosome

X chromosome

Mitochondrial DNA

Autosomes

43. Which of the following crosses would show Mendel’s Law of Independent Assortment?

TtRr × TtRr

TT × tt

TT × Tt

Tt × tt

44. Which of the following is an example of a dihybrid trait?

Flower color in pea plants

Height in pea plants

Blood type in humans

Height and seed shape in pea plants

45. A carrier female for hemophilia would have the genotype:

XʰXʰ

XʰX

46. Which of the following would have a 100% chance of passing on an X-linked recessive trait to daughters?

Normal mother

Carrier mother

Affected father

Carrier father

47. What does a test cross help determine?

The blood group

Whether an individual is heterozygous or homozygous dominant

The number of chromosomes

The presence of recessive traits only

48. In Mendel's dihybrid cross, what phenotypic ratio is expected in the F2 generation?

1:2:1

3:1

9:3:3:1

1:1

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Mustansar KhanLast Updated: October 14, 2025

Important Biology Inheritance Question and Answer

Biology Inheritance Practice Test Online With Explanation

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