Inheritance
The questions are categorized into easy, moderate and tough levels, with a focus on key concepts from Chapter 15.
Easy Questions (18)
1. What is the basic unit of heredity?
- A) RNA
- B) DNA
- C) Gene
- D) Chromosome
Answer: C) Gene
2. Who is known as the father of genetics?
- A) Darwin
- B) Mendel
- C) Watson
- D) Crick
Answer: B) Mendel
3. How many chromosomes do humans have?
- A) 46
- B) 23
- C) 22
- D) 44
Answer:A) 46
4. What does the genotype represent?
- A) The physical appearance
- B) The genetic makeup
- C) The environment
- D) The phenotype
Answer: B) The genetic makeup
5. What is an allele?
- A) A type of chromosome
- B) A variant of a gene
- C) A type of RNA
- D) A protein
Answer: B) A variant of a gene
6. What does Mendel's law of segregation state?
- A) Alleles are independent of each other
- B) Alleles segregate during gamete formation
- C) Traits blend in offspring
- D) Dominant alleles mask recessive alleles
Answer: B) Alleles segregate during gamete formation
7. Which of the following is an example of co-dominance?
- A) Red and white flowers producing pink flowers
- B) AB blood type
- C) Tall and short plants producing medium height
- D) Green and yellow peas
Answer: B) AB blood type
8. Which term describes a genetic characteristic that is not expressed in the phenotype?
- A) Dominant
- B) Recessive
- C) Codominant
- D) Incomplete
Answer: B) Recessive
9. What is the primary purpose of meiosis?
- A) To create identical cells
- B) To produce gametes
- C) To repair DNA
- D) To replicate DNA
Answer: B) To produce gametes
10. What is the role of chromosomes in inheritance?
- A) They provide energy
- B) They store genetic information
- C) They regulate metabolism
- D) They control environmental responses
Answer: B) They store genetic information
11. What is an organism's phenotype?
- A) Genetic makeup
- B) Physical appearance
- C) Chromosome number
- D) Environment
Answer: B) Physical appearance
12. If a plant with genotype Tt (tall) is crossed with a tt (short) plant, what percentage of the offspring will be short?
- A) 25%
- B) 50%
- C) 75%
- D) 100%
Answer: B) 50%
13. What is a dominant allele?
- A) An allele that is always expressed
- B) An allele that is never expressed
- C) An allele that can be masked
- D) An allele that is present in a recessive form
Answer: A) An allele that is always expressed
14. In pea plants, round seeds (R) are dominant over wrinkled seeds (r). What is the phenotype of a plant with genotype Rr?
- A) Round
- B) Wrinkled
- C) Medium
- D) Dwarf
Answer: A) Round
15. What does genetic variation refer to?
- A) Differences in environmental conditions
- B) Differences in DNA sequences among individuals
- C) Identical traits among individuals
- D) Stable characteristics
Answer: B) Differences in DNA sequences among individuals
16. What is meant by "artificial selection"?
- A) Natural selection by environmental factors
- B) Selection of traits by human choice
- C) Random mating of organisms
- D) Selection of traits by chance
Answer: B) Selection of traits by human choice
17. What is the expected phenotypic ratio from a monohybrid cross?
- A) 1:2:1
- B) 3:1
- C) 9:3:3:1
- D) 1:1
Answer: B) 3:1
18. Which of the following best describes Mendel's law of independent assortment?
- A) Alleles segregate together
- B) Alleles segregate independently of one another
- C) Traits blend together
- D) Only dominant traits are passed on
Answer: B) Alleles segregate independently of one another
Moderate Questions (24)
19. What does a Punnett square illustrate?
- A) The physical characteristics of offspring
- B) The genetic combinations that can occur in offspring
- C) The process of natural selection
- D) The environmental factors affecting traits
Answer: B) The genetic combinations that can occur in offspring
20. In incomplete dominance, what phenotype results from a heterozygous genotype?
- A) One of the parent phenotypes
- B) A blend of the two parent phenotypes
- C) No expression of either phenotype
- D) A new dominant phenotype
Answer: B) A blend of the two parent phenotypes
21. What type of inheritance pattern is demonstrated by blood types in humans?
- A) Codominance
- B) Incomplete dominance
- C) Simple dominance
- D) Recessive inheritance
Answer: A) Codominance
22. Which of the following can lead to new traits in a population?
- A) Mutation
- B) Genetic drift
- C) Natural selection
- D) All of the above
Answer: D) All of the above
23. Which of the following is NOT a mechanism of evolution?
- A) Natural selection
- B) Mutation
- C) Migration
- D) Cell division
Answer D) Cell division
24. If two parents with genotypes AaBb and Aabb are crossed, what fraction of the offspring will exhibit the dominant phenotype for at least one trait?
- A) 1/4
- B) 1/2
- C) 3/4
- D) 7/8
Answer: C) 3/4
25. What is the main effect of natural selection on a population?
- A) It reduces variation
- B) It increases mutation rates
- C) It leads to genetic drift
- D) It has no impact
Answer: A) It reduces variation
26. What is an example of a polygenic trait?
- A) Flower color
- B) Skin color in humans
- C) Blood type
- D) Pea shape
Answer: B) Skin color in humans
27. What is the expected ratio of phenotypes in the offspring from a dihybrid cross?
- A) 1:1
- B) 3:1
- C) 9:3:3:1
- D) 1:2:1
Answer: C) 9:3:3:1
28. What is the term for when two different alleles are expressed equally in a phenotype?
- A) Codominance
- B) Incomplete dominance
- C) Complete dominance
- D) Epistasis
Answer: A) Codominance
29. What does genetic drift refer to?
- A) Changes in allele frequencies due to random events
- B) Adaptations to the environment
- C) Selection of favorable traits
- D) Migration of individuals
Answer: A) Changes in allele frequencies due to random events
30. If a trait is linked to a sex chromosome, what is it called?
- A) Autosomal trait
- B) Sex-linked trait
- C) Codominant trait
- D) Incomplete trait
Answer: B) Sex-linked trait
31. How does artificial selection differ from natural selection?
- A) Natural selection is driven by environmental factors, while artificial selection is driven by human choices.
- B) Artificial selection results in extinction, while natural selection does not.
- C) Natural selection only affects plants, while artificial selection affects animals.
- D) There is no difference; both are the same process.
Answer: A) Natural selection is driven by environmental factors, while artificial selection is driven by human choices.
32. In a test cross, what is crossed with the individual of unknown genotype?
- A) Homozygous dominant individual
- B) Homozygous recessive individual
- C) Heterozygous individual
- D) Another unknown individual
Answer: B) Homozygous recessive individual
33. If a tall plant (TT) is crossed with a short plant (tt), what will be the genotype of the F1 generation?
- A) TT
- B) Tt
- C) tt
- D) TTT
Answer: B) Tt
34. What role do environmental factors play in the expression of genetic traits?
- A) They have no impact.
- B) They can modify the phenotype.
- C) They determine the genotype.
- D) They only affect dominant traits.
Answer: B) They can modify the phenotype.
35. Which type of inheritance results in a phenotype that is a mix of both parents?
- A) Codominance
- B) Simple dominance
- C) Incomplete dominance
- D) Complete dominance
Answer: C) Incomplete dominance
36. Which of the following best describes the principle of natural selection?
- A) Organisms are created perfectly adapted to their environment.
- B) Organisms with favorable traits survive and reproduce.
- C) All traits are equally likely to be passed on.
- D) Environmental changes have no effect on survival.
Answer: B) Organisms with favorable traits survive and reproduce.
37. What is the primary function of DNA?
- A) To produce energy
- B) To store genetic information
- C) To provide structural support
- D) To facilitate movement
Answer: B) To store genetic information
38. In which phase of meiosis does independent assortment occur?
- A) Prophase I
- B) Metaphase I
- C) Anaphase I
- D) Telophase I
Answer: B) Metaphase I
Tough Questions (18)
39. What is the significance of Mendel's experiments with pea plants?
- A) They proved that traits are inherited randomly.
- B) They established the basic principles of heredity.
- C) They showed that environment has no role in inheritance.
- D) They disproved the existence of genes.
Answer: B) They established the basic principles of heredity.
40. What is a key difference between mutations and adaptations?
- A) Mutations are beneficial; adaptations are not.
- B) Adaptations are inherited traits that improve survival; mutations can be random and not always beneficial.
- C) Mutations occur slowly; adaptations occur quickly.
- D) Adaptations are always caused by mutations.
Answer: B) Adaptations are inherited traits that improve survival; mutations can be random and not always beneficial.
41. What is the expected ratio of a cross between two heterozygous individuals (Tt) for a single trait?
- A) 1:1
- B) 2:1
- C) 3:1
- D) 9:1
Answer: C) 3:1
42. How does the environment influence the phenotype of an organism?
- A) It does not influence the phenotype.
- B) It determines the genotype.
- C) It can enhance or inhibit the expression of certain traits.
- D) It only influences dominant traits.
Answer: C) It can enhance or inhibit the expression of certain traits.
43. Which of the following represents a phenotypic ratio of a dihybrid cross?
- A) 1:2:1
- B) 9:3:3:1
- C) 3:1
- D) 1:1
Answer: B) 9:3:3:1
44. How can co-dominance be observed in human blood types?
- A) Blood type A is recessive to blood type O.
- B) Blood type B is dominant over blood type A.
- C) Individuals with genotype AB express both A and B antigens.
- D) Blood type O individuals express no antigens.
Answer: C) Individuals with genotype AB express both A and B antigens.
45. Which process contributes to genetic diversity within a population?
- A) Cloning
- B) Asexual reproduction
- C) Sexual reproduction
- D) Budding
Answer: C) Sexual reproduction
46. What is the term for a characteristic that appears in one generation but skips the next?
- A) Dominance
- B) Incomplete dominance
- C) Recessiveness
- D) Codominance
Answer: C) Recessiveness
47. Which statement about Mendel's law of independent assortment is true?
- A) It applies only to linked genes.
- B) It describes the behavior of chromosomes during meiosis.
- C) It means traits are inherited together.
- D) It states that all traits are equally likely to be inherited.
Answer: B) It describes the behavior of chromosomes during meiosis.
48. What type of selection occurs when individuals at one extreme of a trait distribution are favored?
- A) Stabilizing selection
- B) Disruptive selection
- C) Directional selection
- D) Sexual selection
Answer: C) Directional selection
49. In which scenario would you expect to see genetic drift?
- A) In a large population with high gene flow
- B) In a small population with limited migration
- C) In a population with a stable environment
- D) In a population undergoing natural selection
Answer: B) In a small population with limited migration
50. What is the role of epistasis in genetic inheritance?
- A) It determines the dominance of alleles.
- B) It describes the interaction between genes at different loci.
- C) It refers to the location of genes on chromosomes.
- D) It influences the environment's effect on traits.
Answer: B) It describes the interaction between genes at different loci.
51. Which of the following best describes stabilizing selection?
- A) It favors individuals at both extremes of a trait.
- B) It favors individuals with intermediate traits.
- C) It results in a shift in trait distribution toward one extreme.
- D) It has no effect on trait distribution.
Answer: B) It favors individuals with intermediate traits.
52. In what way does mutation contribute to evolution?
- A) It causes immediate changes in phenotype.
- B) It introduces new genetic material into a population.
- C) It has no effect on genetic variation.
- D) It only results in harmful traits.
Answer: B) It introduces new genetic material into a population.
53. What is the result of a cross between two true-breeding plants for different traits?
- A) F1 generation will display one trait.
- B) F2 generation will display a mixture of traits.
- C) All offspring will be heterozygous.
- D) Traits will blend in the F1 generation.
Answer: A) F1 generation will display one trait.
54. Which of the following is true about sex-linked traits?
- A) They are inherited equally by males and females.
- B) They are always recessive.
- C) They are located on the sex chromosomes.
- D) They cannot be passed from father to son.
Answer: C) They are located on the sex chromosomes.
55. What is the genetic composition of an individual with two identical alleles for a trait?
- A) Heterozygous
- B) Homozygous
- C) Dominant
- D) Recessive
Answer: B) Homozygous
56. How does the concept of "survival of the fittest" relate to natural selection?
- A) It means only the strongest survive.
- B) It refers to the survival of the best-adapted organisms.
- C) It has no impact on evolution.
- D) It implies that all organisms have equal chances of survival.
**Answer:** B) It refers to the survival of the best-adapted organisms.
57. What is the primary factor that causes variation in a population?
- A) Environment
- B) Genetic mutations
- C) Reproductive isolation
- D) Migration
Answer: B) Genetic mutations
58. Which of the following describes the Hardy-Weinberg equilibrium?
- A) A population that is evolving
- B) A population that is not evolving
- C) A population that is randomly mating
- D) A population with no genetic drift
Answer: B) A population that is not evolving
59. In a dihybrid cross of two heterozygous parents, what phenotypic ratio is expected?
- A) 3:1
- B) 9:3:3:1
- C) 1:2:1
- D) 1:1
Answer: B) 9:3:3:1
60. What is the primary function of the genetic code?
- A) To provide energy to cells
- B) To determine the amino acid sequence in proteins
- C) To facilitate cell division
- D) To create energy storage molecules
Answer:** B) To determine the amino acid sequence in proteins