Genetics MCQs

1. Which of the following describes the law of segregation? a) Alleles of different genes assort independently b) Alleles segregate independently during gamete formation c) Dominant alleles mask recessive alleles d) Genes are linked on the same chromosome Answer: b) Alleles segregate independently during gamete formation 2. What is a linkage map? a) A map showing the location of genes on chromosomes b) A map showing the physical distances between genes c) A map showing the genetic distances between genes d) A map showing the sequence of nucleotides Answer: c) A map showing the genetic distances between genes 3. Which type of mutation involves a change in a single nucleotide? a) Frameshift mutation b) Silent mutation c) Point mutation d) Nonsense mutation Answer: c) Point mutation 4. What is the result of nondisjunction during meiosis? a) Normal chromosome number b) A change in nucleotide sequence c) An abnormal number of chromosomes d) DNA repair Answer: c) An abnormal number of chromosomes 5. Which type of RNA is involved in the splicing of pre-mRNA? a) mRNA b) tRNA c) rRNA d) snRNA Answer: d) snRNA 6. Which genetic disorder is characterized by the inability to break down phenylalanine? a) Cystic fibrosis b) Tay-Sachs disease c) Phenylketonuria (PKU) d) Hemophilia Answer: c) Phenylketonuria (PKU) 7. What is genetic drift? a) The movement of genes between populations b) The random change in allele frequencies in a population c) The intentional breeding of organisms d) The natural selection of traits Answer: b) The random change in allele frequencies in a population 8. Which of the following describes epigenetics? a) The study of genetic mutations b) The study of gene expression regulation by non-genetic factors c) The study of chromosome structure d) The study of inheritance patterns Answer: b) The study of gene expression regulation by non-genetic factors 9. What is the function of telomeres? a) Protect the ends of chromosomes from degradation b) Initiate DNA replication c) Encode ribosomal RNA d) Regulate gene expression Answer: a) Protect the ends of chromosomes from degradation 10. Which enzyme synthesizes RNA primers during DNA replication? a) DNA polymerase b) RNA polymerase c) Primase d) Ligase Answer: c) Primase 11. Which term refers to the inheritance of traits that are determined by more than one gene? a) Monogenic inheritance b) Polygenic inheritance c) Epistasis d) Codominance Answer: b) Polygenic inheritance 12. What is a transgenic organism? a) An organism that has been cloned b) An organism that carries genes from another species c) An organism that has undergone natural selection d) An organism with a genetic mutation Answer: b) An organism that carries genes from another species 13. Which of the following describes a silent mutation? a) A mutation that results in a stop codon b) A mutation that changes the amino acid sequence c) A mutation that does not change the amino acid sequence d) A mutation that causes a frameshift Answer: c) A mutation that does not change the amino acid sequence 14. Which genetic disorder is caused by a deletion on chromosome 5? a) Down syndrome b) Cri-du-chat syndrome c) Turner’s syndrome d) Klinefelter syndrome Answer: b) Cri-du-chat syndrome 15. What is the function of topoisomerase during DNA replication? a) Unwind the DNA double helix b) Add nucleotides to the growing DNA strand c) Relieve the tension in the DNA helix d) Seal nicks in the DNA backbone Answer: c) Relieve the tension in the DNA helix 16. What is the effect of a nonsense mutation? a) Substitution of one amino acid for another b) Introduction of a premature stop codon c) Addition or deletion of nucleotides d) No change in the amino acid sequence Answer: b) Introduction of a premature stop codon 17. Which technique is used to separate DNA fragments by size? a) PCR b) Gel electrophoresis c) DNA sequencing d) Cloning Answer: b) Gel electrophoresis 18. Which of the following describes codominance? a) One allele masks the effect of another b) Both alleles are expressed equally c) Neither allele is expressed d) One allele is partially expressed Answer: b) Both alleles are expressed equally 19. What is a genetic bottleneck? a) The movement of alleles between populations b) The increase in genetic diversity c) The reduction in genetic diversity due to a decrease in population size d) The selective breeding of organisms Answer: c) The reduction in genetic diversity due to a decrease in population size 20. Which structure is responsible for the separation of chromosomes during mitosis? a) Centromere b) Spindle fibers c) Nucleolus d) Ribosome Answer: b) Spindle fibers 21. What is the Hardy-Weinberg equilibrium? a) A condition where allele frequencies change due to natural selection b) A principle that describes the genetic makeup of a population that is not evolving c) The formation of new alleles through mutation d) The movement of genes between different populations Answer: b) A principle that describes the genetic makeup of a population that is not evolving 22. Which of the following is a type of chromosomal mutation? a) Point mutation b) Frameshift mutation c) Duplication d) Silent mutation Answer: c) Duplication 23. What is a gene pool? a) The total number of genes in an individual b) The total number of alleles in a population c) The physical location of genes on a chromosome d) The sequence of amino acids in a protein Answer: b) The total number of alleles in a population 24. Which enzyme synthesizes new DNA strands by adding nucleotides to an existing strand? a) DNA polymerase b) RNA polymerase c) Ligase d) Primase Answer: a) DNA polymerase 25. What is an operon? a) A cluster of genes under the control of a single promoter b) A segment of DNA that initiates transcription c) A sequence of nucleotides that code for a protein d) A region of DNA that regulates gene expression Answer: a) A cluster of genes under the control of a single promoter 26. Which process is used to determine the sequence of nucleotides in a DNA molecule? a) Gel electrophoresis b) PCR c) DNA sequencing d) Cloning Answer: c) DNA sequencing 27. What is genetic recombination? a) The creation of new alleles through mutation b) The exchange of genetic material between homologous chromosomes c) The movement of genes between different populations d) The inheritance of traits from parents Answer: b) The exchange of genetic material between homologous chromosomes 28. Which genetic disorder is caused by a trisomy of chromosome 18? a) Down syndrome b) Edwards syndrome c) Patau syndrome d) Klinefelter syndrome Answer: b) Edwards syndrome 29. What is the basic unit of heredity? a) Chromosome b) Gene c) Nucleotide d) Protein Answer: b) Gene 30. Which scientist is known as the father of genetics? a) Charles Darwin b) Gregor Mendel c) James Watson d) Francis Crick Answer: b) Gregor Mendel 31. What is the process by which DNA is copied before cell division? a) Transcription b) Translation c) Replication d) Mutation Answer: c) Replication 32. Which type of RNA carries the genetic code from DNA to the ribosome? a) mRNA b) tRNA c) rRNA d) snRNA Answer: a) mRNA 33. What is a genotype? a) The physical appearance of an organism b) The genetic makeup of an organism c) The environment’s effect on an organism d) The combination of proteins in a cell Answer: b) The genetic makeup of an organism 34. What is the principle of independent assortment? a) Genes are inherited together if they are close to each other b) Alleles of different genes segregate independently of each other c) The dominant allele masks the recessive allele d) Genes are linked on the same chromosome Answer: b) Alleles of different genes segregate independently of each other 35. What is a phenotype? a) The genetic makeup of an organism b) The combination of genes in an organism c) The physical appearance of an organism d) The number of chromosomes in a cell Answer: c) The physical appearance of an organism 36. Which term describes a gene that masks the effect of another gene? a) Recessive b) Co-dominant c) Dominant d) Epistatic Answer: c) Dominant 37. What is the term for a variation of a gene? a) Allele b) Chromatid c) Locus d) Centromere Answer: a) Allele 38. What does homozygous mean? a) Having two different alleles for a gene b) Having two identical alleles for a gene c) Having one allele for a gene d) Having multiple alleles for a gene Answer: b) Having two identical alleles for a gene 39. Which type of inheritance involves a single gene influencing multiple traits? a) Polygenic inheritance b) Pleiotropy c) Epistasis d) Co-dominance Answer: b) Pleiotropy 40. What is the result of crossing two heterozygous individuals (Aa x Aa) in terms of genotype ratio? a) 1:1:1:1 b) 3:1 c) 1:2:1 d) 9:3:3:1 Answer: c) 1:2:1 41. Which genetic disorder is caused by an extra copy of chromosome 21? a) Turner’s syndrome b) Klinefelter syndrome c) Down syndrome d) Cystic fibrosis Answer: c) Down syndrome 42. Which enzyme is responsible for unzipping the DNA double helix during replication? a) DNA polymerase b) RNA polymerase c) Helicase d) Ligase Answer: c) Helicase 43. What is a mutation? a) A permanent change in the DNA sequence b) A temporary change in the RNA sequence c) A change in the protein structure d) A change in the cell membrane Answer: a) A permanent change in the DNA sequence 44. What is the role of tRNA in protein synthesis? a) Carries genetic information b) Forms the ribosome c) Transfers amino acids to the ribosome d) Transcribes DNA Answer: c) Transfers amino acids to the ribosome 45. Which process converts mRNA into a protein? a) Transcription b) Replication c) Translation d) Transformation Answer: c) Translation 46. What is incomplete dominance? a) Both alleles are fully expressed b) One allele is not completely dominant over the other c) Neither allele is expressed d) One allele completely masks the other Answer: b) One allele is not completely dominant over the other 47. What type of genetic cross examines the inheritance of two different traits? a) Monohybrid cross b) Dihybrid cross c) Test cross d) Back cross Answer: b) Dihybrid cross 48. What is the term for the physical location of a gene on a chromosome? a) Allele b) Centromere c) Locus d) Chromatid Answer: c) Locus 49. Which of the following is a sex-linked recessive disorder? a) Huntington’s disease b) Hemophilia c) Sickle cell anemia d) Cystic fibrosis Answer: b) Hemophilia 50. What is the function of a promoter region in DNA? a) Encode proteins b) Initiate transcription c) Terminate transcription d) Replicate DNA Answer: b) Initiate transcription 51. Which term describes a cross between an individual with an unknown genotype and a homozygous recessive individual? a) Monohybrid cross b) Dihybrid cross c) Test cross d) Back cross Answer: c) Test cross 52. What is the purpose of the polymerase chain reaction (PCR)? a) To cut DNA into fragments b) To replicate specific DNA sequences c) To transcribe RNA into DNA d) To synthesize proteins Answer: b) To replicate specific DNA sequences 53. What is a karyotype? a) The complete set of genes in an organism b) The physical appearance of an organism c) The number and visual appearance of chromosomes in a cell d) The sequence of amino acids in a protein Answer: c) The number and visual appearance of chromosomes in a cell 54. Which of the following is an autosomal dominant disorder? a) Hemophilia b) Cystic fibrosis c) Huntington’s disease d) Tay-Sachs disease Answer: c) Huntington’s disease 55. What is the central dogma of molecular biology? a) RNA -> DNA -> Protein b) DNA -> Protein -> RNA c) DNA -> RNA -> Protein d) Protein -> RNA -> DNA Answer: c) DNA -> RNA -> Protein 56. Which process involves the exchange of genetic material between homologous chromosomes? a) Replication b) Transcription c) Crossing over d) Translation Answer: c) Crossing over 57. What is the role of DNA ligase in DNA replication? a) Unwind the DNA double helix b) Add nucleotides to the growing DNA strand c) Seal nicks in the DNA backbone d) Initiate replication Answer: c) Seal nicks in the DNA backbone 58. What is a frameshift mutation? a) A change in a single nucleotide b) A change that inserts or deletes a nucleotide c) A change in the amino acid sequence d) A change that affects the structure of the chromosome Answer: b) A change that inserts or deletes a nucleotide 59. Which of the following describes the law of segregation? a) Alleles of different genes assort independently b) Alleles segregate independently during gamete formation c) Dominant alleles mask recessive alleles d) Genes are linked on the same chromosome

Genetics MCQs

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