Genetics of animals MCQs January 8, 2026March 13, 2024 by u930973931_answers 50 min Score: 0 Attempted: 0/50 Subscribe 1. Genetic material in animals is primarily located in which cellular organelle? (A) Mitochondria (B) Nucleus (C) Golgi apparatus (D) Endoplasmic reticulum 2. Which term refers to alternative forms of a gene? (A) Chromosome (B) Genotype (C) Allele (D) Phenotype 3. Mendel’s law of segregation states that: (A) Each allele segregates into separate gametes during gamete formation (B) Genes are inherited in discrete units (C) Genes located on the same chromosome will be inherited together (D) Phenotypic traits are determined by multiple genes 4. In a monohybrid cross between two heterozygous individuals (Aa x Aa), what is the phenotypic ratio of the offspring? (A) 3:1 (B) 1:1 (C) 2:1:1 (D) 9:3:3:1 5. In a dihybrid cross (AaBb x AaBb), what is the expected phenotypic ratio according to Mendel’s law of independent assortment? (A) 9:3:3:1 (B) 3:1 (C) 1:2:1 (D) 1:1:1:1 6. What is the term for an organism with two different alleles for a particular gene? (A) Homozygous (B) Dominant (C) Heterozygous (D) Recessive 7. Which of the following genetic disorders is caused by an autosomal recessive allele? (A) Huntington's disease (B) Cystic fibrosis (C) Hemophilia (D) Duchenne muscular dystrophy 8. In humans, the sex chromosomes of a male individual are: (A) XX (B) XY (C) YY (D) XO 9. Incomplete dominance is characterized by: (A) The expression of both alleles equally in the heterozygous phenotype (B) Intermediate phenotype in heterozygotes (C) One allele completely masking the expression of the other allele (D) Multiple alleles controlling a single trait 10. A trait controlled by multiple genes is called: (A) Monogenic (B) Pleiotropic (C) Polygenic (D) Homologous 11. What is the probability of rolling a six on a fair six-sided die? (A) 1/2 (B) 1/3 (C) 1/6 (D) 1/12 12. What is the probability of flipping a coin and getting heads twice in a row? (A) 1/3 (B) 1/2 (C) 1/4 (D) 1/8 13. Which of the following represents a homozygous recessive genotype? (A) AA (B) Aa (C) aa (D) AB 14. What is the term for the observable characteristics of an organism? (A) Genotype (B) Trait (C) Allele (D) Phenotype 15. Which of the following is a sex-linked trait? (A) Eye color in humans (B) Height in humans (C) Hemophilia in humans (D) Seed color in peas 16. A carrier of a genetic disorder: (A) Always expresses the disorder (B) Is heterozygous for the mutant allele (C) Has two copies of the mutant allele (D) Is homozygous for the mutant allele 17. Which of the following is an example of codominance? (A) Blood type inheritance (B) Flower color in pea plants (C) Height in humans (D) Skin color in humans 18. The Law of Independent Assortment states that: (A) Alleles of different genes assort independently of each other during gamete formation (B) Alleles of the same gene always segregate together during gamete formation (C) Traits are determined by the environment rather than genetics (D) Genetic traits are inherited through blending of parental characteristics 19. Which of the following genetic disorders is caused by a mutation in the X chromosome and primarily affects males? (A) Color blindness (B) Tay-Sachs disease (C) Cystic fibrosis (D) Hemophilia 20. What is the term for a gene located on a sex chromosome? (A) Sex-linked gene (B) Autosomal gene (C) Recessive gene (D) Dominant gene 21. A test cross involves crossing an organism with: (A) An organism that is homozygous recessive (B) An organism that is homozygous dominant (C) Another organism of the same genotype (D) An organism that is heterozygous 22. Which of the following genetic disorders is caused by a trisomy of chromosome 21? (A) Cystic fibrosis (B) Duchenne muscular dystrophy (C) Hemophilia (D) Down syndrome 23. The principle of segregation was first described by: (A) Gregor Mendel (B) Charles Darwin (C) Thomas Hunt Morgan (D) James Watson and Francis Crick 24. Which of the following techniques is used to determine the genetic makeup of an individual? (A) Gel electrophoresis (B) Polymerase chain reaction (PCR) (C) Southern blotting (D) DNA sequencing 25. In a pedigree analysis, squares represent: (A) Affected individuals (B) Females (C) Males (D) Carrier individuals 26. Which of the following represents a homozygous dominant genotype? (A) aa (B) Aa (C) AA (D) AB 27. A Punnett square is used to: (A) Determine the probability of genetic disorders (B) Determine the genotype of an individual (C) Predict the phenotypic ratio of offspring (D) Analyze the inheritance patterns of multiple traits 28. Which of the following genetic disorders is caused by a mutation in a single gene and primarily affects African populations? (A) Cystic fibrosis (B) Huntington's disease (C) Sickle cell anemia (D) Hemophilia 29. Epigenetics refers to: (A) Changes in DNA sequence (B) The study of gene mutations (C) Changes in gene expression without altering DNA sequence (D) The study of genetic disorders 30. The ratio of phenotypes in a dihybrid cross between two heterozygous individuals is: (A) 9:3:3:1 (B) 3:1 (C) 1:1 (D) 1:2:1 31. The process by which DNA is copied into RNA is called: (A) Translation (B) Transcription (C) Replication (D) Mutation 32. Which of the following statements about DNA replication is true? (A) Replication is bidirectional, starting at a single origin of replication (B) Replication occurs during prophase of mitosis (C) Both DNA strands are synthesized in the same direction (D) DNA polymerase adds nucleotides in the 3' to 5' direction 33. In the lac operon of E. coli, the lacZ gene encodes: (A) A repressor protein (B) Permease (C) β-galactosidase (D) Lactose 34. A frameshift mutation results from: (A) The insertion or deletion of nucleotides that are not multiples of three (B) A substitution of one nucleotide for another (C) A mutation in a single nucleotide (D) The deletion of a whole chromosome 35. In eukaryotic cells, mRNA undergoes which of the following modifications before leaving the nucleus? (A) Replication (B) Translation (C) Splicing (D) Transcription 36. The genetic code is said to be degenerate because: (A) Each codon specifies only one amino acid (B) Some amino acids are specified by multiple codons (C) There is no redundancy in the code (D) Each codon specifies multiple amino acids 37. Which of the following is an example of a point mutation? (A) Deletion (B) Substitution (C) Insertion (D) Inversion 38. In DNA, adenine (A) pairs with: (A) Cytosine (C) (B) Thymine (T) (C) Guanine (G) (D) Uracil (U) 39. Which of the following enzymes is responsible for unwinding the DNA double helix during replication? (A) Primase (B) DNA polymerase (C) Helicase (D) Ligase 40. Which of the following is NOT a function of RNA? (A) Carrying genetic information (B) Catalyzing chemical reactions (C) Serving as a template for protein synthesis (D) Regulating gene expression 41. The lac operon is an example of a(n): (A) Repressible operon (B) Inducible operon (C) Constitutive operon (D) Mutagenic operon 42. Which of the following is NOT a type of chromosomal mutation? (A) Deletion (B) Transcription (C) Duplication (D) Inversion 43. A silent mutation: (A) Results in a change in amino acid sequence (B) Results in premature termination of protein synthesis (C) Does not change the amino acid sequence (D) Causes a frameshift mutation 44. What is the term for a region of DNA that regulates gene expression by binding to specific transcription factors? (A) Promoter (B) Enhancer (C) Silencer (D) Operator 45. The central dogma of molecular biology states that: (A) Protein is transcribed into RNA, which is translated into DNA (B) RNA is transcribed into DNA, which is translated into protein (C) DNA is transcribed into RNA, which is translated into protein (D) Protein is translated into DNA, which is transcribed into RNA 46. Which of the following enzymes is responsible for synthesizing RNA during transcription? (A) DNA polymerase (B) RNA polymerase (C) Helicase (D) Ligase 47. What is the term for a mutation that results in the substitution of one amino acid for another in a protein? (A) Silent mutation (B) Nonsense mutation (C) Frameshift mutation (D) Missense mutation 48. Which of the following is a function of tRNA during translation? (A) Joining together adjacent Okazaki fragments (B) Unwinding the DNA double helix (C) Synthesizing RNA from a DNA template (D) Carrying amino acids to the ribosome 49. In eukaryotic cells, mRNA is processed by which of the following modifications before translation? (A) Splicing (B) Capping (C) All of the above (D) Polyadenylation 50. Which of the following genetic disorders is caused by a deletion of a portion of chromosome 15 and is characterized by developmental delays and behavioral problems? (A) Down syndrome (B) Angelman syndrome (C) Turner syndrome (D) Klinefelter syndrome