MCQ on Genetics: Concept and Applications (PDF)

Genetics is the study of genes, heredity, and the variation of organisms. It explains how traits and characteristics are passed from parents to offspring through DNA. Understanding genetics helps in fields like medicine, agriculture, and evolutionary biology. This post is about MCQ on Genetics with Answers PDF. You can download this MCQ as PDF from the download link provided below.

MCQ on Genetics with Answers PDF

(1). The principle of independent assortment was first formulated by:

(a). Watson
(b). Mendel
(c). Crick
(d). Morgan

(2). Which of the following is an example of codominance?

(a). ABO blood groups
(b). Pea plant flower color
(c). Sickle cell anemia
(d). Huntington’s disease

(3). The Hardy-Weinberg equilibrium requires all of the following EXCEPT:

(a). Large population size
(b). No mutation
(c). Migration
(d). Random mating

(4). The genetic code is said to be degenerate because:

(a). A single codon can code for multiple amino acids
(b). Multiple codons can code for the same amino acid
(c). Codons are composed of nucleotides
(d). Each codon codes for only one amino acid

(5). Which of the following is NOT a mechanism of genetic recombination in bacteria?

(a). Conjugation
(b). Transformation
(c). Transduction
(d). Mutation

(6). The enzyme responsible for unwinding the DNA helix during replication is:

(a). DNA polymerase
(b). Helicase
(c). Ligase
(d). Primase

(7). Which of the following represents a transition mutation?

(a). A to T
(b). G to C
(c). A to G
(d). C to T

(8). The phenomenon where one gene affects multiple phenotypic traits is called:

(a). Pleiotropy
(b). Epistasis
(c). Polygeny
(d). Incomplete dominance

(9). In a dihybrid cross, the phenotypic ratio in the F2 generation typically follows:

(a). 9:3:3:1
(b). 3:1
(c). 1:2:1
(d). 2:1

(10). The concept of “one gene, one enzyme” was proposed by:

(a). Watson and Crick
(b). Beadle and Tatum
(c). Avery and Griffith
(d). Hershey and Chase

(11). Which of the following is NOT true about mitochondrial DNA?

(a). It is maternally inherited
(b). It is circular
(c). It undergoes recombination
(d). It has a high mutation rate

(12). Genetic drift is most likely to occur in:

(a). Large populations
(b). Small populations
(c). Populations with high gene flow
(d). Populations under natural selection

(13). In genetic mapping, the unit of measurement for distance between genes is:

(a). Kilobases
(b). Centimorgans
(c). Base pairs
(d). Megabases

(14). Which of the following processes leads to the formation of a Barr body?

(a). Dosage compensation
(b). Genetic imprinting
(c). Mutation
(d). Chromosome duplication

(15). Which of the following is an example of a frameshift mutation?

(a). Insertion of a single nucleotide
(b). Transition mutation
(c). Transversion mutation
(d). Synonymous substitution

(16). Which of the following statements is true about linked genes?

(a). They assort independently
(b). They are always on different chromosomes
(c). They tend to be inherited together
(d). They undergo crossing over frequently

(17). Which of the following enzymes is involved in the synthesis of the RNA primer during DNA replication?

(a). Helicase
(b). DNA polymerase
(c). Primase
(d). Ligase

(18). Which type of RNA is responsible for bringing amino acids to the ribosome?

(a). mRNA
(b). rRNA
(c). tRNA
(d). snRNA

(19). The chromosomal theory of inheritance was proposed by:

(a). Sutton and Boveri
(b). Mendel
(c). Watson and Crick
(d). Morgan

(20). Which of the following statements about genetic recombination is correct?

(a). It only occurs during mitosis
(b). It increases genetic diversity
(c). It decreases genetic diversity
(d). It occurs only in prokaryotes

(21). Which of the following is a characteristic of the lac operon in E. coli?

(a). It is always active
(b). It is inducible
(c). It is repressible
(d). It is constitutive

(22). The term “genotype” refers to:

(a). The physical appearance of an organism
(b). The set of alleles an organism has
(c). The evolutionary history of an organism
(d). The proteins expressed by an organism

(23). Which of the following is an example of a nonsense mutation?

(a). A mutation that changes a codon to one that encodes a different amino acid
(b). A mutation that results in a premature stop codon
(c). A mutation that adds a nucleotide into the sequence
(d). A mutation that occurs in the intronic region

(24). Epigenetic modifications include all of the following EXCEPT:

(a). DNA methylation
(b). Histone modification
(c). RNA interference
(d). Point mutation

(25). In humans, the SRY gene is located on the:

(a). X chromosome
(b). Y chromosome
(c). Autosomes
(d). Mitochondrial DNA

Answer Key

(1). (b) Mendel
Gregor Mendel first formulated the principle of independent assortment through his work on pea plants.

(2). (a) ABO blood groups
The ABO blood group system is an example of codominance where both A and B alleles are expressed.

(3). (c) Migration
Hardy-Weinberg equilibrium assumes no migration, as migration introduces new alleles into the population.

(4). (b) Multiple codons can code for the same amino acid
The genetic code is degenerate because more than one codon can specify the same amino acid.

(5). (d) Mutation
Mutation is not a mechanism of genetic recombination but rather a source of genetic variation.

(6). (b) Helicase
Helicase is the enzyme that unwinds the DNA helix during replication.

(7). (c) A to G
A transition mutation refers to a purine-purine or pyrimidine-pyrimidine substitution, like A to G.

(8). (a) Pleiotropy
Pleiotropy occurs when one gene influences multiple phenotypic traits.

(9). (a) 9:3:3:1
A dihybrid cross typically results in a 9:3:3:1 phenotypic ratio in the F2 generation.

(10). (b) Beadle and Tatum
Beadle and Tatum proposed the “one gene, one enzyme” hypothesis through their experiments on Neurospora.

(11). (c) It undergoes recombination
Mitochondrial DNA does not undergo recombination; it is inherited as a unit.

(12). (b) Small populations
Genetic drift is most significant in small populations where random changes in allele frequencies can occur more easily.

(13). (b) Centimorgans
Centimorgans are the units used in genetic mapping to measure the distance between genes.

(14). (a) Dosage compensation
The formation of a Barr body is a result of dosage compensation, where one X chromosome in females becomes inactivated.

(15). (a) Insertion of a single nucleotide
A frameshift mutation occurs due to the insertion or deletion of nucleotides that alters the reading frame.

(16). (c) They tend to be inherited together
Linked genes are located close together on the same chromosome and are usually inherited together.

(17). (c) Primase
Primase synthesizes the RNA primer required for DNA polymerase to begin replication.

(18). (c) tRNA
tRNA is responsible for bringing amino acids to the ribosome during protein synthesis.

(19). (a) Sutton and Boveri
The chromosomal theory of inheritance was proposed by Sutton and Boveri, linking Mendel’s laws to chromosomes.

(20). (b) It increases genetic diversity
Genetic recombination increases genetic diversity by creating new combinations of alleles.

(21). (b) It is inducible
The lac operon in E. coli is an inducible system that is activated in the presence of lactose.

(22). (b) The set of alleles an organism has
The genotype refers to the specific alleles present in an organism’s genetic makeup.

(23). (b) A mutation that results in a premature stop codon
A nonsense mutation is one that changes a codon into a stop codon, leading to a truncated protein.

(24). (d) Point mutation
Point mutations are changes in a single nucleotide and are not considered epigenetic modifications.

(25). (b) Y chromosome
The SRY gene, which determines male sex development, is located on the Y chromosome in humans.

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