1. What is the term for alternative forms of a gene that occupy the same position on homologous chromosomes?
a. Alleles
b. Phenotypes
c. Genotypes
d. Mutations
Answer: a. Alleles
2. In a monohybrid cross involving a dominant and a recessive allele, what is the genotype of the offspring if the parents are heterozygous?
a. Homozygous dominant
b. Homozygous recessive
c. Heterozygous
d. Phenotypically identical
Answer: c. Heterozygous
3. What is the term for the genetic makeup of an organism, representing the combination of alleles it possesses?
a. Phenotype
b. Genotype
c. Dominance
d. Homozygote
Answer: b. Genotype
4. In a dihybrid cross, how many different combinations of alleles can be produced in the gametes of the parents?
a. 1
b. 2
c. 3
d. 4
Answer: d. 4
5. Which scientist is credited with discovering the laws of inheritance, including the law of segregation and the law of independent assortment?
a. Gregor Mendel
b. Charles Darwin
c. James Watson
d. Rosalind Franklin
Answer: a. Gregor Mendel
6. If a trait is controlled by multiple genes, what type of inheritance pattern is observed?
a. Mendelian inheritance
b. Codominance
c. Polygenic inheritance
d. Incomplete dominance
Answer: c. Polygenic inheritance
7. What is the term for a section of DNA that codes for a specific protein or RNA molecule?
a. Codon
b. Exon
c. Gene
d. Intron
Answer: c. Gene
8. In humans, which sex chromosome combination results in a male individual?
a. XX
b. XY
c. XXY
d. XYY
Answer: b. XY
9. What is the purpose of the Punnett square in genetics?
a. To calculate the probability of genetic outcomes in offspring
b. To determine the dominance of a trait
c. To analyze the DNA sequence of a gene
d. To identify the phenotype of an individual
Answer: a. To calculate the probability of genetic outcomes in offspring
10. In which phase of the cell cycle does DNA replication occur?
a. G1 phase
b. S phase
c. G2 phase
d. M phase
Answer: b. S phase
11. What is the term for an organism that has two different alleles for a particular gene?
a. Homozygous
b. Heterozygous
c. Homologous
d. Monohybrid
Answer: b. Heterozygous
12. In Mendelian genetics, what is the principle that states each pair of alleles segregates independently during gamete formation?
a. Law of Dominance
b. Law of Segregation
c. Law of Independent Assortment
d. Law of Codominance
Answer: c. Law of Independent Assortment
13. What is the name for the specific location of a gene on a chromosome?
a. Locus
b. Allele
c. Chromatid
d. Centromere
Answer: a. Locus
14. If an individual is heterozygous for a particular trait, which phenotype will be expressed?
a. Both alleles are expressed equally
b. The dominant allele is expressed
c. The recessive allele is expressed
d. No phenotype is expressed
Answer: b. The dominant allele is expressed
15. What is the result of a mutation that involves the insertion or deletion of a single nucleotide in the DNA sequence?
a. Silent mutation
b. Missense mutation
c. Frameshift mutation
d. Nonsense mutation
Answer: c. Frameshift mutation
16. Which genetic disorder is caused by the presence of an extra chromosome 21 and is characterized by intellectual disabilities and distinct physical features?
a. Down syndrome
b. Turner syndrome
c. Klinefelter syndrome
d. Cystic fibrosis
Answer: a. Down syndrome
17. In a pedigree chart, how is a male represented?
a. Square
b. Circle
c. Diamond
d. Triangle
Answer: a. Square
18. What is the purpose of gel electrophoresis in genetics?
a. DNA replication
b. DNA sequencing
c. Separating and analyzing DNA fragments
d. Protein synthesis
Answer: c. Separating and analyzing DNA fragments
19. Which enzyme is responsible for unwinding and separating the DNA strands during DNA replication?
a. Helicase
b. Polymerase
c. Ligase
d. Primase
Answer: a. Helicase
20. In a dihybrid cross, what is the term for the offspring that has a combination of alleles different from both parents?
a. Homozygote
b. Homologous
c. Heterozygote
d. Recombinant
Answer: d. Recombinant
21. If a colorblind woman marries an average-visioned man, their sons will be
1. Three-fourths colorblind and one-fourth normal
2. One-half colorblind and one-half normal
3. All normal visioned
4. All colorblind
Answer: a, Three-fourths colorblind and one-fourth normal
22. Which of the following is the significance of dominance?
1. organisms with dominant genes have stronger vitality
2. the dominant gene does not express the deleterious mutation;
3. heterosis is due to a dominant gene
4. all of the above
Answer: d, all of the above
23. An individual’s homozygosity and heterozygosity can be determined by
1. Test cross
2. Back cross
3. Self-fertilization
4. All of the above
Answer: d, All of the above
24. The smallest unit of genetic material that produces a phenotypic effect on mutation is:
1. Gene
2. Muton
3. Nucleic acid
4. Recon
Answer: a, Gene
25. Farmers planted 200 kernels of corn and produced 140 tall & 40 short plants. The genotypes of these offspring are likely similar :
1. TT, tt
2. TT, Tt, tt
3. TT, Tt
4. Tt, tt
Answer: b, TT, Tt, tt.
26. Types of phenotypes of the F2 generation of dihybrid cross?
1. 4
2. 16
3. 8
4. 9
Answer: b, 16
27. Cross XXYy and xxYy yields XxYY: XxYy : Xxyy: xx yy offspring in the ratio of
1. 0 : 3: 1 : 1
2. 1: 2 : 1 : 0
3. 1: 1 : 1: 1
4. 1: 2 : 1: 1
Answer: b, 1: 2 : 1 : 0
28. In the Mirabilis plant, the appearance of the pink hybrid (Rr) between a cross of a red (RR) and white (rr) flower parent indicates
1. Segregation
2. Dominance
3. Incomplete dominance
4. Heterosis
Answer: c, Incomplete dominance
29. If only parental combinations in F2 of a dihybrid cross existed, then Mendel might have discovered?
1. Independent assortment
2. Atavism
3. Linkage
4. Repulsion
Answer: c, Linkage
30. If the distance between the gene on the chromosome is more, then the gene shows
1. less linkage
2. strong linkage
3. weak linkage
4. incomplete linkage
Answer: a, less linkage
31. Degeneracy of genetic code is due to
1. functional 61 codons and 20 amino acids
2. functional 64 codons and 20 amino acids
3. functional 20 codons and 20 amino acids
4. functional 20 codons and 61 amino acids
Answer: b, functional 64 codons and 20 amino acids
32. What if the 25th codon (UAU) of the gene encoding a 50 amino acid polypeptide is mutated to UAA?
1. A 24 amino acid polypeptide is formed
2. A 25 amino acid polypeptide is formed
3. A 49 amino acid polypeptide is formed
4. Two polypeptides of 24 and 25 amino acids are formed
Answer: c, A 49 amino acid polypeptide is formed
33. Signaling between cells usually results in the activation of protein
1. Lipases
2. Kinases
3. Proteases
4. Nucleases
Answer: b, Kinase
34. Cystic fibrosis is
1. Autosomal dominant disorder
2. Sex-linked recessive disorder
3. Sex-linked dominant disorder
4. Autosomal recessive disorder
Answer: d, Autosomal recessive disorder
35. What if Mendel discovered only the parental combinations in F2 of a dihybrid cross?
1. Independent assortment
2. Atavism
3. Linkage
4. Repulsion
Answer: c, Linkage