Đề thi, bài tập trắc nghiệm online Di truyền học – Đề 2

1. In Mendelian genetics, if two heterozygous individuals (Aa) are crossed, what is the expected phenotypic ratio of their offspring?

A. 3:1

B. 1:2:1

C. 9:3:3:1

D. 1:1

2. What type of mutation involves a change in a single nucleotide base in DNA?

A. Deletion

B. Insertion

C. Point mutation

D. Frameshift mutation

3. What is the role of telomeres in chromosomes?

A. To initiate DNA replication

B. To protect the ends of chromosomes from degradation and fusion

C. To organize chromosomes within the nucleus

D. To regulate gene expression

4. What is meant by 'gene mapping'?

A. Identifying the function of a gene

B. Determining the sequence of a gene

C. Locating genes on chromosomes and determining their relative distances

D. Manipulating genes using biotechnology

5. What is the role of DNA ligase?

A. To unwind DNA

B. To synthesize DNA

C. To join DNA fragments together

D. To degrade DNA

6. What is the term for the process by which bacteria transfer genetic material directly between cells?

A. Transformation

B. Transduction

C. Conjugation

D. Mutation

7. What is the role of restriction enzymes in genetic engineering?

A. To join DNA fragments together

B. To cut DNA at specific sequences

C. To replicate DNA

D. To repair DNA

8. What is the definition of pleiotropy in genetics?

A. One gene affecting multiple traits

B. Multiple genes affecting one trait

C. Genes located on the same chromosome

D. Genes that are expressed only in specific tissues

9. What is the definition of 'gene pool' in population genetics?

A. All the genes in a single organism

B. All the genes in a population at a given time

C. All the genes in a species

D. All the genes in a family lineage

10. Which of the following describes a frameshift mutation?

A. Substitution of one base for another

B. Insertion or deletion of bases that is not a multiple of three

C. Inversion of a segment of DNA

D. Duplication of a gene

11. What is the process by which DNA is copied to produce two identical DNA molecules?

A. Transcription

B. Translation

C. Replication

D. Mutation

12. In a dihybrid cross, what phenotypic ratio is typically observed in the F2 generation when genes assort independently?

A. 3:1

B. 1:2:1

C. 9:3:3:1

D. 1:1:1:1

13. Which of the following nitrogenous bases is NOT found in DNA?

A. Adenine

B. Guanine

C. Cytosine

D. Uracil

14. Which of the following is a characteristic of RNA, but not DNA?

A. Double-stranded structure

B. Contains deoxyribose sugar

C. Uses uracil as a base

D. Phosphate backbone

15. What is the difference between incomplete dominance and codominance?

A. Incomplete dominance shows both alleles fully expressed, while codominance shows a blended phenotype.

B. Incomplete dominance shows a blended phenotype, while codominance shows both alleles fully and separately expressed.

C. Incomplete dominance only affects recessive traits, while codominance affects dominant traits.

D. Incomplete dominance involves multiple genes, while codominance involves a single gene.

16. What is the central dogma of molecular biology?

A. Protein -> RNA -> DNA

B. RNA -> DNA -> Protein

C. DNA -> RNA -> Protein

D. DNA -> Protein -> RNA

17. Which of the following is an example of a sex-linked genetic disorder?

A. Cystic fibrosis

B. Sickle cell anemia

C. Hemophilia

D. Tay-Sachs disease

18. What is the significance of studying mitochondrial DNA (mtDNA) in human genetics?

A. mtDNA is used to study paternal lineage.

B. mtDNA is located in the nucleus and is easier to access.

C. mtDNA is maternally inherited and can be used to trace maternal lineage and human migration.

D. mtDNA is more prone to mutations and thus less reliable for genetic studies.

19. What is the term for the observable characteristics of an organism resulting from the interaction of its genotype with the environment?

A. Genotype

B. Phenotype

C. Allele

D. Locus

20. What is the purpose of gel electrophoresis in genetics?

A. To amplify DNA

B. To sequence DNA

C. To separate DNA fragments by size

D. To introduce foreign DNA into cells

21. Which of the following is a characteristic of autosomal dominant inheritance?

A. Skips generations

B. Affects males more frequently than females

C. Affected individuals have at least one affected parent

D. Only homozygous individuals are affected

22. In population genetics, what does the Hardy-Weinberg principle describe?

A. Evolution of new species

B. Genetic drift in small populations

C. Conditions under which allele and genotype frequencies in a population remain constant

D. The effect of natural selection on phenotype frequencies

23. What is the role of tRNA in protein synthesis?

A. Carries genetic information from DNA to ribosomes

B. Forms the structural component of ribosomes

C. Brings amino acids to the ribosome

D. Catalyzes peptide bond formation

24. Which of the following is the fundamental unit of heredity?

A. Chromosome

B. Gene

C. DNA

D. Nucleotide

25. What is the function of DNA polymerase during DNA replication?

A. Unwinding the DNA double helix

B. Synthesizing RNA primers

C. Adding nucleotides to the growing DNA strand

D. Joining DNA fragments

26. What is the term for the condition where an individual has two identical alleles for a particular gene?

A. Heterozygous

B. Homozygous

C. Hemizygous

D. Polyploid

27. Which process directly produces mRNA from a DNA template?

A. Replication

B. Transcription

C. Translation

D. Transformation

28. What is the role of ribosomes in gene expression?

A. DNA replication

B. Transcription of DNA to mRNA

C. Translation of mRNA to protein

D. RNA processing

29. What is the purpose of polymerase chain reaction (PCR)?

A. To cut DNA into fragments

B. To amplify a specific DNA sequence

C. To separate DNA fragments by size

D. To determine the sequence of DNA

30. What is the concept of 'epigenetics' in genetics?

A. The study of gene mutations

B. The study of changes in gene expression that are heritable but do not involve alterations to the DNA sequence

C. The study of gene flow in populations

D. The study of gene editing techniques