Free Chromosomes MCQs with Answers
633 Chromosomes MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Chromosomes are DNA-protein structures that carry genes and become visible during cell division. Coverage includes chromatin, centromeres, sister chromatids, homologous chromosomes, chromosome number, and the distinction between diploid and haploid cells, with links to DNA replication, mitosis and meiosis.
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633 questions · page 27 of 32
- A. Formation of bivalents at the equator
- B. Contraction of the spindle fibres at both poles of the cell
- C. Random orientation of homologous chromosomes at the equator
- D. Dissociation of synaptonemal complex between homologous chromosomes
Explanation: The correct answer is the random orientation of homologous chromosomes at the equator during metaphase-I.
Correct answer: Random orientation of homologous chromosomes at the equator- A. Replication of DNA
- B. Separation of centrioles
- C. Division of centromeres
- D. Formation of chromatids
Explanation: During prophase of the mitotic cell cycle, one of the key processes is the separation of centrioles, which move to opposite poles of the…
Correct answer: Separation of centrioles- A. I and II
- B. III and IV
- C. I, II and III
- D. I, II and IV.
Explanation: In Drosophila melanogaster, the chromosomes are organized into distinct pairs.
Correct answer: I, II and III524. The given diagram shows the karyotype of a person. The abnormality indicated by this karyotype is:
- A. Klinefelter's syndrome
- B. Turner's syndrome
- C. Down syndrome
- D. Patau's syndrome
Explanation: Option A is correct, as the figure shows an extra X chromosome in the male.
Correct answer: Klinefelter's syndrome- A. Deletion
- B. Inversion
- C. Duplication
- D. Translocation
Explanation: The correct answer is Translocation. In the given diagram, segments of chromosomes are exchanged or moved to a different chromosome, which…
Correct answer: Translocation- A. 3
- B. 6
- C. 9
- D. 12
Explanation: In 2nd meiotic division, sister chromatids separate so chromosome number will remain 6. So option B is correct.
Correct answer: 6- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: During mitosis, sister chromatids separate. During meiosis 1, homologous chromosomes separate.
Correct answer: Option C- A. Two genetically identical chromosomes each
- B. Two genetically different chromosomes each
- C. Four genetically identical chromosomes each
- D. Four genetically different chromosomes each
Explanation: In meiosis, a diploid cell with 8 chromosomes undergoes two rounds of cell division to produce four haploid daughter cells, each…
Correct answer: Four genetically different chromosomes each- A. Chromatin will not condense
- B. The nuclear membrane will not disappear
- C. Centrioles will not move to the opposite poles
- D. Migration of chromatids to the opposite poles will not occur
Explanation: Colchicine is a chemical that disrupts the formation of the spindle fibers necessary for chromatid separation during mitosis.
Correct answer: Migration of chromatids to the opposite poles will not occur- A. Mitosis
- B. Meiosis
- C. S-phase
- D. G2 phase
Explanation: The correct answer is meiosis. Meiosis is characterized by two sequential divisions, meiosis I and meiosis II, which result in a reduction…
Correct answer: Meiosis- A. Primary constriction of a chromosome
- B. Point where two sister chromatids meet
- C. Region of DNA in the middle of a chromosome
- D. Protein complex where spindle fibres are attached
Explanation: The correct answer is Option D. The kinetochore is a protein complex that forms at the centromere of each chromosome and serves as the…
Correct answer: Protein complex where spindle fibres are attached- A. An octamer of histone proteins
- B. A length of RNA coiled around a core of histones
- C. A length of DNA coiled around a core of histones
- D. Two polypeptide strands connected by histone protein
Explanation: A nucleosome is the fundamental unit of chromatin structure in eukaryotic cells.
Correct answer: A length of DNA coiled around a core of histones- A. DNA duplication
- B. Spindle fiber formation
- C. Cytoplasmic division
- D. Daughter cells production
Explanation: B is the correct option Because, amitosis is a type of direct cell division in which the nucleus divides without the formation of spindle…
Correct answer: Spindle fiber formation- A. 15
- B. 30
- C. 60
- D. 90
Explanation: Number of chromosomes in G₂ = 30Each chromosome = 2 sister chromatidsSo, total sister chromatids =30 × 2 = 60.So, C is the correct option.
Correct answer: 60535. The given graph shows the amount of DNA in a cell during a cell cycle.The stage X is identified as:
- A. Prophase
- B. Anaphase
- C. Interphase
- D. Metaphase
Explanation: X represents interphase. In the S phase of interphase DNA replicates and increases.
Correct answer: Interphase- A. Diploid number of duplicated chromosomes
- B. Haploid number of duplicated chromosomes
- C. Diploid number of unduplicated chromosomes
- D. Haploid number of unduplicated chromosomes
Explanation: Meiotic division, also known as meiosis, is the process by which a single cell divides twice to produce four cells containing half the…
Correct answer: Haploid number of unduplicated chromosomes- A. Leptotene
- B. Zygotene
- C. Diplotene
- D. Pachytene
Explanation: Zygotene is the sub-phase of Prophase-I where synapsis begins, homologous chromosomes start pairing to form bivalents.Option B is the…
Correct answer: Zygotene- A. Down syndrome (mongolism)
- B. Phenylketonuria (PKU)
- C. Turner's syndrome
- D. Klinefelter's syndrome
Explanation: Phenylketonuria (PKU) is a genetic disorder that results from a mutation in a specific gene responsible for metabolizing the amino acid…
Correct answer: Phenylketonuria (PKU)- A. Increase the chances of mutation
- B. Increase the growth rate of organisms
- C. Replace the worn-out cells by producing identical cells
- D. Maintain the diploid number of chromosomes in zygote
Explanation: The main purpose of meiosis in sexually reproducing organisms is to produce haploid gametes.
Correct answer: Maintain the diploid number of chromosomes in zygote- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: B represents S phase during which DNA replicates.So option B is correct option.
Correct answer: Option B