Objective Questions

Question. Synapsis occurs between
(a) spindle fibres and centromeres.
(b) mRNA and ribosomes.
(c) a male and female gamete.
(d) two homologous chromosomes.

Question. The synaptonemal complex appears
(a) between homologous chromosomes.
(b) in zygotene stage.
(c) composed of DNA + protein.
(d) All of the above

Question. Crossing over occurs between
(a) sister chromatids of homologous chromosomes.
(b) non-sister chromatids of homologous chromosomes.
(c) sister chromatids of non-homologous chromosomes.
(d) non-sister chromatids of non-homologous chromosomes.

Question. Recombination involves
(a) crossing over
(b) chromosome duplication
(c) spindle formation
(d) cytokinesis

Question. In which stage, the chromosomes appear thin and long thread-like ?
(a) Zygotene
(b) Leptotene
(c) Pachytene
(d) Prophase

Question. Electron micrographs of which stage indicate that chromosomes accompanied by the formation of complex structure called synaptonemal complex?
(a) Zygotene
(b) Pachytene
(c) Diplotene
(d) Diakinesis

Question. Cell plate grows from
(a) wall to centre
(b) centre to walls
(c) one wall to another
(d) simultaneously

Statement Type Questions

Question. Which of the following statement is not true for homologous chromosome pairs ?
(a) They come from only one of the individual’s parents.
(b) They usually contain slightly different versions of the same genetic information.
(c) They segregate from each other during meiosis I.
(d) They synapse during meiosis I.

Question. Which one is correct about bivalent ?
(i) Bivalent are tetrads.
(ii) A bivalent means 4 chromatids and 2 centromere.
(iii) One bivalent consists of 2 homologous chromosomes each and sister chromatids.
(iv) Bivalents formation occurs in zygotene.
(a) All of these
(b) Only (iii)
(c) (iii) and (iv)
(d) Only (iv)

Assertion/Reason Type Questions

In the following questions, a statement of Assertion is followed by a statement of Reason.
(a) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
(b) If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
(c) If Assertion is true but Reason is false.
(d) If both Assertion and Reason are false.

Question. Assertion: Karyokinesis follows cytokinesis.
Reason: Karyokinesis is the division of cytoplasm into two daughter cells.

Question. Assertion: The crossing over is an enzyme-mediated process.
Reason: The enzyme involved in crossing over is lyase.

Matching Type Questions

Question. Find out the wrongly matched pair of the stage of prophase I with their feature.
(a) Zygotene – Synaptonemal complex
(b) Pachytene – Mutation
(c) Diplotene – Chiasmata
(d) Diakinesis – Terminalization

Question. Which of the following pair is correctly matched ?
(a) G₁ – Second growth phase
(b) S – Duplication phase
(c) G₂ – Synthesis phase
(d) G₀ – Quiescent stage

Critical Thinking Type Questions

Question. “G0” state of cells in eukaryotic cell cycle denotes
(a) check point before entering the next phase.
(b) pausing in the middle of a cycle to cope with a temporary delay.
(c) death of a cell.
(d) exit of cells from cell cycle.

Question. Mitosis is the process by which eukaryotic cells
(a) expose the genes for protein synthesis.
(b) become specialized in structure and function.
(c) multiply.
(d) grow.

Question. In animal cells, cytokinesis involves
(a) the separation of sister chromatids.
(b) the contraction of the contractile ring of microfilament.
(c) depolymerization of kinetochore microtubules.
(d) a protein kinase that phosphorylates other enzymes.

Question. In Meiosis,
(a) division of nucleus twice but DNA replicates only once.
(b) division of nucleus twice and DNA replicates twice.
(c) division of nucleus once and replication of DNA is also once.
(d) division of nucleus once and DNA – replication is twice.

Question. Number of bivalents are 8 in prophase I. What is the number of chromosomes during anaphase II ?
(a) 8
(b) 4
(c) 13
(d) 32

Question. The separation of two chromatids of each chromosome at early anaphase is initiated by
(a) the interaction of centromere with the chromosomal fibres.
(b) the elongation of metaphasic spindle.
(c) the force of repulsion between the divided kinetochores.
(d) All of the above.

Question. Identify the meiotic stage in which the homologous chromosomes separate while the sister chromatids remain associated at their centromeres.
(a) Metaphase I
(b) Metaphase II
(c) Anaphase I
(d) Anaphase II

Question. At which stage, the homologous chromosomes separate due to repulsion, but are yet held by chiasmata ?
(a) Zygotene
(b) Pachytene
(c) Diplotene
(d) Diakinesis

Question. Crossing over
(a) is important in genetic recombination.
(b) makes a cell become cancerous.
(c) is a key process that occurs during mitosis.
(d) is an important mechanism of chromosome repair.

Question. Which of the following does not lead to genetic variability?
(a) Random fertilization.
(b) Crossing over during meiosis.
(c) Division of chromosomes during anaphase of mitosis.
(d) Orientation of chromosomes during metaphase I of meiosis.

Question. ‘X’ ensures the production of ‘Y’ phase in the life cycle of sexually reproducing organisms whereas fertilization restores the ‘Z’ phase.
Identify X, Y and Z.
. (a) X- Mitosis, Y – haploid, Z – haploid
(b) X- Mitosis, Y – diploid, Z – diploid
(c) X- Meiosis, Y – haploid, Z – diploid
(d) X- Meiosis, Y – diploid, Z – diploid

Question. The following events occur during the process of meiosis.
Arrange the following events of meiosis in the correct sequence.
I. Terminalization
II. Crossing over
III. Synapsis
IV. Disjunction of genomes
(a) I, II, III, IV
(b) II, III, IV, I
(c) III, II, I, IV
(d) IV, I, II, III