1. The given graph shows the change in DNA content j 4. during various phases (A to D) in a typical mitotic cell cycle. Identify the phases and select the correct option.
2. The reappearance of nucleolus towards the end of mitosis is attributed to
(a) nuclear envelope
(b) the specific region of satellite chromosome
(c) the reassemblage of some macromolecules of nucleolus, lost during prophase
(d) the rearrangement of histones present in the nucleus.
3. Chromosome number is reduced during meiosis because the process consists of
(a) two cell divisions without any chromosome replication
(b) a single cell division without any chromosome replication
(c) two cell divisions in which half of the chromosomes are destroyed
(d) two cell divisions and only a single round of chromosome replication.
(a) is the same as prophase, metaphase anaphase and telophase
(b) includes stages G,, S and G2
(c) requires the use of polar fibres and kinetochore fibres
(d) rarely occurs.
5. In which phase of mitosis, the chromosome move towards the poles?
(a) Prophase (b) Metaphase
(c) Telophase (d) Anaphase
6. Which of the following is not a function of mitotic cell division?
(a) Production of gametes
(b) Asexual reproduction
(d) None of the above.
7. During cytokinesis in plants
(a) a bundle of actin microfilaments called the contractile ring, pinch the cell in half
(b) small vesicles, directed by the phragmoplast, move to the spindle
(c) a cleavage furrow encircles the cell
(d) cytoplasmic division is called cleavage.
8. Which of the following occurs during meiosis but not during mitosis?
(a) Chromosomes align at the metaphase plate.
(b) Chromosomes condense.
(c) Chromosomes migrate to opposite poles.
9. At the end of telophase-l and cytokinesis there are
(a) 4 haploid cells (b) 2 diploid cells
(c) 1 haploid ovum and 3 polar bodies
(d) 2 haploid cells.
10. Synapsis occurs during
(a) anaphase-l (b) prophase-l
(c) cytokinesis (d) Prophase-ll.
11. During anaphase-ll
(a) homologues separate and migrate towards opposite poles
(b) sister chromatids separate and migrate towards opposite poles
(c) nuclei reform
(d) chromosomes line up in a single row.
12. Cytokinesis is the
(a) exchange of homologous regions of non-sister chromatids
(b) formation of tetrads
(c) independent assortment of chromosomes
(d) division of one cell into two.
13. Centrioles separate during
(b) prophase-l and prophase-ll
(c) metaphase-l and metaphase-ll
(d) anaphase-l and anaphase-ll.
14. Regions where non-sister chromatids cross are called
(a) inversions (b) homologues
(c) tetrads (d) chiasmata.
15. Which of the following is not true for a cell plate?
(a) It forms at the site of the metaphase plate.
(b) It results from the fusion of microtubules.
(c) It fuses with the plasma membrane.
(d) All of the above.
16. Match Column I with Column II and select the correct option from the codes given below.
17. Cells were cultured in a medium containing heavy
isotope of phosphorous till the entire DNA complement had only this isotope. Subsequently some cells were transferred to a medium with the normal isotope of phosphorous. After a certain period some cells were harvested and analysed for heavy phosphorous. It was found that only 6.25% of phosphorous in DNA was heavy. How many times the cells must have divided?
(a) Twice (b) 10 times
(c) 8 times (d) 4 times.
18. For a somatic cell with 2n = 4, which of the following is true?
(Note G1 – growth phase 1, G2 – growth phase 2, M – metaphase, P-prophase andT-telophase)
(a) (Number of chromatids) G2 = 4;
(Number of chromosomes) G1 = 4
(b) (Number of chromatids) G1 = 2;
(Number of sister chromatids) T = 8
(c) (Number of chromatids) P = 8 (Number of chromosomes) G2 = 4
(d) (Number of chromatids) G2 = 4;
(Number of chromosomes) M = 8.
19. Ɣ-radiations interact directly with the genetic material and induce DNA damage. The maximum damages are expected when the cells are irradiated at
(a) G1 phase (b) S phase
(c) G2 phase (d) M phase.
20. What is the approximate duration of cell cycle for a mammalian cell?
(a) 90 min (b) 24 hrs
(c) 24 days (d) 12 hrs.
21. Which of the following statements are correct for cell cycle?
I. Cell cycle is the sequence of events involving growth and division of a cell from the time of its formation to its own division into daughter cells.
II. Cell growth (in terms of cytoplasmic increase) is a continuous process.
III. DNA synthesis occurs only during one specific stage in the cell cycle.
IV. The replicated chromosomes (DNA) are distributed to daughter nuclei during cell division.
(a) I and III (b) I and II
(c) III and IV (d) I, II III and IV.
22. What is the approximate percentage duration of cell cycle that comes under interphase in humans?
(a) 99% (b) 95%
(c) 25% (d) 5%.
23. Disjunction refers to
(a) the separation of homologous chromosomes at anaphase -1
(b) the type of chromosomal aberration in which there is loss of a part of a chromosome
(c) incompatibility in fungi and other thallophytes
(d) modification of gene action by a nonallelic gene.
24. G0– phase is
(a) the phase after G2-phase, in which nucleus divides
(b) the phase after M-phase, in which daughter cell enters the new cell cycle
(c) the phase of arrest of cell cycle and the onset of differentiation
(d) all of the above.
25. Mature nerve cells are incapable of cell division. These cell are probably considered in
(a) G2-phase (b) S-phase
(c) Mitosis (d) Go-phase.
26. Select the correct statement from the following.
(a) Division of the cytoplasm occurs before the division of the nucleus.
(b) Division of the nucleus occurs before the division of the cytoplasm.
(c) Both the division of the nucleus and cytoplasm occurs at the same- time.
(d) None of the above.
27. The spindles are formed of
(a) chromosome (b) actin
(c) microtubules (d) myosin.
28. What is the nature of cells formed at the end of meiosis-ll ?
(a) Haploid (b) Diploid
(c) Tetrad (d) None of these.
29. Diakinesis is marked by
(a) terminalization of chiasmata
(b) degeneration of nucleolus
(c) disintegration of nuclear envelope
(d) all of the above.
30. Arrange the following events of meiosis in a proper sequence and select the correct option.
I. Terminalization II. Crossing over
III. Synapsis IV. Disjunction of genome
(a) IV, HI, II and I (b) III, II, I and IV
(c) II I, IV and III (d) I, IV, III and II
31. Which stage of meiosis is depicted in the given figure?
(a) Telophase-I (b) Anaphase-I
(c) Metaphase-I (d) Prophase-I.
32. Prophase-I of meiosis is different from prophase of mitosis because in prophase-l
(a) nuclear membrane breaks down
(b) chromosomes become visible
(c) homologous chromosomes pair up
(d) spindle forms.
33. Which of the following stages is responsible for the appearance of lampbrush chromosomes?
(a) Meiotic prophase (b) Mitotic prophase
(c) Mitotic anaphase (d) Mitotic metaphase.
34. Which one of the following precedes re-formation of the nuclear envelope during M-phase of the cell cycle?
(a) Decondensation of chromosomes and reassembly of the nuclear lamina.
(b) Transcription from chromosomes and reassembly of the nuclear lamina.
(c) Formation of the contractile ring and formation of the phragmoplast.
(d) Formation of the contractile ring and transcription from chromosomes.
35. When the number of chromosomes is already reduced to half in the first reductional division of meiosis, what is the necessity of second meiotic division ?
(a) The division is required for the formation of four gametes.
(b) Division ensures equal distribution of haploid chromosomes.
(c) Division ensures equal distribution of genes on chromosomes.
(d) Division is required for the segregation of replicated chromosomes.
36. Which of the following are correctly matched pairs?
I. Leptotene-The chromosomes become invisible.
II. Zygotene – Pairing of homologous chromosomes.
III. Pachytene-Formation of lampbrush chromosomes.
IV. Diakinesis-Terminalization of chiasmata takes place.
(a) I and II (b) III and IV
(c) II and IV (d) II and III
37. The members of a homologous pair of chromosomes
(a) are identical in size and appearance
(b) contain identical genetic information
(c) separate and move to opposite poles of the cell during mitosis
(d) are found only in haploid cells.
38. In diploid organism, phenomenon of crossing over is responsible for
(a) linkages between genes
(b) recombination between homologous genes
(c) segregation between genes
(d) dominance of gene.
39. Which of the following statements are correct for meiosis?
I. Meiosis is a double division. It gives rise to four cells.
II. The cells undergoing meiosis may be haploid or diploid.
III. No bouquet stage is recorded.
IV. Pairing or synapsis of homologous chromosomes takes place during zygotene of prophase-l and continues upto metaphase-l.
(a) I Only (b) I and IV
(c) II and III (d) All of these.
40. If a tissue has at a given time 1024 cells, how many cycles of mitosis had the original parental single cell undergone?
(a) 512 (b) 100
(c) 1024 (d) 256
41. The durations of mitotic stages in two situations, (A and B) are tabulated below
Following are some interpretations
I. ‘A’ and ‘B’ indicate the same plant tissue grown at higher and lower temperatures respectively.
II. ‘A’ indicates a slow growing plant species and ‘B’ indicates a fast growing plant species.
III. Both A’ and ‘B’ indicate dormant plant tissues with excessively long interphase.
The correct interpretations is/are
(a) I and III (b) II and III
(c) III only (d) II only.
42. A cell undergoing meiosis produces four daughter cells, two of which are aneuploids, while two are haploid.
This can occur due to
(a) non-disjunction during first meiotic division only
(b) non-disjunction during second meiotic division only
(c) non-disjunction during either first or second meiotic divisions
(d) non-disjunction during both first and second meiotic divisions.
43. Match the graphs (P-S) showing quantitative change in DNA content at each of four stages in the cell cycle (G1, S, G2, M) with the given statements regarding cell activity and response
I. Taxol treatment, which prevents microtubule depolymerization, arrests the cell at this stage.
II. With a mitogen treatment, such as an epidermal growth factor, an arrested cell at this stage proceeds to the next stage of the cell cycle.
III. The cell cycle check point at this stage confirms that DNA duplication is complete before the cell proceeds to next stage
(a) I – P, II – Q, III – R
(b) I – Q, II – S, III – R
(c) I – R, II – Q, III – S
(d) I – P, II – S, III – Q
44. Which one of the following graphs shows the relative change in the amount of mitochondrial DNA of a cell undergoing mitosis?
45. Given below are some processes which involve mitosis or meiosis categorise them and select the correct option.
2. Maintenance of chromosome number
3. Formation of gametes
4. Evidence of basic relationship among all organisms
5. Growth and repair
46. The given figure is a schematic break-up of the phases/ stages of cell cycle. Select the correct option regarding it.
(a) ‘a’ represents karyokinesis which is the division of cytoplasm.
(b) ‘b’ is telophase which is just reverse of prophase.
(c) ‘c’ is the best phase to count total number of chromosomes in any species.
(d) In’d’ stage, replication of DNA takes place on the template of the existing DNA.
47. Given diagram shows variations in the amount of DNA of a developing eukaryote. What the arrow denotes?
(a) First meiotic anaphase
(b) Second meiotic anaphase
(c) Mitotic anaphase
(d) Mitotic Telophase
48. The diagram represents an eukaryotic cell cycle divided into 5 phases (A – E).
Match phases A-E of the diagram with the processes 1-5 given below.
2. Main growth period of the cell
3. Duplication of DNA
4. Quiescent cells
5. Last stage of interphase