1. The second meiotic division leads to
a) Separation of sex chromosomes
b) Fresh DNA synthesis
c) Separation of chromatids and centromere
d) Separation of homologous chromosomes

2. In meiosis, chromosome number becomes
a) Half of its parent chromosome
b) Same as that of parent chromosome
c) One fourth of its parent chromosome
d) None of the above

3. Consider the following statements about plant cytokinesis
I. It usually occurs by cell plate method
II. The spindle usually persists during cytokinesis
III. Cell plate grows centrifugally
Which of the statements given above are correct?
a) I and II
b) I and III
c) II and III
d) I, II and III

4. I.    A    phase corresponds to the interval between mitosis and initiation of DNA replication
II. In animal cells, during the    B    phase, DNA replication begins in the nucleus and the centriole duplicates in the cytoplasm
III. During the    C    phase, proteins are synthesized for the preparation of mitosis, while cell growth continues
Identify the blanks (A-C) to complete the given statements (I-III) with reference to NCERT textbook
a) A-G₂, B-S, C-G₁
b) A-S, B-G₂, C-G₁
c) A-S, B-G₁, C-G₂
d) A-G₁, B-S, C-G₂

5. Select the matched ones. I . S-phase - DNA replication
II. Zygotene - Synapsis
III. Diplotene - Crossing over
IV. Meiosis - Both haploid and diploid cells
V G₂-phase - Quiescent stage
a) I and II only
b) III and IV only
c) III and V only
d) I,III and V only

6. Which type of cell division helps in regeneration of cells?
a) Mitosis
b) Amitosis
c) Meiosis
d) Karyokinesis

7. Which of the following statement(s) is/are not correct about meiosis?
I. Meiosis involves pairing of homologous chromosomes and recombination between them
II. Two diploid cells are formed at the end of meiosis-II
III. Meiosis involves two sequential cycles of nuclear and cell division called meiosis-I and meiosis-II, but only a single cycle of DNA replication
IV. Meiosis-I is initiated after the parental chromosome replication which produce identical sister chromatids at the S-phase
The correct option is
a) I and III
b) II only
c) II and III
d) I, II, III and IV

8. Choose the correct statements regarding cell cycle
I. Interphase is called the resting phase
II. Interphase is the time during which the cell is preparing for division
III. The interphase is divided into phases, i.e.,G₁, S and G₂-phase
IV. Interphase represents the phase between the two successive M-phases
The option with correct statements is
a) I and IV
b) II and III
c) I and III
d) I, II, III and IV

9. Crossing over occurs during
a) Leptotene
b) Diplotene
c) Pachytene
d) Zygotene

10. During meiosis, the alleles of the parental pair separate or segregated from each other. How many allele(s) is/are then transmitted to a gamete?
a) Four
b) Two
c) Six
d) One

11. The phragmoplast is organized at the
a) Beginning of anaphase
b) End of anaphase
c) Beginning of telophase
d) End of telophase

12. The morphology of chromosomes can be studied most easily in
a) Prophase
b) Metaphase
c) Anaphase
d) Telophase

13. Identify the correct stage of mitosis by viewing the diagram carefully?
a) Interphase
b) Prophase
c) Metaphase
d) Anaphase

14. The number of chromosomes becomes half in
a) Anaphase-I
b) Anaphase-II
c) Telpohase-I
d) Telophase-II

15. In which of the following phase of cell cycle, mitotic division got arrested?
a) G₂-phase
b) G₀-phase
c) S-phase
d) M-phase

16. Which of the following phase of cell cycle is also known as the resting phase?
a) G₁-phase
b) M-phase
c) S-phase
d) Interphase

17. Differentiated cell remains at which stage?
a) G₁
b) G₂
c) G₀
d) M

18. The process of cytokinesis refers to the division of
a) Nucleus
b) Chromosomes
c) Cytoplasm
d) None of these

19. Choose the correct combination of options to select the correct statement for prophase
I. Chromosomal material condenses to form compact mitotic chromosomes
II. The assembly of mitotic spindle is initiated by the microtubules
III. Cells do not show organelles when viewed under the prophase
IV. The nucleolus or nucleoli degenerate completely
a) I only
b) II and III
c) I and II
d) All of these

20. Which of the following event distinguishes prophase-I of meiosis from prophase of mitosis?
a) Nuclear membrane breaks down
b) Chromosomes become visible
c) Homologous chromosomes pair up
d) Spindle forms

1 (c)
Meiosis first is allowed by second meiotic division, which is essentially a mitotic division and is referred as mitotic. In anaphase-II of meiosis-II, the chromosome and centromere divide. The sister chromatids separate and move towards opposite pole.

2 (a)
In meiosis (meiotic-I), chromosome number becomes half to that of parent chromosome.

3 (d)
Plant cytokinesis usually occurs by cell plate method. The spindle usually pesists during cytokinesis. Central part of spindle grows in size and forms an interdigited complex called phragmoplast. Cell plate grows centrifugally

4 (d)
A-G₁, B-S, C-G₂.
Post reproductive stage of a cell includes cell growth. The term cell growth is used in the contexts of cell development and cell division. As we are concerned about growth (development) only, it refers to the growth of cell that is to increase in cytoplasmic and organelle volume that is in G₁-phase
S-phase is the sub-phase between G₁-phase and G₂-phase, during which DNA synthesis or replication takes place.
In animal cells, during the S-phase, DNA replication begins in the nucleus and the centriole duplication in the cytoplasm. The amount of DNA per cell doubles in the nucleus. If the initial amount of DNA is denoted as 2C, then it increases to 4C. However, there is no increase in the chromosome number

5 (a)
S or synthetic phase marks the period during which DNA synthesis or replication takes place. During this phase, the amount of DNA per cell doubles.
The second stage of prophase-I is called zygotene. During this stage, chromosomes start pairing together and this process of association is called synapsis. Such paired chromosomes are called homologous chromosomes. Synapsis is accompanied by the formation of a complex structure called synaptonemal complex. 

6 (a)
Mitosis is one of the types of cell division, which helps in regeneration. Because it keeps all the somatic cells of an organism genetically similar, so that they are able to regenerate a part or whole of the organism

7 (b)
During meiosis, four haploid cells are produced by reductional division from a single diploid cell. Parent cell contains replicated chromosomes, but the daughter cells contains unreplicated chromosomes

8 (d)
The interphase, as called the resting phase, is the time during which the cell is preparing for division by undergoing both cell growth and DNA replication.
It is the phase between two successive M-phases
The interphase is divided into three further classes
G₁-phase (Gap 1), S-phase (synthesis) and G₂-phase (Gap 2)

9 (c)
Crossing over occurs during pachytene or thick thread or pachynema substage of prophase-I of meiosis. During this stage, an exchange of portions of chromatids between homologous chromosomes occur. At chiasma, the chromatids break rejoin in such a way that sections are exchanged.

10 (d)
Out of two alleles present at the same locus of two chromosomes of a homologous pair, one is transmitted to a gamete as the later receive one chromosome of a homologous pair.

11 (b)
In plant cells, cytokinesis occurs by cell plate formation. A number of elements called phragmoplasts are derived from ER and Golgi body. These elements line up at equator during anaphase and later fuse to form cell plate.

12 (b)
During metaphase, the nuclear envelope disintegrates and the chromosomes are spread through the cytoplasm of the cell. Condensation of chromosomes is completed and it can be observed under the microscope. At this stage, the morphology as well as the number of chromosomes can be easily studied

13 (a)
Interphase has variable duration. During this period, the DNA of chromosomes replicates. Chromosome material is in the form of very loosely coiled threads called chromatin. Centrioles already have replicated

14 (a)
During anaphase-I, the number of chromosomes become half.

15 (b)
G₀-phase.
Some cells that do not divide further, exit G₁-phase and enter an inactive stage called quiescent stage (G₀) of the cell cycle. Cells in this stage remains metabolically active but no longer proliferate unless called on to do so depending on the requirement of the organism

16 (d)
The interphase is also called the resting phase. It is the time during  which the cell gets prepared for division by undergoing both cell and DNA replication in an orderly manner

17 (c)
The cells, which do not divide further, do not proceed beyond the G₁-phase and start undergoing differentiation into specific type are said to be in G₀-phase.

18 (c)
Division of cyptoplasm is called cytokinesis ( Gr. kitos=cell; kinesis=movement).

19 (d)
At the end of prophase, several characteristic events can be observed. Chromosomal material condenses to form compact mitotic chromosomes. Two chromatids attach together to form chromosomes
Assembly of mitotic spindle is initiated by, microtubules (proteinaceous components) of the cell cytoplasm. When observed under the microscope cells at the last stage of prophase, do not shows cell organelles like, Golgi complexes, endoplasmic reticulum, nucleolus and the nuclear envelope

20 (c)
Prophase-I of Meiosis Prophase of Mitosis
Prophase-I is very long and elaborate, comprising 5 sub-phases
Prophase chromosomes appear double from the very start
There is no pairing of homologous
Chromosomes, hence no chance of crossing over Prophase is relatively very short and simple
Prophase-I chromosome do not look double in the beginning
Homologous chromosomes pair and often undergo crossing over in prophase-I  

21. During mitosis, number of chromosomes gets
a) Change
b) No change
c) May be change if cell is mature
d) May be change if cell is immature

22. I. Chromosomes cluster at opposite spindle poles their identity is lost as discrete elements
II. Nuclear envelope assembles around the chromosome clusters
III. Nucleolus, Golgi complex and ER reform
Above features indicates which phase of mitosis
a) Anaphase
b) Telophase
c) Cytokinesis
d) S-phase

23. What would be the change in the chromosome number, during S-phase?
a) No change
b) The number of chromosome doubles
c) The number of chromosome doubles only in case of diploid cell
d) The number of chromosome doubles only in case of haploid cell

24. Arrange the following events of meiosis in a correct sequence and choose the correct option
I. Terminalisation
II. Crossing over
III. Synapsis
IV. Disjunction of genomes
a) IV, III, II and I
b) III, II, I and IV
c) II, I, IV and III
d) I, IV, III and II

25. What is the approximate percentage duration of cell cycle that comes under interphase in humans?
a) 99%
b) 95%
c) 25%
d) 5%

26. Which of the following stage of meiosis is responsible for deciding genetic constitution of gametes?
a) Metaphase-II
b) Anaphase-II
c) Metaphase-I
d) Anaphase-I

27. …A…. mitotic cell division is only seen in the diploid somatic cells, while the …B… can show mitotic divisions in both haploid and diploid cells.
Identify A and B form the options given below
a) A-Animals; B-plants
b) A-Plants; B-animals
c) A-Bacterial; B-viruses
d) None of these

28. Given diagram indicates which of the following phase of mitosis? Choose the correct option

a) Interphase
b) Prophase
c) Metaphase
d) Anaphase

29. In meiosis, the chromosome number
a) Reduces by half
b) Increase by twice
c) Increase by four times
d) Reduces by one-fourth

30. The phase between two successive M-phase is called
a) S-phase
b) G₁-phase
c) G₂-phase
d) Interphase

31. At the end of meiosis-II, number of haploid cells formed are
a) Two
b) Four
c) Eight
d) None of these

32. The transition between meiosis-I and meiosis-II is
a) Interkinesis
b) Cytokinesis
c) Diakinesis
d) Karyokinesis

33. Synapsis occurs between
a) A male and a female gamete
b) mRNA and ribosomes
c) Spindle fibres and centromere
d) Two homologous chromosomes

34. In which stage of cell division, chromosomes are most condensed?
a) Prophase
b) Metaphase
c) Anaphase
d) Telophase

35. Which of the protein is found in spindle fibre?
a) Tubulin
b) Albumin
c) Mucin
d) Haemoglobin

36. Which of the following events occurs during G₁-phase?
a) DNA replication
b) Growth and normal function of cell
c) Mutation
d) Fertilization

37. Select the correct statements regarding S-phase of interphase
I. Occurs between G₁andG₂
II. DNA replication begins in the nucleus
III. Centrioles duplicate in the cytoplasm
IV. As DNA is doubled, number of chromosomes also doubles
The option with correct statements is
a) IV and III
b) I, II, III and IV
c) II, III and IV
d) I, II and III

38. A material, which arrests cell division, is obtained from
a) Crocus
b) Colchicum
c) Dalbergia
d) Chrysanthemum

39. During cell division, sometimes there will be failure of separation of sister chromatids. This event is called
a) Interference
b) Complementation
c) Non-disjunction
d) Coincidence

40. I. The cells that do not divide further, exit G₁-phase to enter an inactive stage called …A… phase of the cell cycle II. The cells that are in G₂-phase definitely continue with the …B… phase. Identify A and B to complete the given NCERT statements
a) A-G₀; B-S
b) A-S; B-G₀
c) A-M; B-G₀
d) A-G₀; B-M

21 (b)
Mitosis was first observed by Strasburger and termed by W Flemming. During mitosis, chromosome number remain same in the daughter cells. During meiosis (reduction division), the chromosome number reduced to half in the daughter cells.

22 (b)
Telophase is the reverse stage of prophase. During this phase, the cytoplasmic viscosity decreases and the two chromosome groups reorganize themselves into nuclei. A nucleae envelope appears outside the nucleoplasm collected in the area of chromatin. Spindle fibres disappear around the poles and Golgi complex and endoplasmic reticulum are reformed

23 (a)
During S-phase, there is no increase in the chromosomes number. If the cell has diploid or 2n number of chromosomes at G_1, even after S-phase the number of chromosomes remains the same, i.e., 2n

24 (b)
The correct sequence is
Synapsis → crossing over → terminalisation → disjunction of genomes

25 (b)
The interphase takes approximate 75-95% of the entire generation time

26 (d)
The paternal and maternal chromosomes of each homologous pair segregates during anaphase-I. Although, both (maternal and paternal) chromosomes of a homologous pair have the genes for the same traits, either chromosome of a pair may carry different alleles of the same genes. Therefore, in anaphase-I, homologous chromosomes introduces genetic variability

27 (a)
A-Animals; B-Plants

28 (a)
At the onset of anaphase, each chromosome arranged at the metaphase plate is split simultaneously and the two daughter chromatids, now referred to as chromosomes of the future daughter nuclei, begin their migration towards the two opposite poles. As each chromosome moves away from the equatorial plate, the centromere of each chromosome is towards the pole and hence at the leading edge, with the arms of the chromosome trailing behind. Thus, anaphase stage is chracterised by the following key events
 Centromeres split and chromatids separate
 Chromatids move to opposite poles

29 (a)
After meiosis, the chromosomes get reduce by half, producing haploid cells. The sperm and the egg are haploid cells and when they fuse during fertilization, they produce diploid original

30 (d)
The phase between two successive M-phases is called interphase.
The M-phase represents the phase when the actual cell division or mitosis occurs and the interphase represents the phase between two successive M-phases. It is significant to note that in the 24 hour average duration of cell cycle of a human cell, cell division proper lasts for only about an hour. The interphase lasts more than 95% of the duration of cell cycle

31 (b)
Meiosis start with one diploid containing copies of chromosome, one from mother and one from father. The cell divides twice, producing up to four haploid cells containing one copy of each chromosome

32 (a)
Interkinesis is the transition stage between meiosis-I and meiosis-II.

33 (d)
In zygotene of prophase-I, homologous chromosomes pair up. This process is called synapsis. One chromosome of the pair is from the male parent and other from the female parent.

34 (b)
In metaphase, chromosomes are shortest and show maximum condensation. Chromosomes are arranged at equatorial metaphasic plate. Structure, size and number of chromosomes are best studied at metaphase.

35 (a)
Microtubules are mainly composed of tubulin protein. These are found only in eukaryotic cellular structures like cilia, flagella, centriole, basal body, spindle fibre, etc.

36 (b)
G₁-phase is called as pre-synthetic phase or post-mitotic phase. It is the longest phase of cell cycle. In G₁-phase, a cell has two options:
 Continues cycle and enters S-phase
 Stops cell cycle and enters G₀-phase for undergoing differentiation.

37 (d)
S-phase is the sub-phase between G₁-phase and G₂-phase, during which DNA synthesis or replication takes place.
In animal cells, during the S-phase, DNA replication begins in the nucleus and the centriole duplication in the cytoplasm. The amount of DNA per cell doubles in the nucleus. If the initial amount of DNA is denoted as 2C, then it increases to 4C. However, there is no increase in the chromosome number

38 (b)
Colchicine is an antimitotic drug (alkaloid) which is obtained from Colchicum (family-Liliaceae). It binds to one tubulin molecule and prevents its polymerization. The depolymerisation of tubulin result in disappearance of mitotic spindle blocking the cell’s mitotic chromosomal division at metaphase and anaphase.

39 (c)
Non-disjunction occurs when a pair of homologous chromosomes do not separate in meiosis but migrate to the same pole of the cell, resulting in an even number of chromosomes being present in the daughter cells.

40 (d)
A-G_0; B-M