CELL DIVISON INTRODUCTION 1. In unicellular organism like bacteria,  W.Flemming at first studied mitotic division protozoans, asexual reproduction takes place in Salamander. by  Strasburger discovered meiosis. (A) binary  Strasburger gave the form prophase, (B) metaphase, anaphase, telophase. (C) meiosis  Term meiosis was given by Farmer and (D) sporic meiosis Moore. Ans. (A)  It is important for development, regeneration Solution. In unicellular organisms like bacteria, and reproduction. protozoans, asexual reproduction takes  Hormone cytokinin increases rate of cell place by binary fission division. 2. In amitosis which of the following is true TYPES OF DIVISION (A) no differentiation of chromosomes and  Amitosis spindle  Mitosis (B) chromosomes are equally distributed  Meiosis (C) does not degenerate & Amitosis (No spindle, No chromosome) remains intact  It is the simplest mode of at (D) distinct chromosomes do not appear in first described by Remak (1841). division  This type of division starts with elongation of Ans. (A) nucleus. Solution. In amitosis no differentiation of  Nucleus becomes dumbbell shaped, and gets chromosomes and spindle takes place, so it divided into two daughter nucleus. is a direct division  Nuclear division is followed by the division of EDU CATALYSERS cytoplasm and results in the formation of 3. The division of mitochondria and chloroplasts two daughter cells. occurs in  In this division, no spindle formation and no (A)mitosis distinct chromosome formation occurs. (B)meiosis Nuclear envelope remains intact. The (C)amitosis daughter cells are approximately (D)M phase the two equal halves of a parental cell. E.g. PPLO, Blue-green algae, Bacteria and 4. In mammals, the growth of foetal membranes Eukaryotic cells. Examples are (amnion, chorion, allantois, yolk sac), yeast-budding occurs by amitosis. cartilage of mammals takes place by  Amoeba multiple fission occurs by amitosis. (A) mitosis  division of meganucleus. (B) meiosis  Mammals-growth of foetal membranes (C) M phase (amnion, chorion, allantois, yolk sac) (D) amitosis  Division of mitochondria and chloroplasts. MITOSIS  Mitosis was discovered by Flemming in 1879 in animal cell and in plants cells by Strasburger in 1875.  Mitosis is a cell division in which parent cell divides to form two daughter cells, in which number of chromosome, amount of DNA, number and types of gene are equal to EXAMPLES parent cell.  It occurs in somatic cell (n, 2n, polyploid).  It is called indirect division.

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 Mitosis results in increase in the number of  Enzymes for DNA synthesis and amino acids cells in the body. for histone formation are CELL CYCLE formed.

Nucleolus produces rRNA, mRNA and tRNA. Cell division can be divided into two phases.   Metabolic rate of the cell becomes very high.  It may be called pre DNA synthesis phase. Interphase Division phase or M phase [Resting Phase] [Mitotic Phase] S-PHASE(SYNTHESIS PHASE)  Invisible phase of Mitosis.  Replication of DNA takes place. (DNA gets doubled)  Protein molecules called histones are synthesized that cover each strand of DNA.

INTERPHASE OF CELL CYCLE  Centrosome (Centriole) replicate is late  Interphase is the phase between two cell S-phase in cytoplasm

divisions, divided into three sub stages G1, S G2-PHASE and G . 2  [Step-II Phase or Pre Mitotic Phase]  In this phase, cell prepares itself for division  Tubulin protein synthesis starts for spindle and hence called as preparatory phase. formation.  It is the longest phase of cell cycle. It gets  This phase may be called post DNA synthesis completed approximately in 19-22 hours. phase.  It is also called resting phase (previously)  Cell division involves enormous expenditure  In this phase, cell remains metabolically of energy, thus cell stores ATP in G phase extremely active. 2  In this phase synthesis of protein, enzyme,  Cell organelles like golgibodies, chloroplast DNA and RNA takes place and mitochondria are formed.  After G phase cell enters the division or M-  Centrosome (Centriole) duplicates into two. 2 Thus two centrosomes (4centriole) are phase formed. EXAMPLES 1. The time period required for interphase is  Cell cycle can remain arrested only in G1 phase. Then G is called as G phase. about 1 0 G phase is found in the cells of permanent (A)60% (B)95%  0 tissue. (C)30% (D)50%  Cell cycle runs by a group of special proteins Ans. (B) “Cyclins and Cdks (MPF). Solution. Cell cycle has two phases, Interphase THREE SUB STAGES OF INTERPHASE and M-phase in which interphase takes more

G1 PHASE than 95% of time and M-phase takes less  Step-1 Phase or Post Mitotic Phase]- Most than 5%. variable phase with respect to duration. 2. Interphase is divided into three sub phases  Cell growth occurs in this phase, so most except– probably it is longest stage of interphase. (A)G1 phase (B)S phase  Most of the cell organelles duplicate. (C)G2 phase (D)G0 phase  Structural and functional proteins are Ans. (D) formed. Solution. Interphase is divided into three sub

phases i.e G1 phase, S-Phase and G2 Phase.

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G0 phase is not a part of interphase  They are activated when they are combined EDU CATALYSERS with a key protein called cyclin. 3. Decision of cell division occurs during …..  Kinase is an enzyme that removes a phase of cell cycle. phosphate group from ATP & add it to another protein. (A) G1 (B) G2  At some check points a kinase enzyme (C) S phase (D)G0 combines with cyclin & this moves the cell 4. All of the following takes place in S phase cycle forward. except  S-kinase is capable of starting the (A)Amount of DNA unchanged replication of DNA after it combines with S- (B)Amount of DNA becomes double in cyclin (G - Cyclin). After some time S-cyclin 1 nucleus is destroyed &S-kinase is no longer active. (C)Centriole duplicates in the cytoplasm  M-kinase is capable of turning on mitosis (D)Histone proteins are synthesized after binding with M-cyclin, (G -cyclin). CAUSE OF MITOSIS 2  The detail of cell cycle varied from organism  Kern plasm theory : Hertwig, says that to organism & different time in an organism. mitosis occurs due to disturbance in However certain characteristics are universal karyoplasmic index (KI) of cell. component of cell cycle control. V KI  n Division Phase VVC n

Here V = Volume of nucleus n V = Volume of cell c V – V = Volume of cytoplasm c n Karyokinesis Cytokinesis 1 KI  (Nuclear division) (Cytoplasmic division) Volume of cytoplasm MITOSIS CELL DIVISION CONTROL (A) Karyokinesis  A cell reproduces by performing an orderly It can be divided into four stages for the set sequences of irreversible events in which sake of convinience it duplicates its contents & then divides into (I) Prophase (II) Metaphase two. These events are known as cell cycle. (III) Anaphase (IV) Telophase Mitosis promoting factor  M-Cdk  Prophase : It is the longest phase. Its duration is 2·1% of the total time. It involves Degenerating M-cyclin three phases. M-cyclin (A) Early prophase : M G2 Cdk Cdk G 2  Chromatin undergoes dehydration to G S 1 S form long thin & coiled chromosomes that is called spiralization and their Degenerating S-cyclin ends are indistinct. They look like a ball S-cyclin S-Cdk of wool. This stage is called spireme  DNA replication promoting factor stage.  Molecular biologists identify the  Centrosomes move away from each biomolecules that control or drive the cell other and move towards opposite poles. cycle. Many biologists, worked with invertebrate or frog egg’s and others, with yeast cell or cell culture.  Scientists concluded that the activity of enzymes, known as cyclin dependant kinases (Cdk’s) regulates the cell cycle.

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fungi and Algae, formation of Intranuclear spindle takes place. Nuclear membrane exists.

(B) Metaphase :  Chromosomes are thick, shorten and distinct.  The shape, size and structure of chromosomes can be studied in the metaphase stage. (B) Mid prophase :  Spindle apparatus consists of Spindle fibres.  Chromosomes are thickened and shifted in It consists of 93-95% tubulin protein, 3-5% the peripheral part of nucleus. RNA and trace amount of actin, myosin &  Formation of Astral rays starts. Nuclear lipid. membrane starts to breakdown.  Nucleolus reduces in size. SPINDLE FIBRES ARE OF THREE TYPES. (C) Late prophase : (A) Continuous fibres : That connect two  Chromosomes are comparatively poles. thickened. Centrosomes have reached (B) Discontinuous fibres : They originate from the opposite poles. a pole and do not reach at other pole.  In this phase, nuclear membrane is (C) Chromosomal fibres : They connect disappeared. Nucleolus & ER are also chromosome and poles. disappeared.  The tightening of chromosomal fibres brings  Aster is formed at each pole by a pair of chromosomes at the equator. This process is centrioles and astral rays. Centrioles called congression or metakinesis. start the formation of spindle fibres.  The centromeres of all the chromosomes Centrosome helps in the initiation of arrange in linear sequence at the equator to cell division in animal cells by forming form single metaphase plate. spindle. In plant cells centrosome is  Kinetochore of chromosomes connect absent. chromosomes to the spindle fibre. Each  The spindle fibre arise from tubulin chromosome has two distinct chromatids. protein by gelation in the cytoplasm, The arms of each chromosome lie in thus in plant cell, centriole and asters different direction and the centromere lies have no role in the formation of spindle on the equator. apparatus. The middle broad part of spindle apparatus is called as equator. Points to remember : (1) Prometaphase : Some scientists considered prometaphase stage between prophase and metaphase. In this stage aster formation is completed. Formation of spindle fibres is also completed. Nuclear (III) Anaphase : membrane and nucleolus are  Anaphase Promoting Complex or APC completely disappeared. becomes activated. It causes equatorial (2) Eumitosis : Formation of division in each chromosome. As a result, extranuclear spindle and the no. of chromosomes become double. degeneration of nuclear membrane involve in it.  Now, half chromosomes move towards one (3) Premitosis : In some protists, pole and remaining half chromosomes move

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towards opposite pole by the constriction of (C) anaphase (D) telophase chromosomal fibre. It is called Anaphasic Ans. (B) movement. Solution. During prophase stage, chromatin  The chromosomes are inter-connected by fibers get condensed and coiled interzonal fibres. (spiralisation), to form highly thickened  At this time, centromere of each structures called chromosomes. chromosome lies towards poles and its arms 2. In Spiralization behind it. (A)Chromosomes become long and thread  The rate of Anaphasic movement of each like chromosome is 0·2 mm to 5mm / min. 20–25 (B) Chromosomes become short and thick ATP are consumed by a chromosome during (C)Chromosomes are scattered anaphasic movement.  Each chromosome has single chromatid & it (D)Chromosomes show uneven thickenings is V-shaped / L-shaped / J-shaped / I- Ans. (B) shaped. Solution. During spiralization the chromosomes become thick and get condensed to form chromosomes. EDU CATALYSERS 3. Spindle fibres are made up of (A) Lipids (B) Proteins (C) Pectins (D) Cellulose 4. In late prophase ____ disappears (A) Nucleolus (B) Nuclear membrane (C) Cell cytoskeleton, golgi complex, ER (IV) Telophase : (D) All of these  It is reverse of prophase. Chromosomes CYTOKINESIS reach on the opposite poles and now they  It is a division of cytoplasm. It starts in late become uncoiled and convert into long thin anaphase & completes at the end of chromatin network. telophase. Cytokinesis  Nuclear membrane is reappear, NOR forms

Nucleolus. Thus each pole has a nucleus in

telophase stage

 Spindle fibres disappear. Cell furrow or cell cleavage method Cell plate method  A viscous fibrous dense Mid body is  In case of plant cell, some spindle fibres formed in the centre. Constriction of exist that form phragmoplast. Golgi peripheral microfilaments takes place vesicles and some ER vesicles deposit in the central part of phragmoplast and their toward centre (Centripetal) and finally deposition proceeds towards peripheral both sides meet and two daughter cells part (centrifugal) and finally a cell plate is are formed formed followed by the formation of Ex: Animal cell. middle lamella. Now Primary wall deposits at each side of middle lamella and ultimately both cells get separated to form two daughter plant cells.

Mid body (Cell furrow or cell cleavage)

Phragmoplast Cell Plate EXAMPLES 1. Which phase is marked by the initiation of condensation to form compact mitotic chromosomes (Cell plate method) (A) metaphase (B) prophase

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EXAMPLES  Regeneration and Asexual reproduction 1. During cytokinesis, cell plate is formed from In many lower animals mitotic cell division is (A) Cytoplasm (B) Asters responsible for regeneration and asexual (C) Golgi complex (D) Cell wall reproduction. Ans. (C) Solution. During plant cytokinesis, cell plate is EAGLE’S EYE formed by golgi bodies and cell plate grows centrifugally  Dinomitosis :- Dinomitosis is found in 2. The cell plate grows in … manner in dinoflagellates, which are mesokaryotes. In cytokinesis of plant cell mesokaryotic cells, histones are absent. (A) Centrifugal manner Because of this, the chromosomes fail to (B) Centripetal manner condense properly and hence are not (C) Partly centripetal & partly centrifugal distinctly visible during cell division. (D) Acropetal Nuclear membrane persists throughout the Ans. (A) cell division and the spindle formed is Solution. The cell plate grows in centrifugal intranuclear type. manner i.e., from centre towards periphery. EDU CATALYSERS  Free nuclear division :- Karyokinesis is not 3. In animal cell, cytokinesis takes place by followed by cytokinesis, hence, such (A) cell wall formation divisions lead to coenocytic condition. eg. (B) cell plate formation endosperm, fungi of phycomycetes group. (C) furrow formation  Endomitosis :- This is duplication of (D) phragmoplast formation chromosomes without division of nucleus. 4. In some organisms karyokinesis is not Endomitosis leads to , i.e., Increase followed by cytokinesis as a result of which in number of sets of chromosome. multinucleate condition arises, leading to the  Colchicine induces polyploidy in plants. formation of (A) Multinucleate coenocytic stage Colchicine is a mitotic poison as it arrests (B) Uninucleate syncytium the formation and arrangement of spindle (C) Binucleate coenocytic stage fibres. (D) Multinucleate aseptate  Endoreduplication - Endoreduplication is a SIGNIFICANCE OF MITOSIS modification of endomitosis. The polytene  Identical gene composition In mitotic cell chromosomes are formed by the process of division. Daughter cell contains the same endoreduplication. In endoreduplication, the number of chromosomes as the parent cell. chromatids (DNA) replicate but do not get The daughter cells carry the same hereditary separated. This process is also known as information as in the parental cells. polyteny. It gives a genetic stability within a  Mustard gas and Ribonucleases are also population. mitotic poisons.  Growth Mitotic cells division is responsible for MEIOSIS growth in an organism.  It occurs in male and female germ cells.  Cell Replacement Such cells are called meiocytes. Mitotic cell division is responsible for the  In this type of division, parent cell divides to replacement of lost cells & healing of produce four daughter cells (genetically different). wounds.

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 It is a reduction division in which the number of chromosomes is reduced to half, i.e., diploid number (2n) becomes haploid (n).  It is responsible for transmission of hereditary information from generation to generation.

It is divided into two main phases. MEIOSIS

(B) Zygotene Meiosis I Meiosis II  Chromosomes are comparatively small &  Heterotypic division  Homotypic division or thick. Homologous chromosomes start or reduction division. equational division.  It leads to reduction  It does not lead to any pairing. One homologous chromosome is in chromosome change in chromosome maternal and second is paternal. This pairing numbers. Division of number. of two homologous chromosomes is called chromosome does  Meiosis II is just like synapsis / Syndesis (Mont Gomery 1901). not occur in mitosis. Division of  It forms Bivalent. meiosis-I and only centromere occur in segregation of meiosis II. 1 Number of bivalent = total no. of homologous 2 chromosomes takes chromosomes place. MEIOSIS-I Synapsis involves three types.

(A) Procentric – It starts from centromere and  M-phase It involves karyokinesis & proceeds towards terminal parts. cytokinesis. (B) Proterminal– It begins from terminal part. Karyokinesis It involves Prophase-I, Metaphase-I, Anaphase-I, Telophase-I. (C) Inter mediate type – It can begin at any point of chromosome. (A) Prophase-I It is the longest phase. It can be differentiated  Nucleoprotein core form a complex that is into five sub stages. called synaptonemal complex (Discovered by Moses 1956). (i) Leptotene Chromatin is condensed to

form chromosomes. All the chromosomes converge towards a common point near centrosome and form basket like arrangement. This stage is called bouquet stage. In some plants they form synzetic knot Eg: Lilium.

The chromatids of chromosomes are not (C) Pachytene distinct due to nucleoprotein.  Recombination nodule is formed between two non-sister chromatids.

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 The exchange of segments of non-sister cell. chromatids between two homologous chromosomes of a bivalent is called crossing over (Morgan).  Recombinase enzyme catalyzes this process.

EXAMPLES 1. Synapsis is the pairing of…. during zygotene (A)analogous chromosomes (B)homologous chromosomes (C)centric chromosomes

(D) Diplotene : (D)non homologous chromosomes  Synaptonemal complex is completely Ans. (B) dissolved and chromatids of bivalents are Solution. Synapsis is pairing of homologous distinct. chromosomes during zygotene  Each bivalent has four chromatids and two 2. In zygotene, Synapsis starts at centromeres. (A) telomeres only  Homologous chromosomes of each bivalent (B) centromere only start separation. They are connected at (C) kinetochore only certain points. These are called chiasmata (D) telomeres or centromeres or any place of (Janssen 1909) and the bivalents are now the chromosomes called tetrad. Ans. (D)  Chiasmata are the result of crossing over. Solution. In zygotene synapsis can occur from  In some animals, chromosomes become telomere, from centromere or through any enlarged in size in Diplotene stage. They are place of the chromosome i.e intermediate. called Lampbrush chromosome Eg : (Amphibians). Nuclear membrane starts disintegration. Nucleolus decreases in size. EDU CATALYSERS 1. In Bivalent (A) a pair of non-sister chromatids are present (B) 2 pairs of non-sister chromatids are present (C) 3 pairs of non-sister chromatids are present (D) 4 pairs of non-sister chromatids are present

2. Homologous chromosomes are (e) Diakinesis (A) similar in structure but differ in shape  Terminalization of chiasmata takes place. (B) similar in heredity but differ in structure  Centrioles are reached on opposite poles (C) two chromosomes of same parent and form aster with astral rays spindle is (D) similar in shape & hereditary characters formed that is amphiastral in animal cell and

anastral in plant (B) Metaphase-I

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 Congression brings the bivalents on equator.  Chromosomes undergo despirilization, become thin & elongated. Nucleolus is rarely Bivalents arrange in two rows on equator to formed. Nuclear membrane reappears and form Double metaphasic plate. each pole has a haploid nucleus.  The arms of homologous chromosomes lie parallel to the equator and their centromeres are projected outwardly towards poles.  Each chromosome in a bivalent is connected to the spindle pole of its side by a single kinetochore microtubule (chromosomal

tractile fibre) instead of two as in metaphase Cytokinesis may or may not occur after meiosis-I of mitosis.  In some plants like Trillium and most animals, Metaphase-II directly occurs after Anaphase-I or telophase-I enters into Prophase-II.

Interkinesis It is called intrameiotic interphase. In this phase some deficient substance form but synthesis of DNA does not occur.

(C) Anaphase-I EXAMPLES  In this stage reduction division takes place & 1. The cells in which meiosis occurs are called segregation of Mendelian factors occurs. The (A) Mitocytes (B) Meiocytes chromosome number becomes half (2n–n). (C) Amitocytes (D) Bud cells  Maternal and paternal chromosomes of each Ans. (B) bivalent are completely separated. It is Solution.The cells in which meiosis occurs are called disjunction. called meiocytes  They move in opposite direction towards 2. As the chromosome number is reduced to opposite poles due to constriction of the half of its original number meiosis is chromosomal fibres. It is called anaphasic called as movement. Thus Bivalents are converted in (A) Equational division Univalents. Each univalent has two divergent (B) Reductional division chromatids. (C) Doubling division At the end of this phase chromosomes are (D) Multiplying division reached at opposite poles. Ans. (B) Solution.The chromosome number is reduced to half of its original number in Meiosis 1 which is a real reduction division also called heterotypic division EDU CATALYSERS 3. Why new daughter cells produced by meiosis are genetically dissimilar? (D) Telophase-I (A) Prophase is longer  Regrouping of Dyad chromosomes occur at (B) During anaphase –I reduction occurs each pole (C) Recombination during prophase-I

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(D)Recombination during prophase-II (B) Polyploidy : Failure of chromosomes to 4. Which of the following is not true for meiosis separate during anaphase-I leads to (A)Generally four cells are formed polyploidy. (B)Genetically different cells are formed (C) Maintenance of chromosome number (D) Sexual reproduction (C)Morphologically different cells are formed TYPES OF MEIOSIS (D)Each new cell having half chromosome (i) Zygotic meiosis number It occurs during zygote or zygospore

germination Ex: Ulothrix, Spirogyra, MEIOSIS-II Chlamydomonas. It is also called homotypic or Homoeotypic (ii) Sporic or Intermediate meiosis or equational division. It is just like mitosis Meiosis occurs at the time of microspore or but occurs in haploid nuclei. megaspore formation Ex: Bryophytes, At the end of meiosis-II four haploid cells are Pteridophytes, Gymnosperms, Angiosperms. formed that are genetically different. (iii) Gametic meiosis or Terminal meiosis It occurs at the time of gamete formation Ex: Animals EAGLE’S EYE  Amitosis It was discoverd by Remak. In this type, nucleus elongates& constricted in the middle and divide to form two daughter nuclei. Spindle formation is absent Ex: meganucleus of Paramecium, cells of endosperm.  Brachymeiosis It is found in ascus bearing fungi that includes two reduction divisions SIGNIFICANCE OF MEIOSIS : and one equational division which reduce (A) Variations : the chromosome number from tetraploid (i)Independent assortment of chromosomes to haploid stage.

(ii) Crossing over (iii) Irregular disjunction (iv) Gene mutation during replication & nicking for crossing over.

Difference Between Mitosis & Meiosis

Mitosis Meiosis

1. Mitosis takes place in the somatic 1. It occurs either in the reproductive cells. cells or at the time of germination of zygote or zygospore.

2. The cells undergoing mitosis may be 2. The cells undergoing meiosis are haploid or diploid. always diploid.

3. It is a single division which produces 3. Meiosis is a double division. It gives rise two cells. to four cells.

4. Subsequent mitotic divisions are 4. The two divisions of meiosis are not similar to one is the earlier ones. similar. The first heterotypic or reductional while the second one is homotypic or equational like mitosis.

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5. Each chromosome replicates in the 5. The chromosomes replicate only once, interphase before every division. prior to meiosis.

6. The number of chromosomes remains 6. The number of chromosomes is the same after mitosis. reduced to one half after Meiosis.

Prophase

7. Prophase is of shorter duration. 7. Prophase I is of longer duration while prophase II is very brief.

8. Each chromosome has two distinct 8. Chromosomes of prophase I do not chromatids. show distinct chromatids.

9. No bouquet stage is recorded. 9. Chromosomes of animals and some plants show convergence towards one side during early prophase I. It is known as bouquet stage.

10. Pairing of chromosomes does not 10. Pairing or synapsis of homologous occur in mitosis chromosomes takes place during zygotene of prophase I and continue through out during zygotene of prophase I

11. A synaptonemal complex is absent. 11. Synapsed homologous chromosome develop a synaptonemal complex.

12. Crossing over is absent. 12. Crossing over or exchange of similar segments between nonsister chromatids of homologous chromosomes usually takes place during pachytene stage. 13. Chiasmata are absent. 13. Chiasmata or visible connections between homolo-gous chromosomes of bivalents are observed during diplotene, diakinesis

Metaphase

14. Centromeres produce a single 14. A double metaphasic plate is formed metaphasic plate. by centromeres in metaphase I but only one in metaphase II. 15. Only the centromeres lie at the 15. Limbs of the chromosomes mostly lie equator. The limbs of chromosomes at the equator while the centromeres are oriented invarious directions. project towards the poles in metaphase I. 16. A centromere is connected with both 16. A centromere is connected to one the spindle poles. spindle pole in metaphase I but both in metaphase II.

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17. Two chromatids of a chromosome are 17. The two chromatids of a chromosome genetically similar. are often genetically dissimilar due to crossing over. Anaphase 18. A centromere splits length-wise to 18. Centromeres do not divide during form two centromeres in the anaphase I but do so in anaphase II. beginning of anaphase. 19. Anaphasic chromosomes are single 19. Chromosomes are double stranded in stranded. anaphase I but single stranded in anaphase II. Telophase

20. Telophase is longer and produces 20. Telophase I is shorter and nuclei never interphase nuclei. enter the inter -phase.

Cytokinesis 21. Cytokinesis follows every mitosis. It 21. Cytokinesis often does not occur after produces two cells. the first or reductional division. It is then simultaneous after second division to result in four new cells.

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EXERCISE NO.  1

INTRODUCTION (C) Meiosis (D) Sporic meiosis 9. In …. Cell division daughter cells are having 1. The formation of new daughter cells from structural & functional irregularities. parent cell is called as (A) Mitosis (B) Amitosis (A) Growth (B) Cell differentiation (C) Meiosis (D) Sporic meiosis (C) Cell elongation 10.In Amoeba multiple fission occurs by (D) Cell division (A) Mitosis (B) Meiosis 2. Which of the following is true? (C) Amitosis (D) M phase (A)Prokaryotes divides by amitosis 11. Paramecium division of meganucleus takes (B) Cells of divides by mitosis & place by … & micronucleus by …. meiosis (A) Amitosis, amitosis (C) Both A & B (B) Mitosis, meiosis (D)All organisms divides by mitosis (C) Amitosis, mitosis AMITOSIS 3. ….is also called as direct cell division (D) Meiosis, mitosis (A) Mitosis (B) Meiosis 12.Cell division of bacteria is (C) Amitosis (D) M phase (A) Mitotic (B) Meiotic 4. Amitosis was discovered by …..in RBC of (C) Amitotic (D) All of these chick 13.The division of mitochondria and chloroplasts embryo. is (A) Remak (1855) (B) E.Strasburger(1855) (A) Mitosis (B) Meiosis (C) W.Flemming (1855) (C) Amitosis (D) M phase (D) S.Flemming(1855) 14.In mammals the growth of foetal membranes (amnion, chorion, allantois, yolk sac, cartilage 5. In unicellular organism like bacteria, of mammals takes place by protozoans, asexual reproduction takes place by (A) Mitosis (B) Meiosis (A) Binary Fission (B) Mitosis (C) M phase (D) Amitosis (C) Meiosis CELL CYCLE (D) Sporic meiosis 15.The series of sequential changes through 6. In amitosis which of the following is false which cell passes during its growth and (A)No differentiation of chromosomes and division is called as spindle (A) Cell elongation (B) Cell maturation (B)Chromosomes are equally distributed (C) Nuclear envelope does not (C) Cell cycle degenerate & remains intact (D) Cell multiplication (D) Distinct chromosomes do not appear in 16.The average duration of cell cycle of a human division is 7. During which division nucleus becomes (A) 24 days (B) 24 minutes elongated and constricts in the middle, (C) 24 hours (D) 24 seconds becomes dumbell shaped and divides to form two daughter nuclei. (A) Amitosis (B) Mitosis 17.The average duration of cell cycle of a Yeast (C) Meiosis (D) Sporic meiosis is 8. Which division does not show equal (A) 24 days (B) 90 minutes distribution of chromatin material (C) 24 hours (D) 24 seconds (A) Mitosis (B) Amitosis 18.Cell cycle consist of

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(A) Interphase (B) M phase 29.During G1 phase the amount of DNA will be (C) Meiosis (D) Both A & B (A) Unchanged (B) Becomes double INTERPHASE (C) Increased (D) Decreased 30.Time taken for completion of this is about 19.The period between end of one division & (A) 20% - 30% of total cycle beginning of next cell divisions is called as (B) 30% - 40% of total cycle (A) Interphase (B) Mitosis (C) 50% - 60% of total cycle (C) Meiosis (D) Amitosis (D) 60% - 70% of total cycle 20.The so called resting phase is not really a 31.Decision of cell division occurs during ….. resting phase. What is that phase ? phase of cell cycle. (A) Interphase (B) M-phase (A) G1 (B) G2 (C) Telophase (D) Prophase (C) S phase (D) G0 21.In …. Phase nucleus appears to be physically 32.The regulation of duration of cell cycle is resting hence called as resting phase but it is metabolically most active in the cell cycle. arrested at middle of G1 phase. This is said to (A) M phase (B) Interphase be (C) Meiosis (D) Amitosis (A)M phase (B) G2 22.Non dividing & preparatory phase of cell cycle (C)S phase (D) G0 is 33.All of the following takes place in S phase (A) M phase (B) Meiosis except (C) Interphase (D) Amitosis (A) Amount of DNA remains unchanged 23.All the molecules needed by the cell for (B) Amount of DNA becomes double in division are synthesized during nucleus (A) M phase (B) Meiosis (C) Centriole duplicates in the cytoplasm (D) Histone proteins are synthesized (C) Interphase (D) Amitosis 34.At the end of S phase each chromosome has 24.….is the common phase for both mitosis and (A) One chromatid meiosis. (B)Four chromatids joined by centromere (A) G phase (B) Interphase 0 (C) Two chromatids joined by (C) M phase (D) Cell plate formation centromere 25.The time period required for interphase is (D) No change in chromatid number about 35.The chromosome number in G1, S & G2 (A) 60% (B) 95% phases are (C) 30% (D) 50% (A)2n, 2n, 2n 26.Interphase is divided into three sub phases (B)2n, 4n, 2n, chromatid number becomes except– double & then reduced (A) G phase (B) S phase 1 (C)2n,2n,2n but chromatid number double (C) G2 phase (D) G0 phase (D)4n,2n,2n 27.G1 phase is also called as 36.The time required for S phase of interphase (A) Pre-DNA synthesis is (B) First growth period or first gap period (A) 20% - 30% of total cycle (C) Post mitotic phase (B) 30% - 50% of total cycle (D) All of these (C) 50% - 60% of total cycle 28.In G1 phase synthesis of all takes place (D) 60% - 70% of total cycle except (A)mRNA, rRNA, ribosomes and Proteins 37.DNA duplication occurs in (B)Enzymes required for DNA replication (A)G1phase (B)S phase (C) Nucleotides and ATP are kept ready (C)G2 phase (D)G0 phase (D) DNA duplication takes place

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38.Which of the following is called as second (A) Chromosome number is reduced growth phase or gap phase (B) Chromosome number is doubled (A) G1 (B)G2 (C) Chromosome number remain (C) S phase (D) G0 same 39.Which phase is called as post DNA synthesis (D) chromosome number increased to form phase or pre mitotic phase of cell cycle tetrad stage 46.Mitosis is also called as somatic division (A)G1 (B)G0 because (C) S phase (D) G 2 (A)Mostly takes place in somatic cells 40.The time required for G2 phase of interphase (B) Common in germ cells is (C) Mostly takes place in cells having odd (A) 10% - 20% of total cycle chromosome number (B) 30% - 50% of total cycle (D)It takes place in somatic cells only (C) 50% - 60% of total cycle 47.Which of the following is called as growth (D) 60% - 70% of total cycle division? Mitosis (A) M phase (B) meiosis 41.Which one of the following statement is (C) interphase (D) mitosis correct 48.Which phase is marked by the initiation of (A)Walter Flemming discovered meiosis in condensation to form compact mitotic plant cells chromosomes (B)Walter Flemming discovered mitosis in (A) metaphase (B) prophase plant cells (C) anaphase (D) telophase (C)Walter Flemming discovered meiosis in 49.During prophase which is not possible animal cells (A)Prochromosomes become chromosomes (D)Walter Flemming discovered mitosis in (B) Nuclear envelope and Nucleolus animal cells disappear 42.In plants, mitosis was first observed by (C) Each chromosome shows two (A) W.Flemming (B) Strasburger chromatids (C) R.Virchow (D) Nageli (D)Chromosome become chromatids 43.In the cell cycle 50.In Spiralization (A) Interphase is followed by division phase (A)Chromosomes become long and thread (B) Division phase is not followed by like interphase (B)Chromosomes become short and thick (C)Interphase and division phase both start (C) Chromosomes are scattered at a time (D) Chromosomes show uneventhickenings (D)Interphase and division phase not related 51.The chromosomal arm splits longitudinally with one another. into two chromatids in …phase KARYOKINESIS OF MITOSIS (A) interphase (B) anaphase 44.Which of the following is true for mitosis? (C) prophase (D) telophase (A)Distinct centrioles to form spindle body 52.In karyokinesis of mitosis the chromosomes in animal cell show minimum coiling in (B) Centrioles are absent in plant cell & (A) Anaphase (B) Metaphase called as acentric (C) Prophase (D) Early telophase (C) Both A & B 53.The region of chromosomes to which (D) Both plants & animals show centric type chromosomal fibers are attached during cell of division division. 45.Why mitosis is called as equational cell (A) Centrosome (B) Telomere division? (C) Kinetochore (D) Chromomere

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54.Two chromatids are joined by a disc called as (C) Anaphase (D) Telophase (A) Centromere (B) Kinetochore 64.Chromosome becomes visible at (C) Primary constriction (A) Prophase (B) Metaphase (D) All of these (C) Anaphase (D) Telophase 55.The discoidal area on each chromatid which CYTOKINESIS is the site of attachment of spindle fibres (A) Centromere (B) Kinetochore 65.Division of cytoplasm i.e. cytokinesis name (C) Primary constriction proposed by (D) All of these (A) Flemming (B) Whitman 56.In animal cell Spindle fibre are made up of (C) Strasburger (D) R.Virchow 97%.... type of protein 66.During cytokinesis, cell plate is formed from (A) Actin (B) Myosin (A)Cytoplasm (B) Asters (C) Tubulin (D) Albumin (C)Golgi complex (D)Cell wall 57.Star like radiating fibers are formed around 67.A barrel shaped structure organized by each centriole called as remaining spindle fibres at the interzonal (A) Centrosome (B) Spindle pole region is called (C) Spindle body (A) Leucoplast (B) Chromoplast (D) Aster (C) Phragmoplast (D) Amyloplast 58.Which of the following are true 68.The form of cell plate formed from (A) In animal cell astral mitosis is common phragmoplast during cytokinesis is (B) In plant cell anastral mitosis common (A) Solid (B) Semi-solid (C) Star like radiating fibres are not (C) Liquid (D) Not in any form formed in plant cell 69.The cell plate grows in … manner in cytokinesis of plant cell (D) All of these (A) Centrifugal manner 59.Spindle fibres are made up of (B) Centripetal manner (A) Lipids (B) Proteins (C) Partly centripetal & partly centrifugal (C) Pectins (D) Cellulose (D) Accropteal 70.In animal cell cytokinesis takes place by 60.The chromosomal fibres extend between (A) Cell wall formation (A) Centromere and pole (B) Cell plate formation (B) Between two centromere (C) Furrow formation (C) Pole to pole (D) Phragmoplast formation (D) Equator to centromere 71.In cytokinesis of animal cell furrow formation 61.In late prophase….. disappears takes place in ….. manner (A) Nucleolus disappear (A) Centrifugal manner (B) Nuclear membrane (B) Centripetal manner (C) Cell cytoskeleton, golgi complex, (C) Partly centripetal & partly centrifugal ER (D) Basipetal (D) All of these 72.In some organisms karyokinesis is not 62.In which phase spindle formation is followed by cytokinesis as a result of which completed multinucleate condition arises leading to the formation of (A) Metaphase (B) Prophase (A) Multinucleate coenocytic (C) Anaphase (D) Telophase (B) Uninucleate syncytium 63.In which phase condensation of (C) Binucleate coenocytic chromosomes is completed and they can be (D) Multinucleate aseptate observed clearly under the microscope. 73.Which type of cell division is common in (A) Prophase (B) Metaphase vegetative cell?

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(A) Mitosis (B) Meiosis 83.As the chromosome number is reduced to (C) Both mitosis, meiosis the half of its original number meiosis is (D) Amitosis called as 74.The cell division helpful in the reproduction (A) Equational division of unicellular organisms (B) Reductional division (A) Meiosis (B) Mitosis (C) Doubling division (C) Meiosis or Mitosis (D) Multiplying division (D) Endomitosis 75.How many generations of mitotic divisions 84.In meiosis newly formed cells are occur in a cell of root tip to form 256 cells (A) Morphologically & genetically similar (A) 8 (B) 64 (B) Morphologically dissimilar & genetically similar (C) 16 (D) 128 (C) Morphologically similar & genetically 76.How many successive mitotic divisions occur dissimilar in a cell of the root tip to form 256 cells (D) Morphologically & genetically (A) 8 (B) 127 dissimilar (C) 128 (D) 32 85.Why new daughter cells produced by meiosis 77.Which cell division is responsible for growth, are repair & maintenance. genetically dissimilar? (A) Meiosis (B) Amitosis (A) Prophase is longer (C) Mitosis (D) None of these (B) During anaphase –Ireduction occurs 78.In mitosis newly formed cells are (C) Recombination during prophase-I (A) Morphologically& genetically similar (D) Recombination during prophase-II (B) Morphologically dissimilar& genetically 86.Which of the following is not true for meiosis similar (A) Generally four cells are formed (C) Morphologically similar & genetically (B) Genetically different cells are formed dissimilar (C) Morphologically different cells are (D) morphologically & genetically dissimilar formed (D) Each new cell having half chromosome Meiosis number 87.Meiosis never takes place in 79.The term meiosis was coined by (A) Haploid (B) Triploid (A) Strasburger (B) Flemming (C) Cell having odd chromosome number (C) Whitemen (D) Farmer & Moore (D) All of these 80.Meiosis is a special kind of cell division which 88.The daughter cells formed from parent cells occurs in the during meiosis differ from the parent in their (A)Reproductive cells (A)Chromosome number only (B)Germ cells of sexually reproducing (B)Genetic characters only organism (C)Chromosome number and genetic (C)Vegetative reproducing organisms characters (D) Both A & B (D)None of the above 89.In sexually reproducing organisms, meiosis 81.In animals meiosis occurs at the time of results in the maintenance of constant (A)Spore formation (A) Cell number (B) Bud formation (B) Chromosome number (C)Gamete formation (C) Genes number (D)Gemule formation (D) Cells, chromosomes and genes 82.The cells in which meiosis occurs are called number (A) Mitocytes (B) Meiocytes 90. Mention the odd man out (C) Amitocytes (D) Bud cells (A) Strasburger - observed Mitosis in plant cells

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(B) Farmer & Moore - coined the term (C) One paternal and one maternal meiosis chromosome (C) Flemming - discovered mitosis in animal (D) Ttwo paternal and maternal cells chromosomes (D) August Weisman - coined the term 99.In which phase nucleus appear like bouquet Mitosis stage (in animals) and syndet knot (in plants). 91.Which one of the following is a Meiocyte? (A)Zygotene (B)Leptotene (A)Antherezoid mother cell (C)Pachytene (D)Diplotene (B) Spore mother cell 100.In leptotene stage, chromosome types can (C) Embryo be easily recognized due to the (D) Androcytes (A) Constant chromomere number 92.The chromosome number of plant is 20. (B) Constant chromomere position Which division helps to maintain constant (C) Constant chromomere number, chromosome number in the next generation position after sexual reproduction (D) Constant chromomere number, position and colour (A) Amitosis (B) Mitosis 101.The active genetic centres present on the (C) Meiosis (D) Binary fission chromosomes during leptotene of Meiosis 93.The number of nuclear divisions in Meiosis (A)Chromomeres (B)Chromocentres (A) One (B) Three (C)Centromeres (D)Telomeres (C) Two (D) Four 102.Bead like structures that appear in 94.Meiosis involves two divisions. These are leptotene chromosome are (A)Nucleosomes (B)Chromomeres (A) One nuclear division and other is (C)Telomeres (D)Knobs cytoplasmic 103.Synapsis is the pairing of…. during zygotene (B) One is extranuclear and other is (A)Analogous chromosomes mitotic division (B)Homologous chromosomes (C) One reduction division and other amitotic division (C)Acentric chromosomes (D) One reductional division and one (D)Non homologous chromosomes mitotic division 104.In zygotene, Synapsis starts at (A) Telomeres only 95.Meiosis I is called as (B) Centromere only (A) Actual reduction (C) Kinetochore only (B) Heterotypid division (D) Telomeres or centromeres or any (C) Both A & B place of the chromosomes (D) Equational division 96.Which of the following is of longer duration 105.In Bivalent (A) Prophase (B) Prophase-I (A) A pair of non-sister chromatids are present (C) Anaphase-I (D) Telophase-I (B) 2 pairs of non-sister chromatids are 97.Prophase with many complex changes present appears in (C) 3 pairs of non-sister chromatids are (A) Mitosis (B) Meiosis-I present (C) Meiosis (D) Amitosis (D) 4 pairs of non-sister chromatids are 98.In the leptotene attraction occurs towards present centre & between 106.In Prophase-I pairing of homologous (A) Two paternal chromosomes chromosomes takes place to form bivalents. (B) Two maternal chromosomes The bivalent consist of

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(A) Two chromosome and one centromere 114.The enzyme endonuclease and ligase are (B) Two chromosome and two meant for centromeres (A) Synapsis (B) Spiralization (C) Four chromatids and four centromeres (C) Terminalization (D) Four chromosome and two (D) Crossing over centromeres 115.What is the purpose of pachytene 107.Homologous chromosomes are (A) Terminalization (A) Similar in structure but differ in (B) Spirilization shape (C) Recombination (B) Similar in heredity but differ structure (D) Condensation (C) Two chromosomes of same parent 116.What is importance of crossing over in (D) Similar in shape and hereditary meiosis characters (A)Recombination 108.Which of the following occurs only during (B)Variation zygotene of prophase-I (C)Evolution (A) Pairing of homologous chromosomes (D) All of hese (B) Pairing of maternal chromosomes 117.Depletion of attractive forces between (C) Pairing of paternal chromosomes homologous chromosomes occur in (D) Crossing over takesplace (A) Zygotene (B)Pachytene 109.In meiosis tetrads of chromatids are found (C) Diplotene (D)Diakinasis in 118.Repulsion of homologous chromosomes is (A)Prophase-I (B)Prophase-II initiated during (C)Interphase (D)Metaphase-II (A)Pachytene (B) Diplotene (C)Diakinesis (D) Anaphase-I 110.The process of crossing over occurs during… 119.During terminalization phase of prophase-I (A) Movement of chromosomes towards (A)Leptotene (B) Zygotene the poles occur (C) Dikinesis (D) Pachytene (B) Movement of chromatids towards 111.Exchange of chromosome segments between the poles occur maternal and paternal non sister chromatids (C) Movement of chaisma towards during meiosis is called the poles occur (D) Movement of chromosomes towards (A) Spiralisation (B) Crossing over the centre occur (C) Synapsis (D) Pairing of homologous chromosomes 120.Chaismata is site where …. occurs 112.At chaisma (A) Pairing (B) Crossing over (A) Exchange of chromosomes absent (C) Terminalization (B) Exchange of genetic material between (D) Spiralisation non sister chromatids occurs 121.In meiosis, the nuclear membrane, nucleolous disappear and spindle body is (C) Exchange of chromatid segments organized between sister chromatids occur (A) Leptotene (B) Pachytenea (D) Exchange of chromatids segments (C) Diakinesis (D) Diplotene of same chromosomes occur 122.Mention the sequence of changes occuring 113.Due to the occurence of which phenomenon during the Prophase-I of Meiosis in Meiosis, evolution of organisms takes (A) Bouquet stage, crossing over, place. spiralization, terminalisation, synapsis (A)Synapsis (B)Pairing (C)Crossing over (D)Condensation

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(B) Spiralization, bouquet stage, (D) Both Mitosis and Meiosis crossing over, terminalisation, 133.Which cell division is responsible for growth, synapsis development & repairing (C) Bouquet stage, synapsis, crossing (A)Amitosis (B)Mitosis over, terminalisation ,spiralization (C)Meiosis (D) Bouquet stage, synapsis, crossing (D)Both mitosis & meiosis over, spiralization, terminalisation 134.Which division helps to maintain 123.Sequence of stages in Prophase-I of meiosis chromosome number constant & helps in –I are evolution (A) Leptotene, Zygotene, Pachytene, (A) Amitosis (B) Mitosis Diakinesis,Diplotene (C) Meiosis (B) Leptotene, Zygotene, Pachytene, (D) Both mitosis & meiosis Diplotene, Diakinesis Numerical questions 135.If the number of chromosome of a plant is (C) Zygotene, Diplotene,Leptotene, 40 then what will be the chromosome Pachytene, Diakinesis number in prophase-I, metaphase-I, (D) Pachytene,Diplotene, Diakinesis, Anaphase-I, Telophase-I onwards Zygotene, Leptotene (A) 40,40,20,20 (B) 20, 20, 40,40 124.During Meiosis, actual reduction in (C) 40,20,40,20 (D) 20,40,20,40 chromosome takes place 136.If the diploid chromosomes number is 20, (A) Anaphase-I (B) Anaphase-II the number of chromosomes in gametes (C) Metaphase-I (D) Metaphase-II (A) 20 (B) 30 125.Chromosome number in meiosis is halved during (C) 10 (D) 40 (A) Metaphase-II (B) Anaphase-I 137.Number of minimum reduction divisions (C) Prophase-I (D) Telophase-II required for the production of 100 pollen 126.Movement of homologous chromosomes of grains bivalent to opposite poles is called (A) 100 (B) 25 (A) Disjunction (B) Crossing over (C) Terminalisation (C) 50 (D) 75 (D) Synapsis 138.Number of meiotic divisions required to 127.Disjunction of chromosomes takes place at form 100 seeds is (A) Prophase-I (B) Metaphase-I (A)25 (B) 50 (C) Anaphase-I (D) Telophase-I (C)125 (D) 200 128.Which of the following shows double 139.The number of meiotic and mitotic divisions stranded chromosomes during anaphase required for the formation of 100 embryo (A) Prophase-II (B) Meiosis - II (A) 250, 250 (B) 125, 250 (C) Meiosis - I (D) Anaphase-II (C) 125, 500 (D) 100,250 Importance of mitosis & meiosis 140.Number of mitotic divisions required for the 129.The material commonly used for study of formation of 500 cells from one cell mitosis in laboratory by using (A) 500 (B) 125 (A) Anther (B) Coleoptile (C) Onion roots (D) Root cap (C) 250 (D) 499 130.Meiosis can be best studied in 141.Number of spindle apparatus formed during (A) Root tip (B) Buds the formation of 100 pollen grains from microspore mother cells is (C) Anthers (D) Ovary wall (A) 25 (B) 75 131.In higher plants, meiosis occurs in (C) 50 (D) 100 (A) Roots (B) Leaves 142.If the endosperm cell of a plant has 60 (C) Stems (D) Anthes and ovules chromosomes what will be the number of 132.The cell division is mainly responsible for chromosomes of egg, pollen grain, zygote is the formation of gametes in animal cells & (A) 20,20,30 (B) 20,20, 40 for variation is (C) 20,20, 60 (D) 20, 40,60 (A) Mitosis (B) Meiosis (C) Amitosis Types of meiosis

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143.In fungi, certain protozoan, algae meiosis 147.The life cycle pattern of pteridophyte to occurs in angiosperm is … as the life cycle shows (A) Spore (B) Bud dominant sporophytic phases. (C) Zygote (D)Gametophyte (A) Diplontic (B) Haplontic 144.Which of the following is feature of algae (C) Haplodiplontic (D) Diplohaplontic not common in all remaining groups of 148.When meiosis takes place at the time of kingdom plantae? gamete formation it is called as (A) Sporic (B) Zygotic (A) Sporic meiosis (B) Gametic meiosis (C) Gametic (D) Somatic (C) Somatic meiosis 145.In some lower plant like algae haploid (D) Zygotic meiosis phases are dominant in life cycle hence 149.The life cycle with diploid adult and gametic called as meiosis is known as… type (A) Diplontic (B) Haplontic (A)Diplontic (B) Haplontic (C) Haplodiplontic (D) Diplohaplontic (C)Haplodiplontic (D)Diplohaplontic 146.In higher plants like pteridophytes, 150.Meiosis in plant occurs, when there is a gymnosperms and angiosperms meiosis takes change from place at the time of (A) Gametophyte to sporphyte (A) Spore formation (B)Sporphyte to sporphyte (B) Gamete formation (C) Sporphyte to gametophyte (C) Zygote formation (D) Gametophyte to gametophyte (D) Gametophyte formation

EXERCISE NO :  2 SINGLE CORRECT ANSWER TYPE 1. The stage during which separation of (B)A male and a female gamete paired homologous chromosomes begins (C)mRNA and ribosomes is [2018] (D)Spindle fibres and centromere (A) Diakinesis 3. Given below is a schematic break-up of (B) Diplotene the phases/ stages of cell cycle: Which (C) Pachytene one of the following is the correct (D) Zygotene indication of the stage/phase in the cell 2. Synapsis occurs between:[2009] cycle? [2009] (A)Two homolog chromosomes

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(B) Kinetochore (C) Bivalent (D) Axoneme 10. The enzyme recombinase is required at which stage of meiosis: [2014] (A) Pachytene (B) Zygotene (C) Diplotene (D) Diakinesis (A) A-Cytokinesis 11. In’S’ phase of the cell cycle: [2014] (B) B-Metaphase (A) Amount of DNA doubles in each cell. (C) C-Karyokinesis (B) Amount of DNA remains same in each (D) D-Synthetic phase cell. 4. Which stages of cell division do the (C)Chromosome number is increased following figures A and B represent (D)Amount of DNA is reduced to half in each cell. respectively ? [2010] 12. During which phase(s) of cell cycle, (A) Metaphase - Telophase amount of DNA in a cell remains at 4 C (B)Telophase – Metaphase level if the initial amount is denoted as 2 (C) Late Anaphase - Prophase C? [2014] (D) Prophase – Anaphase (A) G0 and G1 (B) G1 and S 5. The correct sequence of phases of cell (C) Only G2 (D) G2 and M cycle is [2019] 13. A somatic cell that has just completed (A) S  G1  G2  M the S phase of its cell cycle, as compared (B) G1  S  G2  M to gamete of the same species, has: (C) M  G1  G2  S [2015]

(D) G1  G2  S  M (A) Four times the number of chromo 6. Select the correct option with respect to somes and twice the amount of DNA mitosis.[2011] (B)Twice the number of chromosomes (A)Chromosomes move to the spindle and twice the amount of DNA equator and get aligned along equatorial (C)Same number of chromosomes but plate in metaphase twice the amount of DNA (B)Chromatids separate but remain in (D)Twice the number of chromosomes the centre of the cell in anaphase and four times the amount of DNA (C)Chromatids start moving towardsop 14. Select the correct option: [2015] posite poles in telophase

(D)Golgi complex and endoplasmic I II reticulum are still visible at the end of (a) Synapsis aligns (i) Anaphase-II prophase homologous 7. Cell in G phase : [2019] 0 chromosomes (A) Suspend the cell cycle (B) Terminate the cell cycle (b) Synthesis of RNA (ii) Zygotene (C) Exit the cell cycle and protein

(D) Enter the cell cycle (c) Action of enzyme (iii) G2-phase 8. Dissolution of synaptonemal complex recombinase occurs during [2020] (d) Centromeres do (iv) Anaphase-I (A) Leptotene not separate but (B) Pachytene chromatids (C) Zygotene move towards (D) Diplotene opposite poles

(v) Pachytene 9. The complex formed by a pair of synapsed homologous chromosomes is called: [2013] Code : (A)Equatorial plate (a) (b) (c) (d)

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(A) (ii) (iii) (iv) (v) (D)Condensation  arrangment at equa (B) (ii) (i) (iii) (iv) tor - centromere division  segregation (C) (ii) (iii) (v) (iv) - telophase (D) (i) (ii) (v) (iv) 17. Anaphase promoting complex (ATP) is a protein degradiation machinery necessary 15. Arrange the following events of meiosis for proper mitosis of animal cells . If APC in correct sequence: [2015] is defective in a human cellm, which of (A) Crossing over (B) Synapsis the following is expected to occur? (C) Terminalisation of chaismata [2017] (D Disappearance of nucleolus (A) Chromosomes will not condense (A) (b), (c), (d), (a) (B) (b), (a), (d), (c) (B) Chromosomes will not fragmented (C) (b), (a), (c), (d) (D) (a), (b), (c), (d) (C) Chromosomes will not segreate 16.Which of the following options gives the (D Recombination of chromosome arms correct sequency of events during mito will occur sis ? [2017] 18.DNA replication in bacteria occurs [2017] (A) Condensation  nuclear membran (A)During S phase disassembly  crossing over  segrega (B) Within nucleouls tion telophase (C) Prior to fission (B) Condensation  nuclear membran (D)Just before transcription disassembly arrangement at equator-  centromere dividision  segregation - telophase (C)Condensation  crossing over  SKILL BOOSTER 1 nuclear membrane disassembly  seg regation - telophase Cells in -phase of cell cycle (C) Telophase (A)Exit cell cycle (D) Metaphase (B)Enter cell cycle 7. Which is synthesized in -phase? (C) Suspend cell cycle (A) DNA polymerase (D)Terminate cell cycle (B) Histones 2. During the -phase of cell division (C) Nucleolar DNA (A) RNA and proteins are (D) Tubulin protein synthesized 8. Which of the protein is found in spindle (B) DNA and proteins are fibre? synthesized (A) Tubulin (C) Cell prepares for M-phase (B) Albumin (D) Cell undergoes duplication (C) Mucin 3. How many chromosomes will the cell the (D) Haemoglobin cell have at , after S and after M-phase 9. Which one of the following precedes re- respectively, if it has 14 chromosomes at formation of the nuclear envelope during interphase? M-phase of the cell cycle? (A) 14,14,7 (B) 14,14,14 (A) Decondensation from chromosome (C) 7,7,7 (D) 7,14,14 and reassembly of the nuclear 4. Spindle fibre is made up of lamina (A) Humulin (B) Transcription from chromosomes (B)Intermediate filament and reassembly of the nuclear (C) Flagellin lamina (D) Tubulin (C) Formation of the contractile ring and 5. Cell would normally proceed to mitosis formation of the phragmoplast without interruption (D) Formation of the contractile ring and (A) Once it had started the S- period transcription from chromosomes (B) Once it had entered the G- phase 10. During cell cycle, RNA and non-histone (C) At anytime during cell division proteins are synthesized in (D) None of the above (A)S-phase (B) G-phase 6. Colchicine arrests spindle at (C)G-phase (D) M-phase (A) Anaphase 11. Cell division can not be stopped in which (B) Prophase phase of the cell cycle?

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(A)G-phase (B)G-phase 19. In which phase, proteins for spindle fibre (C)S-phase (D)Prophase are synthesized? 12. The S-phase of cell cycle is characterized by (A) G-phase

(A)Duplication of chromosome (B) G-phase (B)Shortening of chromosome (C) S-phase (C)Duplication of DNA (D)Duplication of centriole (D) Anaphase 13. The phragmoplast is organized at the 20.What is the correct sequence of the steps (A) Beginning of anaphase given here? (B)End of anaphase Also work out the process depicted in the (C)Beginning of telophase steps? I. Homologous chromosomes move toward (D)End of telophase opposite poles of the cell; chromatids do 14. Which of the following events occurs not separate.

during -phase? II. Chromosomes gather together at the two poles of the cell and the nuclear (A) DNA replication membrances reform. (B) Growth and normal function of cell III. Homologous chromosomes pair and (C) Mutation exchanges segments. (D) Fertilization IV. Homologous chromosomes align on a central plate. 15. Chromosome number can be doubled by V. The haploid cells separate completely. using which of the following? (A) The correct sequence is III → (A) Indole acetic acid IV → I → II → V and the process is (B) GA meiosis-I (B) The correct sequence is II → I → (C)Zeatin V → IV → III and the process is (D)Colchicines mitosis 16. Given below is a schematic break-up of (C) The correct sequence is IV → I → III → II → V the phases/stages of cell cycle. and the process is meiosis-I Which one of the following is the correct (D) The correct sequence is II → V → indication of the stage/phase in the cell IV → I → III and the process is cycle? mitosis 21.In which phase cell organelles & spindle (A) B-Metaphase proteins are synthesized (B) C-Karyokinesis (A) G1 (B) G0 (C) D-Synthetic phase (C) G2 phase (D)S phase (D) A-Cytokinesis 22.Actual period of cell division in cell cycle 17. In cell cycle, during which phase is (A)G (B)M phase chromosomes are arranged at equatorial 1 (C)G phase (D)S phase plate? 2 23.The time required for M phase of (A)Metaphase interphase is (B)Anaphase (A) 20% - 30% of total cycle (C)Telophase (B) 5% - 10% of total cycle (C) 50% - 60% of total cycle (D)Prophase (D)60% - 70% of total cycle 18. Chromatid formation takes place in 24.During which phase are proteins for (A) S-phase spindle fibres synthesized ? (B)Metaphase (A)G1 phase (B)G2 phase (C)Metaphase (D) Anaphase (C) G-phase 25.The cell may withdraw from cell cycle (D) G-phase after mitosis and it will enter into (A) G0 phase (B) M phase

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(C) G1 phase (D) both ‘A’ and ‘B’ (D)Mitotic/meiotic phase 26.G0 phase occurs 29.Abnormal, unlimited and uncontrolled cell (A) after G2 phase division results in (B) after S phase (A) pleuripotant cell (C) before G2 phase (B) cancer (D) before S phase (C) totipotency (D) 27.Histones are synthesized in asphyxia

(A) prophase (B)G1 phase 30.In a somatic cell which is ready to divide, (C)S Phase (D)Metaphase the amount of DNA.. (A)decreases 28.M phase is also called as (B) gets doubled (A) Resting phase (C)becomes half (B)Preparatory phase (D)remains the same (C)Metabolically active phase

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SKILL BOOSTER 2

1. Which phase comes in between the (B) Phase after M-phase, in which

and phases of cell cycle? daughter cell enters new cell cycle (A) M-phase (B) G-phase (C) Arrest of cell cycle on the onset of (C) S-phase (D) Interphase differentiation 2. Replication of centriole occurs during (D) All of the above (A) Interphase 10. RNA and proteins are formed in

(B) Prophase (A) G-phase (B) G-phase (C) Late prophase (C) S-phase (D) G-phase (D) Latetelophase 11. Most cytogenic activities occur during 3. In which phase, DNA content will be (A) Interphase (B) Telophase doubled? (C) Prophase (D) Anaphase (A) Interphase 12. The number of DNA strands in

(B) Anaphase chromosome at -stage is (C) Prophase (A) One (B) Two (D) Telophase (C) Four (D) Eight 4. A material, which arrests cell division, is 13. At which stage of mitosis, chromatids obtained from separated and passes to different poles? (A) Crocus (A) Prophase (B) Metaphase (B) Colchicum (C) Anaphase (D) Telophase (C) Dalbergia 14. Congression is a phenomenon of (D) Chrysanthemum (A) Movement of sister chromatids 5. Sequence of four phases of cell cycle is towards the poles

(A) G → S → G → M (B) Pairing of homologous (B) G → G → S → M chromosomes (C) S → G → G → M (C) Separation of paired chromosomes (D) M → G → G → S (D) Bringing the chromosomes on 6. Which of the following occurs more than equator of spindle apparatus one and less than five in a chromosome? 15. A cell plate is laid down during (A) Chromatid (A) Cytokinesis (B)Karyokinesis (B) Chromomere (C) Interphase (D) None of these (C) Centromere 16. In animal cell has, cytokinesis involves (D)Telomere (A) The separation of sister chromatids 7. Differentiated cell remains at which (B) The contraction of the contractile stage? ring of micro filament

(A) G (B) G (C) Depolymerization of kinetochore (C) G (D)M microtubules 8. Interphase nucleus is enclosed by (D) A protein kinase that phosphorylaes (A) Non-porous nuclear other enzymes membrane 17. Spindle fibre is made up of (B) Porous double nuclear (A)Tubulin (B) Humulin membrane (C) Intermediate filament (C) Non-porous double (D) Flagellin discontinuous nuclear membrane (D) A single porous unit membrane 18. If you are provided with root-tips of onion in your class and are asked to count the chromosomes, which of the following stages can you most conveniently look 9. -phase is into? (A) Phase after G-phase (A) Metaphase (B) Telophase

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(C) Anaphase (D) Prophase (A) Late prophase (B)Early metaphase 19. Which of the following serves as mitotic spindle poison? (C)Late metaphase (A) Ca (B) Mg (C) Tubulin (D) Colchicine (D)Early prophase 20.The process of cytokinesis refers to the 26.Colchicine arrests which of the following division of (A) Nucleus (B) Chromosomes stage of cell division? (C) Cytoplasm (D) None of these (A)Prophase (B)Anaphase 21. The anaphase promoting complex is (C)Telophase (D) Metaphase activated by (A) M cdkcyclin (B) G cdk cyclin 27.The two chromatids of a metaphase (C) S cdkcyclin chromosome represent (D) Transaction factor 22.Cleavage is a unique form of mitotic cell (A) Replicated chromosomes to be division in which separated at anaphase (A) There is no growth of cells (B) The nucleus does not (B) Homologous chromosomes of a participate (C) No spindle developers to guide diploid set the cells (C) Non-homologous chromosomes (D) The plasma membranes of daughter cells do not separate joined at the centromere 23.Which stages of cell division do the (D) Maternal and paternal following figures ‘A’ and ‘B’ represent respectively? chromosomes joined at the centromere 28.Chromosomes are arranged along the equator during (A) Prophase (B) Metaphase (C) Anaphase (D) Telophase (A) Metaphase - Telophas 29.During mitosis, number of chromosomes (B) Telophase - Metaphase (C) Late anaphase - Prophase gets (D) Prophase - Anaphase (A) Change (B) No change 24.Phragmoplast is (A) Proplasted in cytoplasm of dividing (C) May be change if cell is matur cells (D)May be change if cell is immature (B) Cell plate formed by vesicles ER and dictyosomes during 30.In which stage of cell division, cytokinesis chromosomes are most condensed? (C) Cell plate formed by ER, dictyosomes, secretory vesicles (A) Prophase (B) Metaphase and spindle fibre (C) Anaphase (D) Telophase (D) None of the above 25.During mitosis, ER and nucleolus begin to

disappear at

27

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SKILL BOOSTER 3 1. In Anaphase, the chromosomes attain different (C) centromeres & chromosomal arms lie at shapes. It is due to the same line (A) contraction of spindle fibres (D) only daughter chromosome pulled to (B pressure developed in the centromere poles (C) position of centromere 11. What is the chromosomal condition of (D) movement of chromosomes towards the daughter nuclei formed after Meiosis-I in a poles tetraploid cell 2. The number of chromatid/chromatids present (A) diploid (B) octaploid in a chromosome during anaphase of Mitosis (C) polyploid (D) tetraploid (A) 1 (B) 2 12.In meiosis despiralisation occurs in (C) 4 (D) Many (A) metaphase-I (B) anaphase-II 3. The chromatids are separated into daughter (C) telophase-I,II (D) prophase-I,II chromosomes during … phase of mitosis 13.The spindle apparatus formed in metaphase-I (A) prophase (B) metaphase and II are arranged (C) anaphase (D) telophase (A) parallel with one another 4. Centromere division occurs during (B) right angles to each other (A) prophase (B) metaphase (C) oblique with each other (C) anaphase (D) interphase (D) antiparallel with each other 5. Daughter chromosomes appaear first in 14.The number of times spindle apparatus formed (A) prophase (B) metaphase in Metaphase-II (C) anaphase (D) telophase (A) 1 (B) 2 6. Centromere is concerned with (C) 4 (D) Many (A) duplication of chromosome 15.All of the following are true about meiosis-I (B) movement of chromosome to poles and meiosis-II except (C) attachment of spindle fibres (A) prophase-I show crossing over & no crossing over in prophase-II (D) Both a and b (B) chromosome number is reduced in 7. Despiralisation takes place during anaphase-I & not in anaphase-II (A) prophase (B) metaphase (C) In both spiralization and (C) anaphase (D) telophase despiralization will takes place in both 8. Which one is not possible due to mitosis ? (D) Meiosis–I is equational but meiosis –II (A) wound healing (B) regeneration is reductional 16.In meiosis …. is reduction division & ….. is (C) growth equational division. (D) reduction of chromosome number (A) meiosis-I, meiosis-II 9. Region of chromosomes where force is exerted (B) meiosis-II, Meiosis-I during separation of chromatids of dividing (C) both in Meiosis-II chromosomes (D) both in meiosis-I (A) interzonal fibres 17.When mitosis is compared with meiosis which (B) centromere one takes more duration (C) poles of spindle body (A) mitosis (B) meiosis (D) telomere (C) both Mitosis and Meiosis 10.During the movement of the chromosomes in (D) amitosis anaphase to the poles ..... 18.In Meiosis cytokinasis occurs after (A) centromeres lie ahead followed by (A) telophase – I chromosomal arms (B) meiosis - II (B) chromosomal arms followed by (C) either telophase-I or telophase-II centromere (D) telophase II only 19.Which of the following is correct for meiosis

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(A)Two successive divisions of cytoplasm and 25.Nuclear membrane & nucleolous reappears, nuclei Golgi complex and E.R etc. reform in ….phase (B)Two successive divisions of cytoplasm and (A) anaphase (B) telophase nuclei & one replication of DNA (C) metaphase (D) prophase (C) Two successive divisions of cytoplasm 26.Pick out the wrong pair and nuclei & two replication of DNA (A) anaphase - division of centromere (D) Two nuclear division, two cytoplasm (B) metaphase - chromosomes clearly divisions & two DNA replication appears 20.Match the following (C) prophase - despiralization List  I List  II (D) telophase - chromosomes becomes thin, (A) DNA duplication (I) G2 phase long 27.Find out the correct match (B) doubling of cell (II) S phase List  I List  II organelles (A) Prophase (I) two daughter (C) Cell division (III) G1 phase nuclei arrested formed (D) enzymes, (IV) G0 phase (B) Metaphase (II) Daughter nucleotides chromoso me pulled (A) (B) (C) (D) to opposite (A) II III I IV pole (B) I II IV III (C) Anaphase (III) Counting of chromoso (C) III II I IV mes (D) II I IV III (D) Telophase (IV) Nuclear 21.Anaphasic movement is brought about by the membrane (A) Repolymerisation of continuous , nucleolous fibres disappear (B) Depolymerisation of chromosomal fibres (C) Both A & B (A) (B) (C) (D) (D) non disjunction (A) IV III II I 22.The changes occuring in telophase are (B) III II IV II completely reverse to that of (C) II IV III I (A) anaphase (B) prophase (C) metaphase (D) interkinesis (D) IV II III I 23.In which phase the reconstruction of two daughter nuclei takes place. (A) anaphase (B) prophase (C) metaphase (D) telophase 24.Which of the following is wrong about telophase (A) despiralization of chromosome takes place (B) spindle body disappears (C) nucleologenesis takes place (D) centrioles forms its asters and takes position inside nucleus

30

28.Find out the correct match 30.Find out the correct match List  I List  II List  I List  II (A) reduction of (I) Prophase I (A) Attraction (I) Crossing over chromosome between homologous (B) Separation of (II) Anaphase I chromatids (B) Exchange (II) Synapsis (C) Formation of (III) Anaphase between spindle homologous apparatus (D) Crossing over (IV) Metaphase (C) Repulsion (III) Seggregation between (A) (B) (C) (D) homologous (A) I II III IV (D) Separation of (IV) Terminalisati homologous on (B) II III IV I

(C) III II I IV

(D) IV III II I (A) (B) (C) (D) 29.Arrange the following in correct order related (A) II I IV III to meiosis I. crossing over II. Synapsis (B) I III IV II III. terminalization (C) IV II I III IV. metaphase chromosome (D) II IV III I V. reduction in chromosome number (A) II, III, I, IV,V (B) I, II, IV, III,V (C) II, I, III, IV,V (D) III, II, I, IV,V

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ANSWERS

EXERCISE NO : 1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 D C C A A B A B B C C C C D C 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 C B D A A B C C B B D D D A B 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 A D A C C B B B D A D B A C C 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A D B D B C C C D D C D D B A 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 A A B B B C C C A C B A A B A 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 B C A D D C B B C C C D C B D 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 B C C D C B B C B C A B B D B 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 C D A A D B B C D C D C B C B 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 C D B A B A C C C C D B B C A 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 C B C C D B B C B B A D B A C

EXERCISE NO : 2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

B A D C B A A D C A A D D C C 16 17 18 B C C

SKILL BOOSTER : 1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 C A B D A D A A A C C C B B D

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 C A A B A C B B B A D C D B B

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SKILL BOOSTER : 2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 C A A B A D C B C B A C C D A 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 B A A D C A C C B D D A B B B

SKILL BOOSTER : 3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 C A C C C D D D B A A C B B D

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 A B C B D C B D D B C A B C A

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