CELL CYCLE

Question 1

What is the approximate duration of the cell cycle in human cells?
a) 24 minutes
b) 24 hours
c) 90 minutes
d) 12 hours

Answer 1

b) 24 hours

Question 2

How long does it take for yeast to progress through the cell cycle?
a) 90 minutes
b) 24 hours
c) 12 hours
d) 30 minutes

Answer 2

a) 90 minutes

Question 3

Which of the following phases represents the actual cell division?
a) G1 phase
b) Interphase
c) M Phase (Mitosis)
d) G2 phase

Answer 3

M Phase (Mitosis)

Question 4

What is the phase between two successive M phases called?
a) G1 phase
b) G0 phase
c) S phase
d) Interphase

Answer 4

d) Interphase

Question 5

During a 24-hour human cell cycle, how long does the actual cell division last?
a) 24 hours
b) 1 hour
c) 12 hours
d) 90 minutes

Answer 5

b) 1 hour

Question 6

What happens during the G1 phase of interphase?
a) DNA replication occurs
b) The cell prepares for mitosis
c) The cell grows and remains metabolically active
d) Chromosomes separate

Answer 6

c) The cell grows and remains metabolically active

Question 7

During the S phase, what happens to the amount of DNA in the cell?
a) It doubles
b) It remains the same
c) It halves
d) It triples

Answer 7

a) It doubles

Question 8

What is the quiescent stage (G0) of the cell cycle?
a) A phase where DNA replication occurs
b) A phase where cells stop dividing and become metabolically inactive
c) A phase where cells exit G1 and become metabolically active but stop proliferating
d) A phase where cells continue dividing rapidly

Answer 8

c) A phase where cells exit G1 and become metabolically active but stop proliferating

Question 9

In animals, where is mitotic cell division usually seen?
a) Haploid cells
b) Diploid somatic cells
c) Germ cells
d) All types of cells

Answer 9

b) Diploid somatic cells

Question 10

Which cells in plants can undergo mitosis?
a) Only diploid cells
b) Only haploid cells
c) Both haploid and diploid cells
d) None of the above

Answer 10

c) Both haploid and diploid cells

Question 11

Why is mitosis called equational division?
a) Because the number of chromosomes in parent and progeny cells is halved
b) Because the number of chromosomes in parent and progeny cells remains the same
c) Because it only occurs in haploid cells
d) Because the DNA content is doubled

Answer 11

b) Because the number of chromosomes in parent and progeny cells remains the same

Question 12

Which of the following is not one of the four stages of karyokinesis?
a) Prophase
b) Interphase
c) Metaphase
d) Telophase

Answer 12

b) Interphase

Question 13

What is the first stage of karyokinesis?
a) Anaphase
b) Telophase
c) Prophase
d) Metaphase

Answer 13

c) Prophase

Question 14

What is a key event that occurs during prophase?
a) Chromosomes align at the equator
b) Chromosomal material condenses to form compact mitotic chromosomes
c) Cytokinesis occurs
d) Nuclear envelope reforms

Answer 14

b) Chromosomal material condenses to form compact mitotic chromosomes

Question 15

During prophase, which structures begin moving toward opposite poles of the cell?
a) Chromatids
b) Kinetochores
c) Centrosomes
d) Golgi complexes

Answer 15

c) Centrosomes

Question 16

In which phase does the nuclear envelope completely disintegrate?
a) Prophase
b) Anaphase
c) Metaphase
d) Telophase

Answer 16

c) Metaphase

Question 17

What structures attach to the kinetochores during metaphase?
a) Chromosomes
b) Centrioles
c) Spindle fibres
d) Asters

Answer 17

c) Spindle fibres

Question 18

What is the name of the plane where chromosomes align during metaphase?
a) Kinetochore plate
b) Spindle plate
c) Metaphase plate
d) Equatorial plate

Answer 18

c) Metaphase plate

Question 19

What key feature defines the metaphase stage of mitosis?
a) Chromosomes begin to condense
b) Chromosomes align at the spindle equator
c) Cytoplasmic division begins
d) Chromosomes move toward opposite poles

Answer 19

b) Chromosomes align at the spindle equator

Question 20

What marks the end of prophase when observed under a microscope?
a) Disappearance of the Golgi complex, endoplasmic reticulum, nucleolus, and nuclear envelope
b) Chromosomes condense into chromatin
c) Formation of the nuclear envelope
d) Spindle fibres attach to kinetochores

Answer 20

Disappearance of the Golgi complex, endoplasmic reticulum, nucleolus, and nuclear envelope

Question 21

Which event characterizes the onset of anaphase?
a) Chromosomes align at the equatorial plate
b) Centromeres split, and chromatids move to opposite poles
c) Nuclear envelope reappears
d) Chromosomes condense into visible structures

Answer 21

b) Centromeres split, and chromatids move to opposite poles

Question 22

What direction do centromeres move during anaphase?
a) Away from the poles
b) Toward the poles, leading the chromosome movement
c) Toward the equatorial plate
d) Randomly within the cell

Answer 22

b) Toward the poles, leading the chromosome movement

Question 23

Which event marks the beginning of telophase?
a) Chromosomes align at the metaphase plate
b) Chromosomes decondense and lose their individuality
c) Centromeres split and chromatids separate
d) Cytoplasmic division occurs

Answer 23

b) Chromosomes decondense and lose their individuality

Question 24

What key event occurs during telophase?
a) Chromosomes cluster at opposite spindle poles
b) Nuclear envelope disintegrates
c) Chromosomes align at the equator
d) Spindle fibres attach to kinetochores

Answer 24

a) Chromosomes cluster at opposite spindle poles

Question 25

What structures reform during telophase? a) Spindle fibres and kinetochores b) Chromatids and centromeres c) Nucleolus, Golgi complex, and endoplasmic reticulum d) Chromosomes and centrioles

Answer 25

c) Nucleolus, Golgi complex, and endoplasmic reticulum

Question 26

What is cytokinesis? a) The division of the nucleus b) The separation of chromatids into daughter chromosomes c) The division of cytoplasm into two daughter cells d) The condensation of chromatin material

Answer 26

c) The division of cytoplasm into two daughter cell

Question 27

How does cytokinesis occur in animal cells? a) By the formation of a cell plate b) By the appearance of a cleavage furrow c) By fragmentation of the plasma membrane d) Through spindle fibre attachment

Answer 27

b) By the appearance of a cleavage furrow

Question 28

In plant cells, cytokinesis is achieved by: a) The appearance of a cleavage furrow b) The formation of a cell plate starting at the center c) Splitting of the nuclear envelope d) Merging of spindle fibres at the poles

Answer 28

b) The formation of a cell plate starting at the center

Question 29

What is the result of karyokinesis without cytokinesis? a) The formation of a single nucleus b) The formation of two identical daughter cells c) A multinucleate condition called syncytium d) A decrease in cell size

Answer 29

c) A multinucleate condition called syncytium

Question 30

What structure acts as the middle lamella between two daughter cells in plant cytokinesis? a) Centromere b) Aster c) Cell plate d) Spindle fibre

Answer 30

c) Cell plate

Question 31

In which types of cells does mitosis usually occur? a) Only in haploid cells b) Only in diploid cells c) In both haploid and diploid cells d) Only in prokaryotic cells

Answer 31

b) Only in diploid cells

Question 32

What is one significant contribution of mitosis in multicellular organisms? a) Gamete formation b) Reduction of chromosome number c) Cell repair and growth d) Genetic variation

Answer 32

c) Cell repair and growth

Question 33

Why is mitosis essential for cells in tissues like the epidermis and the gut lining? a) To reduce the size of the cells b) To constantly replace cells that are lost or damaged c) To generate genetic diversity d) To increase the number of chromosomes

Answer 33

b) To constantly replace cells that are lost or damaged

Question 34

What role does mitosis play in the growth of plants? a) It helps in forming haploid gametes b) It occurs only in mature tissues c) It leads to continuous growth through divisions in meristematic tissues d) It replaces non-dividing cells in leaves

Answer 34

c) It leads to continuous growth through divisions in meristematic tissues

Question 35

Meiosis reduces the chromosome number by half. What is this process crucial for? a) Asexual reproduction b) Cell repair c) Sexual reproduction d) Growth of multicellular organisms

Answer 35

c) Sexual reproduction

Question 36

How many haploid cells are formed at the end of meiosis? a) One b) Two c) Four d) Six

Answer 36

c) Four

Question 37

Which phase of meiosis is characterized by the pairing of homologous chromosomes and recombination between non-sister chromatids? a) Prophase I b) Metaphase I c) Anaphase II d) Telophase II

Answer 37

a) Prophase I

Question 38

Meiosis I is initiated after what event in the cell cycle? a) DNA replication b) Cytokinesis c) Telophase I d) Centromere splitting

Answer 38

a) DNA replication

Question 39

What restores the diploid phase in the life cycle of sexually reproducing organisms after meiosis? a) Mitosis b) Fertilization c) DNA replication d) Crossing over

Answer 39

b) Fertilization

Question 40

How many sequential cycles of nuclear and cell division occur during meiosis? a) One b) Two c) Three d) Four

Answer 40

b) Two

Question 41

Which of the following stages of Prophase I involves the formation of a synaptonemal complex? a) Leptotene b) Zygotene c) Pachytene d) Diakinesis

Answer 41

b) Zygotene

Question 42

During which stage of Prophase I does crossing over occur? a) Leptotene b) Zygotene c) Pachytene d) Diplotene

Answer 42

c) Pachytene

Question 43

What is the enzyme responsible for mediating the crossing over of genetic material during Prophase I? a) Helicase b) Ligase c) Recombinate d) Recombinase

Answer 43

d) Recombinase

Question 44

Which of the following terms refers to the X-shaped structures formed at the sites of crossing over in diplotene? a) Centromere b) Bivalent c) Chiasmata d) Kinetochore

Answer 44

c) Chiasmata

Question 45

What happens during the diakinesis stage of Prophase I? a) Chromosomes start pairing together b) Crossing over is initiated c) Terminalisation of chiasmata occurs d) Recombination is completed

Answer 45

c) Terminalisation of chiasmata occurs

Question 46

During which stage do homologous chromosomes align on the equatorial plate in Meiosis I? a) Prophase I b) Metaphase I c) Anaphase I d) Telophase I

Answer 46

b) Metaphase I

Question 47

In which stage of Meiosis I do homologous chromosomes separate, while sister chromatids remain together? a) Leptotene b) Metaphase I c) Anaphase I d) Telophase I

Answer 47

c) Anaphase I

Question 48

What follows the separation of homologous chromosomes during Telophase I in meiosis? a) Formation of chiasmata b) DNA replication c) Reformation of nuclear membrane and cytokinesis d) Separation of chromatids

Answer 48

c) Reformation of nuclear membrane and cytokinesis

Question 49

What is the stage between Meiosis I and Meiosis II called, where no DNA replication occurs? a) Diakinesis b) Interkinesis c) Anaphase I d) G1 Phase

Answer 49

b) Interkinesis

Question 50

How is Prophase II different from Prophase I? a) It is more complex b) It is simpler and shorter c) It involves crossing over d) It involves recombination

Answer 50

b) It is simpler and shorter

Question 51

During which phase of Meiosis II do the sister chromatids separate and move to opposite poles? a) Prophase II b) Metaphase II c) Anaphase II d) Telophase II

Answer 51

c) Anaphase II

Question 51

Which of the following events occurs in Prophase II of meiosis? a) Synapsis of homologous chromosomes b) Reformation of the nuclear membrane c) Disappearance of the nuclear membrane d) Crossing over

Answer 51

c) Disappearance of the nuclear membrane

Question 52

In which phase of Meiosis II do the chromosomes align at the equator of the cell? a) Prophase II b) Metaphase II c) Anaphase II d) Telophase II

Answer 52

b) Metaphase II

Question 53

Which phase of Meiosis II is characterized by the simultaneous splitting of the centromeres? a) Prophase II b) Metaphase II c) Anaphase II d) Telophase II

Answer 53

c) Anaphase II

Question 54

At the end of Meiosis II, what is the outcome in terms of the number and type of cells produced? a) Two diploid cells b) Four haploid cells c) Two haploid cells d) Four diploid cells

Answer 54

b) Four haploid cells

Question 55

In Telophase II of meiosis, what event occurs after the chromosomes reach opposite poles? a) Recombination of genetic material b) Chromosome condensation c) Nuclear envelope formation d) Crossing over

Answer 55

c) Nuclear envelope formation

Question 56

What is the primary significance of meiosis in sexually reproducing organisms? a) Increase in the chromosome number b) Reduction in genetic variability c) Conservation of chromosome number across generations d) Increase in body size

Answer 56

c) Conservation of chromosome number across generation

Question 57

Which of the following processes contributes to the genetic variability seen in populations? a) Mitosis b) Cytokinesis c) Meiosis d) Binary fission

Answer 57

c) Meiosis

Question 58

How many nuclear and cell divisions occur during meiosis? a) One nuclear and one cell division b) Two nuclear and two cell divisions c) One nuclear and two cell divisions d) Two nuclear and one cell division

Answer 58

b) Two nuclear and two cell divisions

Question 59

In Meiosis II, how does the process differ from Meiosis I? a) Meiosis II involves crossing over b) Meiosis II involves homologous chromosome pairing c) Meiosis II resembles mitosis and separates sister chromatids d) Meiosis II involves synapsis

Answer 59

c) Meiosis II resembles mitosis and separates sister chromatids