BIOLOGY M.C.Q (1 Marks)

Choose the correct answer from the options given below

Statement $I$: Chromosomes become gradually visible under light microscope during leptotene stage.

Statement $II$ : The beginning of diplotene stage is recognized by dissolution of synaptonemal complex.

In the light of the above statements, choose the correct answer from the options given below:

$A$. Gap $2$ phase  $B$. Cytokinesis

$C$. Synthesis phase  $D$. Karyokinesis

$E$. Gap $1$ phase

Choose the correct sequence of stages from the options given below :

$A$. Tetrad formation is seen during Leptotene.

$B$. During Anaphase, the centromeres split and chromatids separate.

$C$. Terminalization takes place during Pachytene.

$D$. Nucleolus, Golgi complex and ER are reformed during Telophase.

$E$. Crossing over takes place between sister chromatids of homologous chromosome. Choose the correct answer from the options given below:

Statement $I$ : During Go phase of cell cycle, the cell is metabolically inactive.

Statement $II$ : The centrosome undergoes duplication during S phase of interphase.

In the light of the above statements, choose the most appropriate answer from the options given below:

Choose the correct answer from the options given below.

$(a) -(b) -(c)- (d)$

$(a)$ Zygotene                $(i)$ Terminalization

$(b)$ Pachytene              $(ii)$ Chiasmata

$(c)$ Diplotene                $(iii)$ Crossing over

$(d)$ Diakinesis              $(iv)$ Synapsis

Select the correct option from the following:

$(a)\quad(b)\quad(c)\quad(d)$

$(i)$ Crossing over

$(ii)$ Synapsis

$(iii)$ Terminalisation of chiasmata

$(iv)$ Disappearance of nucleolus

$I.$ S-phase - $DNA$ replication

$II.$ Zygotene - Synapsis

$III.$ Diplotene - Crossing over

$IV.$ Meiosis - Shown by haploid and diploid cells

$V.$ $G_{2}$-phase - Quiescent stage

$R-$ At the end of the meiosis there are $4$ daughter cell with a new form.

$R-$ Exchange of $DNA$ in chromosome seen in mitosis.

$R -$ All organisms doing asexual reproduction.

$R-$ Each pole receive half chromatids numbers in Anaphase

$a -$ cell cycle can vary from organisation to organism and also from cell type to cell type.

$b -$ $DNA$ synthesis occurs only in pachytene.

$c-G_1$ phase corresponds to the interval between mitosis and initiation of $DNA $ reproduction.

 $\begin{array}{|p{0.3\linewidth}|p{0.6\linewidth}|} \hline Column\,\,-I & Column\,\,-II   \\ \hline A.\,\,G_2-\,\,phase & 1.\,\,First\,\,phase\,\,of\,\,prophase\,\,-I  \\ \hline B.\,\,Anaphase & 2.\,\,Proteins\,\,are\,\,synthesized\,\,in\,\,preparation\,\,for\,\,mitosis \\ \hline C.\,\,Leptoteme & 3.\,\,Terminalisation\,\,of\,\,chismata  \\ \hline D.\,\,Diakinesis & 4.\,\,Contromeres\,\,split\,\,and\,\,chromatids\,\,separate  \\ \hline \end{array}$

$(i)$ It increases the genetic variability in the population of organisms from one generation to the next.

$(ii)$ It decreases genetic variability

$(iii)$ It occurs in all cells of our body.

$(iv)$ Important process of evolution.

$Y -$ Crossing over is the exchange of genetic material between two homologous chromosomes.

$I.$ the chromosome number is reduced to haploid state

$II.$ the amount of $DNA$ is reduced to haploid state

The correct option is

$I.$ Terminalization  $II.$ Crossing over

$III.$ Synapsis  $IV.$ Disjunction of genomes

The correct sequence is

$I.$ Meiosis involves pairing of homologous chromosomes and recombinatio 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 calle 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

$(I)$ Diakinesis is middle phase of prophase $-I$

$(II)$ Diakinesis is marked by terminalisation of chiasmata

$(III)$ Meiotic spindle not formed during diakinesis

$(IV)$ By the end of diakinesis, the nucleolus disappears.

$\begin{array}{|p{0.3\linewidth}|p{0.5\linewidth}|} \hline Column\,\,-I & Column\,\,-II   \\ \hline 1.\,\,Leptotene & p.\,\,Homologous\,\,chromosomes\,\,are\,\,separated \\ \hline 2.\,\,Diakinesis & q.\,\,Nucleolus\,\,reappear  \\ \hline 3.\,\,Pachytene & r.\,\,Chromosome\,\,can\,\,observed\,\,in\,\,microscope \\ \hline 4.\,\,Anaphase\,\,-I & s.\,\,Nucleolus\,\,disappear  \\ \hline  & t.\,\,Crossing\,\,over  \\ \hline \end{array}$

$1.$ meiosis is important process for evolution.

$2.$ in meiosis $-II$ mother cell is haploid.

$3.$ In anaphase $-II$ homologous chromosomes are differentiate.

$4.$ after meiosis, each daughter cell has same $DNA$ strands.

$R-$ During meiosis the genetic material is replicated twice and cell divides twice.

$R-$ Theoretical second meiosis is similar to themitosis.

$R-$ It reduce the chromosomes number by half while making the gametes.

$(a)$ Complete disintegration of the nuclear envelope marks the start of the second phase of mitosis.
$(b)$ Metaphase chromosome is made up of one sister chromatid.

$I.$ 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

$1.$ Chromosomes are arranged at the equator.

$2.$ Formation of nuclear membrane.

$3.$ At the end of this phase, nuclear membrane Golgi, complex and endoplasmic reticulum are reformed.

$4.$ End of contraction of chromosome.

$5.$ This phase start with chromosome.according to their vertical contraction.

$a -$ Nuclear envelope assembles around chromosomes clusters.

$b -$ Spindle fibers attach to kinetochores of chromosomes.

$c-$ Condensation of chromosomes.

$d -$ Centromeres split and chromatids separate.

$1.$ Chromosomes cluster at opposite spindle poles

$2.$ Spindle fibres attach to kinetochores of chromosomes

$3.$ Nuclear envelope assembles around the chromosomes clusters.