The drug colchicines, used to obtain polyploidy cells, acts on the cytoskeletal structures of

the plant cells called

1. microtubules

2. actin filaments

3. intermediate filaments

4. all of the above.

Astral rays arise from 

1. centriole 

2. cytoplasm

3. chromatid

4. centromere.

Number of mitotic division required in a cell of root tip for formation of 128 cells is

1. 12

2. 3

3. 7

4. 6

Barr body is found in the cytoplasm during

1. interphase in cell of female mammal.

2. interphase in cell of male mammal.

3. prophase in cell of female mammal.

4. prophase in cell of male mammal.

When synapsis is complete all along the chromosome, the cell is said to have entered a stage called
(1) Zygotene

(2) pachytene

(3) diplotene

(4) diakinesis.

Many cells function properly and divide mitotically even though they do not have 

(1) Plasma membrane

(2) Cytoskeleton

(3) Mitochondria

(4) Plastids

Which of the following is not a characteristic of meiosis?
(1) It involves two stages of DNA replication one before meiosis-I and another before meiosis-II

(2) It involves recombination and crossing over

(3) Sister chromatids separate during anaphase- II

(4) Nuclear membrane disappears during prophase.

Microtubule depolymerizing drug such as colchicine is expected to 

(1) inhibit spindle formation during mitosis 

(2) inhibit cytokinesis

(3) allow mitosis beyond metaphase

(4) induce formation of multiple contractile

Which of the following statements is incorrect about G₀ phase.
(1) Mitosis occurs after G₀ phase.

(2) Biocatalysts can be used to exit G₀ phase.

(3) Cell volume keeps on increasing during this phase.

(4) Cell metabolism occurs continuously in G₀ phase.

Beads on string like structures of A are seen in B, which further condense to form chromosomes in C stage of cell division.

            A                   B                   C

(1) Chromonema  Chromatin       Metaphase

(2) Chromatin      Chromatid       Metaphase

(3) Chromonema  Chromosome    Anaphase

(4) Chromonema  Chromatid       Anaphase.