When synapsis is complete all along the chromosome, the cell is said to have entered a stage called
zygotene
pachytene
diplotene
diakinesis
B.
pachytene
Prophase I consists of 5 stages:
(i) Leptotene- Chromosomes become gradually visible.
(ii) Zygotene- Synapsis, pairing of homlogous chromosomes takes place. It results in the formation of bivalents. Also, formation of special proteinaceous structure called synaptonemal complex occur.
(iii) Pachytene- Cells that eneterd this phase results in spiralling, shortening and thickening of the bivalents.
(iv) Diplotene- Dissolution of synaptonemal complex takes place. Also, recombined homologous chromosomes of the bivalents seperate.
(v) Diakinesis- Terminalisation of chiasmata occur in this phase.
The checkpoint in cell cycle plays important role in
repair DNA damage
apoptosis initiation
assess DNA damage
inhibit cell damage.
Barr Body is found in the cytoplasm during
interphase in cell of female mammal
interphase in cell of male mammal
prophase in cell of female mammal
prophase in cell of male mammal.
Assertion: Meiosis II is similar to mitosis.
Reason : Meiosis I cannot occur in haploid cells.
If both assertion and reason are true and reason is the correct explanation.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false
If both assertion and reason are false.
In a diploid cell, at which stage of cell cycle, the amount of DNA is doubled?
G1 and G2 phase
G0 phase
S, G2 and M phase
S phase
Microtubule depolymerizing drug such as colchicine is expected to
inhibit spindle formation during mitosis
inhibit cytokinesis
allow mitosis beyond metaphase
induce formation of multiple contractile rings
The importance of meiosis lies in :
bringing discontinuous variations
addition in the number of chromosomes
reduction in the number of chromosomes
maintaining the number of chromosomes
Which of the following is not a characteristic of meiosis
It involves two stages of DNA replication one before meiosis-I and another before meiosis-II
It involves recombination and crossing over
Sister chromatids separate during anaphase II
Nuclear membrane disappears during prophase.
Which of the following statements is incorrect about G0 phase
Mitosis occurs after G0 phase.
Biocatalysts can be used to exit G0 phase.
Cell volume keeps on increasing during this phase.
Cell metabolism occurs continuously in G0 phase.
