Multiple Choice QuestionsLampbrush chromosomes are seen in which typical stage
mitotic anaphase
mitotic prophase
mitotic metaphase
meiotic prophase
In meiosis division is
Ist reductional and IInd equational
Ist equational and IInd reductional
both reductional
both equational
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.
Chiasmata are most appropriately observed in meiosis during :
diakinesis
diplotene
metaphase II
pachytene
Colchicine prevents the mitosis of the cells at which of the following stage?
Anaphase
Metaphase
Prophase
Interphase
Which of the following maintain the constant number of chromosomes generation after generation?
Meiosis
Endomitosis
Mitosis
Amitosis
Switch
