Cell Cycle & Mitosis Test - 2

In Anastral mitosis process, the centriole is absent in the cells of the higher plants and some animals. It is the characteristic of higher plants.

• Prophase is the first stage of mitosis.
• In prophase condensation of chromatin material takes place and during condensation, the DNA strands get untangled to form compact mitotic chromosomes.
• Cells at the end of prophase, when viewed under the microscope, do not show Golgi complexes, endoplasmic reticulum, nucleolus, and the nuclear envelope.

The Synaptonemal Complex (SC) is a zipper-like protein structure which is assembled between homologous chromosomes during the prophase of the first meiotic division.

• Diakinesis is the last stage in prophase of Meiosis, in which the nucleolus and nuclear envelope disappear, spindle fibres form, and the chromosomes shorten in preparation for anaphase.
• It can be best seen in flower bud.
• Onion root tip, Lead of dichanthium consists of meristematic cells which divide by mitosis. Therefore, no diakinesis is observed.

• In a plant, meiosis occurs when there is a change from sporophyte to gametophyte.
• In the sporophyte phase, a diploid plant body grows and eventually produces spores through meiosis.
• The gametophyte phase of plant life cycles in which the gametes, i.e. egg and sperm are produced.
• The gametophyte is haploid, that is, each cell contains a single complete set of chromosomes, and arises from the germination of a haploid spore.

Zygotic meiosis – Pteris is the incorrect matching pair out of the given options because zygotic meiosis occurs in Chlamydomonas.

Disjunction is the process of separation of homologous chromosomes during anaphase I of mitotic or meiotic divisions.

Dyad consists of two sister chromatids held together by a protein complex called cohesin.