Question

What are the important events of prophase?

Answer 1

IMPORTANT EVENTS OF PROPHASE

In the cell cycle, at the end of interphase M-phase initiates. Prior to the initiation of Mitotic phase (M-phase) cell prepares for cell division by the process called Prophase.

There are two stages of prophase:

1. Early prophase:
   • Replicated centrioles begin to move towards the pole of the cell
   • Replicated chromosomes become condensed and visible
   • Nucleolus becomes invisible (disappear)
2. Late prophase:

• Formation of spindle fibres between two centrioles
• Chromosomes are visible in the form of two sister chromatids
• Breakdown of nuclear envelope

During meiosis, the events of prophase is divided into 5 subunits:

1. Leptonema: chromosomes begin to condense and visible as thin thread like structure
2. Zygonema: chromosome continue to condense and form synaptonemal complex through the process of synapsis
3. Pachynema: crossing-over takes place between two homologous chromosomes to exchange genetic materials
4. Diplonema: formation of chiasma i.e. crossing-over becomes visible at this stage
5. Diakinesis: chromosomes become more condensed, so that formed tetrads are visible

REFERENCE:

1. Image: http://www.phschool.com/science/biology_place/biocoach/images/meiosis/mepro1.gif