Some of the microtubules attach the poles to the chromosomes by connecting to protein complexes called kinetochores. … During the cell division phase called metaphase, the microtubules pull the chromosomes back and forth until they align in a plane along the equator of the cell, which is called the equatorial plane.
How do microtubules capture chromosomes?
Microtubule plus ends extend and retract from the spindle poles in order to search their local environment in an attempt to capture a kinetochore, the protein complex that links microtubule plus ends to chromosomes.
What phase do microtubules attach to chromosomes?
Following completion of prophase, the cell enters prometaphase—a transition period between prophase and metaphase. During prometaphase the microtubules of the mitotic spindle attach to the kinetochores of condensed chromosomes.
Where is microtubules attach to capture chromosomes?
Kinetochore microtubules attach end-on to the kinetochore, which forms at the centromere of each duplicated chromosome. They serve to attach the chromosomes to the spindle. Overlap microtubules interdigitate at the equator of the spindle and are responsible for the symmetrical, bipolar shape of the spindle.
What are the three types of microtubules?
The overall shape of the spindle is framed by three types of spindle microtubules: kinetochore microtubules (green), astral microtubules (blue), and interpolar microtubules (red). Microtubules are a polarized structure containing two distinct ends, the fast growing (plus) end and slow growing (minus) end.
What is the difference between spindle and microtubules?
During mitosis, the spindle fibers are called the mitotic spindle. … Long protein fibers called microtubules extend from the centrioles in all possible directions, forming what is called a spindle. Some of the microtubules attach the poles to the chromosomes by connecting to protein complexes called kinetochores.
How do microtubules attach to kinetochores?
In prophase, the first step in mitosis, the nuclear envelope breaks down and chromosomes condense and become visible. … The kinetochores appear at the centromeres, the mitotic spindle microtubules attach to kinetochores, and the centrosomes move toward opposite poles.