The mitotic spindle is a special device essential for chromosome segregation ( mitosis) during cell division. It consists of three parts, chromosomes, two asters and a spindle region (Fig. 1).
What are the components of mitotic apparatus?
In eukaryotic cells, the mitotic apparatus is composed of two centrosomes and spindle microtubules (Figure 43.9). The centrosome is 1–2 μm in diameter. Each centrosome is composed of two centrioles of approximately 20 nm in diameter surrounded by a pericentriolar matrix.
What makes up the mitotic apparatus quizlet?
Structure made of spindle fibers, centrioles, and aster fibers, that organizes chromosomes before the cell divides.
What are the parts of the spindle apparatus?
The major components of the mitotic spindle include the spindle fibers (microtubules), microtubule-associated proteins, and the microtubule organizing center. The microtubules associated with mitosis are of three groups: the polar microtubules, the astral microtubules, and the kinetochore microtubules.
What are the 3 types of microtubules?
There are three main subgroups of microtubules: the polar microtubules (those extending across the cell, as in from centrosome to centrosome), the astral microtubules (those that anchor the spindle poles to the cell membrane), and the kinetochore microtubules (those that extend from the centrosome to the kinetochore …
What is mitotic spindle made of?
The mitotic spindle is a highly dynamic molecular machine composed of tubulin, motors, and other molecules. It assembles around the chromosomes and distributes the duplicated genome to the daughter cells during mitosis.
What are microtubules give their role in mitotic apparatus?
Microtubules play a key role in forming the mitotic spindle, also called the spindle apparatus. This is a structure that is formed during mitosis (cell division) in eukaryotic cells. … Polar microtubules intertwine between two MTOCs and help separate chromosomes.
What are the stages of mitosis in order?
These phases are prophase, prometaphase, metaphase, anaphase, and telophase. Cytokinesis is the final physical cell division that follows telophase, and is therefore sometimes considered a sixth phase of mitosis.
What is the mitotic spindle made of quizlet?
The mitotic spindle begins to form. The spindle is a structure made of microtubules, strong fibers that are part of the cell’s “skeleton.” Its job is to organize the chromosomes and move them around during mitosis. In prophase, the spindle grows between the centrosomes as they move apart.
What are the 4 stages of the cell cycle?
In eukaryotes, the cell cycle consists of four discrete phases: G1, S, G2, and M. The S or synthesis phase is when DNA replication occurs, and the M or mitosis phase is when the cell actually divides. The other two phases — G1 and G2, the so-called gap phases — are less dramatic but equally important.
Which protein is the major component of mitotic spindle?
Mitotic spindle is mainly made of microtubules. These microtubules are made by polymerisation of globular tubulin proteins.
How are mitotic apparatus formed?
Microtubules form the mitotic apparatus (mitotic spindle) whose main function is to separate chromosomes to the newly dividing cells (Fig. 5). These microtubules are organized from centrosomes (microtubule organizing centers; MTOCs) at the two opposite mitotic poles.
What are the three types of microtubules in the mitotic spindle?
The overall shape of the spindle is framed by three types of spindle microtubules: kinetochore microtubules (green), astral microtubules (blue), and interpolar microtubules (red).
What are the constituents of microtubules?
Microtubules are the largest type of filament, with a diameter of about 25 nanometers (nm), and they are composed of a protein called tubulin. Actin filaments are the smallest type, with a diameter of only about 6 nm, and they are made of a protein called actin.
What is the function of the mitotic spindle?
The mitotic spindle is the macromolecular machine that segregates chromosomes to two daughter cells during mitosis. The major structural elements of the spindle are microtubule polymers, whose intrinsic polarity and dynamic properties are critical for bipolar spindle organization and function.