Table of Contents
Who makes spindle fibers?
microtubules
Spindle Fibres They are formed by microtubules and play an important role during nuclear division. They are responsible for the segregation of sister chromatids and movement of chromosomes during mitotic and meiotic division.
During which phase are spindle fibers formed?
Prophase
Prophase is the first stage of mitosis, during which the cell begins to position itself in order to separate the chromatids and divide. During prophase, the nuclear envelope and nucleolus are dissolved and the chromosomes condense. The centrioles and spindle fibers begin to form at opposite poles of the cell.
What is the 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.
Where does spindle fibers attach to during metaphase?
centromere
During metaphase, spindle fibers attach to the centromere of each pair of sister chromatids (see Figure below). The sister chromatids line up at the equator, or center, of the cell.
Who produce spindle Fibres in plant cells?
Centrioles
Centrioles are found as single structures in cilia and flagella in animal cells and some lower plant cells. Centrioles are constructed of microtubules. In animal cells centrioles organise the pericentriolar material to produce microtubules including mitotic spindle fibres.
What makes up the spindle apparatus?
The cellular spindle apparatus includes the spindle microtubules, associated proteins, which include kinesin and dynein molecular motors, condensed chromosomes, and any centrosomes or asters that may be present at the spindle poles depending on the cell type.
Does spindle formation occur in mitosis?
Mitosis is the process of nuclear division, which occurs just prior to cell division, or cytokinesis. During this multistep process, cell chromosomes condense and the spindle assembles.
How many type of spindle Fibres are formed?
2. Polar microtubule: These microtubules interdigitate at the spindle middle zone and push the spindle pole apart through the motor proteins. 3. Kinetochore microtubule: The kinetochore microtubules bind directly to the kinetochore.
What happens to spindle fibers in prophase?
During prophase, the nucleus disappears, spindle fibers form, and DNA condenses into chromosomes ( sister chromatids ). During telophase, chromosomes arrive at opposite poles and unwind into thin strands of DNA, the spindle fibers disappear, and the nuclear membrane reappears.