Figure 8 from DESIGN OF ADJUSTABLE MULTISPINDLE ATTACHMENT Biology Diagrams Spindle fiber is a network of filaments that are formed during the cell division process. They help in the movement of chromosomes during both mitosis and meiosis. Q2 . What are spindle fibers made of? Spindle fiber is most abundantly composed of the microtubule, which is a polymer of ๐ถ and ๐ซ-tubulin dimer. Also, the spindle fiber is made When a cell starts to divide, it forms a spindle, a micro-machine made of microtubules, which separates the duplicated chromosomes. The attachment of microtubules to chromosomes is mediated by kinetochores, protein complexes on the chromosome. Spindle microtubules can be divided into three major classes: kinetochore microtubules, which form k-fibers ending at the kinetochore; interpolar
Spindle fiber and cell movement occur when microtubules and motor proteins interact. Motor proteins, which are powered by ATP, are specialized proteins that actively move microtubules. Motor proteins such as dyneins and kinesins move along microtubules whose fibers either lengthen or shorten. The disassembly and reassembly of microtubules As spindle fibers extend from the centrosomes, they seek out kinetochores, establishing robust and bi-oriented attachments vital for chromosome movement. The fidelity of kinetochore-microtubule attachment is safeguarded by molecular checkpoints and feedback mechanisms. Aurora B kinase plays a role in the correction of improper attachments.
Mitotic spindle: kinetochore fibers hold on tight to interpolar bundles Biology Diagrams
Spindle fibers start to form the centrioles at the opposite poles of the cell. In animal cells, the mitotic spindle appears as asters that surround each centriole pair. The sister chromatids attach to spindle fibers at their kinetochores during this phase. Also, the cell elongates as spindle fibers stretch from each pole. Faithful chromosome segregation during mitosis depends on the bi-oriented attachment of chromosomes to spindle microtubules through their kinetochores. The precise regulation of kinetochore
The twisted shape is visible as the rotation of bridging fibers around the spindle axis when the spindle is observed along the axis. The fibers show a left-handed twist, making the whole spindle a chiral structure The mechanics of chromosome attachment to the spindle. Chromosoma. 1967; 21:1-16. Crossref. Scopus (104) PubMed. Google Scholar. 67. The spindle is necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear division: mitosis and meiosis. During mitosis, the spindle fibers
Chromosome Dynamics and Visualization in Metaphase Biology Diagrams
In addition to being the attachment site of KT MTs, KTs are responsible for detecting errors via checkpoints and for ultimately enabling the transport of sister chromatids to poles via K-fibers. In the 1950s, the mitotic spindle was shown to consist of fibrous structures, whose submicroscopic birefringent fibrils turned out to be MTs . Spindle fiber attachment in meiosis differs significantly from mitosis, particularly in chromosome-spindle interactions. In mitosis, each chromosome consists of two sister chromatids, which attach to spindle fibers from opposite poles in amphitelic attachment. This ensures each daughter cell receives an identical chromosome set.
