Mitosis project

Karyotyping Activity Introduction This exercise is a simulation of human karyotyping using digital images of chromosomes from actual human genetic studies.

Mitosis project

Play media Animation of Mitosis project microtubule dynamic instability. Dynamic instability refers to the coexistence of assembly and disassembly at the ends of a microtubule. The microtubule can dynamically switch between growing and shrinking phases in this region.

During polymerization, the tubulin dimers are in the GTP -bound state. Since tubulin adds onto the end of the microtubule in the GTP-bound state, a cap of GTP-bound tubulin is proposed to exist at the tip of the microtubule, protecting it from disassembly.

When hydrolysis catches up to the tip of the microtubule, it begins a rapid depolymerization and shrinkage.

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This switch from growth to shrinking is called a catastrophe. GTP-bound tubulin can begin adding to the tip of the microtubule again, providing a new cap and protecting the microtubule from shrinking.

This is referred to as "rescue". Plus ends that encounter kinetochores or sites of polarity become captured and no longer display growth or shrinkage.

In contrast to normal dynamic microtubules, which have a half-life of 5—10 minutes, the captured microtubules can last for hours. This idea is commonly known as the "search and capture" model. Regulation of microtubule dynamics[ edit ] Post-translational modifications[ edit ] Image of a fibroblast cell containing fluorescently labeled actin red and microtubules green.

Although most microtubules have a half-life of min, certain microtubules can remain stable for hours. Since most modification reactions are slow while their reverse reactions are rapid, modified tubulin is only detected on long-lived stable microtubules.

Most of these modifications occur on the C-terminal region of alpha-tubulin. This region, which is rich in negatively charged glutamate, forms relativey unstructured tails that project out from the microtubule and form contacts with motors.

Thus, it is believed that tubulin modifications regulate the interaction of motors with the microtubule. Since these stable modified microtubules are typically oriented towards the site of cell polarity in interphase cells, this subset of modified microtubules provide a specialized route that helps deliver vesicles to these polarized zones.

This reaction exposes a glutamate at the new C-terminus. As a result, microtubules that accumulate this modification are often referred to as Glu-microtubules.

Although the tubulin carboxypeptidase has yet to be identified, the tubulin—tyrosine ligase TTL is known. This modification occurs on a lysine that is accessible only from the inside of the microtubule, and it remains unclear how enzymes access the lysine residue.

The nature of the tubulin acetyltransferase remains controversial, but it has been found that in mammals the major acetyltransferase is ATAT1.

Enzymes related to TTL add the initial branching glutamate TTL4,5 and 7while other enzymes that belong to the same family lengthen the polyglutamate chain TTL6,11 and These drugs can have an effect at intracellular concentrations much lower than that of tubulin.

However, there are data to suggest that interference of microtubule dynamics is insufficient to block the cells undergoing mitosis. Suppression of microtubule dynamics by tubulin mutations or by drug treatment have been shown to inhibit cell migration.

The drugs that can alter microtubule dynamics include: The cancer-fighting taxane class of drugs paclitaxel taxol and docetaxel block dynamic instability by stabilizing GDP-bound tubulin in the microtubule.

Thus, even when hydrolysis of GTP reaches the tip of the microtubule, there is no depolymerization and the microtubule does not shrink back. The epothilonese. Ixabepilonework in a similar way to the taxanes.

Nocodazolevincristineand colchicine have the opposite effect, blocking the polymerization of tubulin into microtubules.

Eribulin exerts its anticancer effects by triggering apoptosis of cancer cells following prolonged and irreversible mitotic blockade.Since , CELLS alive!

has provided students with a learning resource for cell biology, microbiology, immunology, and microscopy through the use of mobile-friendly interactive animations, video, puzzles, quizzes and study aids.

An embryonic cell divides again and again. Where there was one cell there are two, then four, then eight, Each holds all the genetic information needed to create a human being. Virtual Mitosis Lab: Part I - Onion Root Tip Introduction: Mitosis is considered nuclear division, since its main stages deal strictly with the nucleus and its contents (DNA).

The primary result of mitosis and cytokinesis is the transfer of a parent cell's genome into two daughter cells.

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The genome is composed of a number of chromosomes—complexes of tightly coiled DNA that contain genetic information vital for proper cell function. Because each resultant daughter cell should be genetically identical to the parent cell, the parent cell must make a copy of each.

Molecular Workbench is one of the most versatile ways to experience the science of atoms and molecules, and now it works in web browsers.

Mitosis project

Cell Division 1. The mechanism of cell division; Mitosis and Meiosis. And Cell Cycle regulation. CELL DIVISION;. Cells of all organisms undergo cell division at one or the other stages of their development.

Mitosis Virtual Lab Page 1