Trends in Biotechnology TB 05 The Crowded Cell

We can look at individual molecules. But we must try to keep a sense of the correct size. discussion-1/

That presentation was based on this pdf: /molecule_of_the_month/poster_full.pdf

The following pictures are selected to give you an idea. The cell does not have many big spaces in it. The cell is really very crowded. "Illustrations by David S. Goodsell, the Scripps Research Institute."

You can find labels for the previous pictures by looking through the article “Illustrating the Machinery of life. Eukaryotic Cell Panorama.” Files/12011BAMBEDPanorama.pdf If you want, you can print the pictures and make a poster of a section of the eukaryotic cell, enlarged by one million times to show the distribution and arrangement of macromolecules. The cross section includes eight panels from the nucleus to the cell surface, showing the process of protein synthesis and export.

These diagrams were based on information from: – biochemistry, – electron microscopy, – NMR spectroscopy and – x-ray crystallography.

Organization in the cell. The cell can do many things to manage what happens in the cell. Different proteins, so different reactions and products, can be localized to different areas of the cell.

Other molecules can be used to organize the cell processes.

Compare the following drawing of the crowded phosholipid bilayer, with a ‘normal’ diagram of a cell.

One phosholipid molecule.

National Institute of Standards and Technology (NIST) An image of a membrane without cholesterol An image of a membrane with cholesterol

This movie shows how crowded cells are. Part of an insulin-secreting cell. Golgi compartments (long, multi-colored curves in center), endoplasmic reticulum (yellow structures), ribosomes (tiny orange dots), microtubules (thin green strands), mitochondria (green globs), and various kinds of vesicles (small white spheres, larger blue spheres, and irregularly shaped structures in red and purple).

This means that the transport of materials within the cell needs to be carefully guided. Let’s look at a video which looks inside a cells. It is not crowded enough. xMzZk

3 Trends in Biotechnology: Information is being presented in visual form. Information from many sources is being integrated in many ways. Computers and computer programs are very important for visualizing cells We know that cells are very very complicated.

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Chromosome Territories Because of the crowding of a cell, parts of the cells will contain certain things. This even happens in the nucleus, where chromosomes are found in their own territory. Also different functions occur in different parts of the nucleus.