The code of life / [Ernest Borek].

  • Ernest Borek
Date:
1965
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The code of life / [Ernest Borek]. Source: Wellcome Collection.

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    physical containment but it also mounts an unceasing guard over the ports of entry on the frontiers of the cell. The membrane recognizes with its uncanny molecular memory the hundreds of compounds swimming around it and permits or denies passage according to the cell's requirements. Unknown compounds which fail some subtle test for recognition on the molecular ramparts of the membrane are usually excluded and the cell is thus guarded against their possibly harmful presence. The cell's membrane girds a kingdom of a topography so varied it would astonish the good Doctor Dujardin. Some of these structures are obligatory. These are the organoids, which must be present in every cell of a given tissue. There are other structures whose distribution is more random in otherwise homo geneous cells. These are the inclusions which may be a tiny blob of fat or a grain of starch. Organoids must be reproduced during cell division; inclusions need not be. The function of some of the organoids in the cell is well known; others still manage to hide their activities. Our knowledge of the function of the organoids depends on our ability to remove them in more or less intact form from the cell. In order to achieve this the integrity of the cell must be destroyed. This may be achieved by mechanical grinding with some abrasive powder ; or it may be done by exposure of the cells to sonic vibration; or in the case of bacteria, their cell walls can be dissolved by an enzyme, and without its protective enclosure the cell pops and disintegrates like an overblown balloon. The next step involves a series of centrifugations at higher and higher speeds and, consequently, at gravitational forces of increasing intensity. Exposing the cells' contents to 100,000 times the force of gravity is a routine operation in most biochemical laboratories today. The various components of the cell sediment out sequen tially as increasing centrifugal fields are imposed upon them. The many different fractions are harvested individually; their appearance is examined under an electron microscope; visual