A biologist was looking at a cell with a compound microscope and he observed the small green
Structure called……..These structure are important as they provide the cell with………..that help
In the process of …...The outer boundary of cell is called …….which hold the cell together .
Answers
Explanation:
Looking at the Structure of Cells in the Microscope
A typical animal cell is 10–20 μm in diameter, which is about one-fifth the size of the smallest particle visible to the naked eye. It was not until good light microscopes became available in the early part of the nineteenth century that all plant and animal tissues were discovered to be aggregates of individual cells. This discovery, proposed as the cell doctrine by Schleiden and Schwann in 1838, marks the formal birth of cell biology.
Animal cells are not only tiny, they are also colorless and translucent. Consequently, the discovery of their main internal features depended on the development, in the latter part of the nineteenth century, of a variety of stains that provided sufficient contrast to make those features visible. Similarly, the introduction of the far more powerful electron microscope in the early 1940s required the development of new techniques for preserving and staining cells before the full complexities of their internal fine structure could begin to emerge. To this day, microscopy depends as much on techniques for preparing the specimen as on the performance of the microscope itself. In the discussions that follow, we therefore consider both instruments and specimen preparation, beginning with the light microscope.
Figure 9-1 shows a series of images illustrating an imaginary progression from a thumb to a cluster of atoms. Each successive image represents a tenfold increase in magnification. The naked eye could see features in the first two panels, the resolution of the light microscope would extend to about the fourth panel, and the electron microscope to about the seventh panel. Some of the landmarks in the development of light microscopy are outlined in Table 9-1. Figure 9-2 shows the sizes of various cellular and subcellular structures and the ranges of size that different types of microscopes can visualize.
Figure 9-1. A sense of scale between living cells and atoms.
Figure 9-1
A sense of scale between living cells and atoms. Each diagram shows an image magnified by a factor of ten in an imaginary progression from a thumb, through skin cells, to a ribosome, to a cluster of atoms forming part of one of the many protein molecules (more...)
Table 9-1. Some Important Discoveries in the History of Light Microscopy.
Table 9-1
Some Important Discoveries in the History of Light Microscopy.
Figure 9-2. Resolving power.
Figure 9-2
Resolving power. Sizes of cells and their components are drawn on a logarithmic scale, indicating the range of objects that can be readily resolved by the naked eye and in the light and electron microscopes. The following units of length are commonly