The Cell and Cell Processes. Beth. Cytology The study of the structure and function of cells. Structures. Functions. Cell Membrane Cytosol Cytoskeleton Microvilli Cilia Centrioles Ribosomes Mitochondria Nucleus Nucleolus Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum
The Cell and Cell Processes
Can magnify cellular structures about 1,000 times and show details as fine as 0.25 µm (micrometer or micron). With a light microscope one can identify cell types and see large intracellular structures.
Transmission Electron Microscopy
Scanning Electron Microscopy
Electrons pass through an ultrathin section to strike a photographic plate. Transmission Electron Microscopy shows the fine structure of cell membranes and intracellular structures.
Electrons bouncing off exposed surfaces create a scanning electron micrograph. Although Scanning Electron Microscopy provides less magnification, it provides a three-dimensional perspective on cell structure.
Three characteristics of osmosis should be remembered:
Osmosis is the diffusion of water molecules across a membrane.
Osmosis occurs across a selectively permeable membrane that is freely permeable to water but not freely permeable to solutes.
In osmosis water will flow across a membrane toward the solution that has the highest concentration of solutes, because that is where the concentration of water is lowest.
Carrier molecules work regardless of any concentration gradients.
Creation of vesicles containing fluid or solid material.
The chromatids now move to a narrow central zone called the metaphase plate. A microtubule of the spindle apparatus attaches to each centromere.
Is the separation of the two daughter cells. It usually begins in late Anaphase and continues through Telophase. The completion of cytokinesis marks the end of cell division.