To study the structure and function of organelles in eukaryotic plant and animal cells.
The function of cell membrane is that defines cell boundary; regulates molecule passage into and out of cells.
2. Yes, there is an intercellular space between two cell membranes; water, nutrients, wastes can be found in this space.
3. Each membrane appears as a light layer sandwiched between two darker layers because of the phospholipids bilayer structure. The nonpolar (hydrophobic) tails will be inside which is the light layer, and the polar (hydrophilic) head will be outside which is the darker layers.
4. The role of a cytoskeleton in a living cell is to supply structure to the cell, give the cell the ability to move and ensure proper cell division during cellular reproduction.
5. Microfilaments are two-stranded (double helix) helical polymers of the protein actin. They appear as flexible structures with a diameter of 5 - 9 nm and are organized into a variety of linear bundles, two-dimensional networks, and three-dimensional gels. Microtubules are long, hollow cylinders made of the protein tubulin. With an outer diameter of 25 nm, they are much more rigid than actin filaments. Microtubules are long and straight and have helical lattice structure.
6. The nucleus is separated from the cytoplasm by a double membrane (nuclear envelope). There are 2 membranes are visible.
7. The nuclear pores, serve as the pathways for the exchange of the materials between the nucleus and the cytoplasm. The pore serves as a water filled channel and has an effective diameter of 10 nm. Therefore, transport in and out of the nucleus can occur in several ways.
The diaphragm controls the opening of the nuclear pores.
8. Heterochromatin is always the inner surface of the nuclear membrane, and the Euchromatin is scattered throughout the necleoplasm. .
9. It appears to be a small circle inside the nucleus that creates ribosomes.
10. Polysomes play a major role in protein synthesis, which is the process in which amino acids are linearly arranged into proteins according to DNA sequence.
