Download Part 3

1
2
Definitions of the components:
Part 4: Eukaryotic cell structure
1. Cell wall: Present only in plant cells, these are responsible for providing the cell with
structure and rigidity. They also protect the cell from swelling due to osmosis.
2. Cytoskeleton: Provides the cell with required support and also plays a role in movement of
cellular organelles.
3. Plasmodesmata: Helps in interaction between adjacent plant cells by providing a path
between them.
4. Plasma membrane: Provides a protective layer around the cell by separating it from the
environment and monitoring the movement of molecules into and out of it.
3
4
5. Lysosome: These are found exclusively in animal cells for degrading any intracellular debris.
6. Peroxisome: Organelle containing enzymes that are responsible for protecting the cell
against free radicals and peroxide. They also play a role in metabolism of very long chain fatty
acids.
7. Smooth endoplasmic reticulum (SER): Biosynthesis of lipids and metabolism of several
drugs occurs at the SER.
8. Rough endoplasmic reticulum (RER): This is a site where much of the protein synthesis
occurs as it is studded with ribosomes.
9. Vacuole: These are essential for storage of metabolites and also for degrading and recycling
macromolecules.
5
10. Ribosomes: The function of ribosomes is common to prokaryotes and eukaryotes. They
serve to synthesize proteins from the corresponding RNA.