1. ribosomes are non membrane bound structures.
2. they are ultrmicroscopic structures with RNA.
3. Free ribosomes are suspended in the cytosol.
4. Bound ribosomes are attached to the outer urface of the Endoplasmic reticulum or nuclear envelope.
5. Ribosomes are of two kinds based on their sedimentation co-feeicient They are: 80s type- occur in Eacarytic cells, 70s type- occur in prokaryotic cells and mitochondrial matrix.
6. Ribosomes carry out protein synthesis through a prosess called translation. Hence Ribosomes are the work benches for protiens or protien factories.
E) Centrosome( MTOC- Microtubular organizing centre):
1. centrosome is a spherical cytoplasmic zone seen close to nucleus.
2. It has a pair of centriols that lie at right angles to each other.
3. Centrioles participate in cell division.
4. Centrioles are involved with chromosome movement.
5. Centrosome I conspicuous only at the time of cell division.
6. Centrioles are absent from plant cells.
1. lysosomes are membrane bound spherical rganelles.
2. they contain enzymes called hydrolases. They involved intracellular digestition.
3. lysosomes are often called “suicidal bags” due to their role in autolysis of injured or diseased cells.
4. They are also helpful to recycle worn-out cellular co
1. Cytoskeleton is a flexible cellular frame work, that extend throughout the cytoplasm.
2. It consists of three types of protien elements. They are i) Microtubules ii) Intermediate filaments iii) Micro filaments.
Of these micro tubules are the thickest and micro fiiaments are thinnest.
3. Microtubules are hallow, slender,cylindrical structures. Each microtubule is made of globular protiens called tubulin sub units. Microtubules function in the movement of organelles, such as secretory vessicles, and in chromosome movement during division of the cell nucleus. They are also part of a transport system with in the cell.
4. Intermediate filaments help in t maintain cell shape and the position fo organelles.
5. Micro filaments are action molecules. They are most highly developed in muscle cells where they help in muscle contraction. In non muscular cells they provide mechanical support for various cellular structures and are involved in some cellular movements. E.g. Amoeboid movement.
1. The nucleus is the control and information centre of the cell.
2. It is separated from the cytoplasm by its own nuclear envelope.
3. the nuclear envelope is made of an outer membrane and an inner membrane. The outer membrane is continuous with the endoplasmic reticulum. The nuclear envelope has many nuclear pores that allow materials to enter and leave the nucleus.
4. The nucleopalsm has a semi fluid matrix called karyolymph.karyolymph has chromatin and nucleolus.
5. chromatin consists of a combination of DNA and protien. During cell division chromatin condences into chromosomes.
6. The nucleolus is a non membrane bound structure in the nucleoplasm.
7. some cells have two or more nucleoli. They involved in the biosynthesis of ribosomes.
8. The nucleus transcribes genetic information from DNA into RNA, with then translates this specific information into protiens.
9. the nucleus also stores genetic informatin and transfers it during cell division from one cell to the next and one generation of organisms to the next.