Across
- 2. Both the centrioles in a centrosome lie ........ to each other in which each has an organisation like the ........
- 6. The centrioles form the basal body of cilia or flagella, and .......... that give rise to spindle apparatus during cell division in animal cells.
- 11. Later the material of the nucleus stained by the basic dyes was given the name chromatin by ...........
- 13. Electron microscopy has revealed that the nuclear envelope, which consists of two parallel membranes with a space between (10 to 50 nm) called the ..........., forms a barrier between the materials present inside the nucleus and that of the cytoplasm.
- 14. The central part of the proximal region of the centriole is also proteinaceous and called the ....... , which is connected with tubules of the peripheral triplets by radial spokes made of protein.
- 15. They are made up of nine evenly spaced peripheral fibrils of tubulin protein. Each of the peripheral fibril is a ......... .
- 20. Centrosome is an organelle usually containing two cylindrical structures called ................
- 21. They are surrounded by amorphous ......... materials.
- 22. The outer membrane usually remains continuous with the ................ and also bears ribosomes on it.
- 23. The content of nucleolus is continuous with the rest of the nucleoplasm as it is not a ............. structure.
Down
- 1. Nucleus as a cell organelle was first described by .......... as early as 1831.
- 3. These nuclear pores are the passages through which movement of ....... and ........ molecules takes place in both directions between the nucleus and the cytoplasm.
- 4. The nuclear matrix or the nucleoplasm contains ............ and ...........
- 5. The interphase nucleus (nucleus of a cell when it is not dividing) has highly extended and elaborate nucleoprotein fibres called ..........., nuclear matrix and one or more spherical bodies called nucleoli (sing.: nucleolus)
- 7. Some mature cells even lack nucleus, e.g., ..............of many mammals and .......... cells of vascular plants.
- 8. Normally, there is only .......... per cell, variations in the number of nuclei are also frequently observed.
- 9. The nucleoli are .......... structures present in the nucleoplasm.
- 10. The ............ nucleus has a loose and indistinct network of nucleoprotein fibres called chromatin.
- 12. At a number of places the ............. is interrupted by minute pores, which are formed by the fusion of its two membranes.
- 16. Larger and more numerous nucleoli are present in cells actively carrying out .............
- 17. But during different stages of ............, cells show structured chromosomes in place of the nucleus.
- 18. Nucleolus is a site for active ......... synthesis.
- 19. The ........ triplets are also linked.