The nuclear envelope performs the following functions :
1. It maintains the shape of the nucleus.
2. It keeps the nuclear contents in place and distinct from the cytoplasm.
3. It regulates the flow of materials into and out of the nucleus by active transport and outpocketing.
4. Its pores allow the exit of ribosomal subunits.
Functions of nuclear matrix :
1. It maintains the shape of the nucleus.
2. Chromatin fibres are anchored to nuclear matrix.
3. The machinery for various nuclear activities such as transcription and replication is associated with the matrix.
Functions of nucleolus :
1. It is the site for rRNA synthesis.
1. They have DNA, RNA, ribosomes and other materials required to synthesize their own essential proteins.
2. They manufacture their own enzymes.
3. They can multiply and give rise to new organelles of the same kind. .
Gram +ve bacteria |
Gram -ve bacteria |
1. They remain coloured blue or purple with Gram stain even after washing with absolute alcohol or acetone. 2. The cell wall is 100-200A thick, single layered. 3. The bacteria are less resistant to antibiotics. 4. They are mostly non-pathogenic.
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1. They don't retain the stain when washed with absolute alcohol. 2. The cell wall is 70-120Å thick, two layered. 3.They are more resistant to antibiotics. 4. They are mostly pathogenic.
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