The synthesis of particular gene products is controlled by mechanisms collectively called gene regulation. In prokaryotes, some enzymes are synthesized constitutively (i.e., continuously), indicating that transcription of mRNA is constantly occurring in them. However, other enzymes are synthesized only when a need for their action arises, and when this need has been fulfilled, enzyme synthesis stops. In both prokaryotes and eukaryotes, the regulation of gene expression may occur at three levels : 1. Transcription 2.Translation 3. Post-translation ( folding and processing of proteins). (i) Chromatin packing is the compression of DNA to fit into a cell for the DNA repair and for mitosis (the process of cell division in growth in which DNA replication is needed). (ii) In eukaryotes, in RNA polymerase II -dependent transcription, there are main six transcription factors are required for the initiation of transcription complex. They are TFIIA, TFIIB, TFIID, TFIIF, and TFIIH and involved in the initiation of transcription.Transcription initiation is regulated by additional proteins, known as activators and repressors and, in some cases, associated coactivators or corepressors which amend function and formation of the transcription initiation complex. (iii) Small interfering RNA or siRNA is the most commonly used RNA interference tool for inducing short-term silencing of protein-coding genes. The siRNA is a synthetic RNA duplex designed to exclusively target a particular mRNA for degradation. (iv) The ubiquitin-proteasome system is required for the degradation of intracellular proteins and thus plays a crucial regulatory role in cellular processes including cell cycle progression, differentiation, proliferation, angiogenesis and apoptosis. Solution The synthesis of particular gene products is controlled by mechanisms collectively called gene regulation. In prokaryotes, some enzymes are synthesized constitutively (i.e., continuously), indicating that transcription of mRNA is constantly occurring in them. However, other enzymes are synthesized only when a need for their action arises, and when this need has been fulfilled, enzyme synthesis stops. In both prokaryotes and eukaryotes, the regulation of gene expression may occur at three levels : 1. Transcription 2.Translation 3. Post-translation ( folding and processing of proteins). (i) Chromatin packing is the compression of DNA to fit into a cell for the DNA repair and for mitosis (the process of cell division in growth in which DNA replication is needed). (ii) In eukaryotes, in RNA polymerase II -dependent transcription, there are main six transcription factors are required for the initiation of transcription complex. They are TFIIA, TFIIB, TFIID, TFIIF, and TFIIH and involved in the initiation of transcription.Transcription initiation is regulated by additional proteins, known as activators and repressors and, in some cases, associated coactivators or corepressors which amend function and formation .

1. The synthesis of particular gene products is controlled by mechanisms collectively called gene
regulation. In prokaryotes, some enzymes are synthesized constitutively (i.e., continuously),
indicating that transcription of mRNA is constantly occurring in them. However, other enzymes
are synthesized only when a need for their action arises, and when this need has been fulfilled,
enzyme synthesis stops.
In both prokaryotes and eukaryotes, the regulation of gene expression may occur at three levels :
1. Transcription
2.Translation
3. Post-translation ( folding and processing of proteins).
(i) Chromatin packing is the compression of DNA to fit into a cell for the DNA repair and for
mitosis (the process of cell division in growth in which DNA replication is needed).
(ii) In eukaryotes, in RNA polymerase II -dependent transcription, there are main six
transcription factors are required for the initiation of transcription complex. They are TFIIA,
TFIIB, TFIID, TFIIF, and TFIIH and involved in the initiation of transcription.Transcription
initiation is regulated by additional proteins, known as activators and repressors and, in some
cases, associated coactivators or corepressors which amend function and formation of the
transcription initiation complex.
(iii) Small interfering RNA or siRNA is the most commonly used RNA interference tool for
inducing short-term silencing of protein-coding genes. The siRNA is a synthetic RNA duplex
designed to exclusively target a particular mRNA for degradation.
(iv) The ubiquitin-proteasome system is required for the degradation of intracellular proteins and
thus plays a crucial regulatory role in cellular processes including cell cycle progression,
differentiation, proliferation, angiogenesis and apoptosis.
Solution
The synthesis of particular gene products is controlled by mechanisms collectively called gene
regulation. In prokaryotes, some enzymes are synthesized constitutively (i.e., continuously),
indicating that transcription of mRNA is constantly occurring in them. However, other enzymes
are synthesized only when a need for their action arises, and when this need has been fulfilled,
enzyme synthesis stops.
In both prokaryotes and eukaryotes, the regulation of gene expression may occur at three levels :
1. Transcription
2.Translation
3. Post-translation ( folding and processing of proteins).

2. (i) Chromatin packing is the compression of DNA to fit into a cell for the DNA repair and for
mitosis (the process of cell division in growth in which DNA replication is needed).
(ii) In eukaryotes, in RNA polymerase II -dependent transcription, there are main six
transcription factors are required for the initiation of transcription complex. They are TFIIA,
TFIIB, TFIID, TFIIF, and TFIIH and involved in the initiation of transcription.Transcription
initiation is regulated by additional proteins, known as activators and repressors and, in some
cases, associated coactivators or corepressors which amend function and formation of the
transcription initiation complex.
(iii) Small interfering RNA or siRNA is the most commonly used RNA interference tool for
inducing short-term silencing of protein-coding genes. The siRNA is a synthetic RNA duplex
designed to exclusively target a particular mRNA for degradation.
(iv) The ubiquitin-proteasome system is required for the degradation of intracellular proteins and
thus plays a crucial regulatory role in cellular processes including cell cycle progression,
differentiation, proliferation, angiogenesis and apoptosis.