lesson 2 Transcriptional Regulation

What is the central dogma of molecular biology?

The central dogma describes the flow of genetic information from DNA to RNA to protein. This flow of information is critical for cellular function and organism development.

What is the role of transcription in the central dogma?

Transcription is the first step in the central dogma, where DNA is transcribed into RNA. This process is vital for gene expression, and determines which genes are active in a given cell type or condition.

What does RNA polymerase do during transcription?

RNA polymerase binds to the promoter region of a gene and initiates transcription. It separates the DNA strands, creating a transcription bubble where the RNA is synthesized.

How does transcription control gene expression?

Transcription regulates which genes are expressed in different cell types. Housekeeping genes are expressed in all cells, whereas other genes are activated only in specific cells or under certain conditions.

What is the difference between housekeeping genes and other genes in terms of transcription?

Housekeeping genes are expressed in all cells for essential functions, while other genes are expressed only in specific cell types or in response to environmental stimuli.

How does RNA polymerase create the transcription bubble?

RNA polymerase separates the DNA strands by breaking the hydrogen bonds between them, forming a transcription bubble where RNA synthesis occurs.

How is RNA formed during transcription?

RNA is formed by adding ribonucleotides complementary to the DNA template strand. These ribonucleotides are linked by phosphodiester bonds to form the RNA strand.

What is the difference between transcription in eukaryotes and prokaryotes?

Eukaryotes: Have three RNA polymerases, more complex promoter regions, and processes like capping, splicing, and polyadenylation.

Prokaryotes: Have simpler transcription with a single RNA polymerase and less regulatory complexity.

How do transcription termination mechanisms differ between eukaryotes and prokaryotes?

• Prokaryotes: Use rho-dependent or rho-independent mechanisms for termination.

• Eukaryotes: Use more complex termination mechanisms, such as allosteric and torpedo models.

How is transcription regulated in eukaryotes?

In eukaryotes, transcription is regulated by phosphorylation of the RNA polymerase tail, which influences its ability to move along the DNA and initiate transcription.

How does transcription impact individual and species-specific traits?

Transcription determines which genes are expressed in a given cell or organism. This control over gene expression is crucial for defining individual and species-specific traits, as it determines the proteins produced and their functions in different cell types.