Central Dogma & Operons

Central Dogma

The process of DNA transcription to RNA and then translation to proteins.

How is bacterial DNA different from eukaryotic DNA?

Bacterial DNA is typically circular, has fewer chromosomes, and contains plasmids, while eukaryotic DNA is linear and found in multiple, larger chromosomes.

What are plasmids?

Plasmids are small, circular DNA molecules in bacteria that replicate independently and can be transferred between bacteria.

Why are plasmids important for bacteria?

Plasmids allow for the transfer of genetic information between bacteria, enabling processes such as conjugation.

How is DNA replication similar between prokaryotes and eukaryotes?

Both processes are semiconservative and utilize the same nitrogenous bases.

How is DNA replication different between prokaryotes and eukaryotes?

Prokaryotic DNA is circular with a single origin of replication, while eukaryotic DNA is linear with multiple origins.

What are sigma factors?

Sigma factors are proteins that help initiate transcription in bacteria by binding to the promoter.

Where does transcription and translation occur in bacteria?

Both occur in the cytoplasm, allowing them to happen simultaneously due to the absence of a nucleus.

What is a constitutive gene?

A constitutive gene is always expressed and encodes proteins essential for survival.

What does it mean if a gene is regulated?

A regulated gene's expression can be turned on or off and is influenced by environmental conditions.

What is an operon?

An operon is a set of genes controlled by a single promoter.

What is the structure of an operon?

An operon consists of a promoter, an operator (where a repressor can bind), and the genes that are regulated.

Why is it beneficial for bacteria to organize genes into the same operon?

Organizing genes into the same operon allows bacteria to coordinate the expression of genes with similar functions and target one promoter.

how does the trp operon work?

Repressible: tryptophan turns the operon off by binding to the repressor protein

• enough tryptophan = don’t need any more

How does the lac operon work?

Inducible: presence of lactose turns operator on which make enzymes that break down lactose