Molecular Biology: From DNA to RNA

Flashcards covering the fundamentals of transcription, including DNA/RNA differences, the central dogma, and differences between prokaryotic and eukaryotic transcription processes.

What characterizes the flow of genetic information in the 'Central Dogma'?

Genetic information flows from DNA to RNA and from RNA to protein.

Why is life considered an 'Autocatalytic Process'?

DNA and RNA contain the sequence information to make proteins, and some of those proteins are the enzymes that synthesize DNA, RNA, and themselves, creating a self-replicating system.

What is the definition of a 'Gene' as described in the lecture?

A region of DNA that is transcribed as a single unit and directs the production of a particular protein or functional RNA molecule.

What type of bond links nucleotide subunits together in both DNA and RNA?

Phosphodiester bonds.

In what direction does the polymerization reaction and elongation occur for nucleic acids?

Elongation is always $5'$ to $3'$, proceeding by adding new nucleotides to the $3'$ hydroxyl ($-OH$) group.

What are the two primary chemical differences between DNA and RNA regarding sugar and bases?

RNA contains ribose (with a hydroxyl group at the $2'$ Carbon) instead of deoxyribose, and it contains Uracil instead of Thymine.

How does the structure of Uracil differ from Thymine?

Uracil is characterized by the absence of a methyl group.

What allows single-stranded (ss) RNA to fold into unique shapes?

Conventional and nonconventional base-pairing between ribonucleotides within the single strand.

Identify the enzymes or structures responsible for Replication, Transcription, and Translation.

Replication uses DNA Polymerase; Transcription uses RNA Polymerase; Translation uses the Ribosome.

In which direction does RNA Polymerase move along the template DNA strand?

RNA Polymerase moves along the template DNA strand in the $3'$ to $5'$ direction.

What is a 'Promoter' and what is its primary function?

A promoter is a DNA sequence upstream of the start of transcription that directs RNA Polymerase to the correct location and orients it for transcription.

Where is genetic information located in Prokaryotes vs. Eukaryotes?

In prokaryotes (bacteria), genetic information is in the cytoplasm; in eukaryotes, it is enclosed in the nucleus.

What specific promoter sequences are found in bacteria, and at what positions are they located relative to the transcription start site?

The $-35$ and $-10$ sequences, which are located upstream of the transcriptional start site ($+1$).

What is the role of the 'Sigma factor' in bacterial transcription?

It is a bacterial-specific protein that binds the promoter to help direct RNA polymerase to the start of the gene.

What is the 'TATA box' in eukaryotic transcription?

A promoter sequence in eukaryotes that helps orient RNA polymerase and recruits necessary transcription proteins.

How does the 'TATA-binding protein' (TBP) initiate eukaryotic transcription?

TBP distorts the DNA, creating a surface for general transcription factors (GTF) to assemble, which ultimately recruits RNA Polymerase II.

What are the three stages of transcription in both prokaryotes and eukaryotes?

$1.$ Initiation, $2.$ Elongation, and $3.$ Termination.

Which eukaryotic RNA polymerase is responsible for generating mRNA?

RNA Polymerase II.

What happens during 'Termination' in eukaryotic transcription?

RNA Polymerase II reaches termination sequences, which allow the enzyme to fall off the DNA.

What is 'Promoter escape' in the context of transcription?

The phase where RNA Polymerase II leaves the promoter and transitions from initiation to elongation.