Transcription Flashcards

Study Notes

Transcription Overview

Transcription is the initial step in gene expression, where DNA sequences are copied into RNA.
It is crucial for converting genetic information into proteins.

Initiation of Transcription

RNA polymerase attaches to a specific promoter sequence, which indicates the start of a gene.
This binding can occur directly or via helper proteins that assist the polymerase.

Template Strand

One of the DNA strands serves as a template for synthesizing a complementary RNA molecule.
RNA polymerase specifically uses this template strand during transcription.

Role of RNA Polymerases

RNA polymerases are enzymes responsible for transcribing DNA into RNA.
They synthesize RNA using base pairing rules; for example, a G in DNA corresponds to C in RNA.

Structure of RNA and DNA Strands

DNA and RNA strands possess directionality, marked as 5' and 3' ends.
The 5' end features a phosphate group, while the 3' end has a hydroxyl group from the sugar ring, essential for transcription directionality.

Function of the Promoter

The promoter is a specific DNA region where RNA polymerase binds to begin transcription.
Each gene has a unique promoter that includes sequences for polymerase attachment.

Eukaryotic Promoter Characteristics

Eukaryotes (like humans) have a complex promoter structure, requiring basal transcription factors to bind before RNA polymerase can attach.
A common feature in eukaryotic promoters is the TATA box, which aids the binding of transcription factors and interacts with RNA polymerase.

Transcription Elongation

Following the initiation stage, transcription elongation occurs, during which the RNA strand lengthens as nucleotides are added.
RNA polymerase moves along the template strand in a 3' to 5' direction, incorporating complementary nucleotides into the growing RNA molecule.

Description

This quiz focuses on the key concepts of transcription, the first step of gene expression. It covers important definitions and processes involved in the transcription of DNA into RNA. Enhance your understanding of genetics through these flashcards.