bsc- dna transcription

KILL ME WITH A FUCKING KNIFE

Transcription

DNA to RNA

1. RNA polymerase binds to promoter

2. Promoter dictates which strand will be the template

3. RNA polymerase unwinds the DNA

4. RNA polymerase transcribe the template strand using free nucleotides

5. 4 bases in DNA pair with 4 bases of RNA, creating mRNA

6. The mRNA product is complementary to the template (og DNA) strand and almost identical to the nontemplate strand (RNA)

7. Due to difference in nucleotides (RNA contains uracil instead of thymine)

8. RNA polymerase reaches a terminator (special sequence of bases) ending transcription

Transcription (8 steps)

Promoter

specific sequence in the DNA onto which the proteins and enzymes involved in transcription bind to initiate the process

RNA polymerase unwinds partially unwinds DNA double helix structure in the region of mRNA synthesis called a transcription bubble. Proteins and enzymes bind to initiate the next process at the promoter.

Initiation

Transcription bubble

region in which the DNA double helix structure partially unwinds

upstream

Promoters exist ____ of the genes they regulate.

Determines whether the corresponding gene is transcribed all of the time, some of the time, or hardly at all

Why are promoters important?

RNA polymerase proceeds along the DNA template, adding nucleotides by base pairing with the template. The DNA is continuously unwound ahead of the core enzyme and rewound behind it.

Elongation

The RNA strand being synthesized does not remain bound to the DNA template.

Difference between process of adding nucleotides in DNA replication vs transcription

Repeated nucleotide sequences result in RNA polymerase stalling, leaving the DNA template, and freeing the mRNA transcript.

Termination