Transcription

MMBIO 240 at BYU transcription with Dr.Poole winter 2026

Most not made into new proteins: most become rRNA or ribosomes

Why is the majority of RNA not translated?

rRNA, mRNA, tRNA

What are the three main types of RNA?

rRNA

RNA that makes up the ribosomes, and carries out the chemical reactions in the ribosome

mRNA

The type of rNA that gets transcribed into RNA. Goes into the ribosome to make the proteins

mRNA

Which of the major RNA is most regulated?

tRNA

RNA that speaks both nucleic acid and amino acid; transfer’s the amino acids to the ribosome

transcription

What is the most prominent way of regulating a particular gene pathway?

to save energy on other levels

Why are proteins regulated on the transcriptional level?

it is energy efficient or fast

What ultimatly does it come down to wether or not a gene is transcribed?

a polymer like DNA

What is RNA?

It has an extra OH group on the 2’; single-stranded, more reacive and more unstable than DNA; different RNA’s have different purposes

How is RNA different from DNA?

Active, transient, reactive, and always doing stuff

What to think about when you hear RNA?

coding strand and nontemplate strand

What are the names of the strand that the RNA is not being transcribed into (or 5'-3’ strand)?

Template strand and noncoding strand

What are the names of the strand that the RNA is being transcribed into (or 3’-5’ strand)?

RNA polymerase

What makes RNA?

RNA polymerase attacks the 3’ hydroxyl group and adds on another nucleotide

How is RNA made?

RNA is constantly being made and destroyed so if a c becomes a u it doesn’t really matter

Why can RNA use uracil instead of thymine, even though cytosine could be mutated into uracil?

β, β’ subunits

Where the RNA catalysis happens, where nucleotides come together

ω subunit

Helps with assembly

α subunits

helps with assembly and regulation; binds to other proteins

Initiation

What is the start of transcription?

It starts at the closed complex

How does initiation start?

Closed complex

RNA polymerase and the promotor are stuck together but don’t do anything

Open complex

RNA polymerase takes the DNA and opens it up a little bit forming the transcription bubble

promoter

DNA sequence that is recognized by RNA polymerase; marks the beggining of transcripption

You need a strong promoter that allows the polymase to bind

If you want a lot of genes, or genes on all the time what needs to happen?

You need a weak promotor that allow for the polymerase to be bound less.

If you want less genes, or a gene on not all the time what do you need to happen?

transcription that can occur

The better the promotor is recognized by the RNA polymerase, the more….

Position and orientation

What is the promotor dependent on?