RNA

Chapter 10.2

Structure of RNA

Ribose- the sugar molecule of every RNA nucleotide

Uracil- nitrogen-containing pyrimidine base (replaces thymine)

Uracil pairs with adenine in RNA

Types of RNA

Messenger RNA (mRNA)- consists of RNA nucleotides in the form of a single uncoiled chain

Carries genetic information from DNA in the nucleus to the cytosol

Transfer RNA (tRNA)- consists of a single chain of about 80 RNA nucleotides in a hairpin shape

Binds to specific amino acids

45 varieties

Ribosomal RNA (rRNA)- most abundant form of RNA

Consists of globular RNA nucleotides

Makes up the ribosomes where proteins are made

Transcription

Transcription- the process by which genetic information is copied from DNA to RNA

RNA polymerase binds to the promoter of a specific gene

A complimentary copy of the DNA base sequence is made

Steps of Transcription

RNA polymerase- the primary transcription enzyme

Synthesizes RNA copies of specific sequences of DNA

Promoters- specific regions of DNA where RNA polymerase binds to

Marks the beginning of a single gene

When RNA polymerase binds to DNA, the DNA separates and one side acts as a template

Termination signal- a specific sequence of nucleotides that marks the end of a gene

At a termination signal, RNA polymerase releases the DNA and the newly formed RNA molecule

Products of Transcription

Transcripts- the different types of RNA molecules

Instructions for making a protein are copied from DNA to mRNA