RNA

12.3

What is RNA?

Macromolecule made of nucleotides from DNA

Used to build proteins 3 types total

RNA is different from DNA

1. Single stranded

2. Uracil replaces Thymine

3. Ribose instead of deoxyribose

4. Can leave the nucleus

mRNA

m=messenger Long, stringy (like a snake) Carries the instructions from the nucleus to

the cytoplasm to initiate translation Contains 3-base sequences called “codons” Made in transcription

tRNA

t= transfer Responsible for bringing the amino acids for

translation Contains “anti-codons” that match up with

mRNA temporarily Shaped like a “hair pin” or a T

rRNA

Structurally part of the ribosome organelle Site of translation Globular shaped

RNA is made through “Transcription” RNA is made in the nucleus like DNA

replication

What is transcription?

Making of RNA from DNA in the nucleus1. Initiation at the promoter site by RNA

polymerase opens up the DNA molecule

2. Elongation adds new RNA bases, including Uracil, down the exposed DNA bases

3. Termination occurs when RNA polymerase hits the “stop” signal and detaches the new single strand of RNA

http://207.207.4.198/pub/flash/26/transmenu_s.swf

Review the steps

Transcription Unzip one gene in DNA Match up bases to one side of a gene in DNA mRNA detaches from the DNA mRNA moves out of the nucleus and into the

cytoplasm

 

 

In RNA: A binds with U C binds with G 

DNA strand: GAG AAC TAG TACRNA:

CUC UUG AUC AUG

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