Transcript RNA and Protein Synthesis - Kent City School District

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.
2.
3.
4.
Single stranded
Uracil replaces Thymine
Ribose instead of deoxyribose
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 nucleus
1.
2.
3.

Initiation at the promoter site by RNA
polymerase opens up the DNA molecule
Elongation adds new RNA bases, including
Uracil, down the exposed DNA bases
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 TAC
RNA:
CUC UUG AUC AUG
 Animation 1
 Animation 2