Review Describe the three main difference between RNA and DNA Explain List the three main types of RNA and explain what they do Infer Why is it important for a single genes to be able to produce hundreds or thousands of RNA molecules

Ch 13 RNA and Protein Synthesis

RNA Nucleic acid that consists of a long chain of nucleotides Copied from DNA.

Differences Between RNA and DNA Sugar is ribose instead of deoxyribose RNA is generally single-stranded and not double- stranded RNA contains uracil (U) in place of thymine (T).

Comparing RNA and DNA Roles of DNA and RNA are similar to the master plans and blueprints used by builders Master plan has all the information needed to construct a building.

Never bring a valuable master plan to the building site, where it might be damaged or lost Instead they bring inexpensive copies or blueprints.

Functions of RNA Disposable copy of a segment of DNA Protein synthesis.

3 Types of RNA Messenger or mRNA Ribosomal or rRNA Transfer or tRNA.

Messenger RNA Carry copies of DNA instructions.

Ribosomal RNA Make up ribosomes.

Transfer RNA Transfers each amino acid to the ribosome according to mRNA.

Transcription Segments of DNA serve as templates to produce complementary RNA molecules Makes a copy Occurs in nucleus of eukaryotes.

RNA polymerase Enzyme similar to DNA polymerase Binds to DNA and separate strands Uses one strand of DNA as a template and makes a complementary RNA strand.

Promoters Regions of DNA that have specific base sequences Shows RNA polymerase where to bind and start Similar signal shows where to stop.

RNA Editing Exon Intron The part of the DNA that codes for the protein that is to be made Intron The part of the DNA that does NOT code for the protein that is to be made.

Why Have Introns Genes and Protein instructions may overlap in DNA Instructions for one protein may cut out one set of introns, but different introns may be cut out for a different protein Don’t have a complete answer Neapolitan ice cream.

Chocolate Exon Vanilla Intron Strawberry Intron.