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Chapter 12 DNA & RNA. Section 12-3 RNA & Protein Synthesis. Types of RNA. RNA Used For Protein Synthesis Three Types of RNA Messenger RNA, mRNA Ribosomal RNA, rRNA Transfer RNA, tRNA. Types of RNA. mRNA
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Chapter 12DNA & RNA Section 12-3RNA & Protein Synthesis
Types of RNA RNA Used For Protein Synthesis Three Types of RNA Messenger RNA, mRNA Ribosomal RNA, rRNA Transfer RNA, tRNA
Types of RNA mRNA Template to construct protein. It brings the message from the DNA to the ribosome. rRNA Part of ribosome structure tRNA Transports amino acids from cytoplasm to the ribosomes
Transcription The process of copying part of the DNA nucleotide sequence into a complementary sequence of RNA
Transcription Requires the enzyme RNA Polymerase Step 1. RNA polymerase binds to DNA and separates the DNA strands. Step 2.RNA Polymerase uses one strand of DNA as a template to polymerize nucleotides into RNA
RNA Editing After Making mRNA Introns Are Snipped Out Exons Remain, (active segments of nucleotides)
The Genetic Code Proteins are long chains of amino acids. There are 20 different amino acids The order of amino acids in the protein determine its shape and function
The Genetic Code There are 20 amino acids but only 4 bases in RNA Adenine A Cytosine C Guanine G Uracil U
The Genetic Code The genetic code consists of “words” three bases long Each “word” is called a Codon: three consecutive nucleotides that specifies a single amino acid
The Genetic Code For Example: UCGCACGGU = RNA Sequence UCG-CAC-GGU = Codons UCG codes for Serine CAC codes for Histidine GGU codes for Glycine
The Genetic Code 4 Bases Codons Defined with 3 Bases There Are 64 Possible 3-base codons Since there are only 20 amino acids, some amino acids are represented by multiple codons
Translation Translation is the process of of decoding the mRNA into a polypeptide chain • Ribosomes • Read mRNA and construct the proteins
Translation Step 1 • mRNA leaves the Nucleus
Translation Step 2 • mRNA binds to the ribosome. tRNA attaches • Anticodons on the tRNA line up with codons on mRNA The other end of the tRNA is an amino acid
Translation Step 3 • Ribosome connects the amino acids together as they come into the ribosome
Translation • Step 4 • A polypeptide (Chain of Amino Acids) is formed. • Polypeptide chain grows until the mRNA STOP Codon is reached
The Roles of RNA & DNA DNA = Master Plan RNA = Blueprints of the Master Plan
Proteins • At the end of translation a protein is formed. • Proteins are enzymes that catalyze and regulate chemical reactions • Proteins can also be structural.