RNARibonucleic Acid
Protein Synthesis
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8.4, 8.5, 8.7
Protein Synthesis Terms
define these 11 terms for homework1. Central dogma2. Transcription3. Translation4. Codon5. Anticodon
6. Start codon7. Stop codon8. Mutation9. Point mutation10. Frameshift mutation11. mutagens
The The Central DogmaCentral Dogma of of Molecular BiologyMolecular Biology
Francis Crick
Information flows in one direction
DNA RNA ProteinsReplication Transcription Translation
Structure of RNA
3 main differences between RNA
and DNA1. Sugar in RNA is riboseribose2. RNA is single strandedsingle stranded3. RNA contains uraciluracil in place of thyminethymine
Three Types of RNAThree Types of RNAMessenger RNAMessenger RNA mRNAmRNA- carries message from DNA to ribosome
Ribosomal RNARibosomal RNA rRNArRNA- forms part of a ribosome reads message and assembles protein at ribosome
Transfer RNATransfer RNA tRNAtRNA- brings amino acids from cytoplasm to ribosome to help make protein
The Process of Protein Synthesis
Staringm RNAr RNAt RNA
Act 1: TranscriptionAct 2: Translation
Transcriptionprocess where a
complementary strand of m RNA is formed from
DNAScene: The nucleus
TranscriptionTranscription1. Enzyme (RNA Polymerase) separates DNA strand
2. One strand of DNA used as template to assemble strand of m RNA.
TranslationInformation from DNA is translated
into a protein
Takes place at the ribosome
In the Cytoplasm
TranslationTranslation- Translating language of nucleic acids (base sequences) into language of proteins (amino acids)
1. Gene on DNA carries code to make protein
a. Code written in language with only 4 “letters”, the nitrogen bases A,C,G,Ub. Code read 3 letters at a time, each 3 letter “word” known as a codoncodon
Process uses all 3 types of RNAa. mRNA from nucleus travels to ribosome
b. rRNA at ribosome reads genetic code from mRNA , calls for appropriate tRNA
The Genetic CodeThe Genetic Code consists of 20 amino acidsconsists of 20 amino acids
c. Each tRNA has an anticodonanticodon whose bases are complementary to codoncodon on mRNA. tRNA brings amino acids to ribosomes
anticodonanticodon
codoncodon
d. Ribosome moves along mRNA, binding new tRNA molecules and amino acids
Mutations Change in the DNA May or may not be expressed Can be beneficial or lethal Can be spontaneous or caused by
exposure to radiation or toxic chemicals (mutagens)
Point mutation one nucleotide is substituted for
another
Frameshift MutationChanges the way the DNA is read
The insertion or deletion of a nucleotide
THE CAT ATE THE RAT
Remove the E
THC ATA TET HER AT