RNARibonucleic Acid

Protein Synthesis

&

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