RNA Ribonucleic Acid

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RNARibonucleic Acid

• Protein Synthesis

8.4, 8.5, 8.7
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Protein Synthesis Termsdefine these 11 terms for
homework

1. Central dogma
2. Transcription
3. Translation
4. Codon
5. Anticodon

1. Start codon
2. Stop codon
3. Mutation
4. Point mutation
5. Frameshift mutation
6. mutagens

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The Central Dogma of Molecular BiologyFrancis
Crick

• Information flows in one direction
• DNA RNA Proteins

Replication
Transcription
Translation
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Structure of RNA
3 main differences between RNA and DNA
1. Sugar in RNA is ribose
2. RNA is single stranded
3. RNA contains uracil in place of thymine
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Three Types of RNA
Messenger RNA mRNA- carries message from DNA to
ribosome
Ribosomal RNA rRNA- forms part of a ribosome
reads message and assembles protein at ribosome
Transfer RNA tRNA- brings amino acids from
cytoplasm to ribosome to help make protein
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The Process of Protein Synthesis

• Staring
• m RNA
• r RNA
• t RNA

Act 1 Transcription Act 2 Translation
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Transcriptionprocess where a complementary
strand of m RNA is formed from DNA

• Scene The nucleus

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Transcription
1. Enzyme (RNA Polymerase) separates DNA strand
2. One strand of DNA used as template to
assemble strand of m RNA.
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TranslationInformation from DNA is translated
into a protein

• Takes place at the ribosome
• In the Cytoplasm

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Translation- 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,U
b. Code read 3 letters at a time, each 3 letter
word known as a codon
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Process uses all 3 types of RNA
a. mRNA from nucleus travels to ribosome
b. rRNA at ribosome reads genetic code from mRNA
, calls for appropriate tRNA
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The Genetic Code consists of 20 amino acids
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c. Each tRNA has an anticodon whose bases are
complementary to codon on mRNA. tRNA brings
amino acids to ribosomes
anticodon
codon
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d. Ribosome moves along mRNA, binding new tRNA
molecules and amino acids
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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)

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Point mutation one nucleotide is substituted
for another  
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Frameshift MutationChanges the way the DNA is
read
THE CAT ATE THE RAT Remove the E THC ATA TET HER
AT

• The insertion or deletion of a nucleotide