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PROTEIN SYNTHESIS

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DNA RNA Protein

Nuclear

membrane

Transcription

RNA Processing

Translation

DNA

Pre-mRNA

mRNA

Ribosome

Protein

Eukaryotic Cell

DNA

• DNA contains genes, sequences of nucleotide bases

• These Genes code for polypeptides (proteins)

• Proteins are used to build cells and do much of the work inside cells

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Genes & Proteins

Proteins are made of amino acids linked together by peptide bonds

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Goals of Protein Synthesis! (PS)

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Take DNA and convert it (change it) into

RNA

(there are different types of RNA)

Then use that RNA to create YOUR

specific

Proteins!

So the DNA tells the cell which amino

acids to

Put together to make YOUR proteins!

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Polypeptide is another term for a protein, they mean the same thing!

• Amino acids get bonded together to make the polypeptide (protein)

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DNA Begins the Process

• DNA is found inside the nucleus

• Proteins, however, are made in the cytoplasm of cells in organelles called ribosomes

• Ribosomes may be free in the cytosol or attached to the surface of rough ER

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Starting with DNA

• DNA ‘s code must be copiedand taken to the cytosol

• In the cytoplasm, this code must be read so amino acidscan be assembled to make polypeptides (proteins)

• This process is called PROTEIN SYNTHESIS

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Roles of RNA and DNA

• DNA is the MASTER PLAN

• RNA is the BLUEPRINT or COPY of the Master Plan

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RNA Differs from DNA

• RNA has a sugar ribose

DNA has a sugar deoxyribose

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Remember the Complementary Bases

On DNA:A-TC-G

On RNA:A-UC-G

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Other Differences

• RNA contains the base uracil (U)DNA has thymine (T)

• RNA molecule is single-strandedDNA is double-stranded

DNA

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. Three Types of RNA

• Messenger RNA (mRNA) copies DNA’s code & carries the genetic information to the ribosomes

• Ribosomal RNA (rRNA), is what the ribosomes are made out of

• Transfer RNA (tRNA) transfers amino acids to the ribosomes to be activated and helps to form the protein

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Messenger RNA (mRNA)

• Long Straight chain of Nucleotides

• Made in the Nucleus

• Is a Copy of DNA

• RNA leaves through nuclear pores

• Contains the Nitrogen Bases A, G, C, U ( no T )

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Messenger RNA (mRNA)• Carries the information for a specific amino acid

• We break the mRNA up into sections of 3 bases called a codon

• AUG is called the start codon

• UAA, UAG, or UGA are called the stop codons

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Ribosomal RNA (rRNA)

• rRNA is the “factory”

• It is the site of protein Synthesis

• It is the largest type of RNA

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Transfer RNA (tRNA)• “t” shaped

• Has 3 jobs!

• 1) Bring in the amino acid to the rRNA to get activated

• 2) Bring in a special code to help activate, called an

anticodon

• 3) Hold the growing protein as activated amino acids are added

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tRNA’s anticodon is the opposite of mRNA’s codon

Example if mRNA brings this codon to the ribosome

factory AUG, the matching anticodon would be UAC

Use the picture to see if

you can read the

ANTICODON on the

bottom of our tRNA and

then the matching mRNA

Anticodon = UGG

So the mRNA codon

would be ACC

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So again, Codons+ Anticodons=active

amino acids!• The 3 bases of an

anticodon are complementary to the 3 bases of a codon

• Example: Codon ACU

Anticodon UGA

UGA

ACU

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tRNAamino acid

attachment site

U A C

anticodon

Draw and label this

into your notebooks!

NOTICE THE ANTICODON

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Putting it all together!Using DNA’s message in mRNA to

make your protein!

• Remember: • 3 mRNA base pairs = 1 codon• 1 Codon determines which amino acid we activate

• Example: AUG = the amino acid methionine

• Some codons tell the ribosome to stop translating

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Reading The Genetic Code

•Use the code chart by reading from the center to the outside•Example: AUG codes for Methionine

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Try this! Name the Amino Acids

• GGG?

• UCA?

• CAU?

• GCA?

• AAA?

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SUMMARY!