Protein Synthesis

Protein Synthesis• What: The production of proteins (long chains

of amino acids)

Protein Synthesis• Where: Starts in the nucleus, continues on

ribosomes in the cytoplasm

Protein Synthesis

• Why: Proteins are built according to instructions coded in DNA determine traits

Protein Synthesis• How: Transcription and Translation

Protein Synthesis

• DNA does not leave the nucleus

The nucleic acid that plays key roles in the manufacturing of proteins

Named for the 6-carbon sugar ribose

Uracil replaces Thymine

RNA

RNA vs. DNA

RNA• Single Strand• Ribose Sugar• A, C, G, U• Leaves nucleus

DNA• Double Strand• Deoxyribose• A, C, G, T• Stays in nucleus

Three kinds of RNA

1. Messenger RNA (mRNA)a) Copies the genetic instructions from DNA in the

nucleus, and carries them to the cytoplasm.

Three kinds of RNA

2. Ribosomal RNA (rRNA)Reads the mRNA. Helps form ribosomes, where proteins are assembled.

Three kinds of RNA

3. Transfer RNA (tRNA)a) Brings amino acids to ribosomes, where they are

joined together to form proteins.

CODON

• 3 nucleotide sequence on mRNA

• ANTICODON:• 3 nucleotide sequence on tRNA

complimentary to the mRNA

2 STAGES OF PROTEIN SYNTHESIS

• 1. Transcription– The process of transferring the genetic

information from DNA to mRNA– Takes place in the nucleus

2 STAGES OF PROTEIN SYNTHESIS

• 2. Translation– The process that decodes mRNA into a

protein–Occurs in the cytoplasm on a ribosome

TRANSCRIPTION

• 1. RNA polymerase–Binds to a start signal–Unwinds the DNA–Adds Nucleotides• Uracil replaces thymine

• 2. mRNA leaves the nucleus

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Practice

• TAC GGA TCT AAT CCG CGC TCA TTC AGT

• AUG CCU AGA UUA GGC GCG AGU AAG UCA

Translation

rRNA attaches to mRNA and reads it

TranslationMolecules of tRNA bring amino acids to the

ribosome in the correct sequence.

Translation• Bonds form between adjacent amino

acids forming a polypeptide chain. • The chain of amino acids keeps growing

until a stop codon is reached.

Translation

Translation

Translation

Translation

CODONS

• With few exceptions, most codes are the same in all organisms– Ex GUC codes for valine in bacteria, in eagles, in

plants….

Protein Synthesis

*Think of the bases of DNA like letters…Letters form words…Words form sentences!*