Protein SynthesisProtein Synthesis

DNADNA

Carries genetic informationCarries genetic information Controls protein synthesisControls protein synthesis

BrainstormBrainstorm

What are the functions of proteins?What are the functions of proteins?

Some Functions of ProteinsSome Functions of Proteins

Enzymes

Cell membrane component

Stored energy Transports substances

Cellular communication

Body structure

Build and Repair tissues

Proteins

DNA and ProteinsDNA and Proteins

Besides carrying all of our hereditary Besides carrying all of our hereditary information, DNA carries the codes information, DNA carries the codes for proteinsfor proteins

DNA tells the ribosome of the cell DNA tells the ribosome of the cell what proteins to makewhat proteins to make

DNA never leaves the DNA never leaves the nucleus…..nucleus…..

To prevent damageTo prevent damage

If DNA never leaves the If DNA never leaves the nucleus….nucleus….

How does the message get to the How does the message get to the ribosome in the cytoplasm to make ribosome in the cytoplasm to make proteins?proteins?

RNARNA

RNA = Ribonucleic acidRNA = Ribonucleic acid Nucleic acidNucleic acid Made up of repeating units of nucleotidesMade up of repeating units of nucleotides Single strandedSingle stranded Contains U (uracil) instead of T Contains U (uracil) instead of T

(thymine)(thymine) Its overall function is for protein synthesisIts overall function is for protein synthesis

RNA vs. DNARNA vs. DNA

Types of RNATypes of RNA

Messenger RNA (mRNA)Messenger RNA (mRNA) Reads DNA and carries a copy of the Reads DNA and carries a copy of the

instructions for making a protein out of instructions for making a protein out of the nucleus and into the cytoplasm of the the nucleus and into the cytoplasm of the cell.cell.

Transfer RNA (tRNA)Transfer RNA (tRNA) Carries the amino acids to the ribosome Carries the amino acids to the ribosome

(location of protein synthesis) to be (location of protein synthesis) to be assembled into proteinsassembled into proteins

Amino AcidsAmino Acids There are twenty different amino There are twenty different amino

acids to code for. The sequence and acids to code for. The sequence and the number of amino acids the number of amino acids determine the type of protein that determine the type of protein that will be made.will be made.

How a Protein is FormedHow a Protein is Formed

A. Transcription A. Transcription RNA polymerase (enzyme) binds to DNA RNA polymerase (enzyme) binds to DNA

and separates the DNA strandsand separates the DNA strands Then one strand of DNA is used as a Then one strand of DNA is used as a

template from which nucleotides are template from which nucleotides are assembled into a strand of mRNA. assembled into a strand of mRNA.

Codon – mRNA reads DNA 3 bases at a Codon – mRNA reads DNA 3 bases at a time. Every 3 bases codes for a specific time. Every 3 bases codes for a specific amino acid. Remember: a chain of amino amino acid. Remember: a chain of amino acids makes up a protein.acids makes up a protein.

mRNA leaves the nucleus and brings the mRNA leaves the nucleus and brings the message to the ribosomemessage to the ribosome

Transcription ExampleTranscription Example

DNA – DNA – AGCGTGCCA AGCGTGCCA mRNA – UCGCACGGUmRNA – UCGCACGGU Codon – UCG – CAC - GGUCodon – UCG – CAC - GGU

How a protein is formed How a protein is formed cont….cont….

B. TranslationB. Translation The cell uses information from the The cell uses information from the

mRNA to produce proteinsmRNA to produce proteins tRNA reads the codons and transfers the tRNA reads the codons and transfers the

complimentary amino acids to the complimentary amino acids to the ribosome to be assembled into a proteinribosome to be assembled into a protein

Transcription/Translation Transcription/Translation ExampleExample

DNA:DNA: AGCGTGCCAAGCGTGCCA mRNA: UCGCACGGUmRNA: UCGCACGGU Codon: UCG – CAC – GGUCodon: UCG – CAC – GGU Amino Acids: Serine – Histidine - Amino Acids: Serine – Histidine -

GlycineGlycine

Start and Stop CodonsStart and Stop Codons

Start Codon – Begins protein Start Codon – Begins protein synthesis. Example: AUGsynthesis. Example: AUG

Stop Codon – Stops protein Stop Codon – Stops protein synthesis. Example: UAA, UAG, UGAsynthesis. Example: UAA, UAG, UGA

ExamplesExamples

http://www.lew-port.com/10712041113402793/lib/10712041113402793/Animations/Protein%20Synthesis%20%20long.swf

Practice 1Practice 1

DNA –ATGTACCCGAACTAGDNA –ATGTACCCGAACTAG DNA- TACATGGGCTTGATCDNA- TACATGGGCTTGATC mRNA-AUGUACCCGAACUAGmRNA-AUGUACCCGAACUAG Codon –AUG –UAC-CCG-AAC-UAGCodon –AUG –UAC-CCG-AAC-UAG Amino acids – MET –TYR –PRO –ASN -Amino acids – MET –TYR –PRO –ASN -

TYRTYR

Practice 2Practice 2

DNA – ATGGGTAGTCATTGGDNA – ATGGGTAGTCATTGG DNA - TACCCATCAGTAACCDNA - TACCCATCAGTAACC mRNA- AUGGGUAGUCAUUGGmRNA- AUGGGUAGUCAUUGG Codon – AUG – GGU – AGU – CAU – Codon – AUG – GGU – AGU – CAU –

UGGUGG Amino Acids – MET – GLY – SER – HIS Amino Acids – MET – GLY – SER – HIS

- CYS- CYS