Catalyst: Protein Synthesis 1) Give the complementary DNA sequence for: A T G C C C T A T A A G 2) What is DNA made up of? 3) Think back to our unit on MACROMOLECULES….what is the building block of a protein? T A C G G G A T A T T C Nucleotides (sugar, phosphate, base) Amino Acids

O BJECTIVE SWBAT: investigate protein synthesis in order to explain how a gene is used to express a physical trait.

S O …DNA MAKES US WHO WE ARE BUT HOW???? DNA has the code to eventually make PROTEINS!!!! PROTEINS are what makes us LOOK the way we LOOK! Today’s KEY Questions: 1. How are proteins CREATED? 2. How is DNA related to proteins?

L ET ’ S R EVIEW A FEW THINGS … 1) What is a gene? 2) What are genes made of? 3) What are the building blocks of proteins? Part of DNA that codes for a specific trait DNA Amino Acids

Proteins are what create your PHYSICAL Traits.. Life in a cell is ALL about Making Proteins!! What is the relationship between the following key terms?: physical traits DNA genes proteins _____ → ______ → _________ → _________ DNAgenesproteins Physical traits

PART 1: W HAT ARE THE MAJOR DIFFERENCES BETWEEN DNA AND RNA? 1. Strand #: SINGLE-stranded DOUBLE-stranded 2. Sugar:RIBOSE DEOXYribose 3. Bases:Cytosine, Guanine, Cytosine, Guanine Adenine, URACIL Adenine, Thymine RNA DNA

C pairs with G and A pairs with U

3 T YPES OF RNA… 1.Messenger RNA (mRNA) 2.Ribosomal RNA (rRNA) 3.Transfer RNA (tRNA) Each type has a specific ROLE in the cell!

C HECK FOR UNDERSTANDING ! DNA or RNA?! 1.AATCGTAATGCA ______________ Why? _________________________________________ 2) CGGUGACCAUGG _____________ Why? _________________________________________ DNA RNA Because it has the base T (thymine) Because it has the base U (Uracil)

DNA AND RNA ARE NEEDED TO MAKE PROTEINS ! Protein synthesis is the process of making proteins. More specifically, protein synthesis is: DNA sending information to RNA to make a protein A → RNA → Protein DNA RNA Step 1Step 2

L ET ’ S P RACTICE !! Complete the Venn Diagram

S TEP 1: TRANSCRIPTION DNA is transcribed into mRNA This happens inside the nucleus. DNA CAN NEVER LEAVE THE NUCLEUS! _______________ Occurs in the _________________ Process of Transcription: DNAmRNA nucleus transcription Step 1: Double stranded DNA “unzips” Step 2: RNA bases bond to the DNA strand **Remember RNA uses U NOT T 12

T RANSCRIPTION ….

C HECK FOR UNDERSTANDING 1.What is the major end result of transcription? 2.Where does the process of transcription occur? 3.What are the complimentary strands of mRNA for the DNA template strands: G G T A T T C A A C A T T T A __ __ __ __ __ __ __ mRNA Nucleus C CA A AUG U UGUAA A U

I N YOUR OWN WORDS … Describe the process of transcription to the class using the key words below. mRNA DNA Nucleus Single-stranded

A FTER TRANSCRIPTION … There is a new mRNA strand that was made from the DNA! The mRNA is ready to leave the nucleus But…where is it going???

S TEP 2: RNA MAKES PROTEINS THROUGH TRANSLATION Occurs at the ________________ __ mRNAprotein ribosome translation At the ribosome the mRNA is translated into proteins (amino acids) through the process of TRANSLATION. RNA helpers: 1.rRNA: makes the ribosome 1. tRNA: brings the CORRECT amino acids to the ribosome

P ROCESS OF TRANSLATION 1. mRNA leaves the nucleus and finds the ribosome 1. A set of 3 mRNA bases is called a CODON. Each codon “codes” for a single AMINO ACID. AAG UUA CGC TUG CODONS!

Every codon “codes” for a specific AMINO ACID (protein building block)…. What amino acids do the following codons code for? AUG: Methionine (Start)CUG:Leucine ACC: Threonine UAG:Stop You try! GUU: ____ AGU: ______CCU: ______UAU: __________ valineserineprolinetyrosine

3) A tRNA molecule brings in the CORRECT amino acid for each codon. 4) Eventually a chain of amino acids is created. This is a PROTEIN! Amino acid Label the following: - mRNA - tRNA - Amino Acid mRNA tRNA Histidine is the NEXT amino acid to be added!

mages/Codon_Chart.gif

The correct tRNA molecule will bind to the mRNA and attach an amino acid in the correct sequence The order of the amino acids determines what protein is made!!! Which comes first, TRANSCRIPTION or TRANSLATION? Important Review Points… TRANSCRIPTION!!

P ROTEIN SYNTHESIS ! TRANSCRIPTION RNA is transcribed from a DNA template. DNA RNA polymerase RNA transcript RNA PROCESSING In eukaryotes, the RNA transcript (pre- mRNA) is spliced and modified to produce mRNA, which moves from the nucleus to the cytoplasm. Exon Poly-A RNA transcript (pre-mRNA) Intron NUCLEUS Cap FORMATION OF INITIATION COMPLEX After leaving the nucleus, mRNA attaches to the ribosome. CYTOPLASM mRNA Poly-A Growing polypeptide Ribosomal subunits Cap Aminoacyl-tRNA synthetase Amino acid tRNA AMINO ACID ACTIVATION Each amino acid attaches to its proper tRNA with the help of a specific enzyme and ATP. Activated amino acid TRANSLATION A succession of tRNAs add their amino acids to the polypeptide chain as the mRNA is moved through the ribosome one codon at a time. (When completed, the polypeptide is released from the ribosome.) Anticodon A C C AAA U G G U U UA U G U A C E A Ribosome 1 Poly-A Codon

CFU: W HAT COMES FIRST ?... Transcription or Translation? mRNA or protein? DNA or protein? DNA or mRNA? Process at the RIBOSOME or process at the NUCLEUS? Transcription mRNA DNA NUCLEUS!

C OMPLETE THE Q UESTIONS ON THE BOTTOM OF YOUR N OTES S HEET !

V IDEO CLIP OF PROTEIN SYNTHESIS … Journey inside the cell

E XIT T ICKET : ANSWER THE QUESTIONS ON THE LAST PAGE OF YOUR NOTES

E XIT TICKET ANSWER S: 1. What structure is shown in step I? 2. What process is happening in step II? 3. What is made during step II? 4. What process is occurring is step IV 5. What is the end product of step IV? DNA transcription mRNA translation a protein

L AB ACTIVITY …. Work with your group to complete the LAB posted at your station. You must turn in 1 project PLUS a LAB sheet for your group!