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BELLRINGER: 10-31-10. Draw the following box and fill in the squares, THIRD box on the last bell-ringer page:. REPLICATION. TRANSCRIPTION. Where in the cell does this take place?. Where in the cell does this take place?.
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BELLRINGER: 10-31-10 Draw the following box and fill in the squares, THIRD box on the last bell-ringer page: REPLICATION TRANSCRIPTION Where in the cell does this take place? Where in the cell does this take place? What is created in this process? What is created in this process? When does this take place? WHY does this take place?
There are three types of RNA that help build proteins. Section 11.2 Summary – pages 288 - 295 # 1 Messenger RNA (mRNA) brings instructions from DNA in the nucleus to the cytoplasm. Then mRNA binds to ribosomes.
Section 11.2 Summary – pages 288 - 295 # 2 Transfer RNA (tRNA) is the supplier. Transfer RNA delivers amino acids (the building blocks of proteins) to the ribosome to be assembled into a protein. Amino Acid How it binds with mRNA
Section 11.2 Summary – pages 288 - 295 # 3 Ribosomes are made of Ribosomal RNA (rRNA). rRNA uses the instructions from mRNA and the supplies from tRNA to assemble the amino acids in the correct order.
mRNA brings the instructions. • tRNA supplies the amino acid parts. • rRNA builds the proteins using the instructions and amino acids. RIBOSOME
During Transcription, mRNA is made. The copy of instructions for making proteins on an mRNA strand is in the form of a code.
The Genetic Code Section 11.2 Summary – pages 288 - 295 • Every three letters on a mRNA strand, called a codon, is a code for a specific amino acid (a building block to make protein)
There are thirty different kinds of amino acids. Different types of proteins are made with amino acids in different sequences
The codons on a mRNA strand need to be converted into amino acids. mRNA codons Amino Acids • The process of converting the codons on mRNA into a sequence of amino acids to make a protein is known as translation.
Every three letters on an mRNA strand is a codon. Each codon codes for a specific amino acid. CODON CHART
The Genetic Code Section 11.2 Summary – pages 288 - 295 • Sometimes there are several codons that code for the same amino acid….for instance, What two codons code for the amino acid “Arg” (Arginine)?
Below is a DNA strand…. During Transcription, what mRNA strand would be made from this DNA? T A C C C G T A T T C G A A G G C T A U G G G C A U A A G C U U C C G A Arginine Methionine Glycine Isoleucine Serine Phenylalanine Using this mRNA strand, translate the codons into amino acids using your codon chart.
Section 11.2 Summary – pages 288 - 295 Why does mRNA have to be made? (Why can’t DNA deliver it’s own instructions) Nucleus
Where does mRNA take the instructions so that proteins can be made? Section 11.2 Summary – pages 288 - 295 • Translation takes place at the ribosomes (rRNA) of a cell.
Translation from mRNA to Protein Section 11.2 Summary – pages 288 - 295 • mRNA brings the codons (message) from DNA to the ribosome (rRNA) mRNA Coming from Nucleus RIBOSOME
Section 11.2 Summary – pages 288 - 295 Step 1 • As translation begins, one end of mRNA strand attaches to a ribosome. mRNA strand Ribosome
Translation from mRNA to Protein Section 11.2 Summary – pages 288 - 295 • tRNAs bring amino acids to the ribosomes. mRNA Coming from Nucleus RIBOSOME
Amino acid • Each tRNA only carries one amino acid.
There are also three nucleotides on the bottom of the tRNA called an anti-codon. • Anti-codons complementary base pair with the codons on mRNA. (this is to make sure they are bringing the correct amino acid- If the anti-codon doesn’t base pair with the codon, then the wrong amino acid was brought) Section 11.2 Summary – pages 288 - 295 Anti-codon
AUG is usually the first codon on the mRNA strand. • This signals the ribosome to START making a protein. Section 11.2 Summary – pages 288 - 295 Methionine • A tRNA with anticodon UAC comes and binds with this codon and drops off it’s amino acid “Methionine”.
Section 11.2 Summary – pages 288 - 295 • After the first tRNA binds with its codon, the mRNA slides down so that the ribosome can read the next codon.
Section 11.2 Summary – pages 288 - 295 • A new tRNA molecule carrying an amino acid pairs with the second mRNA codon. Alanine
The amino acids then bond together. • Once the first tRNA lets go of it’s amino acid, it is released from the ribosome. Section 11.2 Summary – pages 288- 295 Methionine Alanine bond
Section 11.2 Summary – pages 288 - 295 • A chain of amino acids is formed until the stop codon is reached on the mRNA strand. The end result is a protein Stop codon