Warm Up… What are the differences between DNA & RNA?

1. Warm Up… What are the differences between DNA & RNA?

3. Why is RNA almost always Single Stranded? What is the benefit gained from RNA being Single Stranded?

4. Genes are the functional unit of Chromosomes • Each Chromosome is made of Genes, and • Each Gene is made of Nucleotides • Gene = Genotype (code); Protein = Phenotype (observable outcome)

5. How do we go from DNA (information) to Proteins (outcome)? Transcription is the synthesis of RNA, using DNA as a template • The RNA strand is the same as one of the DNA strands but has Uracil instead of Thymine • The RNA strand that is formed is called messenger RNA(mRNA) Translation is the synthesis of Protein (polypeptide), using RNA as a template • The mRNA that serves as the template for the new polypeptide • The RNA strand that forms the new polypeptide is called messenger transfer RNA(tRNA)

6. *Baking a Cake Analogy

7. What are the three types of RNA? transfer RNA (tRNA) has a major role in translation ribosomal RNA (rRNA) is a structural and functional component of ribosomes messenger RNA (mRNA) is the “Genetic Code” that delivers the DNA genetic message to the Ribosome

8. Transcription

9. Transcription How do we make mRNA from DNA? The DNA to be transcribed is separated by Helicase in the region of the gene to be transcribed The enzyme RNA polymerase binds to a site called the Promoter on the DNA RNA nucleotides pair with their complementary bases on 1 strand of DNA only • There is NO Thymine in RNA, so Uracil pairs with Adenine RNA polymerase forms covalent bonds between the nucleotides The RNA separates from the DNA and the DNA double helix reforms

11. Which two processes involve the unwinding (uncoiling) of the DNA double helix and its separation into two strands of nucleotides? A concept map involves drawing lines between associated concepts, and labeling the lines to show the relationships between the connected concepts. Create a concept map that links the following terms: DNA, nucleotide, mRNA, tRNA, rRNA, protein, amino acid, ribosome.

12. The Genetic Code What is the Genetic Code? The “translation dictionary” that enables the cellular machinery to convert the base sequence on the mRNA into an amino acid sequence is called the genetic code. What is a Codon and what is an Anti-Codon? A sequence of three bases on mRNA is called a codon A sequence of three bases on tRNA is called an anti-codon • Each codon (except for 3) corresponds to a specific tRNA • Each codon (except for 3) codes for a specific amino acid • Each amino acid has more than one codon that codes for it

13. What is meant by the degeneracy of the Genetic Code? There are 64 possible codons (4 x 4 x 4) Different codons can code for the same amino acid • For example, the codons GUU and GUC both code for the amino acid Valine This is the “degenerate” nature of the Genetic Code… 64 codons = 20 Amino Acids and 3 Stops So… 64 codons, but only 61 anti-codons (tRNA molecules)

16. Translation What is Translation? The last major step in protein synthesis, wherein the genetic code (carried by mRNA) is decoded to produce the specific sequence of amino acids (peptides) that make up a polypeptide chain Where does translation take place? Translation takes place on organelles called ribosomes Each ribosome comprises a small and a large subunit Each ribosome is made of rRNA and Proteins

17. What translates mRNA into Protein? tRNA is the molecule that translates mRNA’s genetic code into Protein DNA polymerase replicates new DNA from old DNA RNA polymerase transcribes DNA into mRNA tRNAtranslates mRNA into Protein

18. How are Proteins translated from mRNA’s genetic code? INITIATION mRNA binds to the small subunit of the ribosome tRNA molecules are present • Each tRNA has a specific anti-codon on one end, and a specific amino acid on the other end First tRNA binds to the ribosome at the site where its anti-codon matches the AUG codon on the mRNA So… first mRNA codon translated is AUG; first tRNA anti-codon matched is UAC; first amino acid on protein is Met (methionine)

19. ELONGATION Second tRNA binds to ribosome (two tRNAs are bound at once) The first tRNA transfers its amino acid to the second tRNA The ribosome moves along the mRNA, releasing the first tRNA These steps are then repeated, elongating the polypeptide chain • 3rdtRNA attaches to ribosome → 2ndtRNA transfers amino acids to 3rdtRNA→ 2ndtRNA leaves… • 4thtRNA attaches to ribosome → 3rdtRNA transfers amino acids to 4thtRNA → 3rdtRNA then leaves… • 5thtRNA attaches to ribosome → 4thtRNA transfers amino acids to 5thtRNA → 4th tRNA then leaves… and so on…

20. TERMINATION The elongation process continues until a stop codon is reached, then the completed protein (polypeptide) is released from the ribosome How can we illustrate the process of Translation?

22. K.I.S.S. it!!!