1. Thursday, March 31 st Objective: Explain and apply laws of heredity and their relationship to the structure and function of DNA Agenda: 1. Introduction to RNA 2. Transcription modeling activity

2. 1.What is base pairing? 2.How did it help Watson and Crick model DNA? Warm-up

3. Why do we care?

4. From genes to proteins DNA RNA amino acid protein Translation Polymerization Transcription

5. RiboNucleic Acid Three main differences: The sugar in RNA is ribose instead of deoxyribose. RNA is generally single-stranded. RNA contains uracil in place of thymine.

6. DNA RNA

7. Is the model below DNA or RNA? How do you know?

8. Three Main Types of RNA Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA)

9. mRNA Carries copies of instructions for assembling proteins from the nucleus to ribosome.

10. Transcription RNA polymerase separates the DNA. It adds nucleotides to make a complementary strand of RNA.

11. Transcription RNA polymerase binds only to regions of DNA known as promoters. Promoters are signals in DNA that indicate to the enzyme where to bind to make RNA.

12. Transcription Sketch this picture and label the RNA polymerase, DNA, and mRNA

13. RNA Editing DNA contains large sequences that are not involved in coding for proteins called introns. The sequences that do code are called exons. During "editing" the introns are cut out and the exons are spliced together. This new version is called mRNA and is ready to leave the nucleus.

14. rRNA Ribosomes are made up two parts: protein and rRNA. These are outside the nucleus.

15. tRNA During protein construction, tRNA brings amino acids to the growing protein.

16. Sketch this picture and label the tRNA, rRNA, and mRNA

17. Modeling questions What is produced in transcription? If the DNA strand is AUTGGGTCAG, what is the complementary DNA strand? If the DNA strand is TGACCTGCCT What is the complementary RNA strand? If the DNA analysis of a gene shows 20% adenine bases (A), what would be the percentage of thymine (T)? Cytosine (C)? Guanine (G)? Uracil (U)?

18. Exit Ticket What is the purpose of transcription? Our DNA contains instructions to build what? The shape of DNA is a(n) ________. What does tRNA do?