1. DNA and RNA Objectives: 8.0 Identify the structure and function of DNA, RNA, and protein. 8.1 Explaining relationships among DNA, genes, and chromosomes

2. DNA Nitrogenous Bases: 1.Adenine 2.Thymine 3.Cytosine 4.Guanine The base pairings: –Adenine and Thymine –Cytosine and Guanine

3. DNA Replication Occurs in S (synthesis) phase of Interphase As the double helix separates into 2 strands, the hydrogen bonds holding together the nucleotide bases break. Each strand has a new complement strand formed: –Each Adenine connects with a new Thymine. –Each Cytosine connects with a new Guanine. –AND VICE VERSA!!!!

4. The Purpose of Replication Replication occurs prior to cell division, so that new cells can form with complete sets of DNA. Practice: –Write out a 24-base nucleotide sequence. (You MUST Use Color!!!!) –Exchange sequences with someone. –Write out the complement strand for your partner’s sequence. What have you just created?

5. Build a DNA Molecule Online Activity http://learn.genetics.utah.edu/content/begin/dna/b uilddna/http://learn.genetics.utah.edu/content/begin/dna/b uilddna/ Diagrams source: http://karimedalla.wordpress.com/2012/11/01/3- 3-7-1-dna-structure/

6. DNA vs. RNA DNARNA Double strandedGenerally Single stranded Sugar: deoxyribose Sugar: ribose Phosphate group bonded to sugar A, T, C, GA, U (uracil), C, G Sugar and phosphate group make up the backbone (sides) of the DNA molecule. Bases attach to the “side chains” and form the “ladder rungs”. Together, each sugar, phosphate, and base combination make up a nucleotide.

7. DNA vs. RNA Diagrams source: http://www.uic.edu/class es/phys/phys461/phys45 0/ANJUM04 http://www.uic.edu/class es/phys/phys461/phys45 0/ANJUM04

8. DNA vs. RNA Diagram source: http://www.biologyrefere nce.com/Re- Se/RNA.html http://www.biologyrefere nce.com/Re- Se/RNA.html Diagram source: www.hbwbiology.net/q uizzes/ch16-molecular -inheritance.htm www.hbwbiology.net/q uizzes/ch16-molecular -inheritance.htm

9. What does DNA do? Most (but not all!) genes contain instructions for assembling amino acids into proteins. Where are proteins made? Where in the cell do you find genes? How do the instructions for making proteins get from the nucleus to the ribosomes?

10. Three Types of RNA Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA) Carries copies of DNA instructions to the rest of the cell in 3-base “code words” Helps form ribosomes; bind tRNA’s and other molecules necessary for protein synthesis (“protein synthesis machinery”) Binds to its “assigned” amino acid and attaches it to the growing chain when mRNA calls for it

11. Transcription Def: the synthesis of an mRNA molecule from a DNA template How does this differ from DNA replication? How is it similar? Source: http://www.my-frugal- money.com/Legal_Transcriber.html

12. Transcription Takes place in the nucleus Enzyme required to separate DNA strands for transcription: –RNA polymerase –binds to regions of DNA called promoters, with specific base sequences to start transcription mRNA strand is a complement to the DNA strand, but ____________ replaces the base ______________.

13. Transcription Once transcribed, the RNA strand is “cleaned up”: Source: http://blo g.canac ad.ac.jp/ bio/Biolo gyIBHL1 /834.ht ml

14. Transcription The mature mRNA leaves the nucleus and enters the cytoplasm. What instructions is it carrying? So where is it headed?

15. Translation Translation of the mRNA message into a protein takes place in ribosomes. Each 3-base segment is called a “codon”. Each codon codes for one of 20 amino acids used to build proteins. (Genetic Code: p.303 and next slide!!) Quick Lab: P.303

16. The Genetic Code Table Source: http://biology.kenyon.edu/courses/biol114/Chap05/Chapter05.html http://biology.kenyon.edu/courses/biol114/Chap05/Chapter05.html

17. Translation 1.As each codon moves through the ribosome, tRNA brings the proper amino acid into the ribosome, where it is attached to the growing polypeptide chain (protein). 2.One end of the tRNA carries the amino acid; the other has the 3- unpaired-base anticodon that allows it to attach to the complementary codon on the mRNA.

19. Translation 3.Once the NEXT tRNA carrying another amino acid attaches to the mRNA, a peptide bond forms between the amino acids. 4.The ribosome then breaks between the first tRNA and its amino acid, and the tRNA can leave the ribosome to pick up another amino acid. 5.This process continues until the ribosome reaches a STOP codon, and the new protein molecule is complete.

20. Transcription and Translation Activities 1.Transcribe and Translate a Gene: http://learn.genetics.utah.edu/conte nt/begin/dna/transcribe/ http://learn.genetics.utah.edu/conte nt/begin/dna/transcribe/ 2.Complete Genes and Consequences Booklet and Activity (source: HudsonAlpha)