1. 1

2. What is this structure? 2

3. DNA! DNA (deoxyribonucleic acid); which stores and provides the information that our body needs to make the various proteins that make us who we are. DNA is normally in the form of a double-helix. 3

4. DNA Model What are the red arrows pointing to? What is the blue arrow pointing to? 4

5. DNA Model The red arrows are pointing to nitrogen bases. The blue arrow is pointing to a hydrogen bond; the specific bond that holds the base pairs together. 5

6. DNA Model What is the black arrow pointing to? What is the green arrow pointing to? 6

7. The black arrow pointing to a deoxyribose sugar. The green arrow is pointing to a phosphate. The sugar and phosphate are two components of a nucleotide. A nucleotide also has a nitrogen base attached to the sugar phosphate backbone. DNA Model 7

8. Base Pairing Rules How are bases always paired in DNA? 8

9. The adenine pairs with thymine and the cytosine pairs with guanine. The purines are adenine and guanine. The pyrimidines are thymine and cytosine. Base Pairing Rules 9

10. Describe what is happening to the DNA in this image. Replication 10

11. The DNA is “unzipping” creating a replication fork. The enzyme DNA helicase binds to DNA and breaks the hydrogen bonds between the bases in the DNA strand. Replication fork 11 Replication

12. Completing Replication The enzyme DNA Polymerase will add free nucleotide bases to the exposed template according to base airing rules forming the complimentary strands. Each new DNA molecule will have 1 side of original DNA and one side of “new” DNA The enzyme DNA Polymerase will continue to work “proofreading” both new strands for errors The enzymes DNA Polymerase and DNA Ligase work to complete the process re-twisting the two new strands 12

13. Complete the following… This strand is called. The backbone is composed with a sugar instead of a deoxyribose sugar. There is a base substitution of instead of. 13

14. This strand is mRNA. Its backbone is composed with a ribose sugar instead of a deoxyribose sugar. It uses a base of uracil instead of thymine. 14

15. Protein Synthesis – Step #1 What step of protein synthesis is being shown in the picture? Why do cells need mRNA? 15

16. The picture is showing transcription - mRNA is matching base pairs (substituting U for T) in order to get the information from the DNA out into the cell’s cytoplasm. Cells need mRNA for two main reasons: 1)DNA strands are too LARGE to leave the nucleus 2) DNA needs to stay in a central location so that it can continuously provide information for differing genes and their protein requirements 16

17. Where in the cell does this mRNA go after leaving the nucleus? 17

18. mRNA goes to the ribosome in the cytoplasm. The mRNA lines up on the ribosome in groups of three bases, called codons. 18

19. What is this structure? Where is this structure found in a cell? What are these three nucleic acid bases called? 19

20. This structure is tRNA. Reminder: Since it is a type of RNA, uracil is used instead of thymine. tRNA is found only in the cytoplasm of a cell. These bases are an anti-codon. This will pair with a corresponding codon from mRNA according to base pairing rules. 20

21. What process is happening in the pictures below? Protein Synthesis – Step #2 21

22. Translation: the codon on mRNA matches up with the anticodon on tRNA. Each tRNA carries a specific amino acid with it when it arrives at the ribosome. The ribosome (made of rRNA) plays a role by helping codon match with anticodon. 22

23. tRNA molecules continually bring specific amino acids to the ribosome according to what the mRNA requests. The amino acids connect with one another using specific bonds called: Complete the following… 23

24. tRNA molecules continually bring specific amino acids to the ribosome according to what the mRNA requests. The amino acids connect with one another using specific bonds called: peptide bonds Complete the following… 24

25. Describe what happens once all of the information originally from the DNA is translated and all of the amino acids are joined together into polypeptide chains. 25

26. The mRNA and tRNA leave the ribosome and release the polypeptides so that they can fold into 3D proteins. 26