DNA

1. DNA Deoxyribonucleic acid Encodes instructions for making many other molecules necessary for life

2. I. Structure of DNA • Long molecule made up of repeating units called Nucleotides.

3. Nucleotide 3 parts > 5 carbon sugar (deoxyribose or pentose) > Phosphate group > Nitrogeneous base

4. Purines Adenine (A) Guanine (G) Pyrimidines Cytosine (C) Thymine (T) Nitrogen Bases

5. Chargaff’s Rule • The amount of purines equals the amount of pyrimidines. • Adenine pairs with Thymine • Cytosine pairs with Guanine • This is known as base pairing. The bases are held together by hydrogen bonds

7. DNA research • Rosalind Franklin - used x-ray diffraction to get information about the structure of DNA - x-shaped and twisted

9. Watson and Crick - figured out the DNA molecule was a double helix (twisted ladder) - sides were held together by hydrogen bonds

10. II. Compare DNA to RNA DNA • Sugar is deoxyribose (pentose) • Nitrogen bases are Adenine, Cytosine, Guanine, & Thymine • 2 strands • Instructions that control the cell’s activities (architect)

11. RNA • Sugar is ribose • Has uracil instead of thymine • 1 strand • Takes the instructions from DNA and makes proteins

12. DNA Replication • Process by which DNA makes copies of itself STEPS: • Double helix unwinds • DNA polymerase moves along the separated parent strand, matching the bases on each parent strand to a new complementary strand.

14. Practice

15. Transcription • Manufacture of mRNA. • Process of transferring information from a strand of DNA to a strand of RNA

16. Messenger ribonucleic acid (mRNA) is a molecule of RNA encoding a chemical "blueprint" for a protein product. mRNA is transcribed from a DNA template, and carries coding information to the sites of protein synthesis: the ribosomes. • In mRNA as in DNA, genetic information is encoded in the sequence of four nucleotides arranged into codons of three bases each. Each codon encodes for a specific amino acid, except the stop codons that terminate protein synthesis.

17. Practice

18. Translation • Takes place on ribosomes • Ribosomes synthesize (make) proteins • Variations of the nitrogen bases determines the composition and manufacture of proteins --- this is called protein synthesis

20. Practice p. 303

21. 3 types of RNA are involved in carrying out the instructions for protein synthsis • Messenger RNA (mRNA) carries the coded instructions for protein synthesis from the DNA in the nucleus to the ribosomes • Transfer RNA (tRNA) brings the amino acids to the ribosome in the correct order so that they can be built into the new protein • Ribosomal RNA (rRNA) along with several proteins, this makes up the structure of a ribosome

22. Relate changes in DNA instructions to cause mutations • A change in the sequence of nucleotides is called a gene mutation (point mutation) • Mutations produces a variation that improves the function of an organism • These variations can contribute to the adaptation of a species to its environment or could be lethal • Mutagens- factors in the environment that cause mutations to occur.

23. Deletion G ----- C C ----- T ----- A T ----- A A ----- U Or G C T T A C A A U Addition G --- C C --- G T --- A A --- U G--- C --- T or G C T A G C G A U C T Types of mutations

24. Substitution G --- C C --- G T --- C T --- A A --- U G --- C

25. Inversion • (think of math and inverting fractions--- flipping them) G C T T A G A C C (mRNA) A G C A U C U G G Or A C T T C G (DNA) T C A T C G

26. DNA Sentences • Choose a card • Write the “sentence” on your paper • Replicate the “sentence” (A matches with T and C matches with G) • Transcribe the new “sentence” (A matches with U, T matches with A, G and C match) • Break into codons (3 bases) • Walk around the room and find the correct codon • Flip the card up and write the anticodon down. • You should have created a sentence with a start and stop codon.