Warm-up 11/08

1. Warm-up 11/08 • If I have an 8% concentration of solute outside of my cell and a 2% concentration of solute inside my cell, which way will the water move in osmosis? • Which way will the solute move in diffusion?

2. DNA Structure

3. What is it? • What is DNA? • Deoxyribosenucleic Acid • DNA is a nucleic acid • DNA is made of nucleotides

4. Nitrogen Bases • Made of three things • Phosphate Groups • Deoxyribose sugar • Nitrogen Base

5. Nitrogen Bases • Nitrogen Bases • Two bases are called purines (larger) • Adenine (A) • Guanine (G) • Two bases are pyrimidines (smaller) • Thymine (T) (only found in DNA) • Cytosine(C)

6. Nitrogen Bases • Chargaff’s Rule • Adenine only pairs with Thymine • Guanine only pairs with Cytosine • Therefore, for every A there is a T and for every G there is a C

7. Nucleotide Practice #1 • You are given a strand of DNA, when you add up all the As, Gs, Cs, and Ts for both sides of the DNA strand you find you have 300 bases. • You know that there are 55 thymine in the strand. How many As, Cs, and Gs do you have? • T: 55 • A: • C: • G:

8. Nucleotide Practice #1 • You are given a strand of DNA, when you add up all the As, Gs, Cs, and Ts for both sides of the DNA strand you find you have 750 bases. • You know that there are 200 cytosine molecules in the strand. How many As, Cs, and Gs do you have? • T: • A: • C: 200 • G:

9. Structure • The DNA has a characteristic double helix • Double because there are two sides • Helix because it forms a spiral • Resembles a twisted ladder • The structure was discovered by Watson and Crick

10. Structure • The nitrogen bases are held together by Hydrogen Bonds

11. Hydrogen Bond (don’t write down) • Weak bond that uses hydrogen • The hydrogen atom gets sandwiched between oxygen and/or nitrogen • Works like a magnet

12. Sequence • How the nitrogen bases are arranged are • Unique to the species • Unique to the individual • The more similar the sequence of DNA is, the more closely related the two species are

13. Warm-up 3/1/2012 What are the three parts that make a nucleotide? What are the four different nucleotides? How do the nitrogen bases pair together?

14. DNA Replication

15. Making A Copy • You need to make an exact copy of the DNA so you can go through Mitosis and Meiosis (S Phase of Interphase)

16. How does it happen? • We use the semi-conservative model • Remember that A pairs with T and C pairs with G • Each strand is complementary to the other (it matches)

17. Helicase • DNA unwinds at the origin • Uses an enzyme called helicase to do so • You need the weak Hydrogen Bonds so you can pull the DNA apart easier

18. Semi-Conservative Model • Semi-Conservative Model • You will use the original piece of DNA as a template (half the old DNA will be used in the new DNA strand) • The right strand will form one new piece of DNA • The left strand will form another new piece of DNA • New nucleotides are added when the 2 DNA strands are pulled apart

19. Making our DNA longer Proteins called polymerases help add the new nucleotides

20. Models of DNA Replication

21. Example of Replication • Example: • Original piece of DNA: A T G C T G T T A • Complementary piece:

22. Practice Problems Original DNA Strand: A T C CC G A T G A Complementary Strand: Original DNA strand: G C C G T A T C A C Complementary strand: Original DNA strand: A T G C T A G C A T Complementary Strand:

23. Mutation • Change in the sequence of DNA • Sometimes it helps the organism and sometimes it hurts it

24. Warm-up 3/02/2012 • Synthesize the complementary strand of DNA. A T C G T T C G A T A G C A T G C • What are the two enzymes that are used in DNA replication and what do they do?

25. Transcription and Translation Making A Protein

26. RNA Structure • Ribonucleic Acid • Made of 3 parts • Phosphate group • Ribose sugar • Nitrogen base

27. RNA Structure • Only has one strand • Nitrogen Bases • Guanine (G) • Cytosine (C) • Adenine (A) • Uracil (U) (only found in RNA)

28. Types of RNA • Types of RNA • Messenger RNA (mRNA): complementary copy of DNA • Ribosomal RNA (rRNA): part of what makes a ribosome • Transport RNA (tRNA): transports amino acids to the ribosome

29. Transcribing RNA • Forms a complement to one of the strands of DNA • C pairs with G and A pairs with U • When the mRNA is done being made it separates from the DNA and leaves the nucleus

30. Example • Example • Original DNA strand: G T C A G T A G T T G C • mRNA strand:

31. Translation • Translation (mRNA  Protein) • Process of turning a mRNA strand into a protein

33. Translation • What is a protein? • Chains of amino acids linked together • DNA encodes the instructions to make proteins • DNA needs to be changed into RNA to make the protein

34. mRNA is read with a ribosome • The ribosome “reads” the mRNA 3 bases at a time • These 3 bases are called codons. • Each codon codes for 1 amino acid

35. tRNA brings the amino acids to the ribosome • Ribsome binds the amino acid to other amino acids with a peptide bond • The tRNA forms a complement to the mRNA codon • Called an anti-codon

36. Practice Problems • Write out the tRNA anti-codons to the mRNA codons below • UUA • GCA • AUG • CUA

37. You use a codon chart to determine which amino acid bonds to the codon

39. Practice Problems • Use the codon chart to match the amino acids to the codons • UUA • GCA • AUG • CUA

40. Mutations

41. Mutations • Change in the DNA of an individual • Can be caused by • Radiation • Chemicals • Spontaneous • If it happens in the gametes, it will be passed on to the children

42. Types of Mutations • Point Mutations • Change in 1 nucleotide base pair in the DNA sequence • EXAMPLE • TTT GGG CCC AAA: Original • TTT AGG CCC AAA: Mutated

43. Types of Mutations • Frameshift Mutations • Causes the codon reading frame to get moved up or down one spot • Insertion: when a new nucleotide gets put into the sequence • TTT GGG CCC AAA: OriginalTTT GGG ACCCAA A: Mutated

44. Frameshift Mutations EXAMPLE • Deletion: when 1 nucleotide gets removed from the sequence • TTT GGG CCC AAA: OriginalTTT GGC CCA AA: Mutated