DNA Structure notes

1. DNA Structure notes

2. DeoxyribonucleicAcid Meaning?

3. Monomers of macro monomers • Carbohydrates- • Proteins- • Lipids- • Nucleic Acids-

4. Carbohydrates- monosaccharides • Proteins- • Lipids- • Nucleic Acids-

5. Carbohydrates- monosaccharides • Proteins- Amino Acids • Lipids- • Nucleic Acids-

6. Carbohydrates- monosaccharides • Proteins- Amino Acids • Lipids- glycerol and fatty acid • Nucleic Acids-

7. Carbohydrates- monosaccharides • Proteins- Amino Acids • Lipids- glycerol and fatty acid • Nucleic Acids- a nucleotide

8. 2 types of nucleic acids DNA and RNA- Monomer is called a nucleotide • There are three parts of a nucleotide

9. Three Parts to a nucleotide • Phosphate group, • sugar (dexyribose or ribose) • Nitrogenous base- 4 different types put into 2 groups

10. a. Purines (5 carbons and 4 Nitrogen’s in a ring) • examples-Adenine (A) and Guanine (G)

11. b. Pyrimidine (4 Carbons and 2 Nitrogen’s in a ring) • examples-Thymine (T) and Cytosine (C)

12. The nitrogenous bases make up the rungs of the DNA spiral stair case • One rung is made of 2 bases bonded together by a weak hydrogen bond

13. Adenine always bonds with thymine • Guanine always bonds with cytosine

14. The phosphate group and the sugar are bonded together with a strong phosphate bond to make the sides of the DNA ladder

16. DNA Replication • When does this occur in the cell cycle?

18. Histone- A protein that DNA can coil around, allows DNA to pack tightly into small space • Nucleosome- a histone with coiled DNA • Page 297-figure 12-10

20. DNA uses enzymes to unzip at the weak hydrogen bonds to replicate. DNA will unzip at hundreds of places at once. Where the DNA unzips is called a replicating fork.

21. An enzyme called DNA Polymerase is used to attach nucleotides to the open DNA strands. • Great picture on page 298 in book

22. As DNA unzips, free floating nucleotides will come in and pair up with the correct nitrogen base

23. The end result should be two identical strands of DNA

24. http://www.youtube.com/watch?v=yqESR7E4b_8 • http://www.youtube.com/watch?v=zdDkiRw1PdU

25. RNA structure • Three main differences between RNA and DNA 1. RNA is a single strand 2. RNA has the sugar- ribose 3. RNA has the nitrogenous base Uracil instead of thymine

26. Found in nucleus starts in nucleus, moves to cytoplasm

27. Types of RNA (3) page 300 figure 12-12

28. Messenger RNA- mRNA • Serves as a messenger from DNA, found in nucleus and cytoplasm

29. Transfer RNA- tRNA • Carries very specific Amino acids to rRNA. Found in the cytoplasm

30. Ribosomal RNA- rRNA • Serves as a meeting place btw mRNA and tRNA. It’s where proteins are assembled. Found in the cytoplasm

31. Protein Synthesis • assembling amino acids into protein • The making of protein is broken into two parts: Transcription and Translation

32. Transcription- using RNA to make a complimentary copy of the information from DNA • An area of DNA called Promoter will identify the part of the DNA that will be used to make the mRNA • RNA polymerase separates the DNA • RNA nucleotides will come in and temporarily bonds with DNA creating a mRNA

33. Once mRNA is made it separates from DNA (which zips back up) • mRNA will check itself. Parts of mRNA that will represent a protein will be kept (exon). Parts of the mRNA that does not represent a protein is cut out (intron).

35. After this mRNA will travel out of the Nucleus and into the cytoplasm.

37. Every three bases on a mRNA is called a codon. Each codon will represent an amino acid • There are 20 different types of amino acids, which are joined together to make proteins. The order of the codons on mRNA determines the order the a.a. are joined and this determines what protein is made.

39. We can use the Codon Wheel to show which codon represents which a.a. • Example: RNA: UCGCACGGU • Codons: UCG CAC GGU • a.a: serine, histidineglycine

42. c. The codon AUG is a start codon • there are three stop codons, UAA UAG UGA, which signal the end of the protein

43. Translation: interpreting mRNA to make proteins- page 304 fig. 12-18 • -once mRNA is made it leaves the nucleus and goes into the cytoplasm where it attaches to a ribosome (rRNA) • -rRNA is in 2 sections, this allows the mRNA to go through it.

45. -tRNA looks like a swiggle it has 3 nitrogen bases at one end has amino acids at the other.

46. -the nitrogen bases are called the anticodon and they each carry a specific a.a.

47. -rRNA “reads” the mRNA one codon at a time. The tRNA that compliments the mRNA will come to the rRNA, match up with the mRNA and drop off the a.a it carries. • -this continues until a stop codon is reached.

48. Mutations • -Change in the genetic material • A. Point mutations- change in one nucleotide that occur at a single point in the DNA sequence, usually only affects one amino acid in a protein. May not cause any changes

49. An example is substitution-the wrong bases bond together • DNA: ATG GCC TAT AAA CGG • mRNA: UAC CGG AUA UUU GCC • Amino acids: • DNA: ATG GTC TAT TTT CGG • mRNA: UAC CAG AUA UUU GCC • Amino acids:

50. B. Frame Shift mutations- a nucleotide is inserted or deleted. All amino acids are changed from that point on, can affect the entire protein, this is the most danderous kind of mutation • DNA: ATG GCC TAT AAA CGG • mRNA: ATT GGC CTA TAA ACG G • Amino Acids: