4. DNA was discovered in 1953 by James Watson and Francis Crick

5. What does DNA stand for? Deoxyribonucleic acid

6. DNA is located in the nucleus of cells

7. DNA: deoxyribonucleic acid, controls the production of proteins in the cell. DNA & RNA are both polymers The repeating subunits of DNA & RNA are nucleotides.

9. DNA Structure – The Twisted Ladder

10. DNA Structure DNA is made of nucleotides. DNA nucleotides are made of: 1. Sugar (deoxyribose) 2. Phosphate 3. Nitrogen Base

11. A phosphate group A 5 carbon sugar called deoxyribose. A nitrogen base

12. Nitrogen Base Pairing- Who pairs with who?

14. The bases on one strand of the DNA molecule are the exact compliment of the bases on the other strand. Thus, they are called complimentary strands.

16. The sugar and the phosphate groups form the backbone of the DNA molecule

17. The “rungs” of the ladder are bonded pairs of nitrogen bases. The bases are bonded together by weak hydrogen bonds.

27. Replication begins when the enzyme DNA HELICASE attaches to the DNA molecule and unzips it by breaking the hydrogen bonds between the bases.

28. The DNA is separated into 2 strands. The unpaired bases on each strand attract the unpaired COMPLIMENTARY bases that float around in the nucleus. They then form new hydrogen bonds.

29. Next, an enzyme called DNA POLYMERASE catalyzes the formation of new sugar and phosphate sides for each of the 2 new DNA molecules.

30. Two new DNA molecules result from replication, with the EXACT same code. Each is one half of the ORIGINAL DNA double helix.

31. Replication occurs at MANY points of the DNA molecule at once. If not, it would take 3 days for one DNA molecule to replicate. This way, it only takes 3 minutes to replicate.

32. DNA contains the information to MAKE proteins but does not actually make it – RNA does….

33. Look… no T’s They are replaced by U’s Notice… only one strand… not two like DNA – not a double helix.

34. RNA’s sugar is RIBOSE, not deoxyribose like DNA

36. mRNA – MESSENGER RNA is a single strand of RNA that copies DNA information during protein synthesis. It serves as a TEMPLATE for assembling amino acid sequences to make proteins.

37. tRNA – TRANSFER RNA is a single strand of RNA that is folded back on itself like a hairpin. There are 20 forms of tRNA that correspond to each of the 20 amino acids which bind to them.

38. rRNA – RIBOSOMAL RNA, is RNA in a globular form. They are ribosomes! What do ribosomes make? Protein!!

39. To transcribe means to re-write or to write something down. RNA is transcribed from DNA through this process…..

41. 1. First, the enzyme RNA POLYMERASE opens up the DNA molecule.

42. 2. Next, RNA polymerase attaches RNA bases floating around in the nucleus to the DNA bases. RNA polymerase also builds a new SUGAR phosphate backbone for the RNA molecule.

43. 3. The transcription process stops when a termination CODE is reached on the DNA molecule. RNA is then released & the DNA closes back up……..

44. All three types of RNA are made this way. RNA then leaves the NUCLEUS through the nuclear pores and enters the cytoplasm where it joins up with RIBOSOMES and proteins are made.

45. Internet site http://www.ncc.gmu.edu/dna/mRNAanim.htm http://www.agresearch.co.nz/scied/search/m olecular/dnatranscription.htm

46. DNA RNA Proteins

47. The GENETIC code is the system that contains information needed by cells for proper functioning. A CODON is a group of 3 sequential mRNA bases that recognize a specific amino acid

49. Codons are UNIVERSAL. For example, UUU is the codon for the amino acid phenylalanine in mice, men, & bacteria. Every organism has the same genetic code for proteins………

51. http://www.cat.cc.md.us/biotut orials/protsyn/peptidea.html

52. Is the formation of protein using the information coded on DNA and carried out by RNA

53. Amino acids must be in the proper sequence for proteins to function properly. The number of different kinds of proteins varies with the COMPLEXITY of an organism.

56. 1. MRNA enters the cytoplasm from the nucleus and finds a ribosome to hook up with. 2. tRNA’s then bring specific amino acids to the ribosomes.

57. 3. The ribosome attaches to an AUG (start codon) on mRNA. 4. TRNA attaches itself to the mRNA and passes its amino acid off to the growing protein chain.

58. 5. TRNA leaves and another tRNA takes its place with a new amino acid. This process continues until a STOP codon is reached and the protein chain is complete and falls off.

59. The part of the tRNA that attaches to the codon is called the anticodon.. The three bases of the anticodon are complimentary to a specific codon in the mRNA.