Unit2 lesson1-dna
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DNA is made up of nucleotides that contain a sugar, phosphate group, and one of four nitrogenous bases: adenine, guanine, cytosine, or thymine. The nucleotides bond together to form two polynucleotide chains that wind around each other in a double helix formation. Hydrogen bonds connect the bases of one chain to the other. DNA contains the genetic code for making proteins and replicates itself for cell division.
Unit2 lesson1-dna
- 1. UNIT 2 - DNA & DNA REPLICATION CH 7.1 & 7.2 P. 137-148
- 3. THE UNITS OF DNA DNA is a polymer. The monomer units of DNA are nucleotides, and the polymer is known as a "polynucleotide." Each nucleotide consists of a 5-carbon sugar (deoxyribose), a nitrogen containing base attached to the sugar, and a phosphate group.
- 5. NUCLEOTIDES There are four different types of nucleotides found in DNA, differing only in the nitrogenous base. The four nucleotides are given one letter abbreviations as shorthand for the four bases. A is for adenine G is for guanine C is for cytosine T is for thymine
- 6. Purine & Pyrimidine Bases Adenine and guanine are purines. Purines are the larger of the two types of bases found in DNA. Cytosine and thymine are pyrimidines.
- 7. DNA BACKBONE The DNA backbone is a polymer with an alternating sugar-phosphate sequence. The deoxyribose sugars are joined to phosphate groups in ester links, also known as "phosphodiester" bonds. Important bonds that can’t break
- 8. DNA DOUBLE HELIX DNA is a normally double stranded macromolecule. Two polynucleotide chains, held together by weak hydrogen bonds, form a DNA molecule. Note H-bonds are an attraction that can pull apart and go back together relatively easily P. 144 FIG 7-11 Also note the two strands run in opposite directions
- 10. FEATURES OF THE DOUBLE HELIX The two polynucleotide chains run in opposite directions The sugar-phosphate backbones of the two DNA strands wind around the helix axis like the railing of a spiral staircase The bases of the individual nucleotides are on the inside of the helix, stacked on top of each other like the steps of a spiral staircase.
- 11. SEE FIG 7-10 p. 143 in your TEXT BOOK
- 13. SO WHAT IS THE POINT? DNA is the brains of every cell because it contains all of the genes that are the codes for making proteins
- 14. PURPOSE OF DNA DNA has two major purposes DNA REPLICATION http://www.youtube.com/watch?v=rpwjZX_z5rg PROTEIN SYSNTHESIS
- 15. DNA REPLICATION Replication = when more cells need to be produced, COMPLETE copies of the original DNA must be made MITOSIS - nuclear division plus cytokinesis, to produces two identical daughter cells for growth and development of an organism MEIOSIS - results in the production of gametes with only 1 set of DNA (more details later!)
- 16. PROTEIN SYNTHESIS Protein synthesis = when proteins are needed as enzymes that control all of the reactions in a cell, PARTIAL copies of a piece of DNA called a gene must be transcribed to be then translated into an amino acid polymer = protein = enzyme