Study Questions: 1) Diagram the parts of an RNA nucleotide.

1. Study Questions: 1) Diagram the parts of an RNA nucleotide.

2. Study Questions: 1) Diagram the parts of an RNA nucleotide. There are three parts to a nucleotide; a pentose sugar (in this case, ribose), a nitrogenous base (in this case, A, G, C, or U), and a phosphate group. PO4 A Ribose OH OH

3. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions.

4. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions. They are linked together through the removal of a water molecule from the 3’ OH and an OH on the Phosphate of the next nucleotide, with energy from cleaving the diphosphate group. OH OH O-P-O O OH O-P-O O OH O-P-O O O O-P-O O H2O OH

5. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions. 3) Why does the purine - pyrimidine structure relate to the complementary nature of double-stranded DNA?

6. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions. 3) Why does the purine - pyrimidine structure relate to the complementary nature of double-stranded DNA? When A binds with T and C bind with G, there is a purine binding with a pyrimidine. This pairing of a double ringed structure with a single ringed structure maintains a constant width to the molecule over its length – allowing all base pairs to bind. A purine-purine pairing won’t ‘fit’ (too fat), while a pyrimidine across from a pyrimidine won’t ‘reach’ one another to bind.

7. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions. 3) Why does the purine - pyrimidine structure relate to the complementary nature of double-stranded DNA? 4)  Draw a DNA double helix, showing three base pairs and the antiparallel nature of the helices.

8. Study Questions: 4)  Draw a DNA double helix, showing three base pairs and the antiparallel nature of the helices. OH 5’ 3’ O O-P-O O O O-P-O O C T A G O O-P-O O O O-P-O O T A O O-P-O O O O-P-O O 3’ 5’ OH

9. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions. 3) Why does the purine - pyrimidine structure relate to the complementary nature of double-stranded DNA? 4)  Draw a DNA double helix, showing three base pairs and the antiparallel nature of the helices. 5) Describe the higher levels of eukaryotic chromosome structure, including the terms nucleosome and solenoid.

10. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions. 3) Why does the purine - pyrimidine structure relate to the complementary nature of double-stranded DNA? 4)  Draw a DNA double helix, showing three base pairs and the antiparallel nature of the helices. 5) Describe the higher levels of eukaryotic chromosome structure, including the terms nucleosome and solenoid. The DNA double helix is wrapped around histone octamers – 2.5 turns per octamer. These structures, with DNA wrapped around histones, are called nucleosomes. DNA bound to histones can’t be read by enzymes, so the genes in this region of DNA are ‘off’. DNA between nucleosomes can be accessed by enzymes, and so can be on (if not off for another regulatory reason). This forms the “beads on a string” level of structure. The genetic material is in this conformation except when the cell is proceeding through division (mitosis or meiosis). In prophase of a divisional cycle, this strong of beads is coiled; each coil – or solenoid – has 6 nucleosomes. This coil is then supercoiled, and the supercoil is folded. All of this coiling and folding shortens and widens the chromosome – packaging it tightly for easy movement during division.

11. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions. 3) Why does the purine - pyrimidine structure relate to the complementary nature of double-stranded DNA? 4)  Draw a DNA double helix, showing three base pairs and the antiparallel nature of the helices. 5) Describe the higher levels of eukaryotic chromosome structure, including the terms nucleosome and solenoid. 6) What are two differences between euchromatin and hetochromatin?

12. Study Questions: 1) Diagram the parts of an RNA nucleotide. 2)  Show how two nucleotides are linked together by dehydration synthesis reactions. 3) Why does the purine - pyrimidine structure relate to the complementary nature of double-stranded DNA? 4)  Draw a DNA double helix, showing three base pairs and the antiparallel nature of the helices. 5) Describe the higher levels of eukaryotic chromosome structure, including the terms nucleosome and solenoid. 6) What are two differences between euchromatin and hetochromatin? Euchromatin is packaged more loosely during division, and has a higher concentration of genes than the heterochromatin, which is packed more tightly and typically contains fewer genes.