1. The study of how the information stored in DNA codes for RNA and protein is called molecular genetics.
2. One complete spiral of DNA consisted of 10 base pairs.
3. Pyrimidine bases of DNA are cytosine and thymine.
4. Nucleotide is the basic subunit of DNA and RNA.
5. Purine is the double-ring organic base.
6. Pentose sugar called deoxyribose is present in DNA.
7. Purine bases of DNA are Adenine and guanine.
8. The phosphate of a nucleotide attaches at the fifth (5') carbon of deoxyribose.
9. Hydrogen bonds between cytosine and guanine are three.
10. Some tissues like the liver contain occasional cells that are polyploid.
11. Each species has a certain content of DNA that is constant in all the individuals of that species called the C-value.
12. The bases and sugars in RNA and DNA are joined together into units called nucleosides.
13. A nucleotide consists of a nucleoside with a phosphate group attached through a phosphoester bond.
14. The bonds that join nucleotides together in DNA and RNA are called phosphodiester bonds.
15. According to Chargaff's rule, the amounts of adenine and thymine were always roughly equal, as were the amounts of guanine and cytosine.
16. The curving sides of the ladder in a DNA molecule represent the sugar-phosphate backbones of the two DNA strands.
17. The spacing between base pairs is 3.32 Ã… in a DNA molecule.
18. In the cell, DNA may exist in the common B form, with base pairs horizontal.
19. The Guanine-Cytosine content of a natural DNA can vary from less than 25% to almost 75%.
20. The temperature at which two strands of a DNA are half-dissociated, or denatured is called melting temperature.
21. Under the proper conditions, the two separated strands of DNA come back together again. This is called annealing or renaturation.
22. Mixing an RNA strand with a complementary DNA strand is called hybridization.
23. The length of human DNA is 1.1m.
24. DNA content per haploid cell is called C-value.
25. In 1953, James Watson and Francis Crick published the double-helical model of DNA structure.
26. Histones contain high content of basic amino acids which are lysine and arginine.
27. The unit of chromatin is called the nucleosome.
28. Nucleosome is a flat disc-shaped particle having a diameter of 11nm and a height of 5.7nm.
29. DNA is not free but is complexed with proteins in a structure called Chromatin.
30. When chromatin is isolated biochemically, it appears as a gelatinous substance that contains RNA, DNA, basic proteins called histones, and non-histone acidic proteins.
31. Histone H1 protein is non-conserved and has tissue-specific forms.
32. The diameter of beads in a chromatin structure is about 10nm.
33. Roger Kornberg proposed a model of nucleosome.
34. There are two turns of DNA per nucleosome.
35. Around 200 bp of DNA is present in a nucleosome.
36. The core DNA in a nucleosome is about 146 bp.
37. The histone H1 sealed off the two turns of DNA per histone octamer.
38. Linker DNA consists of 54 base pairs.
39. Non-histone proteins are very heterogeneous.
40. The most conserved histone proteins are H2A, H2B, H3, and H4.
Reference books:
1. Cell and Molecular Biology by E.D.P. De Robertis
2. Molecular Biology by Robert F. Weaver
3. Zoology by Miller and Harley
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