Nucleic acids - Introduction
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This document discusses nucleic acids and their components. It covers topics like the different types of nucleic acid sugars (ribose, deoxyribose, dideoxy ribose), bases (purines and pyrimidines), nucleosides, nucleotides, polynucleotides, DNA vs RNA, DNA structure (double helix, hydrogen bonding between bases), Chargaff's rule, and more. It also includes review questions related to nucleic acids.
![Chargaff’s rule
In a double stranded DNA,
•Number of Purines = Number of pyrimidine
•[A+G] = [T+C]
[A] = [T]
[G] = [C]
[A+T] # [G+C]
Note: Chargaff’s rule is NOT applicable for RNA and ssDNA.](https://image.slidesharecdn.com/1-170315034437/85/Nucleic-acids-Introduction-24-320.jpg)
Nucleic acids - Introduction
- 1. Nucleic Acids Dr. Karthikeyan Pethusamy
- 2. Nucleic acids are polynucleotides • Polysaccharides • Polypeptides • Polynucleotides
- 4. Sugar: Ribose, Deoxy ribose, Dideoxy ribose Dideoxy ribose
- 6. What exactly is happening?
- 8. Sources of purine ring atoms
- 9. Purine Bases Adenine Guanine Hypoxanthine Xanthine Uric acid
- 11. Deamination of ‘methylated cytosine’ will produce a) Uracil b) Thymine c) Hypoxanthine d) Adenine
- 12. Why CpG dinucleotides are rare in vertebrate genomes?
- 13. Pyrimidine Bases
- 14. Nucleosides
- 16. Cyclic Nucleotide Monophosphate (NMP)
- 21. Polynucleotide
- 22. At physiologic pH, DNA is a. Positively charged b. Negatively charged c. Amphoteric d. Uncharged
- 24. Chargaff’s rule In a double stranded DNA, •Number of Purines = Number of pyrimidine •[A+G] = [T+C] [A] = [T] [G] = [C] [A+T] # [G+C] Note: Chargaff’s rule is NOT applicable for RNA and ssDNA.
- 25. Bacteria X has an adenine content of 33% in its genome. What is the expected thymine content in the genome of X? a. 22% b. 33% c. 44% d. 67%
- 26. In a sample of DNA, if adenine content is 23%, what will be the amount of guanine? a. 23% b. 46% c. 54% d. 27%
- 27. Why purine pairs with only pyrimidine? Why purine-purine & pyrimidine-pyrimidine base pairing is not possible?
- 30. DNA vs RNA
- 31. Which of the following bond is responsible for holding two strands of DNA together? a) N-Glycosidic bond b) Van der Waals interaction c) Salt bridges d) Hydrogen bond
- 32. Secondary structures of RNA
- 33. tRNA – secondary structure
- 34. Double stranded RNA exists in a) A - DNA like conformation b) B - DNA like conformation c) Z - DNA like conformation d) None
- 35. Which of the following is the substrate for the enzyme ribonucleotide reductase? a) Nucleoside monophosphate b) Nucleoside diphosphate c) Nucleoside triphosphate d) All of the above
- 36. Triplex DNA is formed because of a) Palindromic sequences b) Guanosine repeats c) Polypyrimidine sequences d) Hoogsteen pairing
- 37. Nitrogenous bases absorb UV-light lmax ~ 260 nm
- 38. DNA estimation can be done by a. Colorimeter b. Spectrophotometer c. pH meter d. Luminometer
- 40. 260/280 ratio
- 41. Classes of RNA
- 42. Ame’s test for mutagenicity Suspected Mutagen Liver extract
Editor's Notes
- #18: Substrate for ribonucleotide reductase