55. The molecular ion peak [M]⁺ of an analyte as measured by Electron Ionization Mass Spectrometry has an m/z of 149 and a relative abundance of 100%. The [M]⁺ has […]
![55. The molecular ion peak [M]⁺ of an analyte as measured by Electron Ionization Mass Spectrometry has an m/z of 149 and a relative abundance of 100%. The [M]⁺ has a relative abundance of 6.7% and the [M + 2]⁺ peak has a relative abundance of 5%. The abundance of the major isotope of H, C, N, O, and S are ¹H–100%, ¹²C–98.9%, ¹³C–1.1%, ¹⁴N–99.6%, ¹⁵N–0.4%, ¹⁶O–99.8%, ¹⁸O–0.2%, ³²S–95.0%, ³³S–0.75% and ³⁴S–4.2%. The most probable molecular formula of the compound is: (A) C₇H₂₁N₂O (B) C₅H₁₁NO₂S (C) C₆H₁₃O₂S (D) C₆H₁₅NOS](https://www.letstalkacademy.com/wp-content/uploads/2026/07/55.jpg)
Tag: CSIR NET Life Science Previous Year Questions on METHODS IN BIOLOGY
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CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Calculating the Wavelength of Radiation Required
54. For a nuclear spin of spin quantum number (I = 1/2), precessing in a magnetic field at a Larmor frequency of 300 MHz, the wavelength of incident radiation required […]
CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Distinguishing α-Helix, 3₁₀ Helix, and π-Helix
53. Which one of the following correctly describes the spectroscopic experiment that would help distinguish between an α-helix, 3₁₀ helix and π helix? (A) Near UV absorption spectrum between 250–300 […]
CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Comparison of X-ray Crystallography and NMR Spectroscopy
52. The structure of a protein with 100 residues was determined by X-ray analysis at atomic resolution and NMR spectroscopy. The following observations are possible. A. The dihedral angles determined […]
CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Spectroscopic Investigation of Proteins
51. Following are statements related to spectroscopic investigation of proteins. A. Tryptophan fluorescence in a protein is not sensitive to its environment. B. Observation of a large number of Nᵢ […]
CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Identifying Alpha-Helical Peptides Using NOE Patterns
50. Detailed NMR spectra of a 20-residue peptide were recorded using a 600 MHz instrument. If the peptide adopts an α-helical conformation, which one of the following statements is correct? […]
CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Identifying Helical Peptide Conformation
49. The conformation of a 30-residue peptide is studied by NMR spectroscopy. The JNH for most of the amide protons is 4 Hz. The 2D NOESY spectrum shows prominent Nᵢ–Nᵢ₊₁ […]
CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Splitting Pattern of the δ-Methylene Protons
48. The hydrogen atoms in the δ (delta) methylene group of lysine will give the following splitting pattern in the ¹H-NMR spectra of lysine (A) Triplet of triplets. (B) Quintet. […]
CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Interpreting 1D and 2D NMR Spectra
47. The Nuclear Magnetic Resonance (1D and 2D) spectrum of a 30-residue peptide were recorded at 25°C. The following observations were made. A. The NH and CαH resonances were well […]
CSIR NET Life Science Previous Year Questions and Solutions Spectroscopy
Effect of D₂O on Proton NMR of Peptides
46. A 30-residue peptide containing Phe, Tyr and Trp is dissolved in D₂O and the high field proton NMR is recorded after 24 hours. The resonances that are unlikely to […]
