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#nuclear structure

3 public questions tagged with this topic.

Bohr Model Energy Levels and Hydrogen Spectrum

In Rutherford’s scattering experiment, what does a small fraction of alpha-particles rebounding back indicate?

**Bohr energy levels** E_n = -13.6/n² eV for hydrogen, negative indicating bound state, total energy = -13.6 eV ground state n=1, -3.4 eV n=2, -1.51 eV n=3, etc., photon energy for transition n_i → n_f is ΔE =13.6(1/n_f² -1/n_i²) eV, wavelength λ = hc/ΔE, h=6.6×10⁻³⁴ J·s, c=3×10⁸ m/s. Emission line spectrum characterized by discrete wavelengths because energy levels discrete. It indicates that the positive charge and most of the mass are concentrated in a small nucleus, causing strong repulsion in head-on collisions. Using E_n = -13.6/n² eV, r_n = n² a₀, L = n h/2π, R = R₀ A^¹/³, BE = Δm c² an

Ref: NCERT > Physics Book > Atoms and Nuclei > Bohr Model Energy Levels and Hydrogen Spectrum

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Cell Organelles

The nuclear matrix contains proteins such as:

Nuclear interior contains skeletal framework operationally defined as material insoluble after detergent extraction, DNase digestion and high-salt removal of chromatin. This nuclear matrix comprises lamins A and B at periphery plus internal matrin family proteins Matrin-3, Matrin F, hnRNPs, SAF-A and actin-related proteins that form ten nanometer filaments and fibrogranular networks visible by resinless embedding EM. Matrin-3 is RNA- and DNA-binding protein with zinc-finger domains retaining hyperedited RNAs and anchoring matrix attachment regions to organize loops, mutated in familial amyotro

Ref: Berezney Annu Rev Cell Biol; nuclear matrix lamin matrin-3 scaffold MAR organizes transcription factories.

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Cytoskeleton

What is the function of the nuclear lamina?

Interphase nucleus experiences mechanical stresses from cytoskeletal pulling forces migration through constricted spaces and chromatin dynamics requiring reinforcement beyond lipid bilayer envelope alone. Nuclear lamina provides mechanical support as dense meshwork 10 to 20 nm thick apposed to inner nuclear membrane beneath lamina associated chromatin domains. Composed of A type lamins lamin A and C splice isoforms and B type lamins B1 B2 type V intermediate filament proteins forming coiled coil dimers assembling head to tail polymers into orthogonal filaments crosslinked into sheet. Mesh conf

Ref: Dechat et al., Genes Dev 2008 – Nuclear lamina provides mechanical support to nucleus function.

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