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#energy source

15 public questions tagged with this topic.

Nuclear Reactions - Fission, Fusion and Energy Release

What is the primary source of energy in stars like the Sun?

**Nuclear fusion** source of energy in Sun, proton-proton cycle 4p→He+2e⁺+2ν+26.7 MeV, high temperature ~10⁷ K needed to give kinetic energy to overcome repulsion, thermal motion at high T allows tunneling, energy release because He BE/A higher than H. Fission releases energy because heavy nucleus BE/A ~7.6 MeV splits to intermediate ~8.5 MeV. The energy in stars like the Sun is generated through nuclear fusion, where light nuclei (e.g., hydrogen) combine to form heavier nuclei (e.g., helium), releasing energy due to increased binding energy per nucleon. Using E_n = -13.6/n² eV, r_n = n² a₀, L

Ref: NCERT > Physics Book > Atoms and Nuclei > Nuclear Reactions - Fission, Fusion and Energy Release

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Mass Defect, Binding Energy and Binding Energy per Nucleon

What is the main source of energy in nuclear reactors?

**Binding energy calculation** from mass defect, for nucleus mass number 28 BE 224 MeV BE/A=8 MeV, A=18 BE 144 MeV BE/A=8 MeV, BE/A indicates stability, fusion of light nuclei and fission of heavy release energy because product has higher BE/A, difference released. Nuclear reactors produce energy through nuclear fission, where heavy nuclei split into lighter fragments, releasing energy due to the increase in binding energy per nucleon. Using E_n = -13.6/n² eV, r_n = n² a₀, L = n h/2π, R = R₀ A^¹/³, BE = Δm c² and 1 u = 931.5 MeV, evaluation yields Nuclear fission, consistent with Bohr model an

Ref: NCERT > Physics Book > Atoms and Nuclei > Mass Defect, Binding Energy and Binding Energy per Nucleon

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Energy Stored in Inductor and Magnetic Energy

A coil is placed in a magnetic field that increases in strength. The energy stored in the coil’s magnetic field comes fr

**Energy stored in inductor** U =½ L I² (J), L inductance (H), I current (A), resides in magnetic field, energy density u = B²/(2μ₀) (J/m³), B field (T), μ₀=4π×10⁻⁷ H/m. For solenoid B=μ₀ n I, volume V= A l, U = (B²/2μ₀) V =½ (μ₀ n² A l) I² =½ L I², consistent. The energy stored ( (1/2) L I² ) comes from the work done by the external source (e.g., a battery) against the back emf to establish the current. Using Φ = B A cosθ, e = -N dΦ/dt = -N A dB/dt = B l v = N B A ω sinωt,

Ref: NCERT > Physics Book > Electromagnetic Induction > Energy Stored in Inductor and Magnetic Energy

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Animal Tissue Culture 1

Which amino acid is a major energy source for cultured cells?

Glutamine addiction phenomenon observed in many cultured lines including HeLa, HEK293, and cancer cells reflecting elevated anaplerotic demand beyond energy generation. Glutaminase isoforms GLS kidney-type and GLS2 liver-type localized in mitochondria inner membrane convert L-glutamine to glutamate releasing ammonia via deamidation, glutamate dehydrogenase GDH or aminotransferases aspartate transaminase, alanine transaminase produce alpha-ketoglutarate feeding tricarboxylic acid cycle generating ATP via oxidative phosphorylation plus citrate exported via mitochondrial citrate carrier for ATP c

Ref: Newsholme Q J Exp Physiol 2003 glutamine anaplerosis TCA mTOR; Lodish MBoC GlutaMAX stable dipeptide ammonia avoidance.

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Protein Sorting and Trafficking

The major energy source for nuclear transport is:

Energy input driving selective accumulation of proteins inside nucleus does not come from kinesin ATP hydrolysis used for microtubule transport or proton motive force powering mitochondrial import, but from compartmentalized GTP turnover of Ran. RCC1 guanine exchange factor bound to nucleosomes continuously recharges Ran-GDP to Ran-GTP using nuclear GTP pool, while cytoplasmic RanGAP1 SUMOylated and anchored to RanBP2/Nup358 plus co-activator RanBP1 hydrolyze GTP outside. Each import cycle consumes one GTP upon export complex disassembly in cytosol, and each export cycle consumes GTP as Ran-GT

Ref: NCBI Bookshelf, Molecular Biology of the Cell, Section: GTP Hydrolysis by Ran as Energy Source.

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Basic Evolution

Energy source in Miller–Urey experiment was:

Electric discharge reflects key principle in quiz on section b solved pyqs, where evolutionary mechanisms shape genetic variation and adaptation. In this context, Electric discharge aligns with experimental and theoretical evidence from population genetics, behavioral ecology and molecular phylogeny. Textbooks like Campbell Biology, Futuyma Evolution and Hartl Principles illustrate supporting data. Understanding why Electric discharge fits helps integrate natural selection, environment.

Ref: Futuyma, Evolution, Drift and Speciation PYQs.

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