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Zorluk: Çok zorBiotechnology and Nanotechnology

With reference to recent developments in Biotechnology and Nanotechnology, consider the following statements:

1. Quantum dots are semiconductor nanocrystals whose fluorescence wavelength decreases as the particle size increases.
2. Somatic Cell Nuclear Transfer (SCNT) produces embryonic stem cells that inherit nuclear genomic DNA primarily from the somatic cell donor rather than the egg donor.
3. Carbon nanotubes can display either metallic or semiconducting electrical conductivity depending on their chiral angle and diameter.

Which of the statements given above is/are correct?

  1. 2 and 3 onlyCevap
  2. B
    1 and 2 only
  3. C
    1 and 3 only
  4. D
    1, 2 and 3

Cevap

Statements 2 and 3 are correct, while Statement 1 is incorrect.
The option stating '2 and 3 only' is correct because Statement 2 accurately describes how SCNT transfers nuclear DNA from the somatic cell donor, and Statement 3 accurately describes chirality-governed electrical properties of carbon nanotubes. Statement 1 is false because larger quantum dots emit longer wavelengths (red-shift), not shorter wavelengths.

Adım Adım Çözüm

1
Analyze Statement 1 regarding Quantum Dots and optical emission.
Statement 1 is incorrect. In quantum dots, confinement effects broaden the band gap as particle size decreases. Smaller dots emit higher-energy, shorter-wavelength light (blue light), whereas larger dots emit lower-energy, longer-wavelength light (red light).
Quantum confinement correlates bandgap energy inversely with nanoparticle size.
2
Analyze Statement 2 regarding Somatic Cell Nuclear Transfer (SCNT).
Statement 2 is correct. SCNT transfers a somatic nucleus into an enucleated oocyte, making the nuclear DNA virtually identical to the somatic donor cell.
The recipient egg cell contributes only cytoplasm and mitochondrial DNA, while the nuclear gene payload originates entirely from the somatic donor.
3
Analyze Statement 3 regarding Carbon Nanotubes (CNTs).
Statement 3 is correct. The orientation of the graphene roll (chirality vector (n,m)(n, m)) determines whether a single-walled carbon nanotube is metallic or semiconducting.
When (n−m)(n - m) is a multiple of 3, the CNT exhibits metallic conductivity; otherwise, it behaves as a semiconductor.

Anahtar Kavram

Quantum confinement in quantum dots, nuclear donor inheritance in SCNT, and chirality-dependent conductivity of carbon nanotubes
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Konular

Biotechnology and Nanotechnology

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