NEET Practice Questions (MCQs) with Answers & Solutions

The joining of DNA involves cutting source DNA and vector DNA with a specific restriction enzyme, mixing the cut 'gene of interest' and cut vector, and then adding ligase to prepare recombinant DNA. PCR is for amplification of the gene of interest after the recombinant DNA has been formed.

The palindrome in DNA is a sequence of base pairs that reads same on the two strands when orientation of reading is kept the same. For example, 5'—GAATTC—3' and 3'—CTTAAG—5'.

The separated DNA fragments can be visualised only after staining the DNA with a compound known as ethidium bromide followed by exposure to UV radiation (you cannot see pure DNA fragments in the visible light and without staining). You can see bright orange coloured bands of DNA in an ethidium bromide stained gel exposed to UV light.

The separated bands of DNA are cut out from the agarose gel and extracted from the gel piece. This step is known as elution.

Restriction enzymes belong to a larger class of enzymes called nucleases. These are of two kinds: exonucleases and endonucleases.

It was found that Hind II always cut DNA molecules at a particular point by recognising a specific sequence of six base pairs. This specific base sequence is known as the recognition sequence for Hind II.

According to the provided text, 'The gathering and focussing mechanism of light by the eye-lens is well described in the wave picture. But its absorption by the rods and cones (of the retina) requires the photon picture of light.' This directly indicates that the absorption by rods and cones involves the particle nature of light, i.e., photons.

The text states, 'He reasoned that nature was symmetrical and that the two basic physical entities – matter and energy, must have symmetrical character. If radiation shows dual aspects, so should matter.' This is the core reasoning behind de Broglie's hypothesis.

The de Broglie relation is given as $\lambda = h/p$, where h is Planck's constant and p is the momentum of the particle. (Equation 11.5 in the text: $\lambda = h/p = h/mv$).

The text mentions, 'Millikan’s first precise measurements confirmed the Einstein’s photoelectric equation and obtained an accurate value of Planck’s constant h. This led to the acceptance of particle or photon description (nature) of electromagnetic radiation, introduced by Einstein.'