Direct gene transfer is the transfer of naked DNA into plant cells, but the presence of a rigid plant cell wall acts as a barrier to uptake. Thus, protoplasts are the favored target for direct gene transfer. Polyethylene glycol-mediated DNA uptake is a direct gene transfer method that uses the interaction between PEG, naked DNA, salts and the protoplast membrane to affect the transportation of DNA into the cytoplasm.
List-I | List II | ||
---|---|---|---|
A. | Phenol-formaldehyde resin | I | Glyptal |
B. | The copolymer of 1,3-butadiene and styrene | II | Novolac |
C. | Polyester of glycol and phthalic acid | III | Buna-S |
D. | Polyester of glycol and terephthalic acid | IV | Dacron |
A full wave rectifier circuit with diodes (\(D_1\)) and (\(D_2\)) is shown in the figure. If input supply voltage \(V_{in} = 220 \sin(100 \pi t)\) volt, then at \(t = 15\) msec:
A bob of heavy mass \(m\) is suspended by a light string of length \(l\). The bob is given a horizontal velocity \(v_0\) as shown in figure. If the string gets slack at some point P making an angle \( \theta \) from the horizontal, the ratio of the speed \(v\) of the bob at point P to its initial speed \(v_0\) is :
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
Neoprene is formed from chloroprene. It is prepared by free radical polymerisation. The monomer of neoprene is chloroprene. It is used for preparing gaskets, conveyor belts etc.