UGC NTA NET/JRF Exam, Environmental Sciences, June-2020

The spectral reflectance curve of healthy green vegetation has a significant minimum of reflectance in the visible portion of the electromagnetic spectrum resulting from the pigments in plant leaves.

Reflectance increases dramatically in the near infrared. Stressed vegetation can also be detected because stressed vegetation has a significantly lower reflectance in the infrared.

The absorption of electromagnetic radiation by water depends on the state of the water. In liquid water the rotational transitions are effectively quenched, but absorption bands are affected by hydrogen bonding.

In crystalline ice the vibrational spectrum is also affected by hydrogen bonding and there are lattice vibrations causing absorption in the farinfrared. Pure water strongly absorbs radiation from the midinfrared spectral region. Hence Statement I is wrong but statement II is true.

Persistent organic pollutants (POPs) present in foods have been a major concern for food safety due to their persistence and toxic effects.

They are all synthetic chemicals, either intentionally or nonintentionally produced/ released. Some are pesticides, others are industrial products or unintended by-products resulting from industrial processes or combustions.
Persistent Organic Pollutants (POPs)

The pressure (p) of a gas in a solution is determined not only by its concentration, but also by its solubility coefficient.

According to the Henry's law, when temperature is kept constant, the content of gas (n) dissolved in any solution is directly proportional to the partial pressure of a gas, i.e.,
n = pc,
where,
n = concentration (amount) of a gas in a solution,
p = partial pressure of gas and
c = solubility coefficient of the gas.

Ex-situ techniques involves the treatment of contaminated soil, away from the polluted site. Ex-situ bioremediation can be operated in two ways which include solid phase bioremediation and slurry phase bioremediation.

Besides its high cost, these techniques are highly efficient, easy to control, faster and have great potential to treat large number of contaminants from the soil.

Ex-situ techniques involve land farming, biopile, windrow, soil washing, composting, bioreactor, ion exchange, adsorption/absorption, pyrolysis and ultrasound technology.

These techniques can be successfully applied for the treatment of fuel hydrocarbons, halogenated and nonhalogenated organic compounds as well as for various pesticides.

Diesel exhaust particulates (DEPSs) aggravate asthma-like pulmonary inflammation in a mouse model of asthma induced by a house dust extract (HDE) containing cockroach allergens and endotoxin.

One of phytoremediation categories, phytoextraction, can be used to remove heavy metals from soil using its ability to uptake metals which are essential for plant growth (Fe, Mn, Zn, Cu, Mg, Mo, and Ni).

Some metals with unknown biological function (Cd, Cr, Pb, Co, Ag, Se, Hg) can also be accumulated. Some plants that are used in phytoextraction strategies are termed "hyperaccumulators." They are plants that achieve a shoot-to-root metal-concentration ratio greater than one.

Nonaccumulating plants typically have a shoot-to-root ratio considerably less than one. Ideally, hyperaccumulators should thrive in toxic environments, require little maintenance and produce high biomass, although few plants perfectly fulfill these requirements.

Many bacteria carry plasmids, which are much smaller pieces of DNA, also circular and selfreplicating.

These are vitally important in the context of environmental biotechnology in that they frequently carry the genes for degradative pathways. Many of these plasmids may move between different bacteria where they replicate, thus making the metabolic capability they carry transferable.

Bacteria show great promiscuity with respect to sharing their DNA. Hence, Both Statement I and Statement II are correct.

In the Northern Hemisphere the motion of the winds about a cyclone, or low, will be an inblowing spiral and will have a counterclockwise direction; and the winds about an anticyclone will be an outblowing spiral and will have a clockwise direction.

This is illustrated graphically in the figure. The relation of low and high pressure areas to the wind direction is happily expressed by the law known as Buys-Ballot's law, viz:

"If you stand with your back to the wind, the region of low pressure will be on the left hand in the Northern Hemisphere, and on the right hand in the Southern Hemisphere; and high pressure will be on the right hand in the Northern Hemisphere, and on the left hand in the Southern Hemisphere."
Hence, Both Statement I and Statement II are correct.

The rocks that make up the crust can be classified into three types.
Sedimentary Rocks-rocks that are formed from the lithification of sediments, chemical precipitation or by direct biogenic deposition. Some common types are sandstone, shale, coal, limestone and coral.

Igneous Rocks-rocks that cool from a magma. The two most common types are granite and basalt.

Metamorphic Rocks-rocks that have been altered by high pressures, temperatures and/ or chemical reaction while still in the solid state. Two common types are marble, which comes from limestone, and slate that comes from shale.

Increasing order of following rocks by per cent volume in the earth's crust: Sedimentary rocks < Metamorphic rocks < Igneous rocks.