Science and Technology MCQ Set 28
Showing question 136 to 140 of total 301 MCQs
MCQ Set: 28
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Question No: 136
How many biosphere reserves are there in the country?
- 17
- 18
- 19
- 20
Answer and Explanation
Answer: B
Explanation
Biosphere Reserve (BR) is an international designation by UNESCO for representative parts of natural and cultural landscapes extending over large area of terrestrial or coastal/ marine ecosystems or a combination thereof.
BRs are designated to deal with one of the most important questions of reconciling the conservation of biodiversity, the quest for economic and social development and maintenance of associated cultural values.
BRs are thus special environments for both people and the nature and are living examples of how human beings and nature can co-exist while respecting each other’s needs.
There are 18 Biosphere Reserves in the country.
The Biosphere Reserve Programme is guided by UNESCO Man and Biosphere (MAB) programme as India is a signatory to the landscape approach supported by MAB programme.
A scheme called Biosphere Reserve is being implemented by Government of India since 1986, in which financial assistance is given in 90:10 ratio to the North Eastern Region States and three Himalayan states.
It is in the ratio of 60:40 to other states for maintenance, improvement and development of certain items.
The State Government prepares the Management Action Plan which is approved and monitored by Central MAB Committee”.
LIST OF BIOSPHERE RESERVES
1. Agasthyamala, Karnataka-Tamil Nadu-Kerala
2. Nilgiri, Tamil Nadu-Kerala
3. Gulf of Mannar, Tamil Nadu
4. Great Nicobar, Andaman & Nicobar Island
5. Seshachalam, Andhra Pradesh
6. Sundarban, West Bengal
7. Similipal, Odisha
8. Kachchh, Gujarat
9. Achanakmar-Amarkantak, Madhya Pradesh-Chattisgarhv
10. Pachmarhi, Madhya Pradesh
11. Panna, Madhya Pradesh
12. Nokrek, Meghalaya
13. Dibru-Saikhowa, Assam
14. Manas, Assam
15. Dehang-Debang, Arunachal Pradesh
16. Khangchendzonga, Sikkim
17. Nanda Devi, Uttrakhand
18. Cold Desert, Himachal Pradesh
Question No: 137
Research shows Neanderthals split from another group called __________ 7, 44,000 years ago.
- Denisovans
- Denivosans
- Homo Sapiens
- Desinovans
Answer and Explanation
Answer: A
Explanation
A new way to use DNA to peer into the history of humanity is rewriting what experts know about our long-extinct cousins, the Neanderthals, US researchers found on 7th Aug 2017.
Previous research has suggested that near the end of their existence some 40,000 years ago, only about 1,000 Neanderthals were left on Earth.
But the new study shows their population was far larger - likely numbering in the tens of thousands - though they existed in isolated groups across Europe.
The genetic clues include Neanderthal DNA that contains mutations that usually occur in small populations with little genetic diversity.
Also, Neanderthal remains - found in various locations - are genetically different from each other.
The idea is that there are these small, geographically isolated populations, like islands, that sometimes interact, but it’s a pain to move from island to island.
Using a new method to analyse DNA sequence data, researchers also found that Neanderthals split from another mysterious lineage, known as the Denisovans, about 7,44,000 years ago.
This is much earlier than any other estimation of the split.
After that, the global Neanderthal population grew to tens of thousands.
Very little is known about the Denisovans, sometimes described as the Eastern cousins of Neanderthals.
Only a few pieces of their remains - including some teeth and a pinkie bone - have ever been found.
Both Denisovans and Neanderthals mated with the ancestors of modern humans, who emerged from Africa about 60,000 years ago.
Researchers are not sure exactly why Neanderthals or Denisovans eventually died out, but it could have been due to harsh climate, or competition for scare resources with modern humans.
The study was based on comparing the genomes of four human populations: Modern Eurasians, modern Africans, Neanderthals and Denisovans.
This improved statistical method, called legofit, helped researchers estimate the percentage of Neanderthal genes flowing into modern Eurasian populations.
This they confirmed was about 2%.
The method revealed the date at which these ancestral populations diverged from each other, and their population sizes.
Question No: 138
Researchers have found two new species of an ancient plant whose fossils date to Jurassic period and are called living fossils consequently?
- Cycas
- Ficus
- Jacaranda
- Laburnam
Answer and Explanation
Answer: A
Explanation
Research conducted on a tree found in the Acharya Jagadish Chandra Bose Indian Botanic Garden in West Bengal has revealed two new species of Cycas to the world.
Cycas are one of the most ancient plants whose fossils date to the Jurassic period and are often referred to as “living fossils”.
While initial studies on the lone tree revealed that it was Cycas, a gymnosperm, further research based on its morphological and anatomical characters led to the discovery of new species of Cycas pschannae and, later, Cycas dharmrajii in the Andaman and Nicobar Islands.
The species were named after scientists Paramjit Singh Channa and Dharmraj S. Mishra.
This discovery takes the number of Cycas species found in the country to 14.
“The lone Cycas pschannae found in the Botanic Garden may have been planted by the British.
Cycads are very slow growing trees and this particular tree did not catch much attention before 2001 when we started working on it.
Of the nine locations where the species was found, it was only at two places that a congregate population of significant adult plants could be located, Mr. Singh said.
The scientists found about 1,200 plants at Middle Andaman Curt Burt Bay Wildlife Sanctuary, which included only 13 adult trees and 500 in North Andaman, Ross Island which also had 13 adults.
In the rest of the places the population of the new species was scattered with very few adult plants.
It was while hunting for Cycas pschannae that the scientist laid his eyes on Cycas dharmrajii in Table Excelsior Island.
Cycas dharmrajii, whose morphological and anatomical details were made public in the Nordic Journal of Botany in April, is characterised by the abnormal branching habit of its giant trunk and its swollen base.
Unique features of Newly Discovered Cycas
What makes the Cycas dharmrajii distinct from other Cycas found in the country is the well-defined 10 to 28 hook-like structures in the apex of the mega sporophyll (sporophyll are spore-bearing leaf-like female sex organ of the plant).
The sporophylls of Cycas pschannae are characterised by the presence of two lateral horn-like structures.
According to scientists, Cycas evolved on the earth as the first seeded plants and they grow very slowly, adding only a few centimetres every year.
Nearly 65% of Cycas are threatened but what makes the flora unique is that despite being a contemporary of the dinosaur, the genus continues to thrive.
There are over 100 species of Cycas found across the globe.
Question No: 139
IISC researchers discovered sensitive nanometre scale sensor employing innovative fabrication technique centring around detection of which gas?
- Carbon dioxide
- Carbon monoxide
- Calcium carbonate
- Sulphur dioxide
Answer and Explanation
Answer: B
Explanation
Indian Institute of Science researchers have developed a highly sensitive nanometre-scale carbon monoxide sensor by employing an innovative fabrication technique.
It is known that carbon monoxide (CO) can have adverse effects on the health of people exposed to it. Hence, it becomes necessary to have good, low-cost carbon-monoxide sensors.
Typically, a sensor would be a thin, current carrying plate whose resistance changes on exposure to carbon monoxide.
This in turn changes the value of the current flowing through it. This change when measured indicates the level of carbon monoxide in the air.
Most available sensors are in the micrometer range, a nanometer-sized detector would have a higher sensitivity, but the cost of manufacturing it goes up as the size decreases.
This is where the work of C.S. Prajapati and coworkers of Indian Institute of Science comes in.
To build this zinc-oxide (ZnO) nanostructure on a silicon wafer substrate, the researchers first placed tiny polystyrene beads on the wafer.
These beads arrange themselves into what is called a hexagonal close-packed structure on the oxidised silicon wafer.
Maintaining a reasonable level of vacuum, a high voltage is applied which “etches away” the surfaces of the beads until a gap of desired thickness is formed between adjacent beads.
Then zinc oxide is deposited on the system.
This occupies the spaces between the beads, forming a honeycomb like nano-mesh that can function as a nanosenor.
Scaling down from 10 micrometer feature size to 10 nanometer feature (used in this work) can enhance the efficiency 1,000 times.
However, the development cost of nanostructured gas sensors using existing lithography tools is really very high, which eventually impacts the overall cost of the device.
This device is also easy to scale for mass production.
Nanostructure-based gas sensors are very promising in their performance due their high surface-to-volume ratio. The existing techniques to create honeycomb nanostructures using photolithography and e-beam lithography are expensive and time-consuming.
The proposed technique can potentially reduce the cost by more than 50%.
If these sensors were at traffic intersections, we can do real time mapping of pollution hot-spots in a city.
This would be an enabler in realizing smart cities.
Question No: 140
IIT Delhi team of lady researchers have developed a new drug delivery platform using nanoparticles which targets what type of infections?
- Fungal
- Bacterial
- Viral
- Inflammatory
Answer and Explanation
Answer: B
Explanation
An all-women team of researchers from the Indian Institute of Technology (IIT) Delhi has developed a new drug delivery platform, using nanoparticles, which they say will more effectively target bacterial infections.
This is improving chances of recovery from cancer-related secondary infections.
The team consists of two faculty members - Neetu Singh from the Centre for Biomedical Engineering and Shalini Gupta from the Department of Chemical Engineering - and their students Smita Patil and Rohini Singh.
The nanotechnology-based delivery system would be specifically useful for cancer patients because if the bacterial infection in cancer remains untreated, it can infect the host even after the cancer cells are killed by chemotherapy.
The scientists are focusing not on mammalian cells, but on bacteria which slip into the cancer cells.