Hit List Questions 77 -PPP 100 PRELIMS 2024 - 95

Questions & Explanations:

1.

1. Dengue fever

2. Chikungunya 

3. Zika virus

Asian Tiger mosquito is notorious for transmitting

(a) 1 and 3 only

(b) 2 and 3 only

(c) 3 only

(d) 1, 2 and 3

 

2.

Grafting method of vegetative reproduction is seen in

(a) Bougainvillea

(b) Citrus

(c) Both (a) and (b)

(d) Neither (a) nor (b)

 

3.

Which of the following is/are true?.

I. Blood group AB carries both the A and B antigens and have no antibodies.

II. Blood group O have no antigens but both antibodies.

III. If the blood group of the couple is AB positive and O negative, then their biological son’s blood group must be O positive.

Codes:

(a) Only II

(b) Only I and II

(c) Only II and III

(d) I, II and III

 

4.

1. They were active during the Great Oxidation Event.

2. They are coacervates.

3. They are photoautotrophs.

Which of the statements given above is/are correct about the cyanobacteria?

(a) 2 and 3 only

(b) 2 only

(c) 1 and 3 only

(d) 1, 2 and 3

 

5.

With reference to Dengue, consider the following statements: 

1. Wolbachia help control dengue.

2. Dengvaxia is a live, attenuated dengue virus.

3. CYD-TDV is a dengue vaccine.

4. Retro-orbital pain is a symptom of Dengue.

Which of these statements are correct? 

(a) 3 and 4

(b) 2 and 3 

(c) 1, 2 and 3

(d) 1, 2, 3 and 4

6.

Consider the following statements:

1. Caffeine, a constituent of tea and coffee is a diuretic.

2. Citric acid is used in soft drinks.

3. Ascorbic acid is essential for the formation of bones and teeth.

4. Citric acid is a good substitution for ascorbic acid in our nutrition.

Which of the statements given above are correct?

(a) 1 and 2, only

(b) 1, 2 and 3, only

(c) 3 and 4 only

(d) 1, 2, 3 and 4

 

7.

1) Royal haemophilia

2) Tay-Sachs disease

3) Cystic fibrosis

Sex-linked genetic diseases include

(a) 1 and 2 only

(b) 1, 2 and 3 

(c) 1 only

(d) 1 and 3 only

 

8.

Difference(s) between virus and viroid include

1) Absence of protein coat in viroid but present in the virus

2) Presence of low molecular weight RNA in the virus but absent in viroids

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

 

9.

Which of the statements given below is/are correct?.

1.  If the bicarbonates level in saliva is reduced the tooth enamel may get dissolved.

2.   Saliva has an enzyme called Ptyalin.

(a) 1 only

(b) 2 only

(c) 1 and 2

(d) Neither 1 Nor 2

 

10.

1. They are algae.

2. They act as carbon sinks.

3. They have no roots but thallus.

Which of the is/are true w.r.t. Seagrasses?

(a) 2 only

(b) 1 and 3 only

(c) 1 and 2 only

(d) 1, 2 and 3

 

11.

Which of the following is/are incorrect?.

(a) Circadian rhythms follow a 24-hour cycle.

(b) Ultradian rhythms are shorter than a 24-hour cycle.

(c) Both (a) and (b)

(d) Neither (a) nor (b)

 

12.

Canola refers to a special type of oilseed mustard varieties breed for human consumption. The main characteristic of these varieties is that the  

(a) Oil is rich in botoxin   

(b) Oil is rich in unsaturated fatty acid 

(c) Oil has long shelf-life 

(d) Oil has very low uric acid content

 

13.

Ticks and mites are actually

(a) Arachnids

(b) Crustaceans

(c) In sects

(d) Myriapods

 

14.

1. They are originally from South Africa.

2. They have root pockets.

Which of the above statements is/are correct w.r.t. Water hyacinths?

(a) 1 only

(b) 2 only

(c) Both 1 and 2  

(d) Neither 1 nor 2

 

15.

In the context of organic evolution, the loss of limbs of snakes is explained by the phenomenon of

(a) use and disuse of organs

(b) adaptation to living in burrows

(c) natural selection

(d) inheritance of acquired characters

 

16.

1. Increasing tax rates will yield additional tax revenue.

2. It is U shaped.

Which of the above statements is/are correct w.r.t. “Laffer Curve”?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

 

17.

Correct statement(s) about “obelisks” include

1) They are binary stars.

2) They show the Red Shift phenomenon.

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

 

18.

Which one of the following is the correct sequence in the order decreasing the length of the three structural part given below, of the small intestine in the human body?

 (a) Jejunum - Duodenum - Ileum

 (b) Ileum - Duodenum - Jejunum

 (c) Jejunum - Ileum - Duodenum

 (d) Ileum - Jejunum - Duodenum

  

19.

I. Only U-235, not U-238, can sustain a chain reaction.

II. India hosts roughly a quarter of the world’s thorium.

Which of the above statements is/are true?.

(a) Only I

(b) Only II

(c) Both I & II

(d) Neither I nor II

 

20.

“Palaeoloxodon” seen in news refer to the context of

(a) Elephants

(b) Tigers

(c) Dolphins

(d) Olive Ridley Turtles

21.

I. They have double uterus and double vagina.

II. They use scent marking as a form of communication.

III. The Koala is a marsupial.

Which of the above statements is/are true w.r.t. Marsupials?

(a) Only I & III

(b) Only II & III

(c) Only I & II

(d) I, II & III

 

22.

1. Cuttlefish

2. Pufferfish

3. Flying fish

Which of the above is/are chordates?

(a) 2 only

(b) 1 and 3 only

(c) 2 and 3 only  

(d) 1, 2 and 3

 

23.

FitCoal in news is

(a) Coal Grading Index

(b) Imported Coal with less suplhur

(c) Activated Carbon to absorb air pollutants

(d) None of these

24.

With reference to the human body, consider the following statements. 

1. The production of somatotropin goes up when a person exercises. 

2. Stress causes the adrenals to release very less amount of cortisol than usual.  

Which of these statements are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

 

25.

1. The virus that causes COVID-19, SARS-CoV-2, is a positive-sense single-stranded RNA virus.

2. Positive Sense RNA Virus is capable of operating as mRNA and can be directly translated into the protein in the host.

Which of the above statements is/are false?.

(a) Only 1
 

(b) Only 2
 

(c) Both 1 and 2
 

(d) Neither 1 nor 2

 

 

EXPLANATIONS

 

1.

https://timesofindia.indiatimes.com/life-style/health-fitness/health-news/dengue-fear-in-paris-fumigation-for-asian-tiger-mosquitoes-know-symptoms/photostory/103350810.cms?picid=103350842

https://www.hindustantimes.com/opinion/scientifically-speaking-could-a-yellow-fever-outbreak-happen-in-india-101660732105404.html

Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes.

The "yellow" in the name refers to the jaundice that affects some patients.

A flavivirus causes yellow fever.

It is transmitted by mosquito bite, usually the Aedes aegypti mosquito.

The mosquito becomes infected by biting an infected human or a monkey.

An infected mosquito is a source of infection for the rest of its life.

The flavivirus is endemic among monkeys that live in the tree tops of the jungle, known as the jungle canopy, in many parts of Africa and the Americas.

2.

Ø Grafting is especially important for propagation of seedless varieties of plants. It consists of inserting a small branch into a rooted plant.

Ø The rooted plant taken as a stock is resistant to disease and is physically sturdy. In this stock a branch is inserted which is known as scion or graft. This scion or graft is the stem cutting from the desired plant. Usually the grafted end of stock and scion fit well with each other and are bound firmly with tape or rubber-band until their tissues unite and vascular continuity is established.

Ø Grafting is mostly. practised in dicot plants.

Grafting has been found extremely useful in propagating improved varieties of various flowers and fruits like rose, Bougainvillea, Citrus, mango, apple etc.

3.

Subjects with blood group A carry the A antigen on their red blood cells (RBCs) and have antibodies to antigen B; subjects with blood group B have the B antigen and anti-A antibodies.

 

4.

Coacervates were a type of protobionts or prebiotic chemical aggregates. They were colloid aggregates of proteins and polysaccharides but did not have the ability to reproduce nor they developed a covering membrane of lipids.

Coacervates were formed during the chemical evolution of life.

https://www.thehindu.com/sci-tech/science/study-reveals-the-oldest-evidence-of-photosynthesis/article67710011.ece

5.

https://www.downtoearth.org.in/news/health/decoding-dengue-india-s-first-prospective-dna-vaccine-against-disease-is-promising-but-challenges-lie-ahead-87951#:~:text=Published%3A%20Wednesday%2001%20March%202023&text=In%20a%20significant%20development%20in,after%20exposure%20to%20the%20disease.

https://www.thehindu.com/sci-tech/science/explained-why-is-a-viable-dengue-vaccine-not-yet-available/article66803339.ece

6.

Caffeine can increase blood pressure and cause vasoconstriction. Doses of caffeine equivalent to the amount normally found in standard servings of tea, coffee and carbonated soft drinks appear to have no diuretic action.

Citric acid is a natural preservative and is also used to add an acidic (sour) taste to foods and soft drinks. In biochemistry, it is important as an intermediate in the citric acid cycle and therefore occurs in the metabolism of almost all living things.

All vitamins are best for strong bones and teeth. But vitamin C is especially best for the formation of bones and teeth. Vitamin C, also called ascorbic acid, is important to many functions in the body. For example, it is needed to grow and repair tissues throughout the body.

Ascorbic acid acts as a preservative and prevents the browning of fruits. Citric acid is your best options its best substitute. Ascorbic acid has a bitter flavor but citric acid is tart.

7.

Haemophilia acquired the name the royal disease due to the high number of descendants of Queen Victoria afflicted by it. It is assumed that a mutation occurred in the sperm of the Queen''s father, Edward Augustus, Duke of Kent.

Tay-Sachs disease is a rare, neurodegenerative disorder in which deficiency of an enzyme (hexosaminidase A) results in excessive accumulation of certain fats (lipids) known as gangliosides in the brain and nerve cells. This abnormal accumulation of gangliosides leads to progressive dysfunction of the central nervous system. Tay-Sachs disease is categorized as a lysosomal storage disease. Lysosomes are the major digestive units in cells. Enzymes within lysosomes break down or “digest” nutrients, including certain complex carbohydrates and fats (like glycosphingolipids). When one of these lysosomal enzymes (such as hexosaminidase A) is missing or ineffective, glycosphingolipids start to build up in the lysosome. If there is too much accumulation of these materials in the lysosome, the cells in the nervous system degenerate and die, triggering an inflammatory response that amplifies damage in surrounding tissue.

Cystic fibrosis (CF) is a genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine.

https://www.thehindu.com/sci-tech/science/scientists-incentives-study-rare-diseases-breakthrough-prizes-explained/article67671810.ece

8.

https://www.thehindu.com/sci-tech/science/rna-obelisk-next-generation-sequencing/article67891037.ece

Virus

Viroid

The genetic material is both DNA or RNA. DNA is double-stranded while RNA can be both single-stranded or double-stranded.

Their genetic material is composed of single stranded low molecular weight RNA.

A protein coat or capsid is present.

The protein coat or capsid is absent.

It manufactures proteins and enters the host cell.

Viroid RNA does not code for any proteins.

They infect bacteria, plants and animals.

They infect only plants.

The important features of the virus are:

 - The structure of the virus is varied in terms of size, shape, and chemical composition. These obligate intracellular parasites are smaller than prokaryotic cells ranging in size from 0.02 to 0.3μm.

 - A fully assembled infectious virus is termed as a virion.

 - Every virus contains a protein coat or capsid which functions as a shell to protect the viral genome from nucleases. It also helps in its attachment to specific receptors on the host cell during infection.

 - The individual proteins building the capsid are called capsomeres.

 - The nucleic acid along with the capsid forms nucleocapsid.

 - Some viruses have an additional membranous envelope surrounding the nucleocapsid. They are known as enveloped viruses while those in which such an envelope is absent are termed as naked viruses.

A group of viruses with RNA genome carrying reverse transcriptase is known as retroviruses. They make a DNA copy of their genome upon invading a host cell. E.g. Human Immunodeficiency Virus (HIV) causes AIDS or Acquired Immunodeficiency Syndrome in Humans.

Potato Spindle Tuber Viroid infects the tubers of potatoes, leading to its malformation and stunted growth in potato spindle tuber disease.

9.

 

10.

https://iasgoogle.com/n/feb-27-2023-current-affairs 

11.

https://www.thehindu.com/sci-tech/science/ultradian-rhythms-the-cycles-of-life/article67866060.ece

12.

https://www.thehindu.com/news/national/indigenous-gm-mustard-meant-to-make-edible-oil-cheaper-reduce-import-centre-to-supreme-court/article67751742.ece

·    Canola refers to special type of oil seed mustard varieties bred for human consumption. The main characteristic of these varieties is that the oil is rich in unsaturated fatty acids.

·    Rapeseed, also known as rape, oilseed rape, and, in the case of one particular group of cultivars, canola, is a bright-yellow flowering member of the family Brassicaceae, cultivated mainly for its oil-rich seed. It is the third-largest source of vegetable oil and second-largest source of protein meal in the world. Canola is often touted as one of the healthiest oils due to its low level of saturated fat.

Here is the fatty acid breakdown of canola oil (7Trusted Source):

Saturated fat: 7%

Monounsaturated fat: 64%

Polyunsaturated fat: 28%

The polyunsaturated fats in canola oil include 21% linoleic acid — more commonly known as omega-6 fatty acid — and 11% alpha-linolenic acid (ALA), a type of omega-3 fatty acid derived from plant sources.

13.

14.

Water Hyacinths (Eichhornia Crassipes), an ornamental aquatic plant from South America, were introduced to India during British colonial rule.

https://indianexpress.com/article/india/biodiversity-loss-37000-alien-species-introduced-by-human-activities-says-report-8924756/

·   Those plants which stay in the water and known as hydrophytes. Hydrophytes can be of various types they can either be submerged free floating or fixed floating. 

·   In case of free-floating hydrophytes there are modification of the root cap of the plant which helps to maintain the buoyancy of the water. These are known as the root pockets.  The root pockets contain a large amount of air and helps to balance the plant according to the density of the surrounding water.

15.

Theory of use and disuse of organs:

·      The theory of use and disuse of organs was proposed by Lamark.

·      According to him, extensively used organs grow in size and become stronger with each passing generation.

·      Non-use of organs due to environmental changes or alternate development results in their weakening and degeneration.

Examples of ‘use and disuse’ resulting in weakening and degeneration of organs:

·      Loss of limbs in snakes: Early ancestors of snakes used to have limbs. However, they lost their limbs and developed long narrow bodies due to creeping into narrow burrows for avoiding enemies and obtaining prey present in the burrow.

·      Loss of eyesight in cave dwellers: Cave dwellers lived in constant darkness and the use of eyes was completely reduced. Gradually in course of time, they lost their eyesight.

16.

https://www.thehindu.com/opinion/op-ed/what-is-laffer-curve-in-economics/article18201301.ece

17.

https://www.downtoearth.org.in/blog/health/a-new-virus-like-entity-has-just-been-discovered-obelisks-explained-94299

A binary star is a system of two gravitationally bound stars that orbit a common center of mass called a barycenter. Stars in a binary system do not necessarily have the same mass, size or brightness. The larger star of a binary couple is called the primary star, while the smaller one is known as the secondary star or the companion star.

Binary stars are double stars, but not all double stars are binary stars. This is because some double stars comprise two stars close enough in the sky over Earth to appear as a single point of light, but they are actually vastly separated in space and not part of a gravitationally bound binary system–these are called optical doubles.

https://www.esa.int/Science_Exploration/Space_Science/What_is_red_shift#:~:text=''Red%20shift''%20is%20a%20key,moves%20relative%20to%20an%20observer.

The General Theory of Relativity asserts that the redshift and blueshift are entirely due to the Doppler''s Effect, which is caused by the motion of light source: if the source is moving away from the observer the frequency received is lower [redshift], but if the source is moving towards the observer the frequency received is higher [blueshift].

18.

The coiled tube of the small intestine is subdivided into three regions. From proximal (at the stomach) to distal, these are the duodenum, jejunum, and ileum.

The shortest region is the 25.4-cm (10-in) duodenum, which begins at the pyloric sphincter. Just past the pyloric sphincter, it bends posteriorly behind the peritoneum, becoming retroperitoneal, and then makes a C-shaped curve around the head of the pancreas before ascending anteriorly again to return to the peritoneal cavity and join the jejunum. The duodenum can therefore be subdivided into four segments: the superior, descending, horizontal, and ascending duodenum.

The jejunum is about 0.9 meters (3 feet) long (in life) and runs from the duodenum to the ileum. Jejunum means “empty” in Latin and supposedly was so named by the ancient Greeks who noticed it was always empty at death. No clear demarcation exists between the jejunum and the final segment of the small intestine, the ileum.

The ileum is the longest part of the small intestine, measuring about 1.8 meters (6 feet) in length. It is thicker, more vascular, and has more developed mucosal folds than the jejunum. The ileum joins the cecum, the first portion of the large intestine, at the ileocecal sphincter (or valve). The jejunum and ileum are tethered to the posterior abdominal wall by the mesentery. The large intestine frames these three parts of the small intestine.

Parasympathetic nerve fibers from the vagus nerve and sympathetic nerve fibers from the thoracic splanchnic nerve provide extrinsic innervation to the small intestine. The superior mesenteric artery is its main arterial supply. Veins run parallel to the arteries and drain into the superior mesenteric vein. Nutrient-rich blood from the small intestine is then carried to the liver via the hepatic portal vein.

19.

https://www.thehindu.com/sci-tech/science/prototype-fast-breeder-reactor-stage-2-nuclear-programme-thorium/article67912583.ece

20.

https://www.thehindu.com/sci-tech/science/how-climate-change-affected-the-shape-of-elephant-teeth/article67776207.ece

21.

https://www.thehindu.com/sci-tech/science/planting-koala-corridors-to-save-australias-endangered-marsupial/article67565352.ece

22.

Cuttlefish is a molluscan, Pufferfish and Flying fish are chordates. Silverfish is a small, wingless insect in the phylum Arthropoda.

https://www.thehindu.com/sci-tech/energy-and-environment/how-to-stay-safe-from-blue-ringed-octopus/article66373155.ece

23.

https://www.thehindu.com/sci-tech/science/bottleneck-in-human-evolution-explained-using-a-novel-genomic-analysis-technique/article67269354.ece

24.

Human growth hormone, also known as HGH and somatotropin, is a natural hormone your pituitary gland makes and releases that acts on many parts of the body to promote growth in children. Its production increases during exercise, particularly during intense physical activity or resistance training.

When under stress, we produce and release short bursts of cortisol into the bloodstream. The adrenal fatigue theory suggests that prolonged exposure to stress could drain the adrenals leading to a low cortisol state.

Cortisol is a glucocorticoid hormone that adrenal glands produce and release. Glucocorticoids are a type of steroid hormone. They suppress inflammation in all of your bodily tissues and control metabolism in your muscles, fat, liver and bones. Glucocorticoids also affect sleep-wake cycles.

25.

Viruses replicate in the host cell and comprise either RNA or DNA genome enclosed by a protein capsid. The viruses comprise a genome composed of DNA viruses, while the viruses are composed of RNA re RNA viruses.

On the basis of genome type, single-stranded RNA viruses can be classified into positive and negative sense RNA viruses. The positive sense RNA virus is also referred to as sense strand or plus-strand, while on the other hand, negative sense RNA is also referred to as antisense or minus strand.

The key difference between the negative and positive sense RNA virus is that the negative sense RNA virus comprises viral RNA, which is complementary to the viral mRNA, while the positive sense RNA virus comprises viral mRNA, which can be translated into proteins directly.

Positive Sense RNA Virus

·      It is a type of virus containing a positive sense single-stranded RNA

·      It is capable of operating as mRNA and can be directly translated into the protein in the host

·      In the hosts, once the viral proteins are produced, it recruits RNA for the production of viral replication complexes

·      The replication of the virus advances through the double-stranded intermediates of RNA

·      Some examples are – echovirus, poliovirus, SARS Co V2

Negative Sense RNA Virus

·      It refers to the type of single-stranded RNA virus with genetic content being the antisense strand of the viral mRNA

·      It comprises a genome that is complementary to the viral mRNA

·      Consequently, the genome of the virus cannot translate readily into the viral proteins. As a result, the virion must be packed with RNA-dependant RNA polymerase enzyme, which helps in the transcription of the viral RNA

·      Some examples are – the Ebola virus, influenza virus

 

 



POSTED ON 05-06-2024 BY ADMIN
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