CSIR NET Life Sciences Mock Test - 2 - CSIR NET Life Science MCQ

We know that, Mean

Given,

One-third of 12 oranges got rotten

Total rotten oranges

4 oranges can be selected from 12 oranges in ¹²C₄ ways, and four rotten oranges can be selected as a set in ⁴C₄ways

Probability

The probability that all oranges are rotten

Let the number be ABCDE.
Digit at tens place = 9
So, D = 9
Digit at ten thousand place is 9 − 3 = 6
So, A = 6
Digit at handreds place = 6 ÷ 2 = 3
So, C = 3
The digit at the thousand place is double the digit at the ones place.
So, B = 2E
The number will be 6B39E.
From the options number will be 68394.

Given,

Total cost Rs. 60000

Amount spent on labour

Amount spent on steel

Difference

Rs. 6000
Let the amount spent on labour exceeds the amount spent on steel by x% of the total cost.

Then,

The amount spent on labour exceeds the amount spent on steel by of the total cost.

Turgor pressure is the pressure that develops in a cell due to osmotic diffusion of water inside it and is responsible for pushing the membrane against cell wall. Stomata open under conditions of increased turgor pressure of guard cell and stomata get closed under conditions of decreased turgor pressure of guard cells. When turgid, they swell and bend outward. As a result, the stomatal aperture opens. When they are flaccid, the tension from the wall is released and stomatal aperture closes.

Fats provides the maximum energy on breakdown.

Fats:

• Fats are the slowest source of energy but the most energy-efficient form of food.
• Fat molecules consist of primarily carbon and hydrogen atoms and some of them essential for diet.
• Fats provide a source of concentrated energy as well as the fat-soluble vitamins A, D, E, and K.
• It is needed for hormone metabolism, healthy skin and hair, tissue repair, protecting the internal organs and to prevent excessive loss of body heat.

The interaction energy between atom  A and B is  ~ 400 kJ mol^-1.  The type of interaction between them is covalent.

Glutamine synthase catalyzes the reaction of glutamate and NH₄⁺ to yield glutamine.

Glutamine synthetase (GS) (EC 6.3.1.2) is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine:

Traits or characters that the breeders have tried to incorporate into crop plants are increased crop yield, improved quality, increased tolerance to environmental stresses (salinity, extreme temperatures, drought), resistance to pathogens (viruses, fungi and bacteria) and increased tolerance to insect pests.

Glial cells (glia = glue)are also called neuroglia, these cells support, nourish, and protect the neurons while ganglia are the cluster of cell bodies which found in the PNS.

Organogenesis or morphogenesis is the regeneration of an organ from the undifferentiated mass of cells, which is best known as a callus. Skoog and Miller (1957) showed that an appropriate concentration of phytohormone auxin and cytokinin stimulates the morphogenesis or organogenesis.

A higher concentration of auxin with cytokinin promotes cell division in shoots, while a higher concentration of cytokinin with auxin stimulates cell division in roots.

'They have a direct role in photosynthesis, respiration and reproduction' is not true about secondary metabolites.

Metabolites are substances involved in metabolic pathways. Photosynthesis, respiration and reproduction are metabolic pathways and metabolites having a direct role in them are called primary metabolites.

Metabolites which do not have a direct role in the growth and development of an organism are called secondary metabolites. They include chemical compounds of diverse nature, such as pigments, toxins, drugs, lectins, gums and resins. They are not involved directly in the metabolic pathways such as photosynthesis, respiration and reproduction. Their distribution is restricted to a limited taxonomic group.

Endocrine messengers are also called hormones and operate by the endocrine stimulation. In this pathway of cell signaling the messenger molecules travel through the bloodstream before reaching cell surface receptors that are distant.

Hormones are your body's chemical messengers. They travel in your bloodstream to tissues or organs. They work slowly, over time, and affect many different processes, including: Growth and development. Metabolism - how your body gets energy from the foods you eat.

During division of a plant cell, the organelle that split into two is Nucleas. 

Cell division is a process by which the cell duplicates itself either for growth and repair or for the reproduction of the organism.

Mitosis is the process in which a eukaryotic cell nucleus splits in two, followed by the division of the parent cell into two daughter cells. A new cell wall is constructed between the daughter nuclei after the division.

All the proteins exhibit functions after being transported to certain compartments of the cell is an incorrect statement about the terminologies related to protein sorting. 

Silent mutatioN has a negligible effect on the function of a gene. 

Mutations can involve the replacement of one base pair with another (substitution mutation) or the addition or deletion of one or more base pairs (insertion or deletion mutations). 

Silent mutations occur when the change of a single DNA nucleotide within a protein-coding portion of a gene does not affect the sequence of amino acids that make up the gene's protein. 

Mutualism is a positively directed interspecific relationship. It is a biological interaction between organisms of different species in which each individual receives the benefit.

Microsatellite DNA is less than 150bp and found in a dispersed condition all over the chromosome.

Microsatellite, as related to genomics, refers to a short segment of DNA, usually one to six or more base pairs in length, that is repeated multiple times in succession at a particular genomic location. These DNA sequences are typically non-coding. The number of repeated segments within a microsatellite sequence often varies among people, which makes them useful as polymorphic markers for studying inheritance patterns in families or for creating a DNA fingerprint from crime scene samples.

The ventral surface of the body of the earthworm can be distinguished by the dorsal surface by the presence of genital openings or pores. The genital openings in the earthworm help in cross-fertilisation and pores help in removal of the wastes generated in the body.

Bundle of His are the muscle fibres found only in the ventricle.

Bundle of His was discovered in 1893 by Swiss-born cardiologist and anatomist Wilhelm His Jr. The bundle of His is a collection of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from the AV node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the bundle branches. The fascicular branches then lead to the Purkinje fibres, which provide electrical conduction to the ventricles, causing the cardiac muscle of the ventricles to contract at a paced interval.

According to the RNA world hypothesis, in primitive life, RNA catalysts called ribozymes could have played key roles, eg. they could catalyze chemical reactions to copy themselves and such replicating RNA could pass genetic material from generation to generation, thereby fulfilling the most basic criteria for life. Thus, these two roles i.e., their catalytic nature and ability to act as a hereditary material justify the evidence for lack of DNA and enzymes in primitive cells.

Assertion (A): It is crucial to sustaining the Himalayan ecosystem.

• The Himalayan ecosystem is considered very fragile and diverse but vital to the ecological security of the Indian landmass, through providing forest cover, feeding perennial rivers that are the source of drinking water, irrigation, and hydropower, conserving biodiversity, providing a rich base for high value. 
• Tropical moist forests of India border the Himalayas to the south, which give way to low elevation subtropical grasslands of India, Bhutan, and Nepal.
• To the west of the Himalayan region, dry thorn scrub forests and arid shrublands spread extensively throughout eastern Pakistan and western India.
• The most characteristic features of the Himalayas are their great height, complex geologic structure, snowcapped peaks, large valley glaciers, deep river gorges, and rich vegetation.
• The Himalayas play a very significant role in influencing the climate of India.
• By virtue of their high altitude, length, and direction, they effectively intercept the summer monsoons coming from the Bay of Bengal and the Arabian Sea and cause precipitation in the form of rain or snow.

Therefore, Assertion (A) is the correct answer.

Reason (R): The Himalayan ecosystem is home to a number of indigenous tribes.

• A national mission to sustain the Himalayan ecosystem, continuously assess its health status, and formulate policies for sustainable development in the mountainous states, was approved by the government in 2014.
• The mission document on the National Mission for Sustaining the Himalayan Ecosystem (NMSHE), launched under the National Action Plan on Climate Change (NAPCC) with an outlay of Rs.550 crore during the 12th Plan, was approved by the Union Cabinet.
• Its primary objective is to develop a sustainable national capacity in a time-bound manner to continuously assess the health status of the Himalayan ecosystem and enable policy formulation to assist Himalayan states to implement sustainable development programs, an official release said.
• The NMSHE would focus on biodiversity conservation and protection of wildlife, traditional knowledge of societies and their livelihoods, the release said, adding marginalized communities of the Himalayan region would be the major beneficiaries of the mission.
• The Champa, Ladakhi, Balti, and Dard peoples live to the north of the Great Himalaya Range in the Kashmir Himalayas. The Dard speak Indo-European languages, while the others are Tibeto-Burman speakers. The Champa traditionally lead a nomadic pastoral life in the upper Indus valley.

Therefore, Reason (R) is the correct statement.

It is crucial to conserve the Himalayan ecosystem not only because of indigenous tribes but due to Natural geological wealth, forestry, wildlife, flora, fauna and biodiversity, snow, ice and water bodies, traditional knowledge, and mountain agriculture which characterize the region.

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).​

Tidal volume is defined as the volume of air that is breathed in and out during effortless respiration.

Tidal volume: It measures the amount of air that is inhaled and exhaled during a normal breath. On an average adult person, this volume is around one-half liter.

Organs on excretion in Tape worm are Flame cells.

Flatworms have an excretory system that consists of two tubules. The cells in the tubules are called flame cells; they have a cluster of cilia that propel waste matter down the tubules and out of the body.

Neutrophils and macrophages are the phagocytic cells that ingest potentially dangerous microbes; the microbes are then inactivated by the low pH of lysosomes present in these cells followed by their enzymatic digestion.

Phagocytes (neutrophils and monocytes) are immune cells that play a critical role in both the early and late stages of immune responses. Their main role is to circulate and migrate through tissues to ingest and destroy both microbes and cellular debris.

Gene therapy is a technique used to cure hereditary diseases. It involves the introduction of a normal gene into the early embryonic stages to compensate for abnormal or missing genes. The normal gene is introduced into the organism using retrovirus or plasmid.

Natural selection is a process in which organisms which are better adapted to the environment survive and produce more offspring.

Types of natural selection are as follows:

• Stabilising selection
• Directional selection
• Disruptive selection

Stabilisation can occur due to natural selection during which more individuals acquire mean character value and in the graph the peak gets higher for a particular trait.

Directional change can be seen when more individuals acquire values other than the mean character value and the peak shifts in one direction due to this.

Disruptive change can be seen when more individuals acquire peripheral character value at both ends of the distribution curve and due to which two peaks are formed.

Restriction enzymes also known as restriction endonuclease enzymes cleave only at the specific site.

To find out the correct combinations of restriction enzymes, we have to find a particular enzyme that can cleave the site at a complementary site. Hence, C. SalI (G/TCGAC) and EcoRV (GAT/ATC) is the correct combination.

The level of the organization after macromolecule is a cell. Many macromolecules of different types come together and give rise to a living entity called cell. A cell is the smallest and microscopic basic structural and functional unit of life of any organism.

Photochemical oxidant pollution is also known as photochemical smog. Three major photochemical oxidant pollutants are Ozone (O₃ ), NO₂ and PAN (peroxyacetyl nitrate). photochemical smog is produced as a result of photochemical reaction among nitrogen oxides (NOx).