CSIR NET Life Sciences Mock Test - 1 - CSIR NET Life Science MCQ

Given

Given:

Arithmetic mean of 9 terms = 49

Mean of first 7 terms = 37

Formula Used:
Mean

Let sum of last 2 terms be x.
Sum of all 9 terms

Sum of first 7 terms

Sum of all 9 terms = Sum of first 7 terms + Sum of last 2 terms
441 = 259 + x
⇒ x = 182
Mean of last 2 terms  = 182/2 = 91
∴ The mean of last 2 terms is 91.

N = 64 × 3125 × 343 × 343 × 10000000 van be written as 26 × 55 × 73 × 73 × 107 = 26 × 55 × 76 × 107

The prime factorization of 26 × 55 × 76 × 107 is 213 × 512 × 76.

The total number of factors of N = 14 × 13 × 7

We need to find the total number of even factors. For this, let us find the total number of odd factors and then subtract this from the total number of factors. Any odd factor will have to be a combination of powers of only 5 and 7.

Total number of odd factors of 213 × 512 × 76 = (12 + 1) × (6 + 1) = 13 × 7

Total number of factors (T) = (13 + 1) × (12 + 1) × (6 + 1) = 14 × 13 × 7 = 1274

Total number of even factors (E) = 14 × 13 × 7 - 13 × 7

Number of even factors (E) = 13 × 13 × 7 = 1183

Desired Result = T + E = 1274 + 1183 = 2457

Similarly,

Given:

Cost price = Rs. 262.40

Selling price = Cost price

Let the marked price of a shirt be Rs. a

Selling price after discount Rs.

Accordingly,

∴ The marked price of a shirt is Rs. 364.80

Blocks ATP synthesis without inhibiting electron transport by dissipating the proton gradient is the effect of  2, 4 - dinitrophenol on mitochondria.

Atractyloside blocks electron-transport and ATP synthesis by inhibiting the exchange of ATP and ADP across the inner mitochondrial membrane.

Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnormal cell division.

The growth medium of an animal cell contains serum (5-20%), nitrogen sources, inorganic salts, carbon sources, growth factors, buffer in water, and vitamins.

The rate of water reabsorption from the proximal tubule is determined primarily by the rate of dissolved particle (solute) reabsorption from the proximal tubule.

Therefore, a primary determinant of water reabsorption by the renal tubule is the tubule's permeability. One might expect a lipid bilayer, which constitutes the outer membrane of epithelial cells lining the renal tubule, to be fairly hydrophobic, and not allow efficient water entry/exit.

The intermediates in the citric acid cycle provide precursors for many biosynthetic pathways for example Amino acid synthesis following transamination of α-ketoglutarate. Synthesis of fatty acids from citrate.

DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. The DNA replication process uses DNA polymerase III to catalyze the joining of deoxyribonucleoside 5′-triphosphates (dNTPs) at a growing chain of DNA. DNA is read by DNA polymerase in the 3′ to 5′ direction, meaning the new strand is synthesized in the 5' to 3' direction.

In the DNA replication process, one new strand (leading strand) is made as a continuous piece. The other (lagging strand) is made in small pieces. At the leading strand, DNA polymerase III synthesizes the new strand in the 5′ to 3′ direction. The lagging strand is elongated in an antiparallel direction, by the addition of short RNA primers (Okazaki fragment) which are filled with other joining fragments. As explained above during DNA replication RNA Primer is removed by DNA polymerase I.

• DNA replication is semiconservative, meaning that each strand in the DNA double helix acts as a template for the synthesis of a new, complementary strand.
• DNA Polymerase I possess a 3´→5´ exonuclease activity or "proofreading" function, which lowers the error rate during DNA replication.

Other Important Enzymes in DNA Replication

Amphibians are small vertebrates that need water, or a moist environment, to survive. The species in this group include frogs, toads, salamanders, and newts. 

They are sometimes called "indicators." They are called indicators because they are susceptible to environmental changes.

• They breathe through their skin and breathe toxic and non-toxic components with it too.
• Nearly 33% of the amphibian species of the world are categorized as threatened on the Red List.
• Amphibians are dependent for their survival on a plentiful supply of freshwater that is free of chemical contaminants and harmful microbes.

Extra Info-

Reptiles

• These are cold-blooded vertebrates. (Vertebrates have backbones.)
• They have dry skin covered with scales or bony plates and usually lay soft-shelled eggs. It usually refers to lizards, snakes, turtles, alligators, and crocodiles.

Mammals

• Mammals include humans and all other animals that are warm-blooded vertebrates (vertebrates have backbones) with hair.
• They feed their young with milk and have a more well-developed brain than other types of animals.

Insects

• All insects belong to the phylum Arthropoda. 
• Insects live in nearly every habitat, and it’s estimated that there are currently 10 quintillion insects on the globe.
• So far scientists who study bugs, called entomologists, have named one million insect species but studies estimate that four million are still uncategorized.

So, it is clear from the above points that Amphibian is most sensitive to environmental change.

Human IgM is largely restricted to the circulation.

IgM is the largest antibody, and it is the first antibody to appear in the response to initial exposure to an antigen. IgM is constructed of five or six units (i.e. mostly as pentamers but also hexamers occur) which are each comprised of two heavy-chains (mu-chains) and two light chains, bound together by disulfide bonds and a so-called J-chain. Due to the larger size, IgM is unable to cross the placenta, though it's the first antibody produced in the human fetus while IgG is smaller in size and can cross the placenta and provides mother's immunity to developing the embryo.

Exponential growth is shown during Log Phase. 

Bacterial growth is divided into four phases, namely lag phase, log phase, stationary phase and death phase. In lag phase, there is very little or no bacterial growth. In this phase, bacteria are adjusting to environment and synthesizing biochemicals and nutrients. In log phase, the number of bacterial cells doubles at an exponential rate. This phase shows maximum or exponential growth. In stationary phase, the rate of cell death is equal to the rate of cell division. In death phase, there is decrease in the bacterial population due to lack of nutrients and high toxin concentration. 

The lytic enzyme present in semen is Hyaluronidase.

As sperm travel through the conducting tubes, they mix with secretions from three accessory glands. Semen consists of about 200 million sperm cells suspended in the secretions of these glands. The paired seminal vesicles secrete a fluid rich in fructose and prostaglandins into the vasa deferentia. 

The fructose provides energy for the sperm after they are ejaculated. Prostaglandins stimulate contractions of the uterus, which help move sperm up the female reproductive tract. The single prostate gland secretes an alkaline fluid containing calcium, citric acid and enzymes like the lytic enzyme hyaluronidase. The prostatic fluid may be important in neutralizing the acidic environment of the vagina and in increasing sperm cell motility. During sexual arousal, the paired bulbourethral glands, located on each side of the urethra, release a mucous secretion.  

Prostaglandin receptors are cell surface receptors. The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids which includes prostaglandins, prostacyclin, thromboxanes, and leukotrienes; having diverse hormone-like effects in animals. They are derived enzymatically from fatty acid arachidonic acid.

When a species is completely extinct that it is no longer found anywhere on the earth, it is known as biological extinction. While background extinction refers to spontaneous low level of extinction of species that has been occurring continuously during the course of life history on the earth. Ecological extinction is when a few members of species are left that can no longer play their ecological role in biological communities. And local extinction hen a specie sis no longer found in an area where it was once localized.

Interphase chromosomes condense into mitotic chromosomes in M phase of cell cycle. This requires coiling of chromosomes which is facilitated by condensins. Condensins are large protein complexes which make large right-handed loops in the DNA using energy of ATP hydrolysis. While coiling does not require phosphorylation or dephosphorylation of DNA directly, thus kinases and phosphatases are not involved. And hydrolases is a class of enzyme that uses water to cleave chemical bonds, thus does not condense interphase chromosomes.

Mitochondria are rod-shaped organelles that can be considered the powerhouses of the cell.

Mitochondria are tubular-shaped organelles that are found in the cytoplasm of every eukaryotic cell.

Cellular totipotency is the technique of regeneration or development of complete plant from explants or cell or tissue of the plant. This technique was established by F. C. Steward and developed the new carrot plant from carrot root culture.

Incomplete dominance is seen in cross-pollination experiments between red and white snapdragon plants. The allele that produces the red color (R) is not completely expressed over the recessive allele that produces the white color (r). The resulting offspring are pink.

If the physical change accompanying the reaction is heat output, the biosensors are referred to as calorimetric biosensors. In potentiometric biosensors, changes in the distribution of charges cause an electrical potential to be produced. Optical biosensors are those in which light output during the reaction is the physical change. In amperometric biosensors, the movement of electrons produced in a redox reaction is the physical reaction.

Hence, the correct option is (B).

Coiling of garden pea around any structure is an example of thigmotropism.

The growth movement in response to touch, or contact of a foreign body, in plants is called thigmotropism or thigmotropic movement. The stems and tendrils of the climbers are positively thigmotropic in their response. The coiling of garden pea tendrils around any support is an example of thigmotropism. Thigmonastic (haptonastic) movements are induced by some external stimuli. For example tentacles of Drosera leaf curve and the lamina lobes of Dionaea fold on coming in contact with an insect.

Paracrine signaling, Autocrine signaling and Endocrine signaling are the basic categories of chemical signaling found in multicellular organisms.

There are four basic categories of chemical signaling found in multicellular organisms: paracrine signaling, autocrine signaling, endocrine signaling, and signaling by direct contact.

The correct match is A-(iv);B-(ii);C-(iii);D-(i).

Primary metabolites are the substances like amino acids on proteins structure that are used in the day to day function of the cell. Other than that plant and fungi have different molecules like alkaloid and different pigments and these are considered secondary metabolites.

Pigments-Carotenoids, Anthocyanins,

Alkaloids- Morphine, Codeine, etc.

Terpenoides-Monoterpenes, Diterpenes etc.

Essential oils-Lemon grass oil, etc.

Toxins-Abrin, Ricin

Lectins-Concanavalin A

Drugs-Vinblastin, curcumin, etc.

Polymer-Rubber, gums, cellulose

In the first step of gene therapy, lymphocytes from the blood of the patient are grown in a culture outside of the body. Lymphocytes are the white blood cells responsible for maintaining the immunity of an individual. The defective gene is identified and replaced with the normal functional gene.

Dopamine is prolactin inhibiting hormone (PIH), which inhibit the release of prolactin from the anterior pituitary. It also functions as a neurotransmitter.

Generally, the biological spectra are worked out and compared with Raunkiaer’s normal spectrum. The percentage of phanerophytes in different floras ranges from zero to over 74% in the tropical rain forest. The higher percentage of phanerophytes is indicative of phanerophytic climate. The higher percentage of therophytes (above 40%) indicates therophytic climate (desert). High percentage of chamaephytes (above 50%) indicates an extremely cold climate.

High percentage of hemicryptophytes in temperate forest vegetation indicates the conditions favourable for the development of extensive grassland. Geophytes (cryptophytes) are abundant in the regions of Mediterranean climate and in the broad leaf deciduous forest. The biological spectra of different areas differ from one another and there is no base line for comparison.

The primary goal of Gene therapy is to treat inherited or genetic basics of the diseases. The basic principle of gene therapy involves the manipulation of genes and replacing the defective or non-functional gene which is primarily responsible for the cause of the disease, with the desired gene to cure the diseases. Functional gene which replaces non- functional one should make desired amount of protein by showing proper expression of new gene.

The fan-throated lizard is a species of agamid lizard which is found in Southern India. One of the specialties of male fan-throated lizard is dewlap which is used to woo a would-be partner by puffing it into a fan.