CSIR NET Life Sciences Mock Test - 3 - CSIR NET Life Science MCQ

Given


∴ The value of ? is 251

Given:

Average of three numbers = 10

Let the third number be x.

Then the second number =3x

And the first number

∴ Third number = 3
Second number
And, first number

∴ The largest number is 18.

Given:
Selling Price 1 = Rs. 2300

Profit percentage = 25%

Selling Price 2 = Rs. 1656

= Rs. 1840

Loss = Cost Price - Selling Price

Given:
Cost of the first type of sugar = Rs. 85 / kg
Cost of the second type of sugar = Rs. 105 / kg
The selling price of mixture = Rs. 108 / kg
Profit percentage = 20 %
Formula used:

The ratio between two variety of sugar be x : y

∴ The ratio in which two varieties of sugar should be mixed is 3 : 1

Given:

Average weight of number of students in a group 

12 students weight  joined the group, the weight fall the students in the group decreases by 

Formula Used:

Average = Sum of observation/Number of observation

Calculation:

Let the number of students initially = x

Sum = Average × Number of students

∴ There is 20 students initially

Ocean ecosystem is the largest ecosystem in the world.

• An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. An ecosystem can be as small as a pond or as large as a rainforest.
• Ecosystems are analyzed and studied as unique entities. However, all ecosystems feature an energy input such as the sun's heat which keeps life in the system going. The oceans are the world's largest ecosystems and are considered to cover the shore as far as tidal waters come in.

The outermost covering of the plant cell is constituted by Cellulose.

• The epidermis is the protective outer layer of clonally related cells covering all plant organs.
• It is made up of cellulose, hemicelluloses, and pectin.

Speciation is evolutionary process by which new biological species arise. 

Speciation is the evolutionary process by which new biological species arise. There are four modes in speciation namely, a) Allopatric, Parapatric, Peripatric and Sympatric. Peripatric means formation of new species through evolution. 

PCR can be used to amplify the sequences flanking on either sides of a known DNA segment. The process uses primers complementary to the 5’ ends of the interested segment. This is a reverse process of the general PCR mechanism thus is known as the inverse PCR.

The Golgi apparatus, also known as the Golgi complex, is a factory where proteins from the ER are further processed and sorted before being transported to their final destinations: secretion, lysosomes, or the plasma membrane.

Four basic components used in culture media for plant tissue cultivation are Essential elements and mineral ions, amino acids, sugar, and a gelling agent.

Serum albumin is not the basic component of culture media used for plant cultivation. Serum albumin: Essential elements and mineral ions, amino acids, sugar, and a gelling agent are the four basic components used in culture media for plant tissue cultivation. TMV is a virus is cannot be grown in the culture medium.

The amount of water and soil held at which a plant goes flaccid beyond recovery is called the permanent wilting percentage.

A permanent wilting point or wilting point is defined as the minimum amount of water in the soil that the plant requires not to wilt. If the soil water content decreases to this or any lower point a plant wilts and can no longer recover its turgidity when placed in a saturated atmosphere for 12 hours. 

Xerophytes are subjected to high temperatures and water scarcity. Desert plants have modified their leaves into spines and their epidermis is covered with a thick waxy coating to prevent water loss through transpiration or evaporation.

• Stomata are open and close as a result of turgor changes in guard cells.
• When guard cells are turgid, the stomatal pore is open, whereas when they are flaccid, the stomatal aperture closes.
• Swelling of the guard cells due to turgor pressure does not create a pore in between them.
  • Thus, statement (B) is incorrect.

• To reduce transpiration, some xerophytic plants have a waxy coating on the leaf surface and sunken stomata on the lower surface of the leaf.
  • ​Thus, statement (A) is correct.
• Each stoma is composed of two bean-shaped cells called guard cells.
• The outer walls of the guard cells are thin, but the inner walls are thick.
  • ​Thus, statement (C) is correct.
• Succulents keep their stomata closed during the day to prevent transpiration and conserve water.
• Desert plants absorb CO₂ at night and store it as an intermediate for use in photosynthesis during the day (when the stomata are closed).
  • Thus, statement (D) is correct.

Tall plants are dominant over dwarf plants. Being true-breeding parents, the offspring will all be heterozygous. Moreover, hence phenotypically, all of them will be tall.

Specific extracellular signaling molecules are defined for each cell. Extracellular signaling involves the synthesis and release of signal molecules, which bind to the specific receptor and initiate the signal transduction pathway.

The light harvesting complex (LHC) is made up of very few molecule of hundreds of pigment molecules bound to proteins.

The light-harvesting complex (or antenna complex) is an arrangement of various proteins and hundreds of chlorophyll molecules embedded in the thylakoid membrane of plants, which transfer light energy to one chlorophyll ‘a’ molecule at the reaction centre of a photosystem. It is used by plants and photosynthetic bacteria to collect more of the incoming light than would be captured by the photosynthetic reaction centre alone. The main function of the light-harvesting complexes is to gather light energy and to transfer this energy to the reaction centres for the photo-induced redox processes.  

DNA sequences that code for protein are known as Exons. 

The gene encoding for mRNA has two types of sequences called the introns and the exons. 

The introns are the intervening sequences and they do not code for a functional polypeptide. 

The exons are the functional sequences because they contain sequences that are translated into the final protein. 

An orchid growing on epiphyte is an example of commensalism. Epiphytes grow on trees for air and sunlight while the tree is not harmed due to its presence. Another epiphyte growing on trees is a fern.

Cell was discovered by Robert Hooke IN 1665.

• Robert Hooke in 1665 observed slices of cork under a simple magnifying device. 
• He noticed partitioned boxes or compartments in the cork slice.
• These boxes appeared like a honeycomb. He also noticed that one box was separated from the other by a wall or partition.
• Hooke coined the term ‘cell’ for each box. Hooke observed as boxes or cells in the cork were actually dead cells. 
• Cells of living organisms could be observed only after the discovery of improved microscopes.

The silkworm, Bombyx mori is reared on mulberry leaves on a mass scale to get raw silk from the cocoons of the caterpillars (larvae) of the moth. The eggs of the silkworm moth hatch out within a few days into creamy white rapidly moving caterpillars. The latter feed voraciously on the fresh mulberry leaves and soon undergo a fast growth and are popularly referred to as silkworms.

The silk glands of caterpillar secrete a sticky secretion which is spun around the worms to form a hard covering of silk fibres, known as the cocoon. The silk worm with cocoon is known as pupa. After one or two days of cocoon formation, the pupae are killed either by drying them in the sun or by boiling them. The raw silk fibres forming the cocoon are then reeled out into silk threads.

Alkaligenes eutrophus are gram-negative, aerobic, and rod-shaped bacteria and is classified as hydrogen-producing bacteria.

Diabetes Mellitus type II is caused due to insulin resistance that results from the elevated levels of glucose in the blood and subsequent increase in insulin (overstimulation). As a result of this, the target cells, those having insulin receptors stop responding to the presence of the hormone.

Volvox - Colonial, non-flagellated is correctly matched.

Volvox is a colonial alga that consists of several flagella. These flagella allow them to attach to surfaces and move about in the water. These form spherical shaped colonies.

Okazaki fragments are short, newly synthesised DNA fragments that are formed on the lagging template strand during DNA replication. They are complementary to the lagging template strand, together forming short, double-stranded DNA sections. DNA is synthesized from 5' to 3' direction.

Transgenic animals are used to study what is the function of foreign genes. These changes are studied by observing or studying the changes in the organism after the introduction of a foreign gene. These changes can be useful or harmful.

This is correct cladogram on basis of data given in table.

Xenogamy is defined as the transfer of pollen grains from the anther of one plant to the stigma of a different plant. This type of pollination helps in breeding genetically different types of pollens.

Xenogamy is the transfer of pollen grains from the anther to the stigma of a different plant. This is the only type of cross pollination which during pollination brings genetically different types of pollen grains to the stigma. 

The phase in which cell fail to divide further (do not enter S - phase after G₁ phase) and undergo differentiation is known as G₀ phase or quiescent stage. It occurs due to non- availability of mitogen and energy rich compounds. The cells remains metabolically active, grow in size and differentiate for particular function after attaining a particular shape.

50% is the percentage of photosynthetically active radiation(PAR), in the incident solar radiation.

Around 50% of the total radiation from sunlight falls under photosynthetically active radiation and supports the process of photosynthesis. It constitutes the light of 400-700 nm wavelength which is absorbed by chlorophyll pigment. Out of which only 2 - 10% are captured by plants. 

The correct match is a-s, b-q, c-p, d-r.

Down's syndrome is a genetic disorder caused by the presence of all or part of the third copy of chromosome 21.

Cri-du-chat Syndrome is a genetic condition that is caused by the deletion of genetic material on the small arm (the p arm) of chromosome 5. Infants with this condition often have a high-pitched cry that sounds like that of a cat.

Klinefelter syndrome is a sex chromosome disorder in boys and men that results from the presence of an extra X chromosome in cells.

Turner's syndrome is a  chromosomal disorder in which a female is born with only one X chromosome.