VITEEE PCBE Mock Test - 1 - JEE MCQ

In water hyacinth, the flowers emerge over the surface of water and are pollinated by birds, insects or wind.

Action potential is a change in electrical potential that occurs across a plasma membrane during the passage of a nerve impulse. During this period, there is a localized and translent switch in electric potential across the membrane from -70 mV to +45 mV. It is due to the fact that the sodium channels open and the potassium channels remain closed. As a result, sodium channels permit the influx of Na⁺ by diffusion from extracellular fluid to intracellular fluid.

Topic in NCERT: Generation and Conduction of Nerve Impulse

Line in NCERT: "The rise in the stimulus-induced permeability to Na* is extremely short-lived. It is quickly followed by a rise in permeability to K*. Within a fraction of a second, K+ diffuses outside the membrane and restores the resting potential of the membrane at the site of excitation and the fibre becomes once more responsive to further stimulation."

A nutrient depletion zone can develop when there is rapid soil solution uptake, low nutrient concentration, low diffusion rate, or low soil moisture. These conditions are very common; therefore, most plants rely on fungi to facilitate the uptake of minerals from the soil. Mycorrhizae, known as root fungi, form symbiotic associations with plant roots. In these associations, the fungi are actually integrated into the physical structure of the root. The fungi colonize the living root tissue during active plant growth.

Topic in NCERT: Mutualism

Line in NCERT: "Similarly, the mycorrhizae are associations between fungi and the roots of higher plants."

According to Darwin's theory of evolution, nature selects the fittest. Fitness is based on characteristics which are inherited. Therefore, there must be a genetic basis for getting selected and to evolve. Some organisms are better adapted to survive in an otherwise hostile environment. Adaptative ability is inherited. Fitness is the end result of the ability to adapt and get selected by nature. Therefore, branching descent (inheritance) and natural selection are the two key concepts of Darwin's theory of evolution.

Decomposition is the process that involves the breakdown of complex organic matter or biomass from the body of dead plants and animals with the help of decomposers into inorganic raw materials such as carbon dioxide, water, and other nutrients.

The various processes involved in decomposition are as follows:
➢ Fragmentation 

• It is the first step in the process of decomposition.
• It involves the breakdown of detritus into smaller pieces by the action of detritivores such as earthworms.

➢ Leaching

• It is a process where the water soluble nutrients go down into the soil layers and get locked as unavailable salts.

➢ Catabolism

• It is a process in which bacteria and fungi degrade detritus through various enzymes into smaller pieces.

➢ Humification

• The next step is humification which leads to the formation of a dark-coloured colloidal substance called humus, which acts as reservoir of nutrients for plants.

➢ Mineralization

• The humus is further degraded by the action of microbes, which finally leads to the release of inorganic nutrients into the soil.
• This process of releasing inorganic nutrients from the humus is known as mineralization.

Plasmodesmata are the channels that connect plant cell walls and enable molecular exchange between the cells. They are analogous to gap junctions in animal cells. There are two forms of plasmodesmata; primary ones are formed during cell division and secondary ones can form between mature cells. Plasmodesmata provide a simple route for the movement of ions and macromolecules. Larger molecules use actin filaments to traverse the cells. The middle lamella is a pectin layer which cements the cell walls of two adjoining cells together.

The correct sequences of process of recombinant DNA technology are Isolation of DNA, fragmentation of DNA by restriction endonuclease, isolation of desired DNA fragment, ligation of DNA fragment into vector, transferring of into host and culturing in host cell to get desired product.

Solution: Carbon dioxide is transported in the blood in three main ways: dissolved in plasma, as bicarbonate ions in plasma, and bound to hemoglobin as carbaminohaemoglobin. It does not attach to oxygen molecules for transport. This highlights the body's efficient mechanisms for transporting gases where they need to go.

Rate of breathing is mainly controlled by CO₂ level in the blood.
Excess CO₂ decrease the pH of the blood and it mainly stimulate the respiratory centre of the brain (i.e., Medulla oblongata) and increase the inspiratory and expiratory signals to the respiratory muscles.

From Stokes' law:
F_d​ = 6πηRv 
= [ML^-1T^-1]

According to Ohm's law:
V = IR
R =

Dimensional formula of the potential difference is = [M¹L²T^-3A^-1]
Dimensional formula of = = [M¹L³T^-3A^-2]
Or we can say that dimensional formula of conductivity σ = is [M^-1L^-3T³A²]

Using impulse-momentum theorem, we can conclude that, impulse is the change in momentum. Therefore,
[Momentum] = [Impulse]
Hence, the dimensions of both these quantities will be same, i.e., [MLT⁻¹]
Relative density is the ratio of two densities. Hence, relative density is dimensionless.
Also, strain is the ratio of two quantities having same dimensions.
i.e., Strain = Change in length / Original length
Also, power is defined as amount of work done per unit time.
⇒ [ Power ]≠≠[ Work ]

Similarly, 

⇒ 3r + 24 = 4r + 16 ⇒ r = 8Ω

i = = = 2
Thus, (1) is correct.

Peptisation is the process of converting a precipitate into a colloidal solution by shaking it with a dispersion medium and a small amount of electrolyte. The red-coloured colloidal solution obtained when dilute HCl is added to ferric hydroxide is an example of peptisation.

Basic strength: I > III > II > IV

The assertion is true: glycerol is purified by distillation under reduced pressure. However, the reason that glycerol is a trihydric alcohol is not the explanation for why it is purified in this way. The reason for reduced pressure distillation is to avoid decomposition into acrolein, a foul-smelling compound.

Formation constant, β₄ = 1/dissociation constant
= = 2.1 x 10¹³

Iodoform test is given by only those compounds containing CH₃CO – or CH₃CHOH – group.
PhCHOHCH₃ + 4I₂ + 6NaOH ⟶ CHI₃ + PhCOONa + 5NaI + 5H₂O

Aldehydes and ketones containing no α-H-atom on reaction with 50% NaOH or KOH, undergo disproportionation to give an alcohol and Na or K salt of an acid. This reaction is called Cannizaro reaction.
Acetaldehyde does not show Cannizaro reaction due to presence of α-hydrogen atom.
Rather, they undergo aldol condensation reaction with dilute base.

The line "With an increase in competition and marketing efforts, poverty-alleviation experts are concerned that people will be talked into loans they wouldn't otherwise want" suggests the answer. So, option 2 is the correct answer.
Option 1 presents the competition in a positive light, which is not the case. Nothing about micro-financing firms' marketing funds has been mentioned, so option 3 is incorrect. As the writer does not mention anything about the loan recovery means of the micro-financing firms, option 4 is also incorrect.

Let the numbers be x, x + 2, and x + 4.

Given:
The sum of three consecutive odd numbers is 1383.

x + (x + 2) + (x + 4) = 1383

3x + 6 = 1383

Solving for x:

3x = 1383 - 6

3x = 1377

x = 1377 ÷ 3 = 459

Thus, the three consecutive odd numbers are 459, 461, and 463.

Conclusion: The required largest number is 463.