VITEEE PCBE Mock Test - 7 - JEE MCQ

Viroids are unique infectious agents made up solely of a short strand of RNA, without a protein coat, known for causing diseases in plants such as potato spindle tuber disease. This makes Option C correct. Option A incorrectly describes prions, not viroids; Option B is false as viroids are smaller than viruses and lack DNA; Option D describes lichens, not viroids.

Cockroaches, like many other insects, possess an open circulatory system. This system is characterized by a limited network of blood vessels and a heart that pumps the hemolymph (blood) into the body cavity, where it directly bathes the organs. There is no distinction between blood and interstitial fluid in this type of system, unlike in closed circulatory systems.

Renal calculi are characterized by the presence of an insoluble mass of crystallized salts within the kidney. These formations can vary in size and composition, often leading to symptoms such as severe pain, hematuria (blood in urine), and urinary obstruction. It is crucial to manage these calculi through dietary changes, hydration, and medical interventions to prevent complications like kidney damage or recurrent stone formation.

Topic in NCERT: Renal calculi

Line in NCERT: "Renal calculi: Stone or insoluble mass of crystallised salts (oxalates, etc.) formed within the kidney."

Both statements (i) and (iv) are correct. Asthma is a difficulty in breathing caused by inflammation of the bronchi and bronchioles, and the binding of oxygen to hemoglobin is primarily related to the partial pressure of O2.

Statements (ii) and (iii) are not correct. The respiratory system starts at the external nostrils and extends to the alveoli, not the terminal bronchioles. The epiglottis is a flap of cartilage that covers the glottis to prevent the entry of food into the larynx during swallowing, not the other way around.

Auxin is a plant hormone known for its role in promoting cell elongation, especially in the stem. It regulates various aspects of growth and development by facilitating the stretching of cell walls, allowing cells to expand.

Solution: The alveoli are the primary sites for the exchange of gases. They are tiny, balloon-like structures in the lungs where oxygen is absorbed into the blood and carbon dioxide is released from the blood. This process is facilitated by the large surface area and thin walls of the alveoli, making them perfectly suited for gas exchange.

The blood circulation from heart to lungs and back to heart is pulmonary circulation and the circulation between heart to tissue and back to heart is systematic circulation and both are included in double circulation.

Individual frequencies can be represented as p and q. But for a diploid organism, p and q explain the frequency of allele A and allele a. p² represents AA whereas q² represent aa.

Given figures represent the forelimbs of different vertebrates, which possess the same basic structural plan, i.e., in each case, the forelimb consists of humerus, radio-ulna, carpals, metacarpals and digits. Thus, the skeletal parts of these forelimbs are similar in structure and arrangement, but have different shapes and functions. It depicts the example of homologous structures.

Lines in NCERT: 1. Restriction enzymes belong to a larger class of enzymes called nucleases.
2. The cutting of DNA at specific locations became possible with the discovery of the so-called  ‘molecular scissors’– restriction enzymes.
3. Downstream processing is the last process in recombinant DNA technology(6th). After completion of the biosynthetic stage, the product has to be subjected through a series of processes before it is ready for marketing as a finished product.
4. And the last method uses ‘disarmed pathogen’ vectors, which when allowed to infect the cell, transfer the recombinant DNA into the host.

- The Assertion is correct because competitive inhibitors indeed bind to the active site of an enzyme, which prevents the substrate from binding.

- The Reason is also correct as increasing the substrate concentration can outcompete the inhibitor for the active site, thereby restoring enzyme activity.

- Additionally, the Reason effectively explains the Assertion as it describes how competitive inhibition can be mitigated, confirming that both statements are true and that the Reason is the correct explanation for the Assertion.

During G₁ phase, DNA content is 2C.S phase is marked by replication of DNA and the amount of DNA per cell is doubled. During G₂ phase, synthesis of RNA and proteins takes place. During mitosis, DNA content gets equally distributed among two daughter cells.

Line in NCERT: "The interphase is divided into three further phases: G1 phase (Gap 1), S phase (Synthesis), G2 phase (Gap 2)."

When light goes from one medium to another, the frequency of light, and phase of light do not change.
However, the velocity of light and wavelength of light change.
So, velocity of light in glass
v_g = or v_m - v_g = v_m -
∴ 6.25 × 10⁷ = v_m
= 2.5 × 10⁸ m/s

Velocity of the electron orbiting around the nucleus
v ∝ 1/n _____ 1
and
Radius of the orbit
r ∝ n² ____ 2
Magnetic moment (μ) = (mvr)/2 (m is mass of the electron which is constant) ........... (3)
Therefore,
From 1, 2 and 3 we have
μ ∝ n

Velocity of electromagnetic wave in a medium with relative permittivity ε_r = 4 ,

Velocity of wave,  where ε₀, μ₀ are electrical permittivity and magnetic permeability of vacuum.

Frequency (f) is the fundamental property of wave and it doesn't change unless we change the waves itself, hence remains constant hence,

λf = c, where λ is the wavelength of the wave,

Also, When a wave propagates from one medium to the other, then the frequency remains the same. So,

∴ Wavelength is halved and frequency remains unchanged.

Given:

Differentiate w.r.t. x on both sides,

.

Using quotient rule in differentiation i.e. 

Also given, x² + t² = y

Differentiate w.r.t. x on both sides,

Put the value of tand dt/dx from equations (i) and (ii),

Now put x = 2. We get

The virtual image formed by the lens is at the naked eye's true near point.
∴ P = 25 cm


∴ 1/q = – 0.01
∴ q = 100 cm
∴ When the man is not wearing the glasses he should hold the newspaper 1m away for clear vision.
The answer is(A)

The conversion of RCOOH to RCH₂OH can be obtained by lithium aluminium hydride.
NaBH₄ does not reduce carboxylic acids.
Red P/HI would reduce it to the hydrocarbon stage.
Zn-Hg/conc. HCl: Clemmensen reduction is done for conversion of aldehydes to hydrocarbons

2N₂O₅ → 4 NO₂ + O₂

Production rate of O₂ =
Production rate of NO₂ =
Disappearance rate of N₂O₅ =

[Rate of disappearance of N₂O₅ = Twice the production rate of O₂]

Boiling point = T₀ (Solvent) + ΔT_b (Elevation in b.p.)
ΔT_b = miK_b
where, m is the molality (≈ Molarity M)
i, the van’t Hoff factor = [1 + (y – 1)x]
K_b, molal elevation constant.
Thus ΔT_b ∝ i
Assume 100% ionisation
(a) mi (Na₂ SO₄) = 0.01[1 + (y – 1)x] = 0.03
(b) mi (KNO₃) = 0.01 × 2 = 0.02
(c) mi (urea) = 0.015
(d) mi (glucose) = 0.015

These are all Lewis bases as N-atom in each of them has tendency to donate an electron pair. Piperidine (c) is the strongest base among these. In pyrrole (b), the lone pair of electrons on N-atom is involved in delocalisation of π electrons (aromatic sextet). Hence, it has the least tendency to donate an electron pair. Aniline (d) and pyridine (a) are also weakly basic due to resonance. On the other hand, piperidine has no such delocalisation and it is a secondary amine. Hence, it is highly basic.

Both (B) and (C) have 6π electrons and obey Huckel's rule of (4n + 2)π electrons. Hence, they are aromatic in nature. This character is attributed to the structure because -OH group present in the side chain is not directly attached to the ring and hence, the lone pair on the oxygen atom is not in conjugation with the π electrons of the benzene ring.

Na + H₂O → NaOH + 1/2H₂
Zn + 2NaOH → Na₂ZnO₂ + H₂
Na imparts a Golden yellow colour to the flame

'Keep the wolf from the door' means 'have enough money to avert hunger or starvation' 
'Starvation' is a noun which means 'suffering or death caused by lack of food.'
For example: I work part-time to pay the mortgage and keep the wolf from the door
Hence, this is the correct option. 

The line of passage, 'He returned to find that Pablo had completed the picture and it was so amazingly beautiful and lifelike that he gave his son his palette and brushes and never painted again' clearly depicts that Pablo had become an amazing artist so, his father gave up painting.
Hence, option C is the right answer.

Disregarded means pay no attention to or  ignore.
Whereas Addressed is an adjective which means  bearing the name and address of the intended recipient.
Addressed : Disregarded (should be the exact antonym)
Therefore option A is correct option.

In the word, A and C have one letter between them , in alphabetical order A and C have only letter B between them
C and E have one letter between them , in alphabetical order C and E have only letter D between them
A and E have three letter between them , in alphabetical order A and E have three letters B, C and D between them
Therefore, (A,C) ; (C,E) and (A,E) are three pairs which satisfy the given condition.
Option D is correct