VITEEE PCBE Mock Test - 8 - JEE MCQ

Growth is defined as a permanent or irreversible increase in dry weight, size, mass or volume of a cell organ or organism. Plant growth is unique because plants retain the capacity for unlimited growth throughout their life. This ability of the plants is due to the presence of meristems at curtain locations in their body. The cells of such meristems have the capacity to divide and self-perpetuate. The product, however, soon loses the capacity to divide and such cells make up the plant body. This form of growth wherein new als are always being added to the plant body by the activity of the meristem is called the open form of growth.

Increase in growth per unit time is called as growth rate. The growth rate may be arithmetic or geometrical. Arithmetic Growth is a type of growth in which the rate of growth is constant and increase in growth occurs in arithmetic progression-- 2, 4, 6, 8, 10,12. Meristematic cells at the growing point divide in such a fashion that one daughter cell remains meristematic while the other grows and differentiates. the process continues. Mathematically, arithmetic growth is expressed as
L_t =L₀ +rt.
where L_t = length after time t, L₀   = length at the beginning, and r = growth rate. On plotting growth against time, a linear graph is obtained.

Growth, at a cellular level, is principally a consequence of increase in the amount of protoplasm. Growth is measured by a variety of parameters such as  (i) increase in length, e.g, stem,root, pollen tube (ii) increase in volume eg., fruits. (iii) Increase in area, eg.leaves (iv) increase in diameter, eg, tree trunks, fruits (v) Increase in fresh or dry weight. One single maize root apical meristem can given to more than 17,500 new cells per hour, wheres as cell in watermelon may increase in size by upto 3, 50,000 the former, growth is expressed as increase the cell number latter expresses growth as increase in the size of cell.

The meristem which is consumed in the formation of an organ is called determinate meristem. The meristem which continues its activity throughout life of the plant is called indeterminate meristem. Root apical meristem, shoot apical meristem, intercalary meristem (e.g., grass) and lateral meristems are all Indeterminate meristems. Plant growth is generally indeterminate, i.e., plants retain the capacity for unlimited growth throughout their life, whereas it is determinate in the meristem which is consumed in the formation of an organ.

Lateral meristem occurs on the sides and takes part in increasing girth of the plant. Intra fascicular cambium is the primary lateral meristem which lies in vascular bundles of dicot and gymnosperm stems in between phloem and xylem. Examples of  secondary lateral meristems are vascular cambium of the root, inter fascicular cambium of stem,cork cambium etc. that  take part in the secondary growth.

Prehypertension is defined as a systolic pressure from 120–139 millimeters of mercury (mm Hg) or a diastolic pressure from 80–89 mm Hg.

Photophosphorylation is the conversion of ADP to ATP using the energy of sunlight by activation of PSII. This involves the splitting of the water molecule in oxygen and hydrogen protons (H⁺), a process known as photolysis.

Bt toxin is obtained from Bacillus thuringiensis bacterium that can kill certain insects like tobacco budworm, armyworm, beetles and flies.

Double helix model of DNA was proposed by James Watson and Francis Crick in 1953 based on X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin.

Sex in Drosophila is a function of the ratio of the number ofX chromosomes to the number of autosomal sets. Therefore a Drosophila with a X/A =1.0 will be a female whereas the one with a X/Aratio=0.5 will be male However, in humans the presence or absence of the Y chromosome determines sex.

Number of nuclei left undecayed after time t is given by,

Where n is number of half lives in time t.

According to question, N = N₀/e

Substituting in (i), we get

Taking log on both sides, we get

Activity of the sample reduces to half at its half life.

F = 0 when 0 ≤ r ≤ R₁
Because intensity is zero inside the cavity.

F increases when R₁ ≤ r ≤ R₂
As there will be more mass enclosed if the radius of the enclosure is increased.

F ∝ 1/r² when r > R₂
As all mass is enclosed, it will behave as a point mass.

The most suitable reagent for the conversion of 2-phenylpropanamide into 1-phenylethylamine is Br₂, NaOH.

For a 1^st order chemical reaction,


Arrhenius equation:

[A = Pre-exponential factor]
In a 1^st order reaction, the unit of the pre-exponential factor is reciprocal second.
Because the pre-exponential factor depends on the frequency of collisions, it is related to collision theory and transition state theory.

Optical isomerism is shown by chiral molecules, due to the absence of any plane of symmetry, axis of symmetry or centre of symmetry in the molecule. If the molecules possess any of these elements of symmetry, the compound will not be optically active.
[Co(NO₂)₃(NH₃)₃] possesses a plane of symmetry and can be superimposed on its mirror image, so it is an optically inactive complex.

The reaction does not occur because of nascent oxygen. Hence, reason is false.

The carbohydrates or sugar where free aldehyde or ketonic group is absent (utilized in glycosidic bond formation) can not reduce the above reagents are called non-reducing sugar i.e., Sucrose, glycogen, starch.

Substances which can be stretched to couse large strain are called elastomers. e.g. tissue of aorta, rubber etc.

If atom or group of higher priority are on opposite direction at the double bond of each carbon atom then the configuration is known as E and if they are in same direction then the configuration is known as Z configuration.

(ii) Fullerenes are cage-like molecules.
(iii) Graphite is thermodynamically most stable allotrope of carbon.
(iv) Graphite is slippery and hard and therefore used as a dry lubricant in machines.

Bond order is calculated as:
Bond order = (N_b - N_a) / 2

Where:

• N_b = Number of electrons in bonding molecular orbitals
• N_a = Number of electrons in antibonding molecular orbitals

For the following molecules:

• O₂ → Bond order = 2 (Molecular orbital theory)
• O₃ → Bond order = 1.5 (Bond order calculated based on the resonating structures)
• O2²⁻ → Bond order = 1 (Molecular orbital theory)
• O⁻₂ → Bond order = (10 - 7) / 2 = 1.5 (Molecular orbital theory)

As bond order increases, bond length decreases.

Antibiotics which kills or inhibit a wide range of gram-positive and gram-negative bacteria are said to be broad spectrum antibiotics.
So Broad-spectrum antibiotics act on different antigens.

Cannizaro reaction,
HCHO + NaOH → CH₃OH + HCOONa
This reaction takes place by those compounds which has no α−H atom.
Inter molecular shift of hydride ion is key step of Cannizaro reaction

AB || MN and AM is the transversal.
∠1 + (x + 65°) = 180° (Co-interior angles)
90° + x + 65° = 180°
Or x = 25°
Now, CD || MN and BM is the transversal.
y + 65° = 180° (Co-interior angles)
y = 115°
Now, AB || CD and BM is the transversal.
z = y (Corresponding angles)
z = 115°
Now, x + y + z = 25° + 115° + 115° = 255°

Let the age of Guri and Shuri five years ago be x and y, respectively.
According to the question,
x + y = 36
x = 36 - y ... (i)
Also,x - y = 4
Putting the value of x as given in (i) we get,
36 - y - y = 4
36 - 2y = 4
-2y = 4 - 36
-2y = -32
2y = 32
y = 32 ÷ 2
y = 16
Therefore, the age of Shuri, 5 years ago = 16 years
Putting y = 16 in the equation x - y = 4,
x - 16 = 4
x = 4 + 16
x = 20
Hence, age of Guri, 5 years ago = 20 years
Present age of Guri = 20 + 5 = 25 years
Present age of Shuri = 16 + 5 = 21 years
Age of Guri and Shuri, 7 years from now, will be 32 years and 28 years, respectively.
Required ratio = 32 : 28
= 8 : 7