Yakeen NEET 2.0 Comprehensive Practice Test Notes

Examination Logistics and General Instructions

  • Duration: The examination is scheduled for 180 minutes180\,\text{minutes} (3 hours3\,\text{hours}).
  • Structure: The booklet contains $180$ multiple-choice questions with four options and a single correct answer.
  • Subject Distribution: There are $45$ questions each for Physics, Chemistry, Botany, and Zoology.
  • Marking Scheme:
    • Correct response: $+4$ marks.
    • Incorrect response (MCQ): $-1$ mark.
    • Maximum total marks: $720$.
  • Conduct Rules:
    • No textual material, printed or written papers, pagers, mobile phones, or electronic devices are permitted in the exam hall.
    • Use of white fluid for corrections on the Answer Sheet is strictly prohibited.
    • Candidates must hand over the OMR Answer Sheet to the invigilator but are permitted to keep the Test Booklet.
  • OMR Specifics:
    • Use blue or black dark ballpoint pens only; pencils are prohibited.
    • Bubbles must be darkened completely; tick marks, cross marks, half-filled, or over-filled bubbles are invalid.
    • Multiple markings for a single question render the response invalid.
    • Do not fold or make stray marks on the OMR sheet, as it may disrupt scanning.

Physics: Vectors

  • Angle Between Vectors:
    • For vectors A⃗=5i^+5j^\vec{A} = 5\hat{i} + 5\hat{j} and B⃗=5i^−5j^\vec{B} = 5\hat{i} - 5\hat{j}, the angle is 90∘90^{\circ}.
    • For two force vectors of $5\,N$ and $12\,N$:
    • A resultant of $17\,N$ requires an angle of 0∘0^{\circ} (maximum).
    • A resultant of $7\,N$ requires an angle of 180∘180^{\circ} (minimum).
    • A resultant of $13\,N$ requires an angle of 90∘90^{\circ} (Pythagorean).
  • Direction Cosines:
    • If vector P⃗\vec{P} makes angles α,β, and λ\alpha, \beta, \text{ and } \lambda with the X,Y, and ZX, Y, \text{ and } Z axes, then cos⁡2(α)+cos⁡2(β)+cos⁡2(λ)=1\cos^2(\alpha) + \cos^2(\beta) + \cos^2(\lambda) = 1.
  • Vector Identities and Properties:
    • Commutative Law of Addition: P⃗+Q⃗=Q⃗+P⃗\vec{P} + \vec{Q} = \vec{Q} + \vec{P} is true.
    • Scalar Product: P⃗⋅Q⃗=Q⃗⋅P⃗\vec{P} \cdot \vec{Q} = \vec{Q} \cdot \vec{P} is true.
    • Cross Product Anti-commutativity: P⃗×Q⃗=−(Q⃗×P⃗)\vec{P} \times \vec{Q} = -(\vec{Q} \times \vec{P}) is the correct form; P⃗×Q⃗=Q⃗×P⃗\vec{P} \times \vec{Q} = \vec{Q} \times \vec{P} is false.
    • A physical quantity can be a vector even if its magnitude is zero (null vector).
    • Parallel Vectors: If A⃗=2i^+3j^+k^\vec{A} = 2\hat{i} + 3\hat{j} + \hat{k} and B⃗=ai^−6j^−2k^\vec{B} = a\hat{i} - 6\hat{j} - 2\hat{k} are parallel, $a = -4$.
  • Resultants and Components:
    • If the ratio of two forces is $3:5$ and the resultant is $28\,N$ at 60∘60^{\circ}, the individual forces are $12\,N$ and $20\,N$.
    • Resultant of A⃗+B⃗\vec{A} + \vec{B} for A⃗=4i^+3j^+6k^\vec{A} = 4\hat{i} + 3\hat{j} + 6\hat{k} and B⃗=−i^+8j^−8k^\vec{B} = -\hat{i} + 8\hat{j} - 8\hat{k} is 3i^+11j^−2k^3\hat{i} + 11\hat{j} - 2\hat{k}. The unit vector parallel to this is 3i^+11j^−2k^134\frac{3\hat{i} + 11\hat{j} - 2\hat{k}}{\sqrt{134}}.
    • If ∣A⃗+B⃗∣=∣A⃗−B⃗∣|\vec{A} + \vec{B}| = |\vec{A} - \vec{B}|, the angle between A⃗\vec{A} and B⃗\vec{B} is 90∘90^{\circ}.
    • Vector components: A force of $8\,N$ at 30∘30^{\circ} with the $x$-axis has Fx=43 NF_x = 4\sqrt{3}\,N and $F_y = 4\,N$.
    • Sliding a vector parallel to itself does not change the vector.
  • Displacement and Coordinate Systems:
    • Displacement from $P(2, 3, 5)$ to $Q(3, 4, 5)$ is i^+j^\hat{i} + \hat{j}.
    • A vector making equal angles with $X, Y, Z$ axes (e.g., i^+j^+2k^\hat{i} + \hat{j} + \sqrt{2}\hat{k}) has specific direction angles like 60∘,60∘,45∘60^{\circ}, 60^{\circ}, 45^{\circ}.

Chemistry: Some Basic Concepts

  • Laws of Chemical Combination:
    • Law of Small Whole Numbers/Multiple Proportions: If two elements form more than one compound, the masses of one element combining with a fixed mass of the other are in the ratio of small whole numbers.
    • Isotopes: Carbon-12 (${^{12}C}$) is the standard for the atomic mass unit ($amu$), assigned exactly $12\,amu$.
  • Stoichiometry and Molecular Weights:
    • 1 amu=1.66×10−24 g1\,amu = 1.66 \times 10^{-24}\,g or 1NA g\frac{1}{N_A}\,g.
    • Avogadro Number ($N_A$) = 6.022×10236.022 \times 10^{23}.
    • Glucose ($C_{6}H_{12}O_{6}$) molar mass = $180\,g/mol$. To obtain $1.8\,g$ of glucose from 6CO2+6H2O→C6H12O6+6O26CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2, 0.06×6.022×10230.06 \times 6.022 \times 10^{23} molecules of $CO_2$ are needed.
    • Aluminium Reaction: Al+NaOH+H2O→NaAlO2+32H2Al + NaOH + H_2O \rightarrow NaAlO_2 + \frac{3}{2}H_2. Correct stoichiometry for $27\,g$ of $Al$ (1 mole) produces $1.5$ moles of $H_2$ ($33.6\,L$ at STP).
  • Limiting Reagents:
    • The mass of products formed depends on the limiting reactant, which reacts completely.
  • Concentration Terms:
    • Molarity ($M$): Moles of solute per litre of solution. Dependent on temperature.
    • Molality ($m$): Moles of solute per kilogram of solvent. Independent of temperature.
    • Mole Fraction: Ratio of moles of a component to the total moles. Sum of all mole fractions in a solution is unity ($1$).
    • Mass Percentage: Mass of soluteTotal mass of solution×100\frac{\text{Mass of solute}}{\text{Total mass of solution}} \times 100.
    • Mass by Volume Percentage: Mass of soluteVolume of solution×100\frac{\text{Mass of solute}}{\text{Volume of solution}} \times 100.
  • Empirical and Molecular Formulas:
    • Empirical formula is the simplest whole-number ratio of atoms in a compound.
    • Molecular formula = n×(Empirical formula)n \times (\text{Empirical formula}). If empirical formula is $CH$ and molar mass is $84\,g/mol$, molecular formula is $C_6H_6$.
  • Temperature Conversions:
    • Relationship: ∘F=95(∘C)+32^{\circ}F = \frac{9}{5}(^{\circ}C) + 32.

Botany: Cell - The Unit of Life

  • Cell Theory Founders:
    • Matthias Schleiden (1838): German botanist who concluded all plants are composed of different kinds of cells.
    • Theodore Schwann (1839): British zoologist who concluded animal cells have a thin outer layer (plasma membrane) and the presence of a cell wall is unique to plant cells.
    • Rudolf Virchow (1855): Explained that cells divide and new cells are formed from pre-existing cells (Omnis cellula-e cellula).
  • Prokaryotic Cells:
    • Genomic DNA: Usually a single circular chromosome.
    • Plasmids: Small circular DNA outside genomic DNA; confer unique phenotypic characters (e.g., antibiotic resistance) and monitor bacterial transformation.
    • Cell Envelope: Glycocalyx (slime layer/loose or capsule/thick), cell wall (determines shape), and plasma membrane.
    • Ribosomes: $70S$ type ($50S$ and $30S$ subunits). Polyribosomes are several ribosomes attached to a single mRNA.
    • Inclusion Bodies: Membraneless structures in cytoplasm for reserve material (e.g., phosphate granules).
  • Eukaryotic Organelles:
    • Nucleus: Discovered by Robert Brown (1831). Contains chromatin, nucleolus, and nuclear pores for RNA/protein transport.
    • Mitochondria: Site of aerobic respiration.
    • Golgi Apparatus: Observed by Camillo Golgi. Sized 0.5 μm0.5\,\mu m to 1.0 μm1.0\,\mu m. Site for glycoprotein and glycolipid formation.
    • Endoplasmic Reticulum: RER (protein synthesis/secretion) and SER (lipid/steroid hormone synthesis).
    • Lysosomes: Formed by Golgi packaging; rich in hydrolytic enzymes (hydrolases).
    • Vacuoles: In plants, can occupy up to $90\%$ of volume; bound by a single membrane called the tonoplast.
    • Ribosomes (80S): Composed of $60S$ and $40S$ subunits. Measure of density and size.
  • Cell Wall and Membrane:
    • Algae: Cell wall contains cellulose, galactans, mannans, and calcium carbonate.
    • Plasma Membrane: Fluid mosaic model. Lipids are arranged with polar heads outward and hydrophobic tails inward. Contains proteins ($52\%$ in human RBCs) and lipids ($40\%$).

Zoology: Structural Organization in Animals and Frog

  • Animal Tissues:
    • Connective Tissue: Most abundant. Includes loose (areolar, adipose), dense (tendons, ligaments), and specialized (cartilage, bone, blood).
    • Ligament: Joins bone to bone.
    • Tendon: Joins skeletal muscle to bone.
    • Cartilage: Pliable matrix; contains chondrocytes.
    • Bone: Hard, non-pliable matrix; contains osteocytes in lacunae.
    • Areolar Tissue: Joins skin to muscles; contains fibroblasts, macrophages, and mast cells.
    • Muscular Tissue:
    • Skeletal: Voluntary, striated, bundled in sheaths.
    • Smooth: Involuntary, non-striated, found in walls of internal organs (stomach, blood vessels).
    • Cardiac: Found in the heart; branched, striated, with intercalated discs for rapid signal transmission as a single unit.
    • Neural Tissue: Neurons (excitable units) and Neuroglia (support/protect, make up $>50\%$ of volume). Nissl's granules are present in the cell body and dendrites.
  • Cell Junctions:
    • Tight Junctions: Stop substances from leaking across tissue.
    • Adhering Junctions: Cementing neighboring cells together.
    • Gap Junctions: Facilitate communication by connecting cytoplasm for rapid transfer of ions and small molecules.
  • Frog (Rana tigrina):
    • General Characteristics: Poikilotherms (cold-blooded), exhibit camouflage and mimicry.
    • Morphology: Skin is moist (respiratory), dorsal side is olive green with spots, ventral side is pale yellow. Forelimbs have $4$ digits; hindlimbs have $5$ webbed digits.
    • Sexual Dimorphism: Males have sound-producing vocal sacs and a copulatory pad on the first digit of forelimbs.
    • Physiology:
    • Respiration: Cutaneous (skin) and pulmonary (lungs).
    • Vascular System: Closed type; 3-chambered heart (two atria, one ventricle). Sinus venosus joins the right atrium.
    • Portal Systems: Hepatic (liver-intestine) and Renal (kidney-lower body).
    • Nervous System: Includes a brain (forebrain, midbrain, hindbrain with cerebellum and medulla) and spinal cord.
    • Behavioral Adaptations: Aestivation (summer sleep) and Hibernation (winter sleep) in deep burrows.

Questions & Discussion

  • Q: Which vector identity is false?
    • Options provided: $P+Q=Q+P$, P×Q=Q×PP\times Q = Q\times P, P⋅Q=Q⋅PP\cdot Q = Q\cdot P, P×Q=−(Q×P)P\times Q = -(Q\times P).
    • Result: P×Q=Q×PP\times Q = Q\times P is false because the cross product is anti-commutative.
  • Q: What is the unit of the nervous system?
    • Options provided: Cyton, Dendrites, Neuroglial cells, Neurons.
    • Result: The neuron is the basic functional unit.
  • Q: What determines the shape of a bacterium?
    • Options provided: Cell wall, Cell membrane, Glycocalyx, Capsule.
    • Result: The cell wall provides structural support and shape.
  • Q: How does a girl's garden organism enable a response to touch?
    • Result: Primarily through neural tissue, which exerts control over responsiveness to changing conditions.
  • Q: Is the statement that 1 mole of any gas occupies 2.24 litres at STP correct?
    • Result: No, the correct volume is 22.4 litres22.4\,\text{litres}.