UPHESC Assistant Professor Botany 2025 PYQs

Concept: A tissue-culture run goes: clean the explant → place it on the medium → grow it → acclimatise the plantlets.

1. Sterilization of the explant (e.g. 0.1% HgCl₂/NaOCl, 70% ethanol) removes surface microbes.
2. Inoculation = transferring the sterile explant onto the nutrient medium in a laminar air-flow hood.
3. Incubation in the culture room (≈25 °C, 16 h light) for callus/shoot growth.
4. Hardening (acclimatisation) of plantlets before transfer to the field – always the last step.

Short trick: S-I-I-H: Sterilize → Inoculate → Incubate → Harden.

Concept: In a xerarch (lithosere) succession on bare rock, the seral stages follow increasing soil depth and plant size.

1. Crustose → foliose lichens are pioneers; they secrete acids and start soil formation.
2. Mosses colonise the thin soil left by lichens.
3. Herbs, then shrubs, appear as soil deepens.
4. Trees form the climax forest community.

Short trick: Lichen → Moss → Herb/Shrub → Tree: small to big.

Concept: Cotton (Gossypium, Malvaceae) is a surface fibre crop – the lint is made of seed hairs.

1. Each cotton fibre is a single, very long epidermal cell of the seed coat (testa).
2. So cotton is a fibre-yielding plant precisely because these seed hairs form the fibre (lint) – (R) explains (A).
3. Contrast: jute/flax are bast (phloem) fibres; coir is a fruit (mesocarp) fibre.

Short trick: Cotton = seed hair; Jute = bast; Coir = fruit.

Concept: The internationally accepted herbarium sheet is about 11½ × 16½ inches, i.e. roughly 29 × 41–42 cm.

1. 11.5 in ≈ 29 cm and 16.5 in ≈ 42 cm.
2. Option (A) 28.75 × 41.25 cm is the size quoted in Indian texts as the standard.
3. Other options have a wrong width (25, 18.75 cm) or a wrong length (35 cm).

Short trick: Herbarium sheet ≈ 29 × 41 cm (11½ × 16½ inch).

Concept: Phytochrome controls germination of light-sensitive (photoblastic) seeds such as lettuce.

1. Red light (≈660 nm) converts P_r into active P_fr → germination is promoted.
2. Far-red/infra-red (≈730 nm) converts P_fr back to P_r → germination inhibited.
3. In R/FR alternations the last flash decides the response (Borthwick & Hendricks).

Short trick: Red = Ready to germinate; Far-red = Forbid.

Concept: Seres are named after the substratum on which succession begins.

1. Psammosere – on sand (Gk. psammos = sand), e.g. coastal sand dunes.
2. Lithosere – on bare rock; Halosere – in saline soil/water; Hydrosere – in water.
3. Xerosere is the general term for any succession in a dry habitat (lithosere and psammosere are its kinds), so the specific name for sand dunes is psammosere.

Short trick: Psammo = sand, Litho = rock, Halo = salt, Hydro = water.

Concept: Invasive alien species are introduced plants that spread aggressively and harm native biodiversity.

1. Prosopis juliflora (vilayati babool, from Mexico) – invasive in arid zones.
2. Eichhornia crassipes (water hyacinth, 'terror of Bengal', from S. America) – chokes water bodies.
3. Lantana camara (from tropical America) – invades forests.
4. Cynodon dactylon (doob grass) is a common, culturally used grass, not listed among India's invasive aliens.

Short trick: Doob is 'desi' – used in puja, not an invader.

Concept: Water potential (Ψ_w) = Ψ_s + Ψ_p, measured relative to pure water at atmospheric pressure.

1. By definition pure water at standard conditions has Ψ_w = 0 (the maximum value).
2. Adding solutes lowers it, so every solution has a negative Ψ_w.
3. Water always moves from higher (less negative) to lower (more negative) Ψ_w.

Short trick: Pure water = zero; everything else is below zero.

Concept: Coefficient of variation (CV) = (SD ÷ mean) × 100 – a relative measure of dispersion.

1. Because it is unit-free, CV compares the relative variability of data sets with different units or means (e.g. plant height vs leaf number).
2. Mean deviation is an absolute measure of dispersion.
3. Mode/median and 'most frequent occurrence' are measures of central tendency, not variability.

Short trick: CV = SD/Mean × 100 → relative spread.

Concept: Ethylene (C₂H₄) is the gaseous 'ripening hormone'.

1. In climacteric fruits (banana, mango, tomato) an ethylene burst triggers the respiratory climacteric, softening, colour and aroma changes.
2. Ethephon releases ethylene and is used commercially to ripen fruits.
3. ABA – dormancy/stomatal closure; GA – stem elongation, seed germination; cytokinins – cell division, delay senescence.

Short trick: Ethylene = Eats up (ripens) fruit; one bad apple spoils the basket.

Concept: The Golgi apparatus is the cell's 'post office' – it modifies, packages and sorts proteins.

1. In cis → medial → trans cisternae, proteins undergo glycosylation (O-linked, trimming of N-glycans), sulfation, phosphorylation (e.g. mannose-6-phosphate tag).
2. The trans-Golgi network sorts them into vesicles bound for lysosomes/vacuoles, plasma membrane or secretion.
3. Ribosomes only translate; RER starts N-glycosylation but the main sorting station is the Golgi; peroxisomes do not sort proteins.

Short trick: Golgi = modify + pack + sort + ship.

Concept: Watson–Crick B-DNA dimensions are fixed by purine–pyrimidine pairing.

1. Diameter = 20 Å (2 nm) throughout, because every base pair is one purine + one pyrimidine.
2. One complete turn (pitch) = 34 Å with 10 base pairs; rise per base pair = 3.4 Å.
3. 60, 80 and 27 Å are not DNA dimensions.

Short trick: B-DNA: 20 Å wide, 34 Å per turn, 3.4 Å per bp.

Concept: Stability = ability to resist and recover from disturbance; it rises with size, buffering and constancy of the environment.

1. The ocean is the largest ecosystem; its huge water mass buffers temperature, salinity and gas changes.
2. Its physico-chemical conditions have remained almost constant for millions of years, and it is the least altered by man.
3. Deserts and mountains face extreme fluctuations; forests are easily disturbed by fire, felling and climate.

Short trick: Biggest + most buffered = Ocean = most stable.

Concept: India State of Forest Report (FSI) ranks states by forest-cover area.

1. Area-wise order (ISFR 2021/2023): Madhya Pradesh (≈77,000 km²) > Arunachal Pradesh > Chhattisgarh > Odisha > Maharashtra.
2. Arunachal leads only among NE states; by percentage of geographical area Mizoram/Lakshadweep lead.
3. So, of the options, Madhya Pradesh has the largest forest cover.

Short trick: Area – MP first; percentage – Mizoram first.

Concept: Biosphere reserves in India are set up under UNESCO's Man and Biosphere (MAB) programme.

1. Nilgiri BR (Tamil Nadu–Kerala–Karnataka) was the first, notified in 1986; also first Indian BR in the UNESCO world network (2000).
2. Nanda Devi – 1988; Nokrek – 1988; Great Nicobar – 1989.
3. India now has 18 biosphere reserves; the largest is the Gulf of Kachchh / Great Rann of Kutch.

Short trick: N for 'Number one' – Nilgiri 1986.

Concept: Energy flow is unidirectional and obeys the second law of thermodynamics.

1. At each transfer only ~10% (Lindeman) of energy passes up; the rest is lost as heat in respiration.
2. Hence energy at a higher level can never exceed that at a lower level → pyramid of energy is always upright.
3. Pyramid of numbers is inverted in a tree/parasite chain; pyramid of biomass is inverted in the sea (phytoplankton < zooplankton); parasitic food-chain pyramid is inverted.

Short trick: Energy never goes up-hill – its pyramid never turns upside-down.

Concept: William Bateson coined 'genetics' in 1905 (used publicly in 1906 at the 3rd International Conference on Hybridisation).

1. Bateson also introduced allelomorph (allele), homozygote, heterozygote, F₁/F₂ and discovered linkage/coupling-repulsion with Punnett.
2. de Vries, Correns and Tschermak rediscovered Mendel's laws in 1900; de Vries also proposed mutation theory.
3. Johannsen (1909) coined 'gene', 'genotype', 'phenotype'.

Short trick: Bateson → Genetics (1905); Johannsen → Gene (1909).

Concept: Circular dichroism (CD) measures the difference in absorption of left- and right-circularly polarised light by chiral molecules.

1. In the far-UV (190–250 nm) the peptide backbone gives characteristic spectra: α-helix – negative bands at 222 and 208 nm, positive at 193 nm; β-sheet – negative ≈218 nm; random coil – negative ≈200 nm.
2. So CD quickly estimates % helix/sheet/coil in solution.
3. Chromatography (column/TLC) only separates molecules; ordinary EM shows shape/size, not secondary structure.

Short trick: Far-UV CD: double minimum at 222 & 208 nm = α-helix; single at 218 nm = β-sheet.

Concept: A tautonym is a binomial in which the specific epithet exactly repeats the generic name.

1. Malus malus repeats the genus name → tautonym.
2. Tautonyms are not permitted under the ICN (botany) – the correct name is Malus pumila/domestica; they are allowed in zoology (e.g. Rattus rattus, Naja naja).
3. Autonym – automatically created infraspecific name repeating the species epithet (e.g. Acacia nilotica subsp. nilotica); synonym – different names for one taxon; homonym – same name for different taxa.

Short trick: Tauto = same: genus = species → tautonym.

Concept: 'Monosonic' here means monosomic – an aneuploid lacking one chromosome of a pair.

1. Monosomic = 2n − 1 (e.g. Turner syndrome 45,XO).
2. Nullisomic = 2n − 2; trisomic = 2n + 1; tetrasomic = 2n + 2 (or double trisomic 2n + 1 + 1).
3. n = haploid (monoploid in diploids) – a euploid, not aneuploid.

Short trick: Mono-somic = minus one: 2n−1; Tri-somic = plus one: 2n+1.