UPHESC Assistant Professor Zoology 2025 PYQs

Concept: In deuterostomes the blastopore becomes the anus and the mouth forms second; cleavage is radial and indeterminate, coelom enterocoelous.

1. Deuterostomes: Echinodermata (starfish, sea urchin), Hemichordata, Chordata.
2. Arthropods, molluscs and annelids are protostomes (blastopore → mouth, spiral determinate cleavage, schizocoelous).

Short trick: "Deutero = second mouth": Echinoderms + Chordates (E-C).

Concept: Integral membrane proteins have hydrophobic α-helical (or β-barrel) segments that sit among the fatty-acid tails of the bilayer.

1. Hydrophobic interactions between these non-polar amino-acid side chains and lipid tails hold proteins in the membrane (Singer & Nicolson, 1972).
2. That is why detergents are needed to extract integral proteins.
3. Ionic/hydrophilic interactions hold only peripheral proteins; covalent lipid anchors are a minor case.

Short trick: Water-hating protein part hides in the water-hating lipid core.

Concept: Calsequestrin is a high-capacity, low-affinity Ca²⁺-binding protein inside the sarcoplasmic reticulum (terminal cisternae) of muscle.

1. Each molecule binds ~40–50 Ca²⁺, storing calcium for release through ryanodine receptors.
2. Calmodulin and troponin C are cytosolic Ca-binding proteins; titin is an elastic sarcomere protein.

Short trick: Cal-sequester-in = sequesters (stores) calcium inside SR.

Concept: The respiratory rhythm centre (dorsal and ventral respiratory groups, pre-Bötzinger complex) lies in the medulla oblongata.

1. Pons has the pneumotaxic and apneustic centres, which only modify (fine-tune) the medullary rhythm.
2. Medullary central chemoreceptors also sense CO₂/H⁺.
3. Cerebellum – posture/coordination; hypothalamus – temperature, hunger etc.

Short trick: Medulla = "vital centres" – breathing, heartbeat, BP.

Concept: A ligand (Latin ligare, to bind) is the signalling molecule – hormone, neurotransmitter, growth factor – that binds specifically to a receptor.

1. Receptor – the protein that receives the ligand.
2. Effector – downstream enzyme/channel activated (e.g. adenylyl cyclase).
3. "Epitome" is not a signalling term (epitope is the antigenic site for an antibody).

Short trick: Ligand → Receptor → Transducer → Effector → Response.

Concept: In freeze-fracture, a frozen cell is split; the fracture plane runs through the hydrophobic middle of the bilayer, separating the two leaflets.

1. A metal (platinum-carbon) replica of the exposed P-face and E-face is viewed in the EM.
2. Integral membrane proteins appear as intramembrane particles – strong evidence for the fluid mosaic model.
3. Light-microscope methods (phase-contrast, bright field, multiphoton) cannot resolve the inside of a 7–8 nm membrane.

Short trick: Freeze → crack the bilayer → see inside (P-face/E-face).

Concept: Link each respiratory component with its role.

1. Molecular O₂ is the final acceptor of electrons + H⁺, forming water → hydrogen acceptor (II).
2. Cytochrome c is a mobile electron carrier/acceptor between complex III and IV (III).
3. Pyruvate dehydrogenase converts pyruvate → acetyl-CoA (IV).
4. ATP synthase (F_oF₁) is driven by the proton gradient and is reversible as a proton pump (I).

Short trick: PDH → Acetyl-CoA is the sure pair; only option A has c–IV.

Concept: Bacteria have homologues of all three eukaryotic cytoskeletal proteins.

1. FtsZ – tubulin homologue (GTPase); forms the Z-ring at the division site.
2. MreB – actin homologue (ATPase); maintains rod shape.
3. Crescentin – intermediate-filament homologue (Caulobacter).
4. MotA/MotB and PomA/PomB are flagellar motor stator proteins.

Short trick: FtsZ → Z-ring division (tubulin, like spindle); MreB → Body shape (actin).

Concept: Intrinsic bioremediation (natural attenuation) = degradation of pollutants by the indigenous (naturally occurring) microbes without human intervention.

1. Engineered/enhanced bioremediation adds nutrients, oxygen (biostimulation) or microbes (bioaugmentation).
2. In-situ/ex-situ only tell where treatment occurs (at the site vs after removal), not who does it.

Short trick: Intrinsic = "in-built" microbes, nothing added.

Concept: Complementation: two recessive mutants with the same phenotype, when crossed, give wild-type progeny if the mutations lie in different genes.

1. aaBB × AAbb → AaBb: each parent supplies the functional allele the other lacks.
2. Example: two deaf parents with mutations in different genes having children with normal hearing.
3. No wild type → mutations are alleles of the same gene (cis–trans test, Benzer).

Short trick: Complement = "fill each other's gap".

Concept: The backbone has three dihedral angles: φ (N–Cα), ψ (Cα–C) and ω (C–N, the peptide bond).

1. The peptide C–N bond has partial double-bond character (resonance), so it is planar and rigid: ω ≈ 180° (trans, usual) or ≈ 0° (cis, mainly before proline).
2. The Ramachandran plot itself plots φ vs ψ, not ω – so B and C describe φ/ψ, not ω.

Short trick: ω = "peptide plane lock": 180° trans / 0° cis.

Concept: Karl von Frisch decoded the honey-bee dance language: round dance (food near) and waggle dance (direction relative to the sun and distance).

1. He shared the 1973 Nobel Prize with Konrad Lorenz (imprinting) and Niko Tinbergen (stimulus–response, sign stimuli).
2. Emil Fischer – chemist (lock-and-key model of enzymes).

Short trick: "Frisch = Fresh flowers" → bees.

Concept: The middle piece contains a spiral sheath of mitochondria (mitochondrial spiral / nebenkern) around the axoneme.

1. Their oxidative enzymes produce ATP that powers dynein arms of the tail flagellum → motility.
2. The haploid nucleus lies in the head; the acrosome carries hydrolytic enzymes for penetrating the egg.

Short trick: Head = DNA + acrosome; Middle = mitochondria (power house); Tail = movement.

Concept: Mesoderm induction (Nieuwkoop, Xenopus) – vegetal cells induce the marginal zone to form mesoderm.

1. TGF-β family signals (Nodal/Xnr, Activin, Vg1; BMP for ventral mesoderm) are the main inducers.
2. FGF signalling is required in parallel to maintain mesodermal genes (e.g. Brachyury); blocking FGF receptors prevents mesoderm formation.
3. Shh and Notch act later (neural tube patterning, somitogenesis).

Short trick: Mesoderm needs "T + F" – TGF-β (Nodal) + FGF.

Concept: Leishmania and Trypanosoma (Kinetoplastida) cause distinct diseases.

1. Oriental sore (cutaneous leishmaniasis) – L. tropica (iii).
2. Espundia (mucocutaneous) – L. braziliensis (i).
3. African sleeping sickness – T. brucei (gambiense/rhodesiense), tsetse fly (ii).
4. Chagas disease – T. cruzi, reduviid bug (iv).

Short trick: Tropica → Oriental (tropics of Orient); Brazil-iensis → Espundia (S. America); Cruzi → Chagas (both S. American).

Concept: Crustaceans (prawn, crab, lobster) are mainly aquatic and respire by gills (branchiae), usually on thoracic appendages in a branchial chamber.

1. Insects, centipedes, millipedes – tracheae.
2. Arachnids (scorpion, spider) – book lungs; Limulus – book gills.
3. Very small crustaceans (copepods) may use the general body surface, but gills are typical.

Short trick: Crust-acean = aquatic → Gills; Insect = Tracheae; Arachnid = Book lungs.

Concept: Classic deficiency diseases.

1. Vitamin A (retinol, part of rhodopsin) – night blindness (II).
2. Vitamin B₁ (thiamine) – beriberi (I).
3. Vitamin D (calciferol) – rickets in children (IV).
4. Vitamin C (ascorbic acid, collagen hydroxylation) – scurvy (III).

Short trick: A-Andhapan (night blindness), B-Beriberi, C-sCurvy, D-Dwarfed bones (rickets).

Concept: In autoimmune disease the immune system attacks self antigens.

1. Psoriasis – T-cell mediated skin disease; rheumatoid arthritis – attack on synovial joints; Addison's disease – autoimmune destruction of adrenal cortex (commonest cause).
2. Alzheimer's disease is a neurodegenerative disorder (β-amyloid plaques, tau tangles), not classed as autoimmune.

Short trick: Alzheimer = amyloid + memory loss (degeneration), not self-attack.

Concept: Second messengers are small intracellular molecules produced in response to a first messenger (hormone) binding a receptor.

1. cAMP (Sutherland), cGMP, Ca²⁺, IP₃ and DAG (from PIP₂ by phospholipase C) are second messengers.
2. NADH is a reduced coenzyme that carries electrons to the electron transport chain – a metabolic cofactor, not a signalling messenger.

Short trick: Messengers: "cAMP, cGMP, Ca, IP₃, DAG" – NADH belongs to respiration.

Concept: Innate (instinctive) behaviour is genetically programmed, performed correctly the first time without learning or practice.

1. A spider that hatches in isolation spins a species-typical web perfectly – no learning involved, so D is wrong.
2. Its stereotyped sequences are of the fixed-action-pattern kind, but FAP is a sub-type of innate behaviour; the general category is innate behaviour.
3. "Releaser" is the stimulus that triggers a behaviour, not the behaviour itself.

Short trick: Born knowing it = innate (web-spinning, nest building, suckling).