IOM 2011

By Prevost's theory of heat exchange, good absorbers of radiation are also good emitters. A black surface has the highest emissivity/absorptivity among these colors, so it radiates away heat fastest and cools earliest, while a white surface, being a poor absorber and emitter, cools the slowest.

In the male frog, sperm passes from the testis through fine vasa efferentia into Bidder's canal, a longitudinal canal running along the anterior/ventral border of the kidney; from there it enters the kidney's urinogenital ducts and is carried to the cloaca.

Earthworms characteristically burrow into and move down through the soil, orienting their locomotion in the direction of gravitational pull; this gravity-directed movement toward the earth is termed positive geotaxis, as opposed to negative geotaxis (movement away from gravity).

Cephaleuros virescens is a parasitic green alga that causes red rust disease on the leaves of tea, coffee, and other plants. Spirogyra, Oedogonium, and Oscillatoria are all free-living, non-parasitic forms.

The Mesozoic Era (comprising the Triassic, Jurassic, and Cretaceous periods) is popularly called the Age of Reptiles/Age of Dinosaurs, since dinosaurs originated, diversified, and dominated terrestrial ecosystems throughout this era before their extinction at its end.

Mammary glands are developmentally and structurally modified (apocrine) sweat glands, arising embryonically from ectodermal thickenings along the milk line. The one notable exception is in monotremes (e.g., platypus), where the mammary glands are modified sebaceous glands instead; but for the general/human case tested here, sweat glands is the correct answer.

Hydrazoic acid (HN3) loses a proton to form its conjugate base, the azide ion (N3-), a linear, resonance-stabilized anion.

Distributing three chlorine substituents among the carbons of a propane skeleton gives five distinct positional (constitutional) isomers: 1,1,1-; 1,1,2-; 1,1,3-; 1,2,2-; and 1,2,3-trichloropropane. (Note: the 1,1,2-isomer additionally has a chiral center and so exists as a pair of enantiomers, but at the level of counting structural isomers, as this question intends, the answer is 5.)

Transitional epithelium (urothelium) is a stratified epithelium capable of stretching and recoiling without damage, which is why it specifically lines the urinary passages that must accommodate changes in urine volume, including the ureter, urinary bladder, and part of the urethra.

Concentration in g/L = mass(g) / volume(L) = 4 g / 0.25 L = 16 g/L.

Phytochemistry is the branch of botany dealing with the chemical compounds produced by plants (secondary metabolites, pigments, etc.), distinguishing it from general biochemistry, which covers chemical processes in all living organisms.

Coelenterates (Cnidaria) commonly show polymorphism, where a single colony contains structurally and functionally distinct individuals or zooids (e.g., polyp and medusa forms in Obelia, or the specialized zooids of the Portuguese man-of-war, Physalia).

Chlorine disproportionates differently depending on temperature: with cold, dilute NaOH it forms sodium hypochlorite (NaOCl) and NaCl, but with hot, concentrated NaOH the reaction goes further, producing sodium chlorate (NaClO3) along with NaCl.

When unrelated organisms with different genetic backgrounds independently evolve similar structures or forms because they face similar environmental pressures or functional demands, this is convergent evolution (e.g., the streamlined body shape shared by sharks, ichthyosaurs, and dolphins).

Physiological division of labour begins once cells stop being identical and start specializing for different future roles. This first becomes evident during gastrulation, when the three germ layers (ectoderm, mesoderm, endoderm) are laid down, each destined to form different organ systems.

In the archegonium of ferns (pteridophytes), the neck canal region is typically represented by a single neck canal cell that is binucleate, in contrast to bryophytes where several uninucleate neck canal cells are usually present. This binucleate condition is thought to represent an incompletely divided cell.

Homolytic bond fission splits a covalent bond so that each fragment retains one electron from the shared pair, generating free radicals; heterolytic fission, by contrast, gives an ion pair (carbocation and carbanion).

A waterproofing agent makes a surface less wettable, increasing the angle of contact between water and the surface from a small (acute) value, characteristic of wetting, to a larger (obtuse) value, characteristic of non-wetting, causing water to bead up.

Schweitzer's reagent is a deep-blue copper-ammonia complex (tetraamminecopper(II) salt) famous for its ability to dissolve cellulose, a property exploited in the manufacture of rayon fiber.

Coconut water (liquid endosperm) is a rich natural source of cytokinins, plant hormones that promote cell division, which is why coconut water has historically been used as a growth-promoting supplement in plant tissue culture media.

Experiments using isotopically labeled oxygen (notably by C.B. van Niel and later confirmed with 18O tracing) showed that the oxygen released during photosynthesis originates from the splitting (photolysis) of water molecules during the light reactions, not from carbon dioxide.

R is a universal constant with the same numerical value for all ideal gases regardless of their chemical nature, pressure, or volume; its only variation comes from the choice of units used to express pressure, volume, and temperature (e.g., 0.0821 L atm/mol K versus 8.314 J/mol K).

Moles of NaOH = 4/40 = 0.1 mol. Semi-normal (0.5 N) HCl in 0.5 L contains 0.5 x 0.5 = 0.25 mol H+ (since HCl is monobasic, N = M). After neutralizing 0.1 mol NaOH, excess H+ = 0.25 - 0.1 = 0.15 mol in 0.5 L, giving [H+] = 0.3 M. pH = -log(0.3) is approximately 0.52.

Ruby is a gem variety of corundum, which is crystalline aluminum oxide (Al2O3), colored red by trace amounts of chromium ions substituting for aluminum in the crystal lattice.

According to Bohr's model, the angular momentum of an electron in the nth orbit is L = n.h/(2.pi). For n = 2, this gives L = 2h/(2.pi) = h/pi.

In a dihybrid cross between two heterozygous individuals for two independently assorting genes, the classic Mendelian phenotypic ratio in the F2 generation is 9:3:3:1, representing the four possible phenotype combinations.

Among the states of matter, gas molecules are farthest apart and experience the weakest intermolecular attractive forces, giving them the least negative (i.e., highest) intermolecular potential energy compared to the more tightly bound, lower-potential-energy arrangements in liquids and solids.

Schistosoma species (e.g., S. haematobium, S. mansoni) are trematodes that live as adults in the blood vessels (mesenteric or vesical veins) of their host, causing schistosomiasis, which is why they are called blood flukes. Paragonimus is a lung fluke, Dracunculus is the guinea worm (a nematode), and Wuchereria is a filarial nematode.

Nucleic acids (DNA and RNA) are polymers made up of repeating monomer units called nucleotides, each consisting of a nitrogenous base, a pentose sugar, and a phosphate group, linked together by phosphodiester bonds.

By Faraday's law, 1 Faraday deposits one gram-equivalent of a substance, which equals (1/valency) gram atom. For 1 Faraday to liberate exactly 1/2 gram atom, the metal ion must have a valency of 2. Cu2+ in CuSO4 has valency 2, whereas Al3+ and Fe3+ have valency 3, and Na+ has valency 1.

A swinging pendulum gradually loses its mechanical energy to air resistance (and friction at its pivot), which dissipates the energy as heat, causing the amplitude of swing to decrease over time until it stops.

The human vertebral column is conventionally described as having 33 vertebrae during development: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused into the sacrum), and 4 coccygeal (fused into the coccyx). Because the sacral and coccygeal vertebrae fuse in the adult, the functional/movable count is often cited as 26, but 33 is the standard total used in exams.

Intensity = Power / (4 x pi x r^2) = 100 / (4 x pi x 5^2) = 100 / (100 x pi) = 1/pi (in W/m^2), treating the bulb as an isotropic point source radiating uniformly in all directions.

If each cell has emf e, then n.e = 15 for all cells aligned. Reversing one cell subtracts twice its emf from the total (since it now opposes rather than adds), giving (n-2).e = 12. Dividing the two equations gives (n-2)/n = 12/15 = 4/5, which solves to n = 10.

By definition, pH = -log10[H+]. If pH = 2, then [H+] = 10^-2 mol/L.

In Paramecium, the ciliated oral groove continues internally as a short tubular passage called the vestibule, which leads to the cytopharynx (gullet) and ultimately the cytostome, where food vacuoles are formed.

A process is thermodynamically spontaneous (occurs without external energy input) when its Gibbs free energy change (deltaG) is negative, indicating that the products are at lower free energy than the reactants under the given conditions.

Phenol has a hydroxyl (-OH) group that can act as both a hydrogen bond donor and acceptor, allowing it to form intermolecular hydrogen bonds; toluene, chlorobenzene, and nitrobenzene lack an -OH or -NH group capable of donating a hydrogen bond.

The liver fluke (Fasciola hepatica) shows both alternation of generation, with a sexual adult stage in the primary (sheep/cattle) host alternating with asexually reproducing larval stages (sporocyst, redia) in the intermediate snail host, and alternation of hosts between the primary vertebrate host and the intermediate snail host.

Merkel's discs and Meissner's corpuscles are specialized cutaneous mechanoreceptors for touch that are characteristic of mammalian skin, especially in hairless (glabrous) areas such as fingertips. Amphibian skin (frog, toad) lacks these particular receptor types, and although a rabbit is a mammal, 'skin of mammals' is the general/correct classification the question is testing.

Daniel I. Arnon and his colleagues discovered photophosphorylation in the 1950s, demonstrating that isolated chloroplasts could generate ATP from ADP and inorganic phosphate using light energy.

Zymogen (chief) cells of the gastric glands secrete the inactive proenzyme pepsinogen, which is converted into the active enzyme pepsin only after exposure to hydrochloric acid (secreted by parietal cells) and existing pepsin in the stomach lumen. Chymotrypsin and trypsin are pancreatic enzymes, not gastric ones.

The vermiform appendix is a narrow, worm-shaped diverticulum attached to the caecum, which is part of the large intestine. As a structure continuous with the gastrointestinal tract, it belongs to the digestive system, even though it also contains lymphoid tissue with an immune function.

The root mean square velocity of gas molecules is proportional to the square root of the absolute temperature (v_rms is proportional to sqrt(T)). If T increases by a factor of 3, v_rms increases by a factor of sqrt(3).

Tobacco mosaic virus is a well-studied plant virus whose genome consists of single-stranded RNA (positive-sense), encapsidated within a helical protein coat, making it one of the classic examples of an RNA virus used in early molecular biology research.

Gemmules are internal asexual reproductive bodies produced by freshwater sponges (Porifera), especially under adverse conditions. They are packed masses of archaeocytes surrounded by a resistant protective coat, which can survive harsh conditions and later develop into new sponges.

In sp hybridization, the two resulting hybrid orbitals point in exactly opposite directions, 180 degrees apart, giving rise to a linear molecular geometry.

Among the options given, the ileum (part of the small intestine) is correct since the small intestine, not the stomach, colon, or rectum, is the principal site of nutrient absorption. Strictly speaking, most carbohydrate, protein, and fat absorption actually peaks in the jejunum, with the ileum mainly handling vitamin B12 and bile salts, but jejunum is not offered as a choice here, making ileum the best available answer.

A vestigial structure is a reduced, non-functional (or minimally functional) remnant of an organ that was fully developed and useful in an ancestral form, such as the human appendix or the pelvic bones of whales.

Carbogen is a medical gas mixture of oxygen (usually 90-95%) and carbon dioxide (5-10%), used therapeutically to stimulate breathing and improve tissue oxygenation.

Using Newton's Law of Cooling in its average-temperature form, (T1-T2)/t = k[(T1+T2)/2 - T_room]: for the first interval, 10/1 = k(75-30) = 45k, giving k = 2/9. For the second interval, 10/t = k(45-30) = 15k = 10/3, so t = 3 minutes.

Tempering involves reheating steel to a temperature below its critical (red-heat) range and then cooling it, in order to reduce brittleness while retaining useful hardness. This is distinct from full annealing or hardening, both of which require heating the steel up to or above its critical transformation temperature.

Capillary rise gives a fixed vertical height (3 cm here) regardless of the tube's tilt, since this height depends only on surface tension, liquid density, and tube radius. When the tube is tilted, the liquid must travel farther along the slanted tube to reach the same vertical height: length along tube = vertical height / sin(angle with horizontal) = 3 / sin(30 degrees) = 3 / 0.5 = 6 cm.

Propyne is a terminal alkyne with an acidic C-H bond at the triple-bonded carbon; it reacts with ammoniacal silver nitrate (Tollens'-type reagent) to give a pale yellow/white precipitate of silver propynide. Propene, an alkene, has no such acidic terminal hydrogen and gives no precipitate with this reagent, allowing the two to be distinguished.

Dragonflies are hemimetabolous insects whose immature stage (the naiad) is fully aquatic. Females oviposit directly into water or into submerged plant tissue so the naiads can develop and respire underwater until they emerge as winged adults.

Sugarcane is a C4 plant that exhibits Kranz anatomy, in which two structurally and functionally distinct (dimorphic) types of chloroplasts occur: agranal chloroplasts in the bundle sheath cells and granal chloroplasts in the mesophyll cells.

During conjugation, two Paramecia exchange micronuclei and then separate as exconjugants. Each exconjugant's zygote nucleus divides to eventually produce 4 daughter individuals through successive fissions, so the pair of conjugating individuals together give rise to a total of 8 daughter Paramecia.

Since kinetic energy KE = p^2/(2 x mass), momentum p is proportional to the square root of mass at fixed KE. The ratio of momenta is therefore sqrt(m) : sqrt(4m) = 1:2.

Both earthworms and humans excrete nitrogenous waste mainly as urea, making them ureotelic. Ammonotelism (ammonia) is typical of aquatic invertebrates and bony fish, while uricotelism (uric acid) is characteristic of insects, reptiles and birds adapted to conserve water.

Among the choices given, Bartholin's glands (greater vestibular glands) are the conventional answer used in most physiology question banks as the female counterpart of the prostate, since both are accessory glands that secrete lubricating fluid near the reproductive/urogenital opening. Strictly embryologically, the closer homolog of the prostate is actually Skene's (paraurethral) gland, but that option is not offered here, and the other choices (uterus, clitoris) are not glands at all, so Bartholin's gland is the best fit among the given answers.

Young's modulus is defined as stress divided by strain, where stress has units of force per unit area (N/m^2) and strain is dimensionless, so Young's modulus itself has units of N/m^2 (equivalent to Pascals) in the MKS system.

Phenol's -OH group is a strong electron-donating, activating substituent (via resonance donation of a lone pair into the ring), making the aromatic ring highly electron-rich and most reactive toward electrophilic substitution, more so than toluene's weaker-activating methyl group, unsubstituted benzene, or nitrobenzene, whose nitro group is strongly deactivating.

Molarity = (10 x density x % by weight) / molar mass = (10 x 0.6 x 34) / 35 (NH4OH molar mass = 35 g/mol) is approximately 5.83 M. Since NH4OH is a monoacidic base (n-factor = 1), normality equals molarity, so the normality is about 5.8 N.

This configuration corresponds to chromium's actual, stable ground-state electron arrangement ([Ar]3d5 4s1) rather than the naively expected [Ar]3d4 4s2, because a half-filled d-subshell combined with a half-filled s-subshell provides extra stability due to symmetric electron distribution and exchange energy.

Heisenberg's uncertainty principle states that the position and momentum of a quantum particle like an electron cannot both be measured with arbitrary precision simultaneously; increasing the precision of one measurement decreases the precision of the other.

The sensory receptor patches of the inner ear, including the maculae of the utricle and saccule and the cristae of the semicircular canals, are all located within the membranous labyrinth, which floats inside the bony labyrinth and is filled with endolymph.

Kolbe's synthesis (Kolbe-Schmitt reaction) involves treating sodium phenoxide with carbon dioxide under pressure and heat, followed by acidification, to yield salicylic acid via electrophilic carboxylation of the aromatic ring.

The energy of a charged capacitor is stored in the electric field that exists in the region between its plates, not on the plates or charges themselves; this is the basis of the energy density formula for electric fields.

Halophiles are extremophilic archaea/bacteria adapted to thrive in high-salt environments such as salt lakes and salt pans. Methanogens produce methane, and thermoacidophiles are adapted to high temperature and acidity, not high salinity.

Biofertilizers are living organisms that enhance soil nutrient availability. Anabaena (a nitrogen-fixing cyanobacterium) growing in symbiotic association with the water fern Azolla is a classic biofertilizer used especially in rice cultivation to enrich soil nitrogen.

Cytochromes are electron-carrier proteins of the electron transport chain, which is embedded in the inner mitochondrial membrane; the folds of this membrane form the cristae, so cytochromes are located there rather than in the fluid matrix or the outer membrane.

Taenia solium is a protandrous hermaphrodite: in each proglottid the male reproductive organs (testes) mature before the female organs. So immature proglottids already show developing testes but no ovaries; ovaries, vitelline glands and the uterus appear only later as the proglottid matures and moves toward the posterior end of the strobila.

For two thin lenses separated by distance d, the combined power is P = P1 + P2 - d.P1.P2. Setting this equal to zero and simplifying (using P = 1/f) gives d = f1 + f2 as the separation needed for zero net power.

Myxophyceae (blue-green algae/Cyanophyceae) are prokaryotic organisms that reproduce only by asexual means (binary fission, fragmentation, spore formation); true sexual reproduction involving gamete fusion is absent in this group, unlike in Chlorophyceae, Phaeophyceae, and Rhodophyceae, which do show sexual reproduction.

With inert platinum electrodes, Cu2+ ions are preferentially discharged and deposited as copper metal at the cathode. At the anode, since SO4(2-) is not easily oxidized under these conditions, water is oxidized instead, liberating oxygen gas.

Fringe width is directly proportional to wavelength (beta = (lambda D)/d), so for a fixed segment of the screen, the number of fringes is inversely proportional to wavelength. Reducing the wavelength from 600 nm to 400 nm increases the fringe count by a factor of 600/400 = 1.5, giving 12 x 1.5 = 18 fringes.

Enzymes are biological catalysts made of amino acid chains folded into functional 3D shapes, making them proteins in nature (with a small number of catalytic RNAs called ribozymes being an exception, which are not covered by the options here).

Members of the Solanaceae family (e.g., tomato, brinjal) typically have a bicarpellary, syncarpous ovary with axile placentation bearing numerous ovules, which is why these fruits contain many seeds.

In humans, fertilization of the egg by sperm normally occurs in the ampulla of the fallopian tube (oviduct), shortly after ovulation. Note that 'oviduct' and 'fallopian tube' refer to the same structure in human anatomy, so options c and d describe the same location; the source material marks 'Fallopian tubes' as the intended answer.

A floating piece of ice displaces a volume of water whose weight equals the ice's own weight. When the ice melts, it turns into exactly that same weight (and hence, for water, the same volume) of liquid water, so the water level stays unchanged.

Using Charles' Law at constant pressure, V2 = V1 x (T2/T1) = 400 x (273/373), which is approximately 293 ml.

Peyer's patches are aggregates of lymphoid follicles located mainly in the ileum. They are part of the gut-associated lymphoid tissue (GALT) and function in immune surveillance of intestinal contents, making them lymphatic (lymphoid) tissue.

Budding in Hydra involves the outgrowth of a new individual from the parent's body wall without the fusion of gametes, making it a form of asexual reproduction, distinct from binary fission (splitting into two equal parts) or sexual reproduction (fusion of gametes).

Frogs possess homodont dentition, meaning all their teeth are structurally similar (small, conical, and undifferentiated), unlike heterodont dentition in mammals where teeth are differentiated into incisors, canines, premolars, and molars for different functions.

Chile saltpetre is the natural mineral form of sodium nitrate (NaNO3), historically mined in Chile as a major source of sodium nitrate for fertilizers and explosives.

Resistance R = (rho x L) / A, and cross-sectional area A is proportional to the square of the diameter. Halving the diameter reduces the area by a factor of 4, so the resistance increases by a factor of 4 (with length and resistivity unchanged).

Ortho-hydrogen (parallel nuclear spins) and para-hydrogen (antiparallel nuclear spins) differ in the relative orientation of the spins of the two hydrogen nuclei; since a hydrogen nucleus is simply a proton, this is described as being distinguished by proton (nuclear) spin.

This is a classic Friedel-Crafts alkylation, in which anhydrous AlCl3 acts as a Lewis acid catalyst to generate an electrophilic methyl carbocation from methyl chloride, which then substitutes onto the benzene ring to form toluene.

The Islets of Langerhans are clusters of hormone-secreting cells (including insulin-producing beta cells and glucagon-producing alpha cells) scattered within the pancreas, constituting its endocrine portion, while the acini make up the exocrine, digestive-enzyme-secreting portion.

Darzens' method converts an alcohol to the corresponding alkyl chloride using thionyl chloride (SOCl2) in the presence of pyridine, which neutralizes the HCl byproduct and helps control the stereochemical outcome of the substitution.

Aschelminthes (roundworms/nematodes) possess a body cavity called a pseudocoelom, which is not fully lined by mesoderm (unlike the true coelom of annelids and molluscs), and lies between the mesoderm and endoderm.

Nitric oxide (NO) has an odd total number of valence electrons (11), which necessarily leaves one electron unpaired, making it a stable free radical. CO and CN- are isoelectronic with N2 (10 valence electrons, all paired), and O2 has two unpaired electrons (not one) due to degenerate antibonding pi* orbitals.

Overgrazing by livestock strips vegetation cover and exposes topsoil to erosion, which is widely recognized as one of the leading human-driven causes of desertification, especially in arid and semi-arid grasslands.

Ovules, which contain the female gametophyte and develop into seeds after fertilization, are borne on the placenta inside the ovary, the basal part of the pistil (female reproductive organ) in flowering plants.

Electronic transitions (electrons moving between energy levels in an atom) release energy differences typically corresponding to UV, visible, or IR radiation. Gamma rays arise from much higher-energy nuclear transitions, not from electron transitions, so an atom cannot emit gamma rays through this process.

In typical nuclear fission reactions (e.g., of Uranium-235), only a very small fraction of the total rest mass, on the order of 0.1%, is converted into released energy according to E = mc^2.

Glucose is a reducing sugar because it has a free aldehyde group that can reduce agents such as Fehling's or Tollens' reagent. (Note: fructose is also technically a reducing sugar, since under basic test conditions it tautomerizes to an aldose form and can reduce these reagents too, making this question have more than one defensible answer among the choices; glucose is presented here as the most direct, textbook example, since it reduces without needing tautomerization.) Sucrose and glycogen, in contrast, lack free anomeric aldehyde/ketone groups available for reduction and are classified as non-reducing.

The magnetic force on a moving charged particle always acts perpendicular to its velocity, so it changes the particle's direction of motion but does no work on it; consequently, the particle's speed and kinetic energy remain unchanged.

Ginkgo biloba is the classic example of a living fossil: it is the sole surviving species of a gymnosperm lineage that has remained largely unchanged for over 200 million years and is otherwise known mainly from fossil records.

Crossing over is the reciprocal exchange of genetic material between non-sister chromatids of homologous chromosomes during synapsis in prophase I of meiosis, resulting in new combinations of alleles.