Sama-Bajau are Austronesian ethnic groups living along the coastal areas of southern Philippines, Malaysia, and Indonesia. Also known as sea nomads, they have the extraordinary ability to dive for longer periods of time as adaptation to subsistence fishing. It was then discovered that one particular physiological adaptation was linked to the diving ability of Sama-bajau. Which statement explains this adaptation?
Sama-Bajau have larger lung capacity.
Sama-Bajau have higher number of erythrocytes.
Sama-Bajau have larger stomach.
Sama-Bajau have larger spleen.
Sama-Bajau have thinner layer of subcutaneous fat.
Purkinje cells are output neurons of the cerebellum which functions in the integration and modulation of signals coming from the cerebral cortex. These functions are particularly critical in their role in the coordination of movements and other processes. What would be the expected morphology of Purkinje cells?
Reference: Masland. Curr Biol, 2018, 14(13), R497–500.
The physiological property of the protein is largely dependent on its amino acid sequences. For example, hydrophilic amino acids interact more strongly with water which allows the protein to be more soluble. Which of the following amino acids is therefore least hydrophilic?
Translate the hypothetical mRNA sequence into corresponding amino acid sequence using the genetic code below.
5′-CAGCUGAUGGAUCCAGACAUCCCAACAGGGAUGGAGGAGUGGUGACUG-3′
Editorial convention: initiate at the first AUG and stop at the first in-frame termination codon.
The following graph shows the phylogenetic tree of representative genomic sequences of SARS-CoV-2 variants worldwide. Which of the following statements is not true regarding the variants, as demonstrated by the tree?
Historical scope: interpret the pictured 2022-era tree; select the ancestry statement contradicted by its topology. Sampling counts are not a prevalence survey.
The Omicron variant evolved from the Delta variant.
The Omicron variant has currently two subvariants.
The Omicron variant is currently the prevalent strain worldwide.
The Delta variant was the most prevalent strain during 2021.
The Delta variant still exists among the population.
Editorial scope: use at least one external dimension of approximately 1–100 nm; assess the listed dimensions independently of the questionable layer-count wording.
A spherical silver nanoparticle with diameter 10 nm
A gold nanorod with length 500 nm and diameter 10 nm
A rectangular microcrystal with dimensions 200 nm × 500 nm × 70 nm
A 1 μm × 1 μm graphite flake composed of millions of graphene with total thickness 120 nm
A carbon-based wire with length 1 mm and cross-sectional diameter of 50 nm
The structure of Nirmatrelvir, an antiviral drug developed by Pfizer against Covid-19, is shown below. Which of the following groups is present in the compound?
Blue dyes was known to be expensive, necessitating extraction of pigments from rare minerals or organisms, so that painters reserved the blue color only for important subjects until the Renaissance. This was the case until 1703, when a Swiss chemist Johann Diesbach discovered how to make the dye Prussian blue, ushering a paintings with lively blue colors such as the Great Wave Off Kanagawa by Hokusai and Starry Night by van Gogh.
An insoluble form of Prussian blue is synthesized from the reaction of a ferric salt and ferrocyanide complex:
2 Fe₂(SO₄)₃(aq) + 3 K₄Fe(CN)₆(aq) → Fe₄[Fe(CN)₆]₃(s) + 6 K₂SO₄(aq).
In this synthesis said reaction, which species is the Lewis acid?
Hint: potassium and sulfate ions may be considered spectators, so the overall reaction is:
4 Fe³⁺(aq) + 3 [Fe(CN)₆]⁴⁻(aq) → Fe₄[Fe(CN)₆]₃(s).
Shown below are Lewis structures of some hydrocarbons. Which of the following would you expect to have the highest vapor pressure at ambient room and temperature?
0.28 g of an unknown gas was found to exert a pressure of 10.5 kPa and occupy a volume of 2.35 L at 25 °C. What is/are the possible identity/ies of the gas?
Shown below is a periodic table for reference.
A 0.135 g piece of aluminum foil (Al) is dissolved in 100 mL 0.1 M sulfuric acid (H₂SO₄). The resulting solution contains aluminum sulfate Al₂(SO₄)₃ and produces hydrogen gas H₂. What volume, at ambient temperature and pressure, of hydrogen gas is produced?
Use atomic weights: H = 1, Al = 27, S = 32, O = 16.
Editorial convention: use 25 °C and 1 atm for ambient conditions and assume complete reaction.
In 2038, humans from planet earth made contact with the living intelligent beings of the cold moon of Saturn, the planet Titan. In this planet, the atmosphere is composed of 1% methane, which is the source of energy of these beings. These beings therefore developed a temperature scale based on the freezing point (−162 °C) and boiling point (−182 °C) of methane. The freezing point was set to be 0 T while the boiling point was set at 40 T. At this scale, at what would be the absolute zero temperature? (Note: 0 K = −273 °C)
Editorial review: derive the scale from the printed anchors and check whether any original choice matches; do not silently repair them.
Original choices:
A. −222 T
B. −35.6 T
C. −273 T
D. −89 T
E. −263 T
In a 2010 paper published in Nature, Reinabelle Reyes, a Filipino astrophysicist, together with colleagues from the USA and Switzerland, showed that the large scale distribution of galaxies in the universe is consistent with the prediction of what theory?
Glow-in-the-dark stickers come in different shapes and sizes. When exposed to light, these stickers tend to glow long after the light is turned off, thus the name. Which of the following terms most precisely describes this material?
A mass of ice at −50 °C is heated slowly until it melts, becomes liquid, and ultimately steam, at 140 °C. Assuming no mass loss during heating, at what stage of the process is the system requiring the most amount of heat?
Assume constant heat capacities: c(ice)=2.108 kJ/kg K, c(water)=4.187 kJ/kg K, c(steam)=1.99 kJ/kg K.
Other printed constants: ΔH(fus)=334 kJ/kg, ΔH(fus)=334 kJ/kg, ΔH(vap)=2260 J/g.
An engineer is attempting to have an idea of the roughness of a piece of wood by measuring its coefficient of friction. The table and accompanying graph show measurements of the minimum force needed to push objects of different weights. Given the data, what is the coefficient of friction that the engineer should report?
Normal force (N): 6, 12, 18, 24, 30.
Force applied (N): 2, 7, 11, 13, 18.
Editorial convention: use the free-intercept regression line explicitly printed in the graph. Graph labels: Applied Force (N); Normal Force (N); F = 0.633Fn − 1.2.
A physicist is trying to measure the mass of an electron by placing through a uniform electric field of 1.00 × 10⁴ N/C. This resulted in the electron accelerating at 1.7 × 10¹⁵ m/s². What is the % error of this measurement if the accepted value for the mass of an electron is 9.1 × 10⁻³¹ kg and its charge = 1.6 × 10⁻¹⁹ C?
Currents are natural phenomena that occur on water. All of the following statements are true about currents EXCEPT
Editorial review: test each claim and the official exception against physical mechanisms.
Original choices:
A. The force exerted by the winds on the water’s surface leads to the formation of currents.
B. Currents refer to the direction of flow of a body of water.
C. One of the factors that influence the intensity of currents is wind.
D. Trade winds drive both North and South Equatorial Currents westward, so warm ocean-surface waters are transported in the said direction.
E. Currents flow counterclockwise in the Southern Hemisphere.
The massive eruption of this volcano last January 2022 fueled an unparalleled mega-thunderstorm of 590,000 lightning strikes within 3 days and eventually triggered a tsunami in the surrounding areas.
