Bachelor of Science (BS) Comprehensive Exam — Questions and Answers

Question 1: According to Newton's second law, which equation correctly relates net force, mass, and acceleration?

F = pa
F = m/a
F = ma (Correct answer)
F = mv

Correct answer: F = ma

Newton's second law states that net force equals mass multiplied by acceleration (F = ma).

Question 2: Which type of bond holds the two strands of a DNA double helix together?

Peptide bonds
Ionic bonds
Covalent bonds
Hydrogen bonds (Correct answer)

Correct answer: Hydrogen bonds

Hydrogen bonds between complementary base pairs (A-T and G-C) hold the two DNA strands together.

Question 3: When food is broken down, leaving the _, it moves via the duodenum, the first section of the _.

esophagus; stomach
stomach; small intestine (Correct answer)
stomach; large intestine
small intestine; large intestine

Correct answer: stomach; small intestine

After mechanical and chemical digestion in the stomach, the partially digested food, now called chyme, is released into the small intestine. The duodenum is the very first section of the small intestine, where it receives chyme from the stomach and continues the digestive process with the help of bile and pancreatic enzymes. This transition marks a key stage in nutrient absorption.

Question 4: Which kingdom includes organisms that are prokaryotic and lack a membrane-bound nucleus?

Bacteria (Correct answer)
Plantae
Fungi
Protista

Correct answer: Bacteria

Bacteria are prokaryotes that lack a membrane-bound nucleus and other membrane-bound organelles.

Question 5: An object in uniform circular motion experiences centripetal acceleration directed:

Toward the center of the circle (Correct answer)
Tangent to the path in the direction of motion
Perpendicular to the plane of the circle
Away from the center of the circle

Correct answer: Toward the center of the circle

Centripetal acceleration always points toward the center of the circular path, providing the inward force that sustains circular motion.

Question 6: What is oxidation in a chemical reaction?

The removal of hydrogen from an organic molecule
The gain of electrons by an atom or molecule
The addition of oxygen to a compound
The loss of electrons by an atom or molecule (Correct answer)

Correct answer: The loss of electrons by an atom or molecule

Oxidation is defined as the loss of electrons; it always occurs alongside reduction (gain of electrons) in redox reactions.

Question 7: What is the Pythagorean theorem?

The sum of all angles in any triangle equals 180°
The area of any triangle equals half the base times the height
In a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides (a² + b² = c²) (Correct answer)
The ratio of a circle's circumference to its diameter equals π

Correct answer: In a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides (a² + b² = c²)

The Pythagorean theorem states that in a right-angled triangle, a² + b² = c², where c is the hypotenuse (longest side).

Question 8: What is the role of decomposers in an ecosystem?

To break down dead organic matter and recycle nutrients back into the soil (Correct answer)
To convert sunlight into chemical energy
To regulate the population of apex predators
To consume primary producers

Correct answer: To break down dead organic matter and recycle nutrients back into the soil

Decomposers such as bacteria and fungi break down dead organic material, returning essential nutrients to the soil for use by plants.

Question 9: What is acid rain?

Natural rainfall in volcanic regions with high sulfur content
Rain that becomes acidic after falling through polluted soil
Precipitation with a pH below 5.6 caused by sulfur and nitrogen oxides reacting with water in the atmosphere (Correct answer)
Condensation from industrial cooling towers

Correct answer: Precipitation with a pH below 5.6 caused by sulfur and nitrogen oxides reacting with water in the atmosphere

Acid rain forms when sulfur dioxide and nitrogen oxides emitted by burning fossil fuels react with atmospheric moisture to form sulfuric and nitric acids.

Question 10: Which of the following examples of natural selection is NOT one?

Heterozygote selection (Correct answer)
Disruptive selection.
Stabilizing selection
Directional selection.

Correct answer: Heterozygote selection

Disruptive, directional, and stabilizing selection are the three main modes or types of natural selection, describing how phenotypes are favored or disfavored in a population. Heterozygote selection, while a significant evolutionary concept often leading to heterozygote advantage, describes a specific condition where heterozygous individuals have higher fitness. It is not classified as a fundamental *mode* of natural selection in the same way as the other three.

Question 11: What is the difference between weather and climate?

Weather is measured globally; climate is measured locally
They are interchangeable terms for atmospheric conditions
Weather refers to short-term atmospheric conditions; climate refers to long-term patterns (Correct answer)
Climate describes daily temperature changes; weather describes seasonal trends

Correct answer: Weather refers to short-term atmospheric conditions; climate refers to long-term patterns

Weather describes current or short-term atmospheric conditions, while climate refers to the average patterns of weather over long periods (typically 30+ years).

Question 12: Which intermolecular force is responsible for the unusually high boiling point of water compared to similar-sized molecules?

Dipole-dipole interactions
London dispersion forces
Ionic interactions
Hydrogen bonding (Correct answer)

Correct answer: Hydrogen bonding

Hydrogen bonding between water molecules requires more energy to break, raising water's boiling point significantly.

Question 13: Which lipoprotein is primarily responsible for transporting cholesterol from peripheral tissues back to the liver?

VLDL
HDL (Correct answer)
LDL
Chylomicrons

Correct answer: HDL

HDL (high-density lipoprotein) performs reverse cholesterol transport, collecting excess cholesterol from peripheral tissues and returning it to the liver.

Question 14: What is the difference between qualitative and quantitative data?

Qualitative data uses numbers; quantitative data describes categories
Both types use numerical measurements
Qualitative data describes categories; quantitative data uses numbers (Correct answer)
Both types rely on descriptive observations

Correct answer: Qualitative data describes categories; quantitative data uses numbers

Qualitative data involves non-numerical descriptions such as color or opinion, while quantitative data is expressed in measurable numerical values.

Question 15: Which process converts atmospheric nitrogen (N₂) into ammonia (NH₃), making it usable by living organisms?

Denitrification
Nitrification
Nitrogen fixation (Correct answer)
Ammonification

Correct answer: Nitrogen fixation

Nitrogen fixation converts inert N₂ gas into ammonia, carried out by bacteria such as Rhizobium in root nodules.

Question 16: What is a function in mathematics?

A relationship where each input value corresponds to exactly one output value (Correct answer)
A formula with an infinite number of solutions
A graph that crosses the x-axis at least once
An equation with more than one variable

Correct answer: A relationship where each input value corresponds to exactly one output value

A function is a mathematical rule that assigns exactly one output to each input, often written as f(x).

Question 17: What does the periodic table organize elements by?

Increasing atomic number and recurring chemical properties (Correct answer)
Order of discovery by scientists
Decreasing atomic mass
Alphabetical order of element names

Correct answer: Increasing atomic number and recurring chemical properties

The periodic table arranges elements by increasing atomic number, with elements having similar chemical properties grouped in the same vertical column (group).

Question 18: What is an invasive species?

A native species that becomes overpopulated
A species at risk of extinction in its native habitat
A migratory species that travels between ecosystems
A non-native species introduced to an area where it causes ecological or economic harm (Correct answer)

Correct answer: A non-native species introduced to an area where it causes ecological or economic harm

An invasive species is one that is introduced outside its native range and outcompetes native species, disrupting ecosystems.

Question 19: Einstein's explanation of the photoelectric effect demonstrated that light:

Can be polarized
Always behaves purely as a wave
Travels at different speeds in a vacuum depending on color
Has particle-like properties carried in discrete photons (Correct answer)

Correct answer: Has particle-like properties carried in discrete photons

The photoelectric effect showed that light delivers energy in quantized packets (photons), revealing its particle-like nature and earning Einstein the Nobel Prize.

Question 20: Biodiversity is best measured by assessing which combination of factors?

Biomass and productivity
Population size and growth rate
Predator and prey ratios
Species richness and evenness (Correct answer)

Correct answer: Species richness and evenness

Biodiversity indices (like the Shannon index) incorporate both species richness (number of species) and evenness (relative abundance).

Question 21: Your friend's calorie consumption is less than what his Harris-Benedict equation predicted, according to the registered dietitian. Why does this matter?

Your friend's body mass index is positive.
Your friend's caloric balance is negative. (Correct answer)
Your friend's body mass index is negative.
Your friend's caloric balance is positive.

Correct answer: Your friend's caloric balance is negative.

The Harris-Benedict equation estimates an individual's basal metabolic rate and total daily energy expenditure, representing the calories needed to maintain weight. If your friend's actual calorie consumption is less than this predicted expenditure, it means they are in a caloric deficit. This negative caloric balance indicates that the body is using more energy than it's taking in, which typically leads to weight loss over time.

Question 22: What does the term 'carbon footprint' refer to?

The physical area of land needed to absorb CO2 emissions
The amount of carbon stored in soil and vegetation
The total greenhouse gas emissions caused by an individual, organization, or activity (Correct answer)
The carbon cycle's effect on ocean chemistry

Correct answer: The total greenhouse gas emissions caused by an individual, organization, or activity

A carbon footprint measures the total greenhouse gas emissions, expressed as CO2 equivalents, associated with a person, product, or process.

Question 23: What does a p-value less than 0.05 typically indicate?

The experiment failed
The result is statistically significant (Correct answer)
The hypothesis is proven true
The sample size was too small

Correct answer: The result is statistically significant

A p-value below 0.05 means there is less than a 5% probability that the results occurred by chance, indicating statistical significance.

Question 24: What is an independent variable in an experiment?

The variable the researcher manipulates to observe its effect (Correct answer)
The variable that is measured as the outcome
A variable held constant throughout the study
A variable that cannot be controlled

Correct answer: The variable the researcher manipulates to observe its effect

The independent variable is the factor deliberately changed by the researcher to observe its effect on the dependent variable.

Question 25: What is scientific notation used for?

Converting between metric and imperial units
Formatting equations for publication in journals
Expressing very large or very small numbers in a compact form (Correct answer)
Writing chemical formulas in standard form

Correct answer: Expressing very large or very small numbers in a compact form

Scientific notation expresses numbers as a product of a coefficient (between 1 and 10) and a power of 10, simplifying calculations with extreme values.

Question 26: Which macromolecule serves as both a structural component and an enzyme in living organisms?

Nucleotides
Carbohydrates
Proteins (Correct answer)
Lipids

Correct answer: Proteins

Proteins function as enzymes (biological catalysts) and structural components such as collagen and keratin.

Question 27: What is sustainable development?

Economic growth that prioritizes industrial output over environmental concerns
The preservation of natural areas with no human development
Development that uses only renewable energy sources
Development that meets present needs without compromising the ability of future generations to meet their own needs (Correct answer)

Correct answer: Development that meets present needs without compromising the ability of future generations to meet their own needs

Sustainable development balances economic growth, environmental protection, and social equity to ensure resources remain available for future generations.

Question 28: Which enzyme unwinds the DNA double helix during replication by breaking hydrogen bonds between base pairs?

Helicase (Correct answer)
DNA polymerase
Ligase
Primase

Correct answer: Helicase

Helicase uses ATP to unwind and separate the two DNA strands at the replication fork.

Question 29: What is a probability in mathematics?

A percentage representing how often an event has occurred historically
A number between 0 and 1 expressing the likelihood of an event occurring (Correct answer)
The number of ways an event can occur divided by time
The ratio of successful outcomes to total attempts in completed trials

Correct answer: A number between 0 and 1 expressing the likelihood of an event occurring

Probability is a numerical value from 0 (impossible) to 1 (certain) that expresses how likely an event is to occur.

Question 30: What is a catalyst?

An inhibitor that blocks enzyme activity
A product formed during the initial stage of a reaction
A substance that slows down a chemical reaction
A substance that increases the rate of a reaction without being consumed (Correct answer)

Correct answer: A substance that increases the rate of a reaction without being consumed

A catalyst lowers the activation energy required for a reaction to proceed, speeding it up without being permanently changed or consumed.

Question 31: What is the oxidation state of sulfur in H₂SO₄ (sulfuric acid)?

+6 (Correct answer)
+8
+2
+4

Correct answer: +6

In H₂SO₄, with H at +1 and O at -2, sulfur must be +6 to balance the overall neutral charge.

Bachelor of Science (BS) Comprehensive Exam

A comprehensive assessment covering core Bachelor of Science disciplines including cell biology, genetics, chemistry, environmental science, mathematics, and research methodology to evaluate undergraduate science proficiency.

Questions

35 min

Time Limit

70%

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