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

Question 1: The Mediterranean diet is associated with reduced cardiovascular disease risk primarily due to high intake of which food component?

Simple sugars from fruit
Saturated fat from dairy
Omega-3 from fish only
Monounsaturated fatty acids from olive oil (Correct answer)

Correct answer: Monounsaturated fatty acids from olive oil

Extra-virgin olive oil, rich in oleic acid (a monounsaturated fatty acid) and polyphenols, is a cornerstone of the Mediterranean diet linked to reduced LDL oxidation and inflammation.

Question 2: What is biodiversity?

The total number of individual organisms in a population
The rate at which species evolve over time
The variety of life forms within a given ecosystem or on Earth (Correct answer)
The geographic distribution of a single species

Correct answer: The variety of life forms within a given ecosystem or on Earth

Biodiversity refers to the variety of life, including species diversity, genetic diversity, and ecosystem diversity.

Question 3: The pH scale measures hydrogen ion concentration; a solution with pH 4 compared to pH 6 is:

2 times more acidic
100 times more acidic (Correct answer)
1000 times more acidic
10 times more acidic

Correct answer: 100 times more acidic

The pH scale is logarithmic, so a difference of 2 pH units means 10² = 100-fold difference in H⁺ concentration.

Question 4: In the electromagnetic spectrum, which type of radiation is used in MRI (magnetic resonance imaging) machines?

X-rays
Ultraviolet radiation
Infrared radiation
Radio waves (Correct answer)

Correct answer: Radio waves

MRI machines use radio waves combined with strong magnetic fields to produce detailed images of internal body structures.

Question 5: What is an ionic bond?

A bond formed by equal sharing of electrons between atoms
A bond formed by the electrostatic attraction between oppositely charged ions (Correct answer)
A bond formed by overlapping atomic orbitals
A weak intermolecular force between polar molecules

Correct answer: A bond formed by the electrostatic attraction between oppositely charged ions

Ionic bonds result from the transfer of electrons from one atom to another, creating positively and negatively charged ions that attract each other.

Question 6: What is the slope of a line in a graph?

The area under the curve between two points
The average of all y-values on the line
The rate of change, calculated as rise over run (Δy/Δx) (Correct answer)
The point where the line crosses the y-axis

Correct answer: The rate of change, calculated as rise over run (Δy/Δx)

Slope measures the steepness and direction of a line, calculated as the change in y divided by the change in x between any two points.

Question 7: Which of the following is a renewable energy source?

Solar energy (Correct answer)
Coal
Nuclear fission
Natural gas

Correct answer: Solar energy

Solar energy is renewable because it is continuously replenished by the sun, unlike fossil fuels which are finite.

Question 8: In a food web, organisms that obtain energy by decomposing dead organic matter are called:

Herbivores
Primary producers
Decomposers (Correct answer)
Apex predators

Correct answer: Decomposers

Decomposers (fungi and bacteria) break down dead organic matter, recycling nutrients back into the ecosystem.

Question 9: Which human activity is the largest contributor to deforestation in the US?

Urban residential development
Recreational tourism
Agricultural expansion and land clearing for farming (Correct answer)
Mining and mineral extraction

Correct answer: Agricultural expansion and land clearing for farming

Converting forests to agricultural land, including for crops and livestock grazing, is the primary driver of deforestation globally and in the US.

Question 10: What is eutrophication?

The removal of nutrients from soil by heavy rainfall
Increased salinity in freshwater ecosystems due to runoff
The natural aging process of a lake over thousands of years
Excessive nutrient enrichment of water bodies that leads to algal blooms and oxygen depletion (Correct answer)

Correct answer: Excessive nutrient enrichment of water bodies that leads to algal blooms and oxygen depletion

Eutrophication occurs when excess nutrients, usually nitrogen and phosphorus from fertilizers, cause rapid algal growth that depletes oxygen in water.

Question 11: Which property of a sound wave determines the pitch perceived by a listener?

Frequency (Correct answer)
Wavelength
Wave speed
Amplitude

Correct answer: Frequency

Frequency determines pitch — a higher frequency produces a higher perceived pitch.

Question 12: Which process converts light energy into chemical energy stored in glucose?

Fermentation
Cellular respiration
Photosynthesis (Correct answer)
Glycolysis

Correct answer: Photosynthesis

Photosynthesis uses light energy to synthesize glucose from CO₂ and water in chloroplasts.

Question 13: Which molecule carries genetic information in most living organisms?

DNA (Correct answer)
ATP
Protein
RNA

Correct answer: DNA

DNA (deoxyribonucleic acid) is the double-stranded molecule that stores the genetic blueprint of most living organisms.

Question 14: What does the term 'carbon footprint' refer to?

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

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

Proteins (Correct answer)
Nucleotides
Carbohydrates
Lipids

Correct answer: Proteins

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

Question 16: What is an exponential function?

A function whose graph forms a straight line
A function in which the variable appears as an exponent (e.g., y = aˣ) (Correct answer)
A function that grows at a constant rate
A function in which the variable is raised to a fixed power (e.g., y = x²)

Correct answer: A function in which the variable appears as an exponent (e.g., y = aˣ)

Exponential functions have a variable exponent, causing rapid growth or decay, and are used to model population growth, radioactive decay, and compound interest.

Question 17: Imagine that you exerted a force on a 13 kilogram item, forcing it to accelerate at a velocity of 0.5 m/s2. How many times would the force being applied to this item need to be multiplied in order to achieve an acceleration of up to 1.25 m/s2?

2.5 (Correct answer)
2.25
3
2.75

Correct answer: 2.5

This problem uses Newton's second law, F = ma. First, calculate the initial force: F1 = 13 kg × 0.5 m/s² = 6.5 N. Next, calculate the new force needed for the desired acceleration: F2 = 13 kg × 1.25 m/s² = 16.25 N. To find the multiplication factor, divide the new force by the initial force: 16.25 N / 6.5 N = 2.5.

Question 18: What is the purpose of a control group in an experiment?

To randomize the sample selection
To introduce the independent variable
To provide a baseline for comparison against the experimental group (Correct answer)
To eliminate the dependent variable

Correct answer: To provide a baseline for comparison against the experimental group

A control group does not receive the experimental treatment, providing a baseline to compare against the treatment group.

Question 19: Which law states that the total momentum of a closed system remains constant if no external forces act on it?

Ohm's law
Boyle's law
Conservation of momentum (Correct answer)
Law of universal gravitation

Correct answer: Conservation of momentum

Conservation of momentum states that total momentum of an isolated system remains constant.

Question 20: In alpha decay, the particle emitted from the nucleus consists of:

A neutron and an antineutrino
A high-energy electron
A helium-4 nucleus (2 protons and 2 neutrons) (Correct answer)
A gamma-ray photon only

Correct answer: A helium-4 nucleus (2 protons and 2 neutrons)

An alpha particle is identical to a helium-4 nucleus, containing 2 protons and 2 neutrons, and is the heaviest of the common decay particles.

Question 21: What are isotopes?

Atoms of the same element with different numbers of electrons
Atoms of different elements with the same mass number
Molecules with the same formula but different structures
Atoms of the same element that have different numbers of neutrons (Correct answer)

Correct answer: Atoms of the same element that have different numbers of neutrons

Isotopes are variants of the same element that contain the same number of protons but different numbers of neutrons, giving them different mass numbers.

Question 22: Which of the following methods of natural selection makes use of the claim that newborns with medium weights often fare better than those who are especially little or large?

Disruptive selection.
Typical selection.
Stabilizing selection. (Correct answer)
Median selection.

Correct answer: Stabilizing selection.

Stabilizing selection is a type of natural selection where genetic diversity decreases as the population stabilizes on a particular non-extreme trait value. In this scenario, newborns with medium weights have a higher survival rate compared to those who are either very small or very large. This selective pressure favors the average phenotype, leading to a reduction in variation around the mean.

Question 23: What is the difference between physical and chemical change?

Chemical change alters shape without changing composition; physical change creates new substances
Both types of changes result in new chemical substances
Physical change alters form without changing composition; chemical change produces new substances (Correct answer)
Physical changes are irreversible; chemical changes are always reversible

Correct answer: Physical change alters form without changing composition; chemical change produces new substances

Physical changes alter the form or appearance of matter (such as cutting or melting) without changing its chemical identity, while chemical changes create new substances.

Question 24: What is scientific notation used for?

Converting between metric and imperial units
Expressing very large or very small numbers in a compact form (Correct answer)
Formatting equations for publication in journals
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 25: What is a double-blind study?

Neither the participants nor the researchers know who is in the treatment group (Correct answer)
Only researchers do not know group assignments
Only participants do not know their group assignment
Both groups receive the same treatment

Correct answer: Neither the participants nor the researchers know who is in the treatment group

In a double-blind study, both participants and researchers are unaware of group assignments, minimizing bias.

Question 26: What is the difference between weather and climate?

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

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 27: What is standard deviation used to measure?

The relationship between two variables
The probability of an event occurring
The highest value in a dataset
The spread or dispersion of data around the mean (Correct answer)

Correct answer: The spread or dispersion of data around the mean

Standard deviation quantifies how much individual data points deviate from the mean of the dataset.

Question 28: What is a solution in chemistry?

A mixture that separates over time
A homogeneous mixture in which one substance is dissolved in another (Correct answer)
A pure substance composed of one type of atom
A heterogeneous mixture of two or more substances

Correct answer: A homogeneous mixture in which one substance is dissolved in another

A solution is a homogeneous mixture where a solute is uniformly dissolved in a solvent, resulting in a single-phase mixture.

Question 29: What is a probability in mathematics?

The ratio of successful outcomes to total attempts in completed trials
The number of ways an event can occur divided by time
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)

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 the process by which DNA is copied before cell division?

Transcription
Meiosis
Translation
DNA replication (Correct answer)

Correct answer: DNA replication

DNA replication is the process by which a cell copies its DNA so that each daughter cell receives a complete genome.

Question 31: Which micronutrient deficiency is the most common nutritional deficiency worldwide, affecting primarily women and children in developing regions?

Zinc deficiency
Iodine deficiency
Iron deficiency (Correct answer)
Vitamin A deficiency

Correct answer: Iron deficiency

Iron deficiency is the most prevalent nutritional deficiency globally, causing iron-deficiency anemia that impairs oxygen transport and cognitive development.

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.

100

Questions

120 min

Time Limit

70%

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