STEM Science Content Knowledge 2 — Questions and Answers
Question 1: Which type of chemical bond involves the sharing of electron pairs between atoms?
- Ionic bond
- Covalent bond (Correct answer)
- Hydrogen bond
- Metallic bond
Correct answer: Covalent bond
Covalent bonds form when two atoms share electron pairs, unlike ionic bonds where electrons are fully transferred.
Question 2: What is the primary function of mitochondria in eukaryotic cells?
- Protein synthesis
- DNA replication
- ATP production via cellular respiration (Correct answer)
- Lipid storage
Correct answer: ATP production via cellular respiration
Mitochondria are the powerhouses of the cell, generating ATP through oxidative phosphorylation during cellular respiration.
Question 3: According to Newton's Second Law of Motion, if the net force on an object doubles while mass remains constant, what happens to acceleration?
- It halves
- It stays the same
- It doubles (Correct answer)
- It quadruples
Correct answer: It doubles
Newton's Second Law states F = ma, so if F doubles and m is constant, acceleration a must also double.
Question 4: Which layer of Earth's atmosphere contains the ozone layer?
- Troposphere
- Stratosphere (Correct answer)
- Mesosphere
- Thermosphere
Correct answer: Stratosphere
The ozone layer is located within the stratosphere, approximately 15–35 km above Earth's surface.
Question 5: What is the name of the process by which plants convert light energy into chemical energy?
- Cellular respiration
- Chemosynthesis
- Photosynthesis (Correct answer)
- Fermentation
Correct answer: Photosynthesis
Photosynthesis is the process by which plants use sunlight, water, and CO₂ to produce glucose and oxygen.
Question 6: Which subatomic particle determines the atomic number of an element?
- Neutrons
- Electrons
- Protons (Correct answer)
- Quarks
Correct answer: Protons
The atomic number equals the number of protons in an atom's nucleus, uniquely identifying each element.
Question 7: When a wave moves from air into water, which property remains constant?
- Wavelength
- Speed
- Amplitude
- Frequency (Correct answer)
Correct answer: Frequency
Frequency remains constant when a wave changes medium; speed and wavelength change while frequency does not.
STEM Science Content Knowledge 2
Which type of chemical bond involves the sharing of electron pairs between atoms?