BGS, BSGS Bachelor of General Studies BSGS Natural Sciences 2 — Questions and Answers
Question 1: Which organelle is responsible for producing ATP through cellular respiration in eukaryotic cells?
- Ribosome
- Mitochondria (Correct answer)
- Golgi apparatus
- Endoplasmic reticulum
Correct answer: Mitochondria
Mitochondria are the sites of aerobic respiration and generate most of the cell's ATP via the electron transport chain.
Question 2: What is the primary greenhouse gas emitted by human agricultural activities, particularly from livestock and rice paddies?
- Carbon dioxide
- Nitrous oxide
- Methane (Correct answer)
- Ozone
Correct answer: Methane
Methane (CH₄) is produced by enteric fermentation in ruminants and anaerobic decomposition in flooded rice fields.
Question 3: In Mendelian genetics, if two heterozygous parents (Aa × Aa) are crossed, what fraction of offspring are expected to be homozygous dominant?
- 1/4 (Correct answer)
- 1/2
- 3/4
- 1/3
Correct answer: 1/4
A Punnett square for Aa × Aa yields AA:Aa:aa in a 1:2:1 ratio, so 1/4 are homozygous dominant (AA).
Question 4: Which layer of the Earth's atmosphere contains the ozone layer that absorbs most incoming ultraviolet radiation?
- Troposphere
- Stratosphere (Correct answer)
- Mesosphere
- Thermosphere
Correct answer: Stratosphere
The ozone layer sits within the stratosphere, roughly 15–35 km above Earth's surface, shielding life from harmful UV-B and UV-C radiation.
Question 5: What type of chemical bond involves the sharing of electron pairs between two nonmetal atoms?
- Ionic bond
- Metallic bond
- Covalent bond (Correct answer)
- Hydrogen bond
Correct answer: Covalent bond
Covalent bonds form when atoms share electrons, as seen in molecules like H₂O and CO₂.
Question 6: Which principle states that the position and momentum of a particle cannot both be precisely known at the same time?
- Pauli exclusion principle
- Heisenberg uncertainty principle (Correct answer)
- Aufbau principle
- Hund's rule
Correct answer: Heisenberg uncertainty principle
Heisenberg's uncertainty principle (ΔxΔp ≥ ħ/2) establishes a fundamental limit on simultaneous measurement precision.
Question 7: In ecology, which term describes a species that has a disproportionately large impact on its ecosystem relative to its abundance?
- Invasive species
- Keystone species (Correct answer)
- Endemic species
- Apex predator
Correct answer: Keystone species
A keystone species, such as sea otters or wolves, maintains ecological balance and biodiversity far beyond what its population size would suggest.
BGS, BSGS Bachelor of General Studies BSGS Natural Sciences 2
Which organelle is responsible for producing ATP through cellular respiration in eukaryotic cells?