BS Bachelor of Science: Intro to Life Sciences 3 — Questions and Answers
Question 1: Which domain of life includes organisms with membrane-bound nuclei and complex internal organelles?
- Bacteria
- Archaea
- Eukarya (Correct answer)
- Protista
Correct answer: Eukarya
Domain Eukarya encompasses all organisms whose cells have a true membrane-bound nucleus.
Question 2: The scientific name of an organism consists of its genus and species following which naming convention?
- Common nomenclature
- Binomial nomenclature (Correct answer)
- Trinomial nomenclature
- Monomial nomenclature
Correct answer: Binomial nomenclature
Binomial nomenclature, developed by Linnaeus, uses a two-part Latinized name (genus + species).
Question 3: Which type of natural selection favors individuals at both extremes of a phenotypic range over intermediate phenotypes?
- Directional selection
- Stabilizing selection
- Disruptive selection (Correct answer)
- Sexual selection
Correct answer: Disruptive selection
Disruptive selection increases the frequency of extreme phenotypes, potentially leading to speciation.
Question 4: The Krebs cycle (citric acid cycle) takes place in which part of the mitochondria?
- Outer membrane
- Intermembrane space
- Inner membrane
- Matrix (Correct answer)
Correct answer: Matrix
The Krebs cycle enzymes are located in the mitochondrial matrix, the fluid-filled interior.
Question 5: Which macromolecule provides the structural framework for cell membranes?
- Proteins
- Phospholipids (Correct answer)
- Carbohydrates
- Nucleic acids
Correct answer: Phospholipids
Phospholipids form the bilayer that constitutes the basic structural framework of all cell membranes.
Question 6: An organism that can fix atmospheric nitrogen into a usable form for plants is called a:
- Nitrifying bacterium
- Denitrifying bacterium
- Nitrogen-fixing bacterium (Correct answer)
- Ammonifying bacterium
Correct answer: Nitrogen-fixing bacterium
Nitrogen-fixing bacteria (e.g., Rhizobium) convert N₂ gas into ammonia (NH₃) using the nitrogenase enzyme.
Question 7: Which phenomenon describes the evolutionary process where unrelated species develop similar traits due to similar environmental pressures?
- Divergent evolution
- Coevolution
- Convergent evolution (Correct answer)
- Adaptive radiation
Correct answer: Convergent evolution
Convergent evolution produces analogous structures in unrelated lineages facing similar selective pressures.
BS Bachelor of Science: Intro to Life Sciences 3
Which domain of life includes organisms with membrane-bound nuclei and complex internal organelles?