OAT Biology 5 — Questions and Answers
Question 1: Which of the following is the correct order of taxonomic classification from broadest to most specific?
- Kingdom, Phylum, Class, Order, Family, Genus, Species (Correct answer)
- Kingdom, Class, Phylum, Order, Family, Genus, Species
- Phylum, Kingdom, Class, Order, Family, Genus, Species
- Kingdom, Phylum, Order, Class, Family, Genus, Species
Correct answer: Kingdom, Phylum, Class, Order, Family, Genus, Species
The standard Linnaean hierarchy proceeds: Kingdom → Phylum → Class → Order → Family → Genus → Species.
Question 2: The resting membrane potential of a typical neuron is approximately:
- +35 mV
- 0 mV
- -70 mV (Correct answer)
- -90 mV
Correct answer: -70 mV
The resting membrane potential of most neurons is approximately −70 mV, maintained by K⁺ leakage and the Na⁺/K⁺ pump.
Question 3: Which hormone is produced by the beta cells of the islets of Langerhans and lowers blood glucose?
- Glucagon
- Cortisol
- Insulin (Correct answer)
- Epinephrine
Correct answer: Insulin
Beta cells of the pancreatic islets secrete insulin in response to high blood glucose, promoting cellular glucose uptake.
Question 4: In which stage of cellular respiration is the majority of ATP produced?
- Glycolysis
- Pyruvate oxidation
- Krebs cycle
- Oxidative phosphorylation (Correct answer)
Correct answer: Oxidative phosphorylation
Oxidative phosphorylation via the electron transport chain and ATP synthase generates ~32–34 of the ~36–38 ATP per glucose.
Question 5: A cell lacking functional lysosomes would be MOST impaired in its ability to:
- Synthesize proteins
- Digest engulfed pathogens (Correct answer)
- Replicate DNA
- Produce ATP
Correct answer: Digest engulfed pathogens
Lysosomes contain hydrolytic enzymes that break down engulfed material; without them, intracellular digestion fails.
Question 6: Which type of symbiosis is demonstrated when a barnacle attaches to a whale, benefiting the barnacle while neither helping nor harming the whale?
- Mutualism
- Parasitism
- Commensalism (Correct answer)
- Amensalism
Correct answer: Commensalism
Commensalism describes a relationship where one organism benefits and the other is neither helped nor harmed.
Question 7: The gene for colorblindness is X-linked recessive. A colorblind woman (X^c X^c) mates with a man with normal vision (X^N Y). What fraction of their daughters will be colorblind?
- 0% (Correct answer)
- 25%
- 50%
- 100%
Correct answer: 0%
All daughters inherit X^c from their mother and X^N from their father, making them carriers (X^c X^N) with normal vision.
OAT Biology 5
Which of the following is the correct order of taxonomic classification from broadest to most specific?