OAT General Biology 2 — Questions and Answers
Question 1: Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?
- Rough endoplasmic reticulum
- Golgi apparatus (Correct answer)
- Lysosome
- Peroxisome
Correct answer: Golgi apparatus
The Golgi apparatus receives proteins from the ER and modifies, sorts, and packages them into vesicles for secretion or intracellular use.
Question 2: During which phase of meiosis do homologous chromosomes separate?
- Meiosis I anaphase (Correct answer)
- Meiosis II anaphase
- Meiosis I metaphase
- Meiosis II metaphase
Correct answer: Meiosis I anaphase
Homologous chromosome pairs separate during anaphase I of meiosis, while sister chromatids separate during anaphase II.
Question 3: Which type of RNA carries amino acids to the ribosome during translation?
- mRNA
- rRNA
- tRNA (Correct answer)
- snRNA
Correct answer: tRNA
Transfer RNA (tRNA) has an anticodon that matches the mRNA codon and carries the corresponding amino acid to the ribosome.
Question 4: The sodium-potassium pump moves ions against their concentration gradient, making it an example of:
- Facilitated diffusion
- Simple diffusion
- Active transport (Correct answer)
- Osmosis
Correct answer: Active transport
Active transport uses ATP energy to move substances against their concentration gradient, as the Na⁺/K⁺ pump does by moving 3 Na⁺ out and 2 K⁺ in per cycle.
Question 5: Which enzyme unwinds the DNA double helix ahead of the replication fork?
- DNA polymerase
- Primase
- Helicase (Correct answer)
- Ligase
Correct answer: Helicase
Helicase breaks hydrogen bonds between base pairs to unwind and separate the two DNA strands at the replication fork.
Question 6: In a food web, organisms that obtain energy by consuming primary producers are called:
- Detritivores
- Primary consumers (Correct answer)
- Secondary consumers
- Decomposers
Correct answer: Primary consumers
Primary consumers (herbivores) feed directly on producers (plants/algae), occupying the second trophic level.
Question 7: Which blood vessel type has walls only one cell layer thick, facilitating gas and nutrient exchange?
- Arteries
- Arterioles
- Veins
- Capillaries (Correct answer)
Correct answer: Capillaries
Capillaries have walls composed of a single layer of endothelial cells, enabling efficient diffusion of gases, nutrients, and wastes.
OAT General Biology 2
Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?