MTTC MTTC Biology 5 — Questions and Answers
Question 1: Which of the following is an example of a density-dependent limiting factor on a population?
- A volcanic eruption
- A drought
- Competition for food resources (Correct answer)
- A hurricane
Correct answer: Competition for food resources
Density-dependent factors like intraspecific competition intensify as population density increases, regulating population growth.
Question 2: During which stage of embryonic development does gastrulation produce the three primary germ layers?
- Morula
- Blastula
- Gastrula (Correct answer)
- Neurula
Correct answer: Gastrula
Gastrulation transforms the blastula into a gastrula, forming the three germ layers: ectoderm, mesoderm, and endoderm.
Question 3: A biome characterized by permafrost, very low precipitation, and dominated by mosses and lichens is:
- Taiga
- Tundra (Correct answer)
- Desert
- Chaparral
Correct answer: Tundra
The tundra biome has permanently frozen subsoil (permafrost), extremely low precipitation, and supports only cold-adapted vegetation like mosses, lichens, and grasses.
Question 4: Which type of symbiosis benefits one organism while the other is neither harmed nor helped?
- Mutualism
- Parasitism
- Commensalism (Correct answer)
- Competition
Correct answer: Commensalism
In commensalism, one organism benefits and the other is unaffected; an example is barnacles attaching to a whale.
Question 5: Which structure connects a muscle to a bone?
- Ligament
- Cartilage
- Tendon (Correct answer)
- Fascia
Correct answer: Tendon
Tendons are dense connective tissue that attach skeletal muscles to bones, transmitting the force of muscle contraction to move the skeleton.
Question 6: A plant cell in a hypertonic solution undergoes plasmolysis. Which of the following describes this condition?
- The cell wall detaches from the nucleus
- The plasma membrane pulls away from the cell wall as water leaves (Correct answer)
- The chloroplasts break down due to osmotic pressure
- Water enters the cell, causing the central vacuole to expand
Correct answer: The plasma membrane pulls away from the cell wall as water leaves
Plasmolysis occurs when water leaves a plant cell by osmosis into a hypertonic environment, causing the plasma membrane to shrink away from the rigid cell wall.
Question 7: Which of the following best explains why the Hardy-Weinberg equilibrium is rarely observed in natural populations?
- Natural populations always experience mutation, selection, and genetic drift (Correct answer)
- Hardy-Weinberg only applies to asexual populations
- Dominant alleles always increase in frequency over time
- Natural populations never have two alleles for any given gene
Correct answer: Natural populations always experience mutation, selection, and genetic drift
Hardy-Weinberg equilibrium requires no mutation, random mating, no selection, infinite population size, and no gene flow — conditions virtually impossible in nature.
MTTC MTTC Biology 5
Which of the following is an example of a density-dependent limiting factor on a population?