AZSCI Structure and Function 1 — Questions and Answers
Question 1: The alveoli in the human lungs are tiny, thin-walled air sacs. This structure is directly related to which function?
- Filtering dust and particles from the air
- Producing mucus to trap pathogens
- Efficiently exchanging gases with the blood (Correct answer)
- Strengthening the lung tissue against pressure changes
Correct answer: Efficiently exchanging gases with the blood
The thin walls of the alveoli (one cell thick) create a very short distance for gases to travel, allowing for rapid and efficient exchange of oxygen and carbon dioxide between the lungs and the bloodstream.
Question 2: A cactus has a thick, waxy coating called a cuticle, and its leaves are modified into spines. How do these structures help the cactus survive in a desert environment?
- They help the cactus absorb more sunlight for photosynthesis.
- They reduce water loss and provide protection. (Correct answer)
- They increase the plant's ability to absorb nutrients from the soil.
- They allow the cactus to grow taller than other desert plants.
Correct answer: They reduce water loss and provide protection.
The waxy cuticle prevents water from evaporating from the plant's surface, and the spines reduce the surface area exposed to the sun and wind, further minimizing water loss compared to broad leaves. Spines also deter animals from eating the cactus.
Question 3: The shape of a water molecule (Hâ‚‚O) is bent, with the oxygen atom having a slight negative charge and the hydrogen atoms having slight positive charges. This polar structure is primarily responsible for which important function of water?
- Its ability to exist as a solid, liquid, and gas on Earth
- Its ability to dissolve many different substances (Correct answer)
- Its neutral pH of 7
- Its high boiling point compared to other similar-sized molecules
Correct answer: Its ability to dissolve many different substances
The polarity of water molecules allows them to form hydrogen bonds with each other and to attract other polar molecules and ions. This makes water an excellent solvent, capable of dissolving a wide variety of substances, which is crucial for biological and chemical processes.
Question 4: Engineers often use a honeycomb structure in materials for airplanes and spacecraft. What is the primary functional advantage of this structure?
- It provides a high strength-to-weight ratio. (Correct answer)
- It is the easiest structure to manufacture.
- It is completely waterproof.
- It is an excellent electrical insulator.
Correct answer: It provides a high strength-to-weight ratio.
The hexagonal shape of the honeycomb is incredibly efficient at distributing forces. This allows it to be very strong and rigid while using a minimal amount of material, resulting in a structure that is very light for its strength.
Question 5: The hollow bones of a bird are an adaptation for flight. How does this structure support this function?
- They make the bird more flexible for maneuvering.
- They store extra oxygen for long flights.
- They reduce the overall mass of the bird. (Correct answer)
- They provide better protection for internal organs upon landing.
Correct answer: They reduce the overall mass of the bird.
Hollow bones, often reinforced with internal struts, significantly reduce the bird's overall weight. A lighter body requires less energy to lift and keep airborne, making flight more efficient.
Question 6: How does the structure of a neuron, with its long axon and branching dendrites, relate to its function in the nervous system?
- It allows for the storage of large amounts of energy.
- It provides structural support to surrounding tissues.
- It enables the production of hormones for the endocrine system.
- It allows for transmitting and receiving signals over distances. (Correct answer)
Correct answer: It allows for transmitting and receiving signals over distances.
Dendrites are structured to receive signals from many other neurons, while the long axon is structured to transmit that signal over a distance to other cells (neurons, muscles, or glands). This specialized shape allows for the rapid transmission of information throughout the body.
Question 7: The layered appearance of sedimentary rock is a direct result of its formation process. This structure provides evidence for what function or process?
- The cooling and crystallization of molten magma.
- The deposition of materials in layers over time. (Correct answer)
- The intense heat and pressure changing a rock's form.
- The rapid erosion of a single type of rock by wind.
Correct answer: The deposition of materials in layers over time.
Sedimentary rocks are formed from the accumulation and compaction of sediments (like sand, silt, and clay) over long periods. Each layer represents a different period of deposition, so the layered structure is a direct record of this process.
AZSCI Structure and Function 1
The alveoli in the human lungs are tiny, thin-walled air sacs.
This structure is directly related to which function?