AZSCI Structure and Function

Question 1

The alveoli in the human lungs are tiny, thin-walled air sacs. This structure is directly related to which function?

Accepted Answer

Efficiently exchanging gases with the blood

Answer

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?

Accepted Answer

They reduce water loss and provide protection.

Answer

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 (H₂O) 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?

Accepted Answer

Its ability to dissolve many different substances

Answer

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?

Accepted Answer

It provides a high strength-to-weight ratio.

Answer

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?

Accepted Answer

They reduce the overall mass of the bird.

Answer

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.

(AZSCI) Arizona Science Test Practice Test

(AZSCI) Arizona Science Test Practice Test

AZSCI Structure and Function