Question

1. glucose serves as a nutrient and fuel for cells. in which process is glucose primarily used?

(a) cellular respiration
b. the electron - transport chain
c. photosynthesis
d. photorespiration

1. oil spills in the ocean present significant environmental challenges. the largest oil spill in history was the deepwater horizon spill in 2010, where millions of barrels of crude oil were released into the gulf of mexico after an explosion on the oil rig. this spill had devastating effects on marine life, coastal ecosystems, and human industries. as soon as oil is spilled, it starts to spread out over the sea surface, initially forming a single slick. over time the oil spreads more and moves on the water surface, driven by wind and currents, and undergoes various chemical and physical changes known as weathering. processes such as natural dispersion, evaporation, oxidation, biodegradation, and emulsification play a role in the fate of the oil. given this, which option best describes why oil spilled in the ocean will float on the surface rather than dissolve into the water?

a. oil is a charged molecule, which means it repels water and cannot form ionic bonds with water molecules, causing the oil to remain on the surface.
b. oil is nonpolar and less dense than water, which causes it to float. because oil molecules cannot form hydrogen bonds with water molecules, they do not mix and instead spread out over the waters surface.
c. oil is polar and less dense than water, which causes it to float. the polar nature of oil molecules prevents them from mixing with water, so they stay on the surface.
d. oil is nonpolar and forms covalent bonds with water molecules, which keeps it on the waters surface.

1. cystic fibrosis (cf) is a genetic disorder that affects the respiratory and digestive systems. it is caused by mutations in the cftr gene, which encodes the cystic fibrosis transmembrane conductance regulator protein. read through the information below detailing the differences between the normal and abnormal cftr protein.

normal cftr protein:

• primary structure: the normal cftr protein is encoded by the cftr gene and has a specific sequence of amino acids.
• secondary and tertiary structure: cftr folds into a stable structure with alpha - helices and beta - sheets, forming a chloride channel that regulates the movement of chloride ions across the cell membrane.

abnormal cftr protein:

• primary structure: the most common mutation in the cftr gene is a deletion resulting in the loss of a single amino acid (phenylalanine) at position 508.
• structural change: this deletion causes improper folding and trafficking, preventing it from reaching the cell membrane and functioning correctly.

based on the passage above, which structural level of the cftr protein is affected, leading to the diseases symptoms?
(a) primary level
b. secondary level
c. tertiary level
d. quaternary level

Explanation:

1. Glucose is primarily used in cellular respiration as a nutrient and fuel for cells. In cellular respiration, glucose is broken - down to release energy.
2. Oil is non - polar and less dense than water. Non - polar molecules cannot form hydrogen bonds with water molecules (which are polar), so oil floats on water.
3. The most common mutation in CFTR is a deletion of a single amino acid in the primary structure of the protein. This change in the primary structure leads to improper folding and trafficking, causing the disease symptoms.

Answer:

1. a. Cellular respiration
2. b. Oil is nonpolar and less dense than water, which causes it to float. Because oil molecules cannot form hydrogen bonds with water molecules, they do not mix and instead spread out over the water's surface.
3. a. Primary level