AP Biology 2.4 Diagnostic

Front

What is the structure of the plasma membrane?

Back

The plasma membrane is primarily composed of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates. The hydrophilic phosphate heads face outward towards the aqueous environments, while the hydrophobic fatty acid tails face inward, away from water.

Front

What role do unsaturated fatty acids play in the plasma membrane?

Back

Unsaturated fatty acids increase the fluidity of the plasma membrane, especially in cooler environments, by preventing the fatty acid chains from packing closely together.

Front

How does cholesterol affect the plasma membrane?

Back

Cholesterol helps maintain membrane fluidity by preventing the fatty acid chains of phospholipids from packing too closely together, thus allowing for flexibility and stability.

Front

What types of molecules can easily diffuse through the plasma membrane?

Back

Small and nonpolar molecules can easily diffuse across the plasma membrane due to their ability to pass through the hydrophobic lipid bilayer.

Front

What is the function of the Na+/Cl− pump in epithelial cells?

Back

The Na+/Cl− pump helps regulate the transport of sodium and chloride ions across the plasma membrane, which is crucial for maintaining electrolyte balance and proper mucus hydration.

Front

What happens to mucus in cystic fibrosis?

Back

In cystic fibrosis, the transport of chloride ions is disrupted, leading to decreased electrolyte concentration in mucus, resulting in thick, dehydrated mucus that obstructs airways.

Front

What is the significance of the hydrophilic and hydrophobic regions of phospholipids?

Back

The hydrophilic (water-attracting) phosphate heads face the aqueous environments, while the hydrophobic (water-repelling) fatty acid tails face inward, creating a barrier that regulates what enters and exits the cell.

Front

How does arsenic poisoning affect ATP production?

Back

Arsenic poisoning inhibits enzymes in the oxidative phosphorylation pathway, leading to decreased ATP production, which is essential for various cellular processes, including ion transport.

Front

What is the impact of decreased ATP on ion transport in cells?

Back

Decreased ATP levels impair the function of ion pumps, such as the Na+/Cl− pump, leading to disrupted ion balance and altered fluid movement in tissues.

Front

What is the role of carrier proteins in the plasma membrane?

Back

Carrier proteins facilitate the transport of specific molecules across the plasma membrane by changing shape to move substances from one side to the other.