Obtaining and Removing Materials

Obtaining and Removing Materials

by Christine Boudreau

Multiple Choice

An amoeba is a single-celled organism. Amoebas extend their cell membrane around a food particle or prey organism. Then, they bring the food into the cell, as is shown in the illustration.

Which term best describes the cell process amoebas use to get food?

• exocytosis

• endocytosis

• passive transport

• facilitated diffusion

Multiple Choice

Cholera is a disease caused by Vibrio cholerae bacteria. Cholera gets into the body through contaminated water or food. Severe diarrhea from cholera can kill a person in just a few hours. In the first stage of cholera, the bacterium finds a host cell in the small intestine. The bacterium then releases toxic proteins called toxins near the host cell. Through which process could a large molecule such as a protein leave the cholera cell?

• osmosis

• diffusion

• exocytosis

• endocytosis

Multiple Choice

Cholera is a disease caused by Vibrio cholerae bacteria. Cholera gets into the body through contaminated water or food. Severe diarrhea from cholera can kill a person in just a few hours. Intestinal cells are fooled by the shape of the cholera toxin and let it into the cell. Next, the toxin causes the cell to eject its small particles the cell needs to function outside the cell membrane. Soon, the cell has a lower concentration of the particles than the intestinal fluid. Which process could the cell use to eject the particles?

• The cell uses passive transport and the particles diffuse across the cell membrane.

• The cell uses active transport and the particles diffuse across the cell membrane.

• The cell uses passive transport to pick up the particles and move them across the cell membrane.

• The cell uses active transport to pick up the particles and move them across the cell membrane.

Multiple Choice

Preventing cholera is as simple as providing safe, clean drinking water. Emergency water filter pouches help to do exactly this. They are filled with sugar syrup and salt. You drop the pouch into muddy water or even urine. After a few hours, the pouch fills with enough drinking water for a whole day. The flavor is like a sports drink. Which of the following could explain how an emergency water filter pouch makes a safe drink out of dirty water?

• The pouch brings in water by endocytosis. The water combines with the salt and sugar to make a safe drink.

• Dirty water passes into the pouch. Microorganisms are pushed out of the pouch by exocytosis, making a safe drink.

• The pouch is a semipermeable membrane. Water moves into the pouch by osmosis and dissolves the syrup to make a safe drink.

• The salt and sugar in the pouch pass through the pouch into the water by facilitated diffusion. They kill any germs in the dirty water, making it safe to drink.