Investigation of Molecule Transport in Cells

Elizabeth is conducting an investigation to study how molecules are transported into and out of a cell. Elizabeth builds a model of a cell using a U-shaped tube. A barrier, which is permeable to water, but not sugar, is placed on the bottom of the tube to model the cell membrane. Elizabeth adds two different solutions to each side of the tube. The solute in each solution is sugar and the solvent is water. The initial levels of solution in Side A and Side B are equal. The concentration of sugar in Side A is lower than the concentration of sugar in Side B. What is Elizabeth likely to observe?

• Water molecules will move from Side A to Side B. The solution level on Side A will fall and the solution level on Side B will rise.

• Water molecules will move from Side B to Side A. The solution level on Side A will rise and the solution level on Side B will fall.

• Sugar molecules will move from Side A to Side B. The solution level on Side A will fall and the solution level on Side B will rise.

• Sugar molecules will move from Side B to Side A. The solution level on Side A will rise and the solution level on Side B will fall.

Which are examples of active transport across the cell membrane?

• osmosis and diffusion

• diffusion and facilitated diffusion

• osmosis and chemiosmosis

• endocytosis and exocytosis

Wes places red blood cells in a petri dish with pure water and observes them under a microscope. He drew a model to illustrate his observations.

• The red blood cells were placed into an isotonic solution. Water moved into and out of the cells to maintain homeostasis.

• The red blood cells were placed into an isotonic solution. Water moved into the cells until the cells burst.

• The red blood cells were placed in a hypertonic solution. Water moved from the inside of the cells to the outside of the cells to maintain homeostasis.

• The red blood cells were placed in a hypotonic solution. Water moved from the outside of the cells to the inside of the cells until the cells burst.

Tags

NGSS.HS-LS1-3

The pancreas produces enzymes that aid in digestion. By what process are these digestive enzymes excreted from pancreas cells?

• osmosis

• exocytosis

• endocytosis

• diffusion

The movement of matter across a cell membrane against a concentration difference is called ​ (a)   , and it requires ​ (b)   .

• active transport
• passive transport
• facilitated diffusion
• osmosis
• energy
• aquaporins
• homeostasis
• osmotic pressure

The model illustrates a process by which a substance is taken up by a cell. Which statements describe the process? Select the correct answer.

• The cell wall shown in the model is changed into a cell membrane.

• The process shown in the model requires energy from the cell.

• The cell membrane in the model remains intact throughout the process.

• The model shows the process of facilitated diffusion.