CFA #3 Cell Transport & Homeostasis (16.3 & 16.4)

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 rise.
• 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. What is the most likely explanation for Wes's 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.

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

• osmosis
• exocytosis
• endocytosis
• diffusion

The movement of matter across a cell membrane against a concentration difference is called ___________, and it requires (aquaporins / energy / homeostasis / osmotic pressure).

• active transport
• passive transport
• facilitated diffusion
• osmosis

The movement of matter across a cell membrane against a concentration difference is called (active transport / passive transport / facilitated diffusion / osmosis), and it requires ____________.

• aquaporins
• energy
• homeostasis
• osmotic pressure

The model illustrates a process by which a substance is taken up by a cell. Which of the 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.

Which represents the hierarchical organization of a multicellular organism, from least complex level to most complex level?

• cell, organ, organ system, tissue
• tissue, cell, organ, organ system
• cell, tissue, organ, organ system
• organ, cell, tissue, organ system

Escherichia coli, or E. coli, is a species of bacteria. Entamoeba histolytica, or E. histolytica, is a single-celled amoeba. What do E. coli and E. histolytica have in common? Select the correct answer.

• They live without an energy source
• They are unable to respond to changes in their environment
• They maintain homeostasis by cell specialization
• They reproduce, or make more of their own kind

In the human nervous system, the brain is an example of what level of organization?

• cell
• tissue
• organ system
• organ