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Properties of Cells
Concept Questions
Question #1

What is the minimum level of organization (atoms, molecules, macromolecules, etc.) that must exist before a structure can be said to be alive?

In which of the links below are biological structures described that may be either on or below this minimum level of organization?

Link-#12 Link-#63 Link-#81 Link-#44

Question #2

All eukaryotic cells are surrounded by a plasma membrane that performs a variety of roles. One of these roles is to act as a selective barrier to the passage of materials into and out of the cell.

There are many substances, however, that are to large to pass directly through the fluid mosaic of the membrane. In which of the links below is a solution to this problem discussed?

Link-#39 Link-#17 Link-#19 Link-#26

Question #3

To survive, cells must constantly try to accumulate vital molecules and substances within themselves. Many of these substance are in solution outside the cell in very low concentration.

In order to obtain as much of a vital substance as it can, a cell may have to transfer materials across the plasma membrane against a concentration gradient (i.e. more of the substance inside the cell than outside the cell). In which of the links below is the mechanism for this kind of process discussed and described?

Link-#88 Link-#82 Link-#83 Link-#85

Question #4

When dissolved in a solution, many molecules and substances start off as solids. These slowly dissolve in the surrounding water, and then, driven by thermal movement, begin to move away from their original location.

Slowly, the molecules and substances move, and move again further and further away from where they started. In which of the links below is this phenomenon discussed in relation to the needs of a living cell to find and accumulate vital materials?

Link-#22 Link-#31 Link-#42 Link-#53

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© 2002, Professor John Blamire