Membrane Review

Membrane Review

Molecules are constantly in motion… this motion is referred to as ______motion. As the molecules move, they bump into the cell membrane. The cell membrane’s job is to maintain cellular ______and therefore, it only allows some substances across. The two characteristics that determine what goes across are ______and ______. The term that describes the “picky-ness” of the membrane is ______. State three examples of how the structure of the cell membrane plays an important role in the body:

Some molecules are able to move across the membrane without the cell having to expend any energy. This form of transport is called ______transport. There are three processes that are in this category.

DIFFUSION is the spreading out of molecules from ______concentration to ______concentration. Initially, a concentration ______exists across a membrane. But, after the molecules move, then they are evenly spread out, scientifically called ______. State and explain one situation in which diffusion is seen in our body:

The second form of passive transport is similar to the first and is called FACILITATED DIFFUSION This is when molecules cross the membrane through ______. The type of molecules that go through the membrane are ______(give examples: ______) OR ______(give examples: ______).

The third form of passive transport, OSMOSIS specifically refers to the movement of ______across a selectively permeable membrane. This transport can dramatically affect cells. If a cell’s concentration of salt is higher than the surrounding liquid (meaning there is LESS / MORE water inside the cell), water will ENTER / EXIT the cell causing it to EXPAND / SHRINK. This type of solution is called ______. If there is more salt on the outside of the cell (meaning there is LESS / MORE water on the outside of the cell), water will ENTER / EXIT the cell causing it to EXPAND / SHRINK. This type of solution is called ______. If the levels of salt and water are equal both inside and outside the cell, then the cell is in an ______solution and no net change occurs. State and describe at least three examples of the effects of osmosis on living things:

The next type of transport uses energy in the form of ______. This type of transport is therefore called ______transport. The protein ______in the membrane function in moving the molecules across. Molecules are usually moved from ______to ______concentration through these proteins. They go AGAINST the concentration gradient. The type of molecules that go through the membrane by this process are ______(give examples: ______) OR ______(give examples: ______).

Lastly, ______molecules such as ______and ______cannot even get through the membrane. The membrane opens up and surrounds particles in a process called ______. If the substance is being expelled, the process is called ______. State and explain one example of endoxytosis:

State and explain one example of exocytosis: