Can water carbon dioxide and oxygen pass through a cell wall?

Answer 1

Cell walls (membrane) have a layer of a type of fat called phosphor lipid)

Gasses such as oxygen and carbon dioxide can pass through the cell membrane through the process of diffusion (as in gas exchange in the lungs) from an area of high concentration to an area of low concentration.

Water can pass into the cell if the membrane is "selectively permiable" via the process of Osmosis. Osmosis can make water cross a membrane according to the amount of solutes in the water (sodium etc). The water will move where there is higher concentration of solutes. without letting the sodium though.

Other molecules such as Sodium, Potassium, Calcium, Glucose (all large molecules) cannot diffuse across the membrane into cells so they use dedicated protein channels embedded into the membrane. These channels can act as "switched gates" that can be opened or closed by other chemicals, this controls the amount of substances in and out of the cell.

Special Sodium, Potassium and Calcium channels (ion channels) which are opened when voltage in the cell increases and triggers the "open switch" letting in high levels of these molecules which results in a further increase in the cell voltage (action potential) which is the main mechanism for muscle contraction.

I hope this helps and is not too complicated. This is a subject that can get very involved but ive included some terms you can research further which can maybe help you out.

Check out diffusion (passive transport), Osmosis and action potential for further reading :)

Sources: Studied biochemistry

Answer 2

Yes. There are substances that are permeable.

Answer 3

H2O is able to travel across a plasma membrane fairly easily via osmosis. Most gases, including Oxygen and Carbon dioxide are able to easily cross a plasma membrane via diffusion.

Answer 4

Yes

Answer 5

water can, oxygen I'm not sure