CELL 18 Cell Transport

For water to travel across the cell membrane at a substantial rate, the water molecules travel through PROTEIN CHANNELS known as aquaporins.

• Simple diffusion
• Facilitated diffusion
• Active transport

While water molecules are polar, they are also very small. One fact not mentioned in the video is that some water molecules are able to squeeze DIRECTLY through the phospholipid bilayer due to their small size.

• Simple diffusion
• Facilitated diffusion
• Active transport

Charged ions are traveling through PROTEIN CHANNELS in the cell membrane with the concentration gradient.

• Simple diffusion
• Facilitated diffusion
• Active transport

Cells lining the gut need to take in glucose, but at a certain time, the concentration of EXTRACELLULAR glucose is LOWER than the concentration already stored in the cells.

• Simple diffusion
• Facilitated diffusion
• Active transport

At a certain time, glucose is in a HIGH concentration OUTSIDE of a cell and needs to travel through the membrane INTO the cell.

• Simple diffusion
• Facilitated diffusion
• Active Transport