Through integral proteins (tube shaped proteins that have one opening in the extra cellular matrix and the other opening inside the cell).
Small particles move faster across the membrane.
large particles or cells are engulfed by the cell plasma membrane
cell membrane
exocytosis
exocytosis
The process that moves materials into cells is called endocytosis. During endocytosis, the cell membrane surrounds particles or substances outside the cell, forming a vesicle. The vesicle then fuses with the cell membrane and releases its contents into the cell.
The cell use something called a protein channel that helps larger particles across the cell membrane.
The Lugol's solution particles were able to cross the model cell membrane, while the starch particles were too large to pass through. Starch is a large molecule that cannot diffuse across the membrane, while Lugol's solution contains smaller molecules (iodine and iodide ions) that are able to pass through.
During Phagocytosis large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a phagosome, or "food vacuole."
Endocytosis - the way in which cells take in food and other materials. The cells membrane wraps around the particle it needs on its outside, ingesting it. This then becomes trapped within a vacuole inside the cells cytoplasm where it is broken down, digested, and absorbed by enzymes.
The cell membrane keeps out unwanted particles from the cell.
The method by which large particles and macromolecules enter the cell by an infolding of the plasma membrane is called endocytosis. This process involves the formation of vesicles that engulf the molecules and bring them into the cell. Endocytosis includes phagocytosis for solid particles and pinocytosis for liquid molecules.