What regulates the movement of molecules into and out of cytoplasm?
The membrane separates the extracellular space, outside of the cell, from the cytosol inside the cell. The plasma membrane is the border between the interior and exterior of a cell. As such, it controls passage of various molecules—including sugars, amino acids, ions, and water—into and out of the cell.
How do small molecules move between adjacent cells in a plant shoot?
The existence of plasmodesmata means that molecules can move between adjacent plant cells without the aid of transport proteins. Plasmodesmata exhibit some control of what passes through them. Small molecules such as ions or simple sugars can pass through more or less unrestricted.
Why are the cell membrane cytoplasm and nucleus considered the major parts of the cell?
Animal cells contain three main regions: plasma membrane, nucleus, and cytoplasm. The nucleus is a cell’s central organelle, which contains the cell’s DNA (Figure 3.6). Cytosol, the jelly-like substance within the cell, provides the fluid medium necessary for biochemical reactions.
What can pass through Plasmodesmata?
Smaller molecules (e.g. sugars and amino acids) and ions can easily pass through plasmodesmata by diffusion without the need for additional chemical energy. Larger molecules, including proteins (for example green fluorescent protein) and RNA, can also pass through the cytoplasmic sleeve diffusively.