GRE Subject Test: Biochemistry, Cell, and Molecular Biology › Help with Junction Functions
What is the main purpose of gap junctions?
Allows molecules and ions to travel between cells
Prevents water from moving between cells
Prevents cells from separating from one another
Allows large molecules to move between cells
Gap junctions can be thought of as small tunnels between cells. They allow for the immediate transport of ions and molecules between the cells. Gap junctions are prominent in cardiac myocytes, and help spread action potentials via electrical synapses to coordinate the contraction of the heart.
Which cellular junction will be most useful in preventing the movement of material between cell membranes?
Tight junctions
Desmosomes
Gap junctions
Hemidesmosomes
The movement of substances between cells is most commonly controlled by tight junctions. These junctions can be regulated, which can alter how strongly they resist the movement of material between cells, like those in the digestive tract during absorption.