Discuss the Movement of Substances in Cells
Discuss the movement (of substances) inside cells
Substances can travel from inside the cell out and from outside of the cell inwards across a membrane. Movement of substances also occurs inside the cell and is part of many of the processes that occur inside cells in both eukaryotic and prokaryotic cells as well as animal and plant cells.
The movement of substances may occur across a semi-permeable membrane such as the phospholipid bilayer membrane on the outside of a cell in the digestive tract of an animal. A semi-permeable membrane allows some substances to pass through, but not others.
The substances, whose movements are being described, are made up of a solvent and the substance dissolved in the solvent, the solute.
Movement of substances may occur from higher to lower concentrations (down the concentration gradient) or from the opposite direction (up or against the gradient).
Solute concentrations vary. A solution may be hypertonic, a higher concentration of solutes, hypotonic (a lower concentration of solutes), or isotonic (an equal concentration of solutes) compared to another region.
The movement of substances may be passive or active. If movement is with the concentration or gradient, it is passive. If movement is against the gradient, it is active and requires energy.
Passive transport describes the movement of substances down a concentration gradient and does not require energy consumption. There are many types of passive transport, for example: Diffusion, diffusion is the net movement of substances from an area of higher concentration to an area of lower concentration. This movement occurs as a result of the random and constant motion characteristic of all molecules, atoms, or ions (due to kinetic energy) and is independent from the motion of other molecules. Since at any one time some molecules may be moving against the concentration gradient and some molecules may be moving down the concentration gradient (remember, the motion is
Substances can travel from inside the cell out and from outside of the cell inwards across a membrane. Movement of substances also occurs inside the cell and is part of many of the processes that occur inside cells in both eukaryotic and prokaryotic cells as well as animal and plant cells.
The movement of substances may occur across a semi-permeable membrane such as the phospholipid bilayer membrane on the outside of a cell in the digestive tract of an animal. A semi-permeable membrane allows some substances to pass through, but not others.
The substances, whose movements are being described, are made up of a solvent and the substance dissolved in the solvent, the solute.
Movement of substances may occur from higher to lower concentrations (down the concentration gradient) or from the opposite direction (up or against the gradient).
Solute concentrations vary. A solution may be hypertonic, a higher concentration of solutes, hypotonic (a lower concentration of solutes), or isotonic (an equal concentration of solutes) compared to another region.
The movement of substances may be passive or active. If movement is with the concentration or gradient, it is passive. If movement is against the gradient, it is active and requires energy.
Passive transport describes the movement of substances down a concentration gradient and does not require energy consumption. There are many types of passive transport, for example: Diffusion, diffusion is the net movement of substances from an area of higher concentration to an area of lower concentration. This movement occurs as a result of the random and constant motion characteristic of all molecules, atoms, or ions (due to kinetic energy) and is independent from the motion of other molecules. Since at any one time some molecules may be moving against the concentration gradient and some molecules may be moving down the concentration gradient (remember, the motion is