Admin Table of Contents
- 1 What happens when the concentration of a substance is unequal on each side of the cell membrane?
- 2 What happens when the concentration of molecules on both sides of a cell membrane is in equilibrium?
- 3 What is it called when there are equal amounts of a substance on the inside and outside of a cell?
- 4 When the concentration of a substance is the same on both sides of the membrane the concentration is in?
- 5 Why is the plasma membrane selectively permeable?
- 6 What are the hydrophilic and hydrophobic parts of the cell membrane?
What happens when the concentration of a substance is unequal on each side of the cell membrane?
Suppose a substance is present in unequal concentrations on either side of a cell membrane, as shown in the figure at right. If the substance can cross the cell membrane, its particles will tend to move toward the area where it is less concentrated until equilibrium is reached.
What happens when the concentration of molecules on both sides of a cell membrane is in equilibrium?
Since diffusion moves materials from an area of higher concentration to the lower, it is described as moving solutes “down the concentration gradient.” The end result of diffusion is an equal concentration, or equilibrium, of molecules on both sides of the membrane. At equilibrium, movement of molecules does not stop.
What is it called when there are equal amounts of a substance on the inside and outside of a cell?
An isotonic solution is a solution in which the amount of dissolved material is equal both inside and outside of the cell.
When the concentration of water molecules on both sides of a membrane is the same the water molecules will?
When the concentration is the same on both sides of the membrane, the movement of water molecules will be the same in both directions. At this point, the net exchange of water is zero and there is no further change in the liquid levels.
When molecules are even throughout a space it is called?
When the molecules are even throughout a space – it is called EQUILIBRIUM. Concentration gradient – a difference between concentrations in a space. Molecules will always move down the concentration gradient, toward areas of lesser concentration.
When the concentration of a substance is the same on both sides of the membrane the concentration is in?
Vocabulary Language: English ▼ English
| Term | Definition |
|---|---|
| diffusion | the tendency of molecules to move from an area of high concentration to an area of low concentration until the concentration is uniform. |
| equilibrium | equal concentration of molecules on both sides of the membrane. |
Why is the plasma membrane selectively permeable?
The plasma membrane is selectively permeable. This means that the membrane allows some materials to freely enter or leave the cell, while other materials cannot move freely, but require the use of a specialized structure, and occasionally, even energy investment for crossing. 8.1 | Membrane Components and Structure
What are the hydrophilic and hydrophobic parts of the cell membrane?
The hydrophilic “head” of these molecules are in contact with the aqueous fluid both inside and outside the cell. The hydrophobic “tails” face each other in the inside of the bilayer.
What molecules do not pass through the plasma membrane?
Molecules of oxygen and carbon dioxide have no charge and so pass through membranes by simple diffusion. Polar substances present problems for the membrane. While some polar molecules connect easily with the outside of a cell, they cannot readily pass through the lipid core of the plasma membrane.
What is the fabric of the cell membrane composed of?
The main fabric of the membrane is composed of amphiphilic phospholipid molecules. Recall from chapter 4 that a phospholipid is a molecule consisting of glycerol, two fatty acids, and a phosphate-linked head group ( Figure 8.3) . The hydrophilic “head” of these molecules are in contact with the aqueous fluid both inside and outside the cell.