Cell Membrane
Phospholipids are described as having both hydrophilic and hydrophobic regions, making them this type of molecule.
What is amphipathic?
The movement of substances from an area of high concentration to an area of low concentration is called this.
What is diffusion?
These two types of proteins can help substances cross the membrane during facilitated diffusion.
What are channel proteins and carrier proteins?
During osmosis, water moves toward the side of the membrane with this relative concentration of solute.
What is the higher solute concentration?
A molecule is small and nonpolar and moves directly through the phospholipid bilayer down its concentration gradient. What type of transport is occurring?
What is simple diffusion?
A phospholipid's tail region contains two chains made primarily of these nonpolar molecules.
What are fatty acids?
This type of transport moves substances down their concentration gradient and does not require ATP.
What is passive transport?
A membrane protein that provides a passageway for specific molecules or ions is called a protein ________.
What is a channel protein?
A cell is placed in a solution with a lower solute concentration than the cell. What will happen to water?
Water will move into the cell.
An ion moves from an area of high concentration to an area of low concentration through a membrane channel. Does this require ATP?
No. This is facilitated diffusion, a form of passive transport.
The cell membrane is described as selectively permeable. Explain what this means
The membrane allows some substances to cross more easily than others, controlling what enters and leaves the cell.
This type of transport requires ATP and can move substances against their concentration gradient.
What is active transport?
A membrane protein that binds to a substance and changes shape to move it across the membrane is called this.
What is a carrier protein?
A red blood cell is placed in a solution with a much higher solute concentration than the cell. Predict what will happen to the cell.
Water will leave the cell by osmosis, causing the cell to shrink.
A cell is placed in a solution with a higher concentration of solutes outside the cell. Water moves out of the cell, causing the cell to shrink. What type of solution is the cell in?
What is a hypertonic solution?
If phospholipids are placed in water, predict what would happen to the hydrophobic tails and explain why.
The tails would cluster together away from water because they are nonpolar and hydrophobic. This drives formation of structures such as bilayers and liposomes.
Oxygen moves directly through the phospholipid bilayer from an area of high concentration to low concentration. What type of transport is this?
What is simple diffusion?
These specialized membrane proteins form channels that allow water to rapidly cross the plasma membrane.
What are aquaporins?
A cell has a 10% solute concentration. It is placed in a solution containing 20% solute. Which direction will water move, and why?
Water will move out of the cell, from the area of lower solute concentration toward the area of higher solute concentration.
A cell is placed in a solution with a higher solute concentration than the cell. Predict what will happen to the cell's water and explain why.
Water will move out of the cell by osmosis toward the area with the higher solute concentration. The cell will lose water and may shrink.
This type of fatty acid would make a cell membrane more permeable.
What is an unsaturated fatty acid?
A cell uses ATP to move sodium ions from an area where they are less concentrated to an area where they are more concentrated. Identify the type of transport and explain your reasoning.
Active transport, because the ions are moving against their concentration gradient and the cell is using ATP.
How many sodium ions are pumped out of the cell and how many potassium ions are pumped into the cell by the sodium-potassium pump during each cycle?
3 sodium ions out and 2 potassium ions in.
What happens when a cell is placed into a solution with a lower solute concentration, causing water to enter the cell until it expands and bursts?
What is cell lysis?
A cell uses ATP to pump sodium ions out of the cell even though there is already a higher concentration of sodium outside the cell. What type of transport is this, and why?
Active transport, because sodium is being moved against its concentration gradient and the process requires ATP.