Phospholipid Membrane Flashcards
What molecules is the plasma membrane of a cell made of?
Phospholipids
Can you draw a simple diagram of a phospholipid? Indicate on your diagram which part of the phospholipid is hydrophilic, and which part of it is hydrophobic.
Yes
Phospholipids form what bilayer?
Forms lipid bilayer spontaneously in water
The ___ of a substance determines how it moves through the cell membrane. (semi-permeable)
Structure (size & polarity)
Do smaller or larger molecules move more easily through the cell membrane?
Smaller
Do polar or non-polar move more easily through the cell membrane?
Non-polar
Is this true? Small hydrophobic molecules move more easily through the cell membrane than large, charged hydrophilic ones.
Yes
When water moves across a selectively permeable membrane down its concentration gradient, this is called?
Osmosis
What is diffusion?
Substances moving from high concentration to low concentration, then eventually become equally distributed across cell membranes.
What are the 3 solution types?
Hypertonic, Hypotonic, Isotonic
What is a hypertonic solution? If you put a cell into a hypertonic solution what will happen to the cell?
A hypertonic solution is a higher concentration of solutes than comparison.
The cell will shrink.
What is a hypotonic solution? If you put a cell into a hypotonic solution what will happen to the cell?
A hypotonic solution is a lower concentration of solutes than comparison.
The cell will swell.
What is an Isotonic solution? If you put a cell into an Isotonic solution what will happen to the cell?
An Isotonic solution is an equal concentration of solutes with comparison.
The cell will stay the same size.
What type of protein would you expect to find in the membrane of a kidney cell that must be highly permeable to water?
Aquaporins
Can glucose cross the plasma membrane of a cell quickly and easily by simple diffusion? Explain your answer.
Larger uncharged polar molecules such as glucose are unable to cross the plasma membrane by passive diffusion.
What are the 2 types of passive transport and define them.
Simple diffusion: substance freely moves across the membrane.
Facilitated diffusion: substance moves across with help.
How are simple and facilitated diffusion the same?
Simple diffusion and facilitated diffusion are similar in that both involve movement down the concentration gradient.
How are simple and facilitated diffusion different?
The difference is how the substance gets through the cell membrane. In simple diffusion, the substance passes between the phospholipids. In facilitated diffusion, there are specialized membrane channels.
What are the 2 types of transport?
Passive & Active
What is active transport and its requirements?
When the substance is actively moved across the membrane.
Membrane protien
Energy (ATP)
When substances are too big for membrane proteins in Active Transport what happens?
The membrane becomes a transport vessel.
Exocytosis: moving substances outside the cell.
Endocytosis: moving substances inside the cell.
Rank these from most to least likely to cross a cell membrane by simple diffusion.
Large non-polar
Small non-polar
Large polar
Small polar
Charged
Most - Least
Small non-polar, Large non-polar, Small polar, Large polar, Charged
What’s the difference of hydrophilic and hydrophobic?
Something defined as hydrophilic is actually attracted to water, while something that is hydrophobic resists water.
