Lecture 6: How Does A Cell Maintain Its Internal Environment? Flashcards
What 5 main things does a cell have to do to survive?
- Manufacture cellular materials
- Obtain raw materials
- Remove waste
- Generate the required energy
- Control all of the above.
What does the cell membrane mainly consist of?
A phospholipid bilayer.
What does the phospholipid bilayer consist of?
Hydrophilic phosphate groups on either side with hydrophobic fatty acids in between.
What is a fluid membrane?
A membrane that has gaps between the phosphates and fatty acid bonds.
What does it mean if a membrane is viscous?
That there are no gaps between the phosphates and fatty acids.
What is the function of cholesterol in a cell membrane?
To help strengthen and decrease the permeability.
What types of molecules can diffuse through the phospholipid bilayer?
The phospholipid bilayer is permeable to lipid soluble (hydrophobic) molecules, which travel down the concentration gradient into the cell.
The movement of hydrophobic molecules through the phospholipid bilayer requires ________ ________.
The movement of hydrophobic molecules through the phospholipid bilayer requires MEMBRANE PROTEINS.
What is the movement of a specific substance down the concentration gradient through a protein called?
Facilitated diffusion.
What are the three types of gated membrane channels?
Gated, voltage-gated, and ligand gated.
What is active transport?
The movement of specific substances against their concentration gradient. Involves pumps and requires ATP.
Is energy required for facilitated diffusion?
No
What type of condition is epilepsy an example of?
A membrane channel defect (K+ channel)
What are three things that membrane proteins are involved in other than transport?
Cell recognition, intracellular joining, lining the cytoskeleton and matrix.
What are four examples of diseases caused by defects in transport proteins?
Epilepsy, albinism, Wilson’s disease, cystic fibrosis.
