Chapter 5- The Working Cell Flashcards
What membrane protein is responsible for allowing water to pass through the cell membrane?
Aquaporin
What is aquaporin’s function?
To allow the passage of water molecules, water channels
One molecule of _____ allows ______ of _____ to stream through the cellular membrane every _____.
Aquaporin
Billion
Water molecules
Second
Aquaporin are common in cells involved in what?
Water balance
Give an example of a human organ where aquaporin proteins are vital to the organ’s proper functioning.
Kidneys
The kidneys filter and reabsorbs many liters of water per day
Defective aquaporin proteins could lead to what in humans? (Rare cases)
An inability of the kidneys to function properly and reabsorb water.
These people, though rare, must drink 20L per day to stay hydrated
Fluid retention during pregnancy is likely caused by what?
An increased synthesis of aquaporin proteins
What is the plasma membrane?
The boundary that encloses a living cell
The plasma membrane exhibits what traits?
Selective permeability
What is selective permeability?
Allowing some substance to cross (the plasma membrane) more easily than others
What are the 6 types of protein found in the plasma membrane?
Glycoprotein Junction protein Active transport protein Channel transport protein Receptor proteins Attachment proteins
Glycoproteins serve what function in the plasma membrane?
Serve as ID tags that are recognized by membrane proteins of other cells
The junction protein serves what function in the plasma membrane?
May form intercellular junctions that attach to adjacent cells
What is the function of Active Transport Proteins in the plasma membrane?
Allows specific ions or molecules to enter or exit the cell (ATP)
Give an example of a molecule allowed out of the cell through the Active Transport Protein?
Solute molecule
What is the plasma membrane composed of?
A phospholipid bilayer with protein molecules suspended in it, as well as enzymes and cholesterol.
Phospholipids are the key ingredient of _____?
Biological membranes
Phospholipids were probably among the first organic molecules that formed from _____.
Chemical reactions on early earth
What would have been a critical step in the evolution of the first cells?
The formation of membrane-enclosed collections of molecules.
What is a basic requirement for life for cells?
The ability to enclose a successful assembly of molecules
The ability to regulate chemical exchanges with its environment
What are the 4 functions of the plasma membrane?
- Maintains a high concentration of materials in the cell
- Keeps harmful materials out
- Control the movement of materials to and from the cell
- Let the cell sense its environment
Where are plasma membranes found?
Cell Nucleus Vacuoles Mitochondria Chloroplasts
The plasma membrane is embedded with what?
Proteins
Cholesterol
_____ gives the plasma membrane extra _____.
Cholesterol
Strength