Fluidity and Proteins
The cell membrane is known to be _______
Fluid (not static)
What aspect of hormone (ie cortisol) composition is key for their direct movement through a cell?
Small and nonpolar
What are the five types of membrane proteins?
Channel, transporter, enzyme, structural, receptor
An ion molecule is an example of a what?
Ligand
What is the name of the region that divides the epithelia into apical and basolateral regions?
Tight junction
Do carbon carbon bonds increase or decrease membrane fluidity?
Increase
The head of the phospholipid is considered ___________. The tail of the phospholipid is ___________.
Hydrophilic (water loving), hydrophobic (water hating)
What is the receptor/channel that would be most beneficial in the medical field and why?
G-protein coupled receptor, AMPLIFICATION (can argue enzyme-linked tho for medications)
What is the main difference between G-protein and enzyme linked receptors?
G-protein amplifies reaction, enzyme speeds up reaction
When a molecule enters the cell through the apical region and exits through the basal region, which pathway has been used?
Transcellular
What is one thing that influences membrane fluidity?
Composition of polar head; degree of saturation for tail (%of unsaturated vs saturated)
Phospholipids have the formation of what?
Self assembly, heads align with heads, tails align with tails
What is the difference between carbohydrates and proteins?
Carbohydrates are only on exterior for cell recognition, proteins can be inside or outside of membrane for multiple functions
What is the only receptor that doesn’t interact with extracellular fluid?
intracellular
What makes up the tight junctions?
structural proteins
Which proteins cannot be removed from the membrane without damage?
Integral (transmembrane)
What is the name of phospholipids and what is the overall net charge?
amphipathic, neutral
Explain why a sea bass would decrease the % of unsaturated fatty acids with increasing temperature.
Due to fish inability to thermoregulate, increasing water temperatures will lead to an increase in membrane fluidity of their cells. In order to counteract this and reestablish a more ideal membrane fluidity the animal will decrease the percentage of unsaturated hydrocarbon tails.
Where does the ligand bind and what happens after?
On receptor protein, ligand does NOT flow in, but opens channel to allow passage of other molecules
The microvilli on epithelial cells of the gut of animals are found on what side of the cell?
Apical
Where can peripheral proteins be found?
On both intracellular and extracellular sides of the membrane
What are the two groups that make up the phospholipid head?
+ choline group, - phosphate group
Explain how an integral protein can be multifunctional
Ligand gated channels can serve as a receptor in one region (where the ligand binds). Also as a channel in another region (where (x) molecule is passing through).
The ligand used for intracellular receptor proteins are what?
Transcription factors
Where does the apical region of the epithelium face?
Lumen (body cavity)