Physiology - Cellular Flashcards
What lipids does the plasma membrane consist mostly of?
Phospholipids and cholesterol
What is the plasma membrane?
A fluid lipid bilayer embedded with proteins
What appearance does the plasma membrane have on an electron microscope?
Trilaminar
Describe the head of a phospholipid
Negatively charged, polar, hydrophilic
Describe the tail of a phospholipid
Uncharged, non-polar, hydrophobic
What contributes to the fluidity and stability of the membrane?
Cholesterol
Name the 3 types of membrane porteins that are insterted within or attached to the lipid bilayer
Integral proteins - embedded in the lipid bilayer (receptors)
Transmembrane proteins - extend through the membrane (e.g. transporters, channels)
Peripheral proteins - do not penetrate the membrane (more common intracellularly) (e.g. receptor-associated enzymes)
What is there a small amount of located on the outer surface of cells?
membrane carbohydrate
What layer do glycoproteins and glycolipids together form?
The glycocalyx
What do some transmembrane proteins form?
Water-filled highly-selective ion channels
What are calcium channel blockers used to manage?
Hypertension and abnormal heart rhythms
What disease is directly linked to genetic mutations in channels?
Cystic Fibrosis
What do carrier or transport proteins exhibit?
Substrate specificity - accept only a particular molecule (or ion) or group of closely related molecules.
Where are docking-marker acceptors located and what do they do?
Located on the inner membrane surface
Interact with secretory vesicles leading to exocytosis of the vesicle contents
Name a membrane bound enzyme?
Protein kinase C
Rececptors are commonly found on the outer surface and bind specific molecules such as?
Hormones
Name two types of cell adhesion molecules (CAMs)
- Cadherins
2. Integrins
What do cadherins do?
Help hold cells within tissues together
What do integrins do?
Span the plasma membrane acting as a link between extra and intracellular environments
What serve as self-identify markers?
Membrane carbohydrates
Name the three types of cell junctions
- Desmosomes
- Tight junctions
- Gap junctions
What are desmosomes?
Adhering junctions that anchor cells together, especially in tissues subject to stretching.
What are tight junctions?
They join the lateral edges of epithelial cells near their lumenal (apical) membranes. They can be tight or leaky.
What are gap junctions?
Gap junctions are communicating junctions that allow the movement of charge carrying ions and small molecules between two adjacent cells.