(DSA2) Cell Membranes and Transport Flashcards
What is a glycocalyx and what is its function?
DSA2 S19
Carbohydrate shell formed by glycoproteins and glycolipids in the outer leaflet.
Functions:
- protection
- cell adhesion
- cell identification (eg. RBCs)
What factors affect membrane fluidity and how do changes in these factors affect fluidity?
DSA2 S25-26;28 LO3
Temperature:
- increase in temp -> increase in fluidity
- decrease in temp -> decrease in fluidity
Lipid composition:
- long, saturated FAs -> decrease fluidity
- short, unsaturated FAs -> increase fluidity
Cholesterol:
- dampens fluidity due to temperature changes
- increases fluidity when added to rigid, saturated FA membrane
- decreases fluidity when added to fluid, unsaturated FA membrane
What are the main classifications of primary active transporters and what are examples of each?
DSA2 S47 LO6
P-type:
- hydrolyzes ATP and is phosphorylated at an ASPARTATE
- examples:
- Na+/K+-ATPase
- -Ca++-ATPase
ABC Transporter:
- hydrolyzes ATP but is not phosphorylated
- example:
- -P glycoprotein
What type of transporter is SGLT1 and what does it transport?
DSA2 S57 LO6
Sodium-glucose transporter 1
2 Na+ and 1 glucose
Unidirectional, secondary active transporter
What type of transporter is NCX and what does it transport?
DSA2 S57 LO6
Sodium-calcium exchanger
3 Na+ and 1 Ca++
Secondary active antiporter
What is Invokana?
DSA2 S59
SGLT2 inhibitor used to lower blood sugar and blood pressure by increasing urine output
How are dietary monosaccharides uptaken in the gut?
DSA2 S63-65 LO7
Polysaccharides are broken down into monosaccharides (glucose, galactose, and sucrose)
Across apical membrane of enterocyte:
- glucose and galactose
- -SGLT1 via secondary active transport
- sucrose
- -GLUT5 via facilitated diffusion
Across basolateral membrane of enterocyte:
-all transported by GLUT2 via facilitated diffusion
