Principles Of Cell And Membrane Function Flashcards
Which phospholipids are primarily located in the outer leaflet of the cell membrane?
- Phosphatidylcholine
- Sphingomyelin
Which phospholipids are primarily located in the inner leaflet of the cell membrane?
- Phosphatidylethanolamine
- Phosphatidylserine
- Phosphatidylinositol
What is the significance of phosphatidylinositol?
It is a substrate for signal transduction via PLC
How does aspirin work to reduce clotting?
Blocking cyclooxygenase
How is the rate of Diffusion calculated for substances which diffuse through simple diffusion?
J (Rate) = -P (Permeability) * A (Surface Area) * [Ci-C0] (concentration gradient)
What is the partition coefficient (Beta)?
- Used to quantify interactions of molecules within the lipid portion of the bilateral of a membrane
- The more lipid soluble the molecule, the greater the rate of diffusion across the bilayer
What is the glycocalyx?
A layer of glycoproteins across the cell membrane which help to trap and digest, protect against toxic substance, or adhere to substances for uptake
What is the relevance of the
Nernst equation?
The Nernst equation describes the equilibrium potential for an ion. That is the potential across a
membrane that will produce an electrical force
equal and opposite to the chemical force
produced by the difference in concentration of the
ion across the membrane
Explain the role of aquaporins and vasopressin in the renal collecting ducts.
- Cells of the renal collecting ducts contain AQP3/4 in the basolateral membrane
- In the absence of vasopressin, There is no way for water to be reabsorbed into the blood.
- In the presence of vasopressin, AQP is inserted into the apical membrane allowing water to move from urine to blood.
- In the presence of vasopressin, urea recycling is increased
What are the two primary ways glucose is transported?
- Facilitated diffusion
- Secondary transport
Describe the site and primary characteristics of the GLUT 1 receptor?
- Brain, RBC, Endothelium, Muscle, Adipose
- Broad expression, high affinity
Describe the site and primary characteristics of the GLUT 2 receptor?
- Liver, Pancreas, intestine
- Low affinity, high capacity sensor
Describe the site and primary characteristics of the GLUT 3 receptor?
- Brain, Placenta, testes
- Primary GLUT in neurons
Describe the site and primary characteristics of the GLUT 4 receptor?
- Skeletal/cardiac muscle, adipose
- High affinity
Describe the site and primary characteristics of the GLUT 5 receptor?
- Small Intestine, Sperm
* *- Transports fructose
What process allows glucose to continually enter the cell by lowering intracellular glucose?
- Conversion Of Glucose to G6P via Hexokinase
Describe the pathology of Cystic Fibrosis?
- Autosomal recessive disease
- defect in CFTR which is an ATP binding transporter which functions as a Cl- channel, while also regulating other membrane transporters
What is P-g, and what is it’s significance?
- P-glycoprotein or ABCB1
- Common cause of individual variation of response to drugs
- ATP-dependent efflux pump with broad substrate deficiency
- Likely a defense mechanism against toxins
Differentiate SGLT1 and SGLT2.
- SGLT1 is in the intestinal mucosa, as well as proximal tubules of the kidney
- SGLT1 is approximately 2% of renal glucose reabsorption
- SGLT2 is 1 Glu/1Na+ transporter, while SGLT1 is 1Glu/2 Na+
Describe Why Oral rehydration therapy works for cholera.
- Na+ and Glu are cotransported from the gut to the blood.
- ORT using water with sodium Potassium, and glucose can increase uptake of water.
How does caveolae endocytosis differ from many other types of endocytosis?
It is clathrin independent
What is 2,4-dinitrophenol?
- Metabolic protein which uncoupled oxidative phosphorylation
- Carries proteins across my membrane
- results in hyperthermia
What is Sodium Azide?
- Metabolic poison
- Inhibits Cytochrome C oxidase (Complex IV)
- affects organs with high rates of respiration
