Nutrient Absorption Flashcards
Diffusion
Which fibers pass through?
Water & small lipids cross membranes freely —> equalizes 2 sides of the membrane
Soluble fibers that pass through: pectin, cellulose
Facilitated Diffusion/Passive Transport System
Carrier protein facilitates transport of nutrients: regulated by the affinity of a protein to makeup of nutrients
Active Transport System
Protein does its own job
Requires ATP & sodium
Endocytosis
Large molecules have certain affinity when they touch-down on membrane & engulfed into the cell (ex. Pinocytosis)
Vitamin K function
Important for blood coagulation
Glucose Transporter in the Membrane
Na+ glucose symporter & a glucose unioorter operate on opposite sides of epithelial cells to facilitate movement of glucose from intestine to the blood
(Active transport)
Cell Membrane Composition
Phospholipids
Proteins
Carbohydrates
Cholesterol
(Held together by non-covalent interactions)
Cell Membrane & Cholesterol Function
Membrane: Facilitates transport in & out of cell
Cholesterol: enhances mechanical stability & membrane fluidity (affects protein function)
Phospholipid Structure (head to tail)
- Polar group head (hydrophilic)
- Phosphate
- Glycerol
- 2 Fatty acid chains (hydrophobic non polar tails)
Non polar Tails
They are hydrophobic
One saturated fatty acid (straight)
One unsaturated fatty acid (bent)
Cardiolipin
Major component of inner mitochondrial membrane (NOT plasma membrane)
Phosphatidylcholine, Phosphatidylethanolamine, & Phosphatidylglycerol function
Important in signal transduction triggered by hormones
Smooth ER function
Region of ER involved in lipid synthesis
No ribosomes and not involved in protein synthesis
Rough ER function
Series of membrane sacks that contain ribosomes that synthesize proteins
ER function
Provides continuity between the nuclear envelope, the Golgi apparatus, and the plasma membrane
