Membrane Proteins that Bind Molecules have what types activity? What is the function of receptors? What do they bind and what is the result of if?
Membrane associated enzymes --> Internal/External reactions Receptor bind specific ligand and Ligand-receptor complex trigger intracellular response.
Name two types of Transport proteins?
Channel proteins and Carrier proteins
Channel proteins are
Open or Gated Open - have gates but spent most time in the open state Gated - usually closed, respond to chemical/ligand, mechanical, and voltage
Carrier proteins are
VERY SELECTIVE and never in open bind to substrate Slower transporters than channel proteins Do NOT depend on ATP energy
Name two types of Body fluid? What are they made up of?
1. Intracellular (ICF) 2. Extracellular (ECF) made up of plasma and Interstitial
Movement Across Membranes requirements? (Two types) explain each?
1. Energy requirements are required by all, difference is in the type of energy 2. Physical requirements: Simple diffusion - N/A Facultative diffusion - channels Secondary active transport - moving molecules based on the conc. gradient via primary active transport Primary active transport - ATP
Diffusion (3 things to mention)
1. Passive & down a concentration gradient 2. Stops at equilibrium 3. Rate factors: membrane, temperature, distance, & size
Fick's law of Diffusion:
= (Surface Area Conc. gradient)/(membrane resistance thickness of membrane)
Membrane resistance =
lipid solubility/molecular size
Carrier Mediated Transport can be
Passive or Active
Name three types of CMTransport?
Uniport & Contransport (Antiport or symport)
transport only one kind of substrate
move two or more substrates in the same direction across the membrane
move substrates in opposite directions
Facilitated Diffusion requires "_" and is "___"
uses transport proteins passive diffusion to equilibrium
Name example of Facilitated Diffusion and elaborate? Give example of regulation with/with out insulin
Glut transport: - found in most cells - transports in/out of cell [down conc. gradient] - several isoforms, some regulated by insulin/others not Ex. Glut4-skeletal muscle- insulin regulated Ex. Glut3-neurons-not insulin regulated
Primary Active Transport does what and why?
Pumps products uses ATP to move molecules up conc. gradient major function to create conc. gradient via unequal transfer of molecules across membrane
Secondary Active Transport uses
Kinetic Energy of [ion] - Cotransports [ion] restored - using ATP - Na+ --> glucose secondary active transport (SGLT) - Can only transport glucose into cells --> Intestinal and kindney epithelial cells
Modulation of Protein Transport is
similar to enzyme activity 1) Specificity 2) competition 3) Saturation
Vesicles in Membrane Transport
- move particles - large molecules - Phagosome - Phagocytes are cells that degrade bacteria
Endocytosis and Exocytosis Pinocytosis is non-selective Receptor mediated: specific substrate
Transepithelial and Transcytosis
Cross two membranes, APICAL and BASOLATERAL (bottom) Absorption Secreation
Transepithelial What transporters are used in moving glucose from gut lumen to extracellular fluid? Explain what they do and why?
SGLT = Na+ glucose symporter brings glucose into cell against its gradient using energy stored in the Na+ conc. gradient GLUT transporter transfers glucose to ECF by facilitated diffusion. Na+/K+ ATPase pumps Na+ out of the cell, keeping ICF Na+ conc. low.
Transcytosis What type of transporters used in transfer of plasma proteins from blood plasma to Interstitial fluid? Explain?
1. Plasma proteins are concentrated in caveolae, which then undergo endocytosis and form vesicles. 2. Vesicles cross the cell with help from the cytoskeleton. 3. Vesicles contents are released into interstitial fluid by exocytosis.
About what % of body weight is water?
What % of water is intracellular?
What % of water is extracellular? Of that, what % is plasma and what % is interstitial?
33%, 8%, and 25%.
% of water distribution varies? Give an example where would this be important?