BSI Lecture 13 Membrane Transport part 2 Flashcards
All carrier-mediated transport systems (excluding ion channels) exhibit _______ kinetics.
saturation
Saturation Kinetics is due to a _________ number of transporter molecules.
finite
T or F? When multiple substances are transported, the binding of one substance often enhances subsequent binding.
true
In facilitated transport, a substance is normally impermeable to the membrane and uses a form of transport that relies purely on the flow of a substance down it’s ________ _________
concentration gradient
Most glucose uptake by cells are done by __________ transport
facilitated
_________ exerts its effects by increasing the number of transporter molecules in the cell membrane.
insulin
Insulin exerts its effects by changing the kinetics or turning transporters “on.” T of F?
False. It increases the number of transporter molecules in the cell membrane.
What other molecules does facilitate diffusion transport besides glucose?
fructose and galactose
After the glucose binds to the receptor site, what happens next?
Conformational change resulting in the glucose facing the opposite side of the membrane.
Facilitated diffusion only happens in efflux. T or F?
False, transport can usually occur in either direction depending on the gradient, (if not coupled).
After release of the transported sugar, the transporter must re-orientate back to its original conformation, this is probably the _____ Limiting Step.
rate
What year was the first GLUT transporter protein cloned and found to be 492 AA monomer constitutively expressed in virtually all cells.
1985
How many different sugar transporters are there?
14
Sugar transporters are composed of how many transmembrane domain.
12
In a sugar transporter, each transmembrane domain (TMD) is compose of an alpha-helix with a central _______ pore for sugar to pass.
aqueous
Sugar transport substrate specificity appears to be determined by_________ bonding between specific sugar hydroxyl groups and the hydrophilic AA side-groups lining the binding site
hydrogen
Coupled transport slide: Ion Channels: Which way does Ca2+ flow?
Outside in
Coupled transport slide: Ion Channels: Which way does Cl- flow?
Outside in
Coupled transport slide:Ion Channels: Which way does K+ flow?
Inside out
Coupled transport slide: Ion Channels: Which way does Na+ flow?
Outside in
Coupled transport slide: Primary Active Transport: Which way does H+ flow?
Inside out
Coupled transport slide: Primary Active Transport: Which way does Na+ flow?
Inside out
Coupled transport slide: Primary Active Transport: Which way does K+ flow?
Outside in
Coupled transport slide: Primary Active Transport: Which way does Ca2+ flow?
Inside out
Coupled transport slide: Secondary Active Transport: Which way does amino acid flow?
Outside in
Coupled transport slide: Secondary Active Transport: Which way does H+ flow?
Inside out
Coupled transport slide: Secondary Active Transport: Which way does Ca2+ flow?
Inside out
Coupled transport slide: Secondary Active Transport: Which way does HCO3- flow?
Inside out
Coupled transport slide: Secondary Active Transport: Which way does Cl- flow?
Outside in
Coupled transport slide: Facilitated Diffusion: Which substance does facilitated diffusion that is not an Ion?
glucose
Coupled transport slide: Facilitated Diffusion: Which direction does glucose flow?
Outside in
What is another name for “Symport”
cotransport
What is another name for “Antiport”
countertransport
When two substances are transported together by the same transporter the transport is said to be ________.
coupled
When a substance coupled and moved against its gradient by means of another substance moving with its gradient is called??
secondary active transport
Secondary Transport does it directly use ATP?
no
Sodium is coupled w/AA or Glucose which are absorbed against their gradient to the GI tract and Kidney tubules, no ATP is required, which direction Na+ flowing?
Towards the GI tract/Kidney tubules
Cotransporter of Na+ and glucose is the _______. (transporters name)
SGLT1
The symporter Na+ and glucose is called the SGLT1, what year was it cloned and by whom?
1980 by Wright et al
How many TMD’s does SGLT1 have and how is it different from other transporter?
14, normal sugar transporter has 12 TMD’s
The best characterized active transporter is called _______
The Na+-K+ATPase or Sodium Potassium Pump
T or F? In the sodium potassium pump, only the Na+ gradient is maintained.
False, both gradients are maintained
Osmolarity is very important because cell swelling stimulates what transporter?
Sodium Potassium pump
Sodium Potassium Pump moves ions evenly (balanced) through it’s pump. T or F
False, 3 sodium ions are moved out and 2 potassium ions are moved in
Producing a change in the electrical potential of a cell is called ________
electrogenic
The sodium potassium pump makes the cell ELECTROGENIC which increases the membrane potential slightly this causes an ~-4 mV _________ in neurons.
hyperpolarization
Sodium Potassium Pump can be blocked by ouabain which binds _____ _____.
to the K+ site
Ca2+ functions as a secondary messenger and is _____ at high levels.
toxic
In the parietal cells of the stomach, distal tubules, and collecting ducts of the kidneys, Na+ are transported against their gradients to aid in digestion and reverse acidosis. T or F?
False, H+ not Na+
The amount of energy required depends on the gradient produced, energy required is described by what equation?
Energy (calories/osmole) = 1400 log (C1/C2)
Which organelle synthesis ATP?
mitochondria
The mitochondrial outer membrane contains the electron transport system (ETC). T or F?
false, inner membrane
In the mitochondria, H+ are pumped against their electrochemical gradient. T or F?
true
Mitochondria: The proton pump allows H+ ions to diffuse back across the inner membrane through what enzyme?
ATP synthase
ATP Synthase forms what as the protons diffuse through it?
ATP
T for F? Drugs can freely cross membranes.
false
One principle transporter “super families”, ATP Binding Cassettes (ABCs) affecting drug uptake, uses which transport method?
primary active transport requiring ATP hydrolysis
Solute Linked Carriers (SLCs), another “super families” operates as which transport method(s)?
Facilitated transporters or Secondary active transport
Cystic fibrosis is caused by a single gene mutation that encodes for the cystic fibrosis transmembrane regulator (CFTR) which is an epithelial chloride channel and affects ____ _____.
fluid secretion
If to co-transport of X out of a cell required it be linked to K+ movement what type of transport/transporter would this be? (transporter does NOT use ATP)
Secondary active transport/coupled symport; linked to K+ efflux (K+ gradient maintained by primary active transport)
What forms of membrane transport would cyanide affect?
primary and secondary active transport
What kind of transport do tissues use to uptake glucose?
Na+ coupled transport
