L6-7 Membrane Transport Flashcards
Understand types of membrane transport and the types of protein through which they occur.
Each membrane has a characteristic set of membrane proteins present which determine…
It’s properties
Membrane transport proteins are highly…
Specific 🏹
There are 2 main types of membrane transport protein (MTP)…
Carrier proteins and Channel proteins
Channel proteins are ? pores through which ions can diffuse
Hydrophilic 💘💧
🚲 Transport is either…
Active (additional energy required) or Passive
Give two examples of passive transport
- Simple diffusion
2. Facilitated diffusion
Passive transport occurs from…
high to low concentration, using the inherent energy in the “downhill” gradient
A carrier protein which transports only 1️⃣ one substance is known as a…
Uniporter
The carrier proteins known as GLUT are…
GLUcose Transporters
Transport via facilitated diffusion depends on the concentration gradient, thus may occur…
In either direction👈👉
GLUT carrier proteins, such as GLUT2 in the liver, transport glucose via…
Facilitated diffusion (passive)
Active transport…
Requires additional energy
In primary active transport, the protein gains energy from the dephosphorylation of of ATP to ADP + Pi (releasing energy from the high energy phosphate bond). This protein is thus known as an ATPase pump.
In secondary active transport, uphill transport of a molecule is coupled to …
The downhill transport of another (with the concentration gradient).
Often this gradient has been generated by Primary Active Transport elsewhere
The Sodium/Potassium pump is the most common example of Primary Active Transport (PAT). It maintains the…
Disequilibrium of sodium and potassium ions between ECF/ICF
The pumping cycle of the Sodium/Potassium pump occurs at a rate of…
100 cycles per second 💯
The sodium gradient created by the Na+/K+ pump is utilised…
By many secondary active transport processes
If secondary active transport (SAT) occurs in the same direction as the co-transported molecule this is known as…
Symport 👇👇
If SAT occurs in the opposite direction to the co-transported molecule this is known as…
Antiport 👇👆
The body transports glucose by passive (in the case of GLUT uniporter) and active (Na+/glucose symporter) means.
Why?
Because of the differing relative concentrations of glucose across membranes. From the intestinal lumen across the apical membrane, transport is AGAINST the gradient, thus must be active. Conversely, when travelling across the basal membrane, glucose may move passively, as transport is in the direction of the concentration gradient.
Common (Primary) active transporters include (3)…
Sodium/Potassium ATPase antiporter
Calcium ATPase uniporter
Proton ATPase (Proton Pump) uniporter
Common (Secondary) active transporters include (3)…
Sodium/Glucose symporter
Sodium/Amino Acid symporter
Sodium/Calcium antiporter
