unit 2, diffusion Flashcards
what is diffusion?
net movement of particles from an area of high concentration to an area of low concentration, this continues until particles are evenly distributed
what is simple diffusion?
diffusion across membranes without the use of protein channels or carrier proteins
what is facilitated diffusion?
larger molecules (e.g. glucose) and charged particles (e.g. ions) cant easily diffuse across membrane so require channel/carrier proteins
how do channel proteins work?
- channels are specific for a certain molecule
-filled with water for movement of water soluble ions
how do protien
channels act as gates?
-they open briefly and then close again
-regulates movement of ions
how do carrier proteins work?
-large molecule attaches to the protein
-it changes the shape pf the molecule
-releases molecule to other side of membrane
what makes the process passive?
moving down a concentration gradient , even when facilitated
how is an alveoli well adapted for diffusion?
- one cell thick, so there is a short diffusion pathway
-making diffusion quicker as less distance for particle to travel
what factors effect facilitated diffusion?
- if there is a higher concentration gradient it means an increase in diffusion
-however the carrier/ channel proteins can become a limiting factor as they will all be used up so diffusion will stay the same rate eventually
how is glucose absorbed?
absorbed from blood plasma using protein GLUT 1 , via facilitated diffusion
is GLUT 2 efficient?
least efficient for blood plasma as it is used in the liver, therefore it is the protein with the least number used
is GLUT 3 effective?
most efficient for absorbing, therefore it has the largest number of proteins
What is the difference between GLUT1 and GLUT3?
GLUT3 has a higher natural liking for glucose and greater transport capacity than GLUT1
