Lesson 1 Flashcards
(11 cards)
How can lipid-soluble substances pass through the membrane?
By dissolving in phospholipid tails and diffusing across cell membranes as they are either small and uncharged like O2 or non-polar like vitamin A
How can water-soluble substances pass through the membrane?
By passing through transport proteins because they are polar or charged meaning they can’t diffuse through cell membrane
Name and explain factors affecting permeability of membrane
Temperature - Membrane molecules and molecules pass through have greater kinetic energy so faster diffusion
Organic solvents - Such as ethanol can dissolve/emulsify the phospholipids which makes the membrane more porous
Name methods of transport across the membrane
Diffusion, facilitated diffusion, co-transport, active transport, bulk transport, osmosis
Name and describe factors affecting diffusion
• Conc. grad. - Steeper conc grad means more molecules will dissolve per unit time
• Shorter diffusion means increased diffusion and vice versa
• Certain types of molecules will diffuse faster such as non-polar ones
• Larger molecules will require more enegy
What is facilitated diffusion?
When proteins in membrane act as a pathway for polar molecules to pass through the cell membrane
What is a channel protein?
Protein with water-filled pore to attract ions which are hydrophobic and they can open and close based on cellular needs
What is a carrier protein?
Protein which facilitates diffusion of large polar molecules such as glitches and amino acids. They change based on shape when molecule attaches to binding, creating an opening for molecule to be released
Why might facilitated diffusion rate stop increasing even when conc. grad. increases?
All proteins are already in use
What are gated protein channels?
Protein which open and close after specific stimuli
Describe an example of co-transport
Sodium ions can only move through carrier proteins with glucose, this can allow glucose to move against conc grad without ATP
