Membranes Flashcards
What determines the specifics of membrane transporters and channels
Transporters and channels provide specificity by allowing only certain substrates to cross membrane. This is determined by the structures and selectivity of transport proteins
What factors contribute to the establishment and maintenance of a concentration gradient in cells
Conc gradient are created by selective permeability, active transport. Eg Na,K, ATPase pump.
What is passive transport
Passive transport occurs without energy input and moves molecules from areas of high concentration to areas of low concentration until eqm is reached
How does active transport function and why is it important?
Active transport enables the movement of molecules against their concentration gradient, often powered by ATP hydrolysis. This process is critical for maintaining ion gradients, nutrients uptake, and waste removal.
What are the main types of transporters?
Uniporters (one substances, one direction), symporters ( two substances, same direction) , and Antiporters (two substances, opposite direction) .
Describe the role of the Na+/K+ ATPase pump.
Na+/K+ ATPase pump actively transport 3 Na+ ions out of the cell, 2 K+ ions into the cell per ATP molecule, maintaining electrochemical gradients.
How do gated ion Channels function ?
Gated ion channels open or close in response to specific stimuli, such as voltage changes, ligand binding or mechanical forces.
What are the key properties of membranes?
Membranes act as selective barriers, maintain concentration gradients and provide surface for interaction with environment.
What is the significance of amphiphilic molecules in the membranes structure?
Amphiphilic molecules, such as phospholipids, have hydrophilic heads and hydrophobic and tails, forming bilayers spontaneously in aqueous environment.
What is the role of cholesterol in membranes?
Cholesterol modulates membrane fluidity, reducing mobility at high temperatures and increasing fluidity at low temperatures, maintains consistency.
How do lipid bilayers form membranes?
Lipid bilayers self-assemble through hydrophobic interactions causes a cage like structure with polar heads facing outwards and hydrophobic tails shielded inside.
What are integral and peripheral membrane proteins?
Integral proteins span the membranes, while peripheral proteins associate with surface through ionic interactions or hydrophobic loops.
What are the universal feature of a cell
All cells have DNA for info, RNA for information transfers, proteins for functions and plasma membranes as selective barriers .
Compare prokaryotic and Eukaryotic cells
Prokaryotes are unicellular with no membrane bound organelles and smaller ribosomes and no mitochondria or nucleus. Eukaryotes are larger and contain a true nucleus and have complex organelles such as mitochondria and Golgi apparatus and ER for special cell functions.
Structure and function of Golgi apparatus
Processes sorts and ships proteins and lipids consist of cis and trans faces for sequential modifications
