Cell membrane Flashcards
(26 cards)
What is the primary function of the cell membrane?
The cell membrane regulates what enters and leaves the cell, maintaining homeostasis.
: What is the structure of the cell membrane often described as?
: The fluid mosaic model.
What are the main components of the cell membrane?
Phospholipids, proteins, cholesterol, and carbohydrates.
What role do phospholipids play in the cell membrane?
They form a bilayer that acts as a barrier to most water-soluble substances.
How do proteins contribute to the function of the cell membrane?
Proteins serve as channels, carriers, and receptors, facilitating communication and transport.
What is the significance of cholesterol in the cell membrane?
Cholesterol helps to stabilize the membrane’s fluidity and structure.
What are glycoproteins and glycolipids?
They are carbohydrates attached to proteins and lipids, respectively, and play roles in cell recognition and signaling.
Define passive transport.
Passive transport is the movement of substances across the membrane without the use of energy, typically down their concentration gradient.
What are the types of passive transport?
Simple diffusion, facilitated diffusion, and osmosis.
What is active transport?
Active transport is the movement of substances against their concentration gradient, requiring energy (ATP) from a low conc to high conc
Give an example of active transport.
The sodium-potassium pump.
What is the difference between endocytosis and exocytosis?
Endocytosis is the process of taking substances into the cell, while exocytosis is the process of expelling substances from the cell.
What is simple diffusion?
Simple diffusion is the movement of small, nonpolar molecules directly through the lipid bilayer. from high to low conc
What is facilitated diffusion?
Facilitated diffusion is the process where specific molecules pass through membrane channels or transport proteins down their concentration gradient.
What is osmosis?
Osmosis is the diffusion of water molecules through a selectively permeable membrane from a region of high water potential to a region of low water potential
What are isotonic solutions?
Isotonic solutions have equal concentrations of solutes inside and outside the cell, leading to no net movement of water.
What happens in a hypertonic solution?
In a hypertonic solution, the concentration of solutes outside the cell is higher, causing water to move out and the cell to shrink.
What occurs in a hypotonic solution?
In a hypotonic solution, the concentration of solutes is lower outside the cell, causing water to enter the cell and potentially leading to swelling or bursting.
What is the function of receptor proteins?
Receptor proteins bind to signaling molecules (ligands) and initiate a response inside the cell.
What is the role of channel proteins?
Channel proteins provide passages for specific ions or molecules to pass through the membrane.
Define membrane potential.
Membrane potential is the difference in charge across a cell membrane, crucial for processes like nerve impulse transmission.
What is the role of endocytosis?
Endocytosis allows cells to engulf large particles or other cells, bringing them into the cell within vesicles.
What are the three types of endocytosis?
Phagocytosis (cell eating), pinocytosis (cell drinking), and receptor-mediated endocytosis.
Describe the process of exocytosis.
Exocytosis involves vesicles fusing with the plasma membrane to release their contents outside the cell.
