B9 cell membrane +B10 Flashcards
Structure: Phospholipids
Molecules with a hydrophilic head and two hydrophobic tails.
Function: Phospholipids
Form the lipid bilayer, providing a barrier and structure to the membrane.
Structure: Proteins
Molecules embedded in or associated with the lipid bilayer.
Function: Proteins
Serve as channels, receptors, and enzymes, facilitating communication and transport.
Structure: Glycoproteins
Proteins with carbohydrate chains attached.
Function: Glycoproteins
Involved in cell recognition, signaling, and adhesion.
Structure: Glycolipids
Lipids with carbohydrate chains attached.
Function: Glycolipids
Contribute to cell recognition and signaling, helping to stabilize membrane structure.
Structure: Carbohydrates
Sugar molecules found on the outer surface of the membrane.
Function: Carbohydrates
Play a role in cell recognition and interaction.
Structure: Cholesterol
Lipid molecule interspersed within the phospholipid bilayer.
Function: Cholesterol
Stabilizes membrane fluidity, maintaining structure and integrity.
Factor: Concentration Gradient
A steeper gradient increases the diffusion rate.
Factor: Temperature
Higher temperatures increase molecular movement, speeding up diffusion.
Factor: Surface Area of the Membrane
Larger surface area allows more molecules to diffuse at once.
Factor: Membrane Thickness
Thicker membranes slow diffusion; thinner membranes speed it up.
Factor: Size of the Molecules
Smaller molecules diffuse faster than larger ones.
Factor: Lipid Solubility
Lipid-soluble molecules diffuse faster across the membrane.
Factor: Presence of Membrane Proteins
Facilitated diffusion via proteins speeds up transport of large or polar molecules.
Factor: Charge of the Molecules
Charged molecules require transport proteins, affecting the diffusion rate.
Active Transport
Moves molecules against the concentration gradient using ATP.
Endocytosis
Cell engulfs materials into a vesicle from the membrane, requiring energy.
Phagocytosis
Engulfs large particles into the cell through vesicle formation.
Pinocytosis
Engulfs extracellular fluid and dissolved solutes into the cell.
Exocytosis
Expels materials from the cell by vesicles fusing with the membrane.
High Surface Area to Volume Ratio (Characteristic)
Smaller cells with more surface area relative to volume, promoting efficient exchange.
Low Surface Area to Volume Ratio (Characteristic)
Larger cells with less surface area relative to volume, limiting efficient exchange.
Process: Diffusion
Concentration Gradient: Moves down (high to low).
Channel/Carrier Protein: Not used.
Energy Use: No energy required.
Molecules Transported: Small, non-polar (e.g., O₂, CO₂).
Process: Osmosis
Concentration Gradient: Moves down (water gradient).
Channel/Carrier Protein: May use aquaporins.
Energy Use: No energy required.
Molecules Transported: Water (small, polar).
Process: Facilitated Transport
Concentration Gradient: Moves down (high to low).
Channel/Carrier Protein: Uses channel or carrier proteins.
Energy Use: No energy required.
Molecules Transported: Larger or charged (e.g., glucose, ions).
Process: Endocytosis
Concentration Gradient: Not gradient-dependent.
Channel/Carrier Protein: Not used (vesicles involved).
Energy Use: Requires ATP.
Molecules Transported: Large particles or fluids (e.g., bacteria).
Process: Exocytosis
Concentration Gradient: Not gradient-dependent.
Channel/Carrier Protein: Not used (vesicles involved).
Energy Use: Requires ATP.
Molecules Transported: Large particles, secretions, or waste.
