9 Questions
What is the process where a cell brings in macromolecules and particulate matter by forming new vesicles from the plasma membrane?
Receptor-mediated endocytosis
What is the process called 'cellular eating' where a cell engulfs a particle by extending pseudopodia around it and packaging it in a large vacuole?
Phagocytosis
Which process involves the movement of a transport vesicle from the Golgi apparatus to the plasma membrane, followed by fusion of the bilayers to release contents outside the cell?
Exocytosis
Osmosis is the active transport of water molecules across a selectively permeable membrane from the hypertonic solution to the hypotonic solution.
False
The sodium-potassium pump uses the energy of one ATP to pump 3 Na+ ions out and 2 K+ ions in.
True
Facilitated diffusion is a form of active transport that requires an investment of energy to move molecules against their concentration gradient.
False
Which type of transport process involves the movement of molecules across the membrane aided by specific transport proteins?
Facilitated diffusion
What is the most favorable configuration for lipids in a cell membrane?
Hydrophilic heads in contact with water and hydrophobic tails in a lipid environment
What provides selective permeability in cell membranes?
Both lipid bilayer and membrane proteins
Study Notes
- The most favorable configuration for lipids in a cell membrane is when all hydrophilic heads are in contact with water and all hydrophobic tails are in a lipid environment.
- Membrane proteins are amphipathic, consisting of hydrophobic and hydrophilic regions.
- Membranes are mosaics of structure and function, with integral and peripheral proteins.
- The plasma membrane is composed of various membrane proteins, including both peripheral and integral proteins, which provide a range of functions.
- Aquaporins, for example, act as transport proteins facilitating the passage of water through the membrane.
- Carrier proteins, such as glucose transporters, are integral proteins that transport specific molecules across the membrane.
- Membranes have selective permeability due to both the lipid bilayer and membrane proteins.
- Passive transport involves the movement of molecules across the cell membrane without the need for cellular energy, driven by concentration gradients.
- Diffusion is a type of passive transport, where molecules move from areas of higher concentration to lower concentration.
- Osmosis is a transport process where water molecules move across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.
- Facilitated diffusion is a transport process where the movement of molecules across the membrane is aided by specific transport proteins.
- The cell membrane provides selective permeability, allowing certain molecules to enter and exit while preventing others.
- Passive transport plays a role in the movement of water, lipids, and other lipid-soluble substances across the membrane.
- Membrane proteins facilitate passive transport and also enable specific functions such as ion regulation and energy production.
Test your knowledge on the selective permeability of the cell membrane, where nutrients enter and waste products leave, O2 is absorbed and CO2 is expelled. Learn about the regulation of inorganic ions and the selective nature of substance movement across the membrane.
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