Chapter 3 Flashcards
What are the 4 main functions of the plasma membrane?
- Barrier (keeps contents inside)
- Regulation (protein channels)
- Sensitive to the environment/sends signals. ex. glycocalyx (made up of carbohydrates)
- Structural support- phospholipid bilayer.
What are the physical properties of a phospholipid bilayer?
Hydrophilic head, hydrophobic tails, selectively permeable membrane.
How does simple diffusion differ from facilitated diffusion?
Simple diffusion involves small, hydrophobic molecules that can pass through the membrane while facilitated diffusion involves molecules that bind to a protein channel to move in/out of the cell.
Diffusion involves the movement of a substance from a _____ concentration to a ______ concentration.
Higher, lower.
What kind of transport is osmosis?
Passive. It involves the movement of water molecules from higher concentrations to lower.
Why does osmosis occur more rapidly than diffusion?
Because there are a ton of aquaporins, or channels for water to flow through. These channels outnumber solute channels.
Explain the specificity, saturation limits, and regulation of a carrier mediated transport protein.
The transport is an active transport protein whose rate depends upon the availability of transport proteins and substrates and is regulated by cofactors such as hormones that can affect the activity of the transport protein.
Explain the difference between primary active transport and secondary active transport.
Primary active transport involves DIRECTLY using ATP to move solutes against a gradient while Secondary active transport INDIRECTLY uses ATP due to needing a high abundance of NA^+ for glucose molecules to go down the gradient as Na needs to bind first before this can happen. This is possible due to the Na, K pump. Without this, secondary active transport wouldn’t be possible.
Vesicular transport involves ____ to help transport materials into the cell.
Endocytosis.
Define Receptor Endocytosis:
occurs when receptors on the cell surface are bound by their ligands and internalized in clathrin-coated pits or caveolae that become endocytic vesicles.
What is the difference between receptor endocytosis and pinocytosis?
Pinocytosis involves the ingestion of extracellular fluid while Receptor endocytosis involves the ingestion of macromolecules.
Phagocytosis vs. receptor endocytosis
Phagocytosis invaginates around large macromolecules and helps bring them into the cell while RE helps with macromolecules being identified by receptors and binds to the receptor.
The plasma membrane is more permeable to _____
K^+
