Topic 7- Cell Membranes Flashcards
What is the term for a membrane that allows certain substances to pass while blocking others?
Partially Permeable
Cell membranes are selectively permeable, allowing some molecules to pass while restricting others.
Define simple diffusion in the context of cell membranes.
The net movement of particles from an area of high concentration to an area of lower concentration
This process does not require energy and occurs until equilibrium is reached.
What is osmosis?
The movement of water across a selectively permeable membrane
Osmosis occurs from a region of low solute concentration to a region of high solute concentration.
What type of transport requires energy to move molecules against their concentration gradient?
Active transport
This process involves the use of ATP to transport substances from areas of low concentration to areas of high concentration.
What are the two types of proteins found in cell membranes?
- Channel proteins
- Carrier proteins
Channel proteins facilitate the passage of smaller ions and polar molecules, while carrier proteins transport larger molecules.
What type of molecules can pass through the phospholipid bilayer easily?
Small, non-polar, lipid-soluble molecules
Examples include oxygen, carbon dioxide, and lipids.
Fill in the blank: _______ are molecules that have both hydrophilic and hydrophobic regions.
Amphipathic
This property is crucial for the formation of cell membranes.
What is facilitated diffusion?
The process by which larger molecules and ions pass through the membrane via channel proteins for pores- for smaller ions and polar molecules. And carrier proteins- For large molecules including polar and ion
This process does not require energy and occurs down the concentration gradient.
Describe hypotonic and hypertonic solutions.
Hypotonic: High water potential; Hypertonic: Low water potential
In hypotonic solutions, cells may swell due to water influx, while in hypertonic solutions, cells may shrink.
What role do co-transporters play in active transport?
They bind 2 molecules at a time, using the concentration gradient of one to move the other
This mechanism is crucial for transporting nutrients across the cell membrane.
True or False: Water-soluble substances can easily diffuse through the hydrophobic core of the bilayer.
False
Water-soluble substances, such as ions and polar molecules, diffuse slowly through the membrane due to the hydrophobic nature of the bilayer.
What are the main components that make up plasma membranes?
- Phospholipids
- Proteins
- Cholesterol
- Glycoproteins
- Glycolipids
These components contribute to the fluidity and functionality of the membrane.
