Topic 7 Cell Membranes Flashcards
What is the term for a membrane that allows some substances to pass while restricting others?
Partially Permeable
This property is essential for maintaining homeostasis in cells.
Define diffusion.
The net movement of particles from an area of high concentration to an area of lower concentration
This process continues until equilibrium is reached.
What is osmosis?
The movement of water across a selectively permeable membrane
This process occurs from an area of high water potential to low water potential.
What type of transport requires energy to move substances across a membrane?
Active transport
This process often involves the movement against a concentration gradient.
What are the two main types of molecules that can pass through the phospholipid bilayer?
- Small molecules
- Non-polar/lipid-soluble molecules
Examples include oxygen and carbon dioxide.
What are the main components of cell membranes?
- Phospholipids
- Proteins
- Cholesterol
- Glycoproteins
- Glycolipids
These components contribute to the fluid mosaic model of cell membranes.
What is facilitated diffusion?
The process by which larger or charged molecules cross the membrane with the help of transport proteins
This process does not require energy.
What type of proteins facilitate the transport of smaller ions and polar molecules across the membrane?
Channel proteins
These proteins create pores in the membrane.
What are carrier proteins used for?
Transporting larger molecules, including polar molecules and ions
They undergo a conformational change to move the molecule across the membrane.
True or False: Active transport can only move molecules down their concentration gradient.
False
Active transport moves molecules against their concentration gradient.
What is a co-transporter?
A type of carrier protein that binds two molecules at a time
It uses the concentration gradient of one molecule to move another.
Fill in the blank: The _______ is the likelihood of water moving into or out of a cell.
water potential
Water potential influences the direction of osmosis.
What does ‘hypotonic’ refer to in terms of water potential?
A solution with high water potential
This means it has a lower concentration of solutes compared to another solution.
What does ‘hypertonic’ mean?
A solution with low water potential
This indicates a higher concentration of solutes compared to another solution.
What is the importance of making notes during lectures?
To enhance understanding and retention of the material
Note-taking is a key study strategy for effective learning.
