Podcast
Questions and Answers
What is the structure of the cell membrane described as?
What is the structure of the cell membrane described as?
- Rigid Structure Model
- Solid Barrier Model
- Fluid Mosaic Model (correct)
- Layered Membrane Model
The cell membrane is found in only plant cells.
The cell membrane is found in only plant cells.
False (B)
Name one basic molecule found in the cell membrane.
Name one basic molecule found in the cell membrane.
Phospholipids
The molecules in the cell membrane can flow like a _____ .
The molecules in the cell membrane can flow like a _____ .
Match the following components with their role in the cell membrane:
Match the following components with their role in the cell membrane:
Which of the following is NOT one of the basic molecules in the cell membrane?
Which of the following is NOT one of the basic molecules in the cell membrane?
The Fluid Mosaic Model indicates that molecules in the cell membrane are fixed in place.
The Fluid Mosaic Model indicates that molecules in the cell membrane are fixed in place.
What type of model explains the structure of the cell membrane?
What type of model explains the structure of the cell membrane?
The phospholipid bilayer consists of 2 layers of ________________________.
The phospholipid bilayer consists of 2 layers of ________________________.
Which of the following types of molecules can easily pass through the phospholipid bilayer?
Which of the following types of molecules can easily pass through the phospholipid bilayer?
Phospholipids are hydrophobic and do not interact with water.
Phospholipids are hydrophobic and do not interact with water.
What does the term 'selectively permeable' refer to in the context of cell membranes?
What does the term 'selectively permeable' refer to in the context of cell membranes?
Only _______________ molecules are able to ____________ __________ membrane.
Only _______________ molecules are able to ____________ __________ membrane.
Which of the following is an example of a molecule that cannot directly pass through the phospholipid bilayer?
Which of the following is an example of a molecule that cannot directly pass through the phospholipid bilayer?
Match the following types of proteins with their functions in the cell membrane:
Match the following types of proteins with their functions in the cell membrane:
Water can pass through the membrane freely without any assistance.
Water can pass through the membrane freely without any assistance.
What type of proteins are permanently stuck in the membrane?
What type of proteins are permanently stuck in the membrane?
Cholesterol decreases the stability and movement of the cell membrane.
Cholesterol decreases the stability and movement of the cell membrane.
What do glycoproteins and glycolipids provide to a cell?
What do glycoproteins and glycolipids provide to a cell?
Diffusion is the movement of molecules from a region of high concentration to a region of low concentration. This movement is called a __________ concentration gradient.
Diffusion is the movement of molecules from a region of high concentration to a region of low concentration. This movement is called a __________ concentration gradient.
Which type of protein only adheres to one side of the membrane?
Which type of protein only adheres to one side of the membrane?
Aquaporins are specialized channels that facilitate the movement of __________ across the cell membrane.
Aquaporins are specialized channels that facilitate the movement of __________ across the cell membrane.
Match the following proteins with their function:
Match the following proteins with their function:
Water, being small but polar, diffuses rapidly across cell membranes without the help of channels.
Water, being small but polar, diffuses rapidly across cell membranes without the help of channels.
Osmosis is the diffusion of __________ across a _________ _________.
Osmosis is the diffusion of __________ across a _________ _________.
Osmosis is the diffusion of __________ across a _________ _________.
Osmosis is the diffusion of __________ across a _________ _________.
Osmosis is the diffusion of __________ across a _________ _________.
Osmosis is the diffusion of __________ across a _________ _________.
Study Notes
Cell Membrane
- The cell membrane is also known as the plasma membrane
- The cell membrane is super important for all cells
- The cell membrane follows the Fluid Mosaic Model: molecules are not fixed, but move like a fluid
- 3 basic molecules in the cell membrane:
- Phospholipids
- Proteins
- Cholesterol
Structure of the Cell Membrane
- The cell membrane has a phospholipid bilayer: 2 layers of phospholipid molecules
- Phospholipids have a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail.
- The cell membrane is selectively permeable, meaning only small molecules can pass through
- The hydrophobic tails of phospholipids prevent large or polar molecules from passing through
- The cell membrane is semipermeable, meaning it lets some things through but not others
- Examples of molecules that can pass through the cell membrane: oxygen, carbon dioxide, water
- Examples of molecules that cannot pass through the cell membrane: amino acids, carbohydrates (glucose), ions
- Surface proteins can be used for different functions:
- Transport (transport proteins/ion channels)
- Binding/attaching (anchor proteins)
- Receiving signals (receptor proteins with binding pockets for signaling molecules)
- Catalyzing reactions (enzymes)
- Identifying/marking (glycoproteins with sugar "nametags")
- There are two types of surface proteins: integral proteins and peripheral proteins
- Integral proteins are permanently stuck in the membrane
- Peripheral proteins only adhere to one side of the membrane.
- Cholesterol keeps the membrane from becoming too rigid or too fluid
- Cholesterol increases both stability and movement of the membrane
- Cholesterol is a type of lipid
Movement Across the Cell Membrane
- Movement across the cell membrane happens by diffusion, osmosis, and active transport
- Diffusion: movement of molecules from high concentration to low concentration
- Diffusion is passive transport: no energy is required
- Osmosis: diffusion of water across a selectively permeable membrane
- Water moves from an area of high water concentration/low solute concentration to an area of low water concentration/high solute concentration
- Osmosis requires active transport
- Passive transport requires no energy to move molecules across the membrane
- Active transport requires energy to move molecules across the membrane
- Facilitated diffusion uses a protein to help molecules go through the cell membrane
- Facilitated diffusion is passive transport because it does not require energy
- Dynamic Equilibrium: movement of water continues, but net movement is zero
- Hypertonic Solution: higher solute concentration in the solution than in the cell.
- Isotonic Solution: same amount of solute in the solution as in the cell
- Hypotonic solution: lower solute concentration in solution than in the cell
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Description
This quiz explores the essential components and functions of the cell membrane, also known as the plasma membrane. You'll learn about the Fluid Mosaic Model, the phospholipid bilayer, and the semipermeable nature of the membrane, as well as the molecules that can cross it. Test your knowledge on cell membrane biology!
