2.4 Plasma Membranes

• Selective permeability allows the plasma membrane to regulate the movement of materials in and out of the cell
• What does the fluid mosaic model describe?

  Plasma membrane structure
• Order the factors affecting membrane fluidity from least to most fluid:

  1️⃣ Low temperature

  2️⃣ Saturated fatty acids

  3️⃣ Cholesterol at high temperature

  4️⃣ Unsaturated fatty acids

  5️⃣ High temperature
• What type of bilayer is found in the fluid mosaic model?

  Phospholipid
• Match the component of the plasma membrane with its description:

  Phospholipids ↔️ Form the bilayer

  Proteins ↔️ Perform various functions

  Cholesterol ↔️ Stabilizes the membrane

  Carbohydrates ↔️ Involved in cell signaling
• The presence of cholesterol reduces membrane fluidity at low temperatures.

  False
• The fluidity of the plasma membrane is maintained by unsaturated fatty acid tails and the presence of cholesterol
• Match the component of the plasma membrane with its description:

  Proteins ↔️ Embedded within or attached, perform various functions

  Cholesterol ↔️ Stabilizes the membrane and affects fluidity

  Carbohydrates ↔️ Involved in cell signaling and recognition
• High temperatures increase membrane fluidity
• Steps of how phospholipids form the plasma membrane

  1️⃣ Hydrophobic tails face inward

  2️⃣ Hydrophilic heads face outward

  3️⃣ Phospholipid bilayer is formed
• Match the function of membrane proteins with its description:

  Transport ↔️ Facilitates the movement of substances

  Enzymatic Activity ↔️ Catalyzes biochemical reactions

  Cell Signaling ↔️ Receives and transmits signals

  Cell Recognition ↔️ Identifies and interacts with other cells
• The plasma membrane acts as a selective barrier
• Match the function of the plasma membrane with its description:

  Selective Permeability ↔️ Regulates the movement of materials

  Cell Signaling ↔️ Receives and transmits signals

  Cell Attachment ↔️ Provides a surface for cell binding
• The fluidity of the plasma membrane is maintained by unsaturated fatty acid tails and cholesterol.


  True
• The fluid mosaic model consists of a phospholipid bilayer with hydrophilic heads facing outward
• What are the two main components of a phospholipid molecule?

  Hydrophilic head and hydrophobic tails
• Match the phospholipid component with its characteristic:

  Hydrophilic Head ↔️ Polar, attracted to water

  Hydrophobic Tails ↔️ Nonpolar, repelled by water
• Integral proteins have hydrophobic regions that interact with the nonpolar tails of phospholipids.


  True
• Carbohydrates in the plasma membrane attach to lipids (glycolipids) or proteins
• Carbohydrates in the membrane can help bind cells together through cell adhesion.

  True
• Passive transport allows substances to move down their concentration gradient without requiring energy
• Diffusion is the movement of water across a semipermeable membrane.

  False
• Cholesterol reduces membrane fluidity at high temperatures and increases it at low temperatures
• The balance of membrane fluidity is essential for the cell's metabolic processes.


  True
• What is the plasma membrane's primary function?

  Selective barrier
• The plasma membrane's selective permeability is essential for maintaining the appropriate internal environment for metabolic processes.


  True
• The fluidity of the plasma membrane is maintained by unsaturated fatty acid tails and cholesterol
• Match the component of the plasma membrane with its description:

  Phospholipids ↔️ Form the bilayer

  Proteins ↔️ Perform various functions

  Cholesterol ↔️ Stabilizes the membrane

  Carbohydrates ↔️ Involved in cell signaling
• The fluid mosaic model is crucial for understanding how cells interact with their environment.


  True
• The fluidity of the membrane is maintained by unsaturated fatty acid tails and cholesterol
• What does the fluid mosaic model describe?

  Plasma membrane structure
• Phospholipids form the phospholipid bilayer, providing a flexible barrier.


  True
• Unsaturated fatty acids increase membrane fluidity due to kinks
• What are the two main regions of a phospholipid molecule?

  Hydrophilic head and hydrophobic tails
• Integral proteins are embedded within the phospholipid bilayer with their hydrophobic regions interacting with the nonpolar tails
• What are the two main types of membrane proteins?

  Integral and peripheral
• Selective permeability of the plasma membrane allows certain substances to pass through while blocking others.

  True
• The fluid mosaic model describes the plasma membrane as a dynamic arrangement of lipids and proteins
• Order the factors affecting membrane fluidity from least to most effect:

  1️⃣ Saturated Fatty Acids

  2️⃣ Unsaturated Fatty Acids

  3️⃣ Cholesterol

  4️⃣ Temperature
• Phospholipids are the primary building blocks of the plasma membrane