Membranes

• What is the primary composition of biological membranes?

  They are composed primarily of lipids and proteins
• What does it mean for biological membranes to be selectively permeable?

  They allow some substances to pass through while blocking others
• How do biological membranes adapt to cellular needs?

  They are dynamic structures that constantly change
• What is the basic structure of biological membranes composed of?

  A lipid bilayer, membrane proteins, cholesterol, and carbohydrates
• What is the arrangement of phospholipids in the lipid bilayer?

  Hydrophilic heads face outwards and hydrophobic tails face inwards
• What role does cholesterol play in animal cell membranes?

  It helps maintain membrane fluidity
• What are glycolipids and glycoproteins?

  Carbohydrates attached to some lipids and proteins on the outer surface
• What is one of the main functions of biological membranes?


  Compartmentalization
• What role do receptors in biological membranes play?

  They allow cells to respond to external stimuli
• What does the fluidity aspect of the fluid mosaic model describe?

  The lipid bilayer behaves like a fluid, allowing lateral movement
• What does the mosaic arrangement in the fluid mosaic model refer to?

  Proteins are embedded in or associated with the lipid bilayer in a mosaic-like pattern
• What does the dynamic nature of the fluid mosaic model imply?

  The composition and arrangement of membrane components can change over time
• What are the main functions of biological membranes?

  • Compartmentalization
  • Selective permeability
  • Cell signaling
  • Energy transduction
  • Cell recognition
  • Cell adhesion
  • Enzyme activity
• What are the key features of the fluid mosaic model?

  • Fluidity of the lipid bilayer
  • Mosaic arrangement of proteins
  • Asymmetry of inner and outer leaflets
  • Dynamic nature of membrane components
  • Selective permeability
• What are biological membranes also known as?

  Biomembranes
• What do the hydrophobic tails of phospholipids do in the bilayer?

  They face inwards, away from the aqueous environments
• What orientation do the hydrophilic heads of phospholipids have in the bilayer?

  They face outwards towards the aqueous environments
• What are the main types of lipids found in biological membranes?

  Phospholipids, cholesterol, and glycolipids
• What role does cholesterol play in biological membranes?

  It provides stability and fluidity
• What are integral proteins in biological membranes?

  Proteins embedded in the membrane
• What are peripheral proteins in biological membranes?

  Proteins attached to the membrane surface
• What are transmembrane proteins?

  Proteins that span the entire membrane
• What are carbohydrates' roles in biological membranes?

  They form glycolipids and glycoproteins important for cell recognition and signaling
• What does selective permeability in biological membranes control?

  What enters and exits the cell
• What are the two types of transport proteins mentioned in the study material?

  Channel and carrier proteins
• What is the primary function of intrinsic proteins?

  They are transmembrane proteins embedded through both layers of a membrane
• How do channel proteins facilitate transport?

  They provide hydrophilic channels for passive movement of ions or polar molecules
• What triggers the gating of channel proteins?

  A specific stimulus, such as a change in membrane potential
• What are glycoproteins?

  Intrinsic proteins attached to carbohydrates of varying lengths and shapes
• What role do carrier proteins play in transport?

  They assist in both passive and active transport by binding to substrates
• What is one function of glycoproteins in cell membranes?

  They aid in cell adhesion and recognition
• How do glycoproteins contribute to cell signaling?

  They stimulate a response from the receiving cell when a chemical signal is received
• What are glycolipids?

  Lipids with attached carbohydrate chains found on cell surfaces
• What role do glycolipids play in multicellular organisms?

  They can be recognized by the immune system
• How do extrinsic proteins interact with the membrane?

  They interact with the polar heads and are usually easily removed
• Where are extrinsic proteins located in the membrane?

  On the polar heads of phospholipids or with intrinsic proteins
• What is the role of cholesterol in the membrane?

  It helps maintain membrane fluidity and stability
• How does cholesterol interact with phospholipids in the membrane?

  Its hydroxyl group interacts with polar heads, while its hydrocarbon tail interacts with hydrophobic tails
• What is the fluid mosaic model?

  A model representing the dynamic arrangement of proteins and phospholipids in the membrane
• What is the significance of membrane fluidity?

  It allows for the movement and interaction of membrane components