Topic 2 Bio

• What is the primary function of the lungs?

  Rapid gas exchange between atmosphere and blood
• How is air drawn into the lungs?

  Due to low pressure created by thorax volume increase
• What happens when the diaphragm muscles relax?

  Volume decreases, pressure rises, air is expelled
• What do the bronchi do?

  Carry air to and from each lung
• What are alveoli?

  Tiny balloon-like structures for gas exchange
• What is the role of mucus in the gas exchange system?

  Traps dust, debris, and microorganisms
• How is mucus removed from the airways?

  By the wave-like beating of cilia
• How does cystic fibrosis (CF) affect mucus in the lungs?

  Causes sticky mucus that cilia cannot move
• What are the two major health effects of sticky mucus in CF?

  Increases lung infection risk and reduces gas exchange
• What are epithelial cells?

  Cells forming outer surfaces and lining cavities
• What is the structure of the basement membrane?

  A protein-carbohydrate matrix anchoring epithelial cells
• What type of epithelium lines the alveoli and capillaries?

  Squamous epithelial tissue
• How thick can squamous epithelial cells be?

  Less than 0.2 µm thick
• What type of epithelium is found in the small intestine?

  Columnar epithelium
• What do microvilli do in the small intestine?

  Increase surface area for absorption
• What is the function of ciliated epithelial cells in the airways?

  Move substances along the tube they line
• Why does ciliated epithelium appear stratified?

  Cells have nuclei at different heights
• What is the term for the epithelium that appears stratified but is not?

  Pseudostratified epithelium
• What is the effect of more cholesterol on the membrane?

  It creates a less fluid membrane
• What are the main components of the membrane?

  It is composed of lipids, proteins, and carbohydrates
• What is a glycoprotein?

  A protein with carbohydrates attached
• What is the structure that describes the arrangement of membrane components?

  Fluid Mosaic Model
• Why is the phospholipid bilayer described as fluid?

  Because phospholipids are constantly moving
• How are proteins arranged in the phospholipid bilayer?

  They are scattered throughout the bilayer
• What do the hydrophilic heads of phospholipids do?

  They face outwards on either side of the membrane
• What is the orientation of the hydrophobic tails in the phospholipid bilayer?

  They face inwards, creating a hydrophobic center
• What role does the phospholipid bilayer play regarding water-soluble substances?

  It acts as a barrier to water-soluble substances
• How does the structure of phospholipids compare to triglycerides?

  Phospholipids have a similar structure to triglycerides
• What replaces one of the fatty acids in phospholipids?

  A phosphate group replaces one fatty acid
• What is the charge and polarity of the phosphate group in phospholipids?

  It has a negative charge and is polar
• What is the nature of the fatty acids in phospholipids?

  They are non-polar and hydrophobic
• What is the role of cholesterol in membrane fluidity?

  It stabilizes the membrane and reduces fluidity
• What is the function of membrane proteins?

  They assist in transport and communication
• Why are carbohydrates important in membrane structure?

  They help in cell recognition and signaling
• How does the Fluid Mosaic Model explain membrane structure?

  It describes the dynamic arrangement of components
• What is the significance of hydrophilic and hydrophobic regions in membranes?

  They create a selective barrier for substances
• How do phospholipids and triglycerides differ in structure?

  Phospholipids have a phosphate group, triglycerides do not
• What is the function of the phosphate group in phospholipids?

  It contributes to the hydrophilic nature of the molecule
• What is the role of fatty acids in the phospholipid structure?

  They provide hydrophobic properties to the bilayer
• Where are proteins found in relation to the phospholipid bilayer?

  Associated with the phospholipid bilayer