Science 21-30

• What is the primary function of the lungs?

  To transfer oxygen to the blood and remove carbon dioxide.
• What are the tiny air sacs in the lungs called?

  Alveoli
• Why are alveoli specialized for gas exchange?

  They have a large surface area, moist lining, thin walls, and a good blood supply.
• What is the approximate surface area of alveoli in humans?

  About 75 m²
• How do villi contribute to nutrient absorption?

  They increase the surface area for quicker absorption of digested food.
• What are the tiny projections inside the small intestine called?

  Villi
• What features do villi have to assist absorption?

  They have a single layer of surface cells and a good blood supply.
• What is the role of stomata in leaves?

  They allow carbon dioxide to diffuse into the leaf.
• How do guard cells function in relation to stomata?

  They control the size of the stomata to prevent water loss.
• What happens to water vapor in leaves?

  It evaporates from the cells and escapes by diffusion.
• What is the gas exchange surface in fish?

  The gills
• How does oxygen enter the blood in fish?

  Oxygen diffuses from the water into the blood in the gills.
• What are gill filaments and their function?

  They are thin plates that provide a large surface area for gas exchange.
• What do lamellae do in fish gills?

  They increase the surface area and contain blood capillaries.
• How does blood flow in relation to water in fish gills?

  Blood flows through the lamellae in one direction while water flows in the opposite direction.
• Why is the concentration of oxygen in water higher than in blood?

  To ensure maximum diffusion of oxygen from water into blood.
• What is the basic building block of all organisms?

  Cells
• What is differentiation in the context of multicellular organisms?

  It is the process by which cells become specialized for a particular job.
• What is a tissue?

  A group of similar cells that work together to carry out a particular function.
• What are the three types of tissues mentioned in mammals?

  Muscular, glandular, and epithelial tissues.
• What is an organ?

  A group of different tissues that work together to perform a certain function.
• What is an organ system?

  A group of organs working together to perform a particular function.
• What is the function of the digestive system?

  To break down and absorb food.
• What are digestive enzymes?

  Enzymes that break down large molecules into smaller ones for absorption.
• What is an example of a carbohydrase?

  Amylase
• What does amylase break down?

  Starch
• What are the key adaptations of alveoli for gas exchange?

  • Large surface area (about 75 m²)
  • Moist lining for dissolving gases
  • Very thin walls
  • Good blood supply
• What are the key adaptations of villi for nutrient absorption?

  • Millions of tiny projections
  • Single layer of surface cells
  • Very good blood supply
• What are the main features of leaf structure that facilitate gas exchange?

  • Stomata for gas entry and exit
  • Guard cells to control stomata size
  • Air spaces to increase surface area
  • Flattened shape for efficiency
• What are the main components of the fish gills that aid in gas exchange?

  • Gill filaments for large surface area
  • Lamellae with blood capillaries
  • Thin surface layer of cells
  • Counter-current flow of blood and water
• What is the hierarchy of organization in multicellular organisms?

  1. Cells
  2. Tissues
  3. Organs
  4. Organ systems
  5. Organisms
• What are the roles of different types of tissues in mammals?

  • Muscular tissue: contracts to move
  • Glandular tissue: makes and secretes chemicals
  • Epithelial tissue: covers body surfaces
• What is the role of digestive enzymes in the digestive system?

  • Break down large molecules (starch, proteins, fats)
  • Convert them into smaller molecules (sugars, amino acids, fatty acids)
• Why are digestive enzymes important?

  They break down big molecules into smaller ones for absorption
• What are the enzymes used in digestion produced by?

  Cells
• What are the big molecules that digestive enzymes break down?

  Starch, proteins, and fats
• What smaller molecules do digestive enzymes produce from starch?

  Glucose and maltose
• Where is amylase produced?

  In the salivary glands, pancreas, and small intestine
• What do proteases convert proteins into?

  Amino acids
• What is the name of the protease produced in the stomach?

  Pepsin