2.9 Mechanisms of Transport

• There are two main types of cell transport: passive and active.


  True
• Active transport requires energy in the form of ATP to move substances against their concentration gradient.

  True
• In passive transport, substances move down their concentration gradient
• Match the transport type with an example:

  Passive Transport ↔️ Diffusion

  Active Transport ↔️ Sodium-potassium pump
• Simple diffusion requires energy from the cell.

  False
• Small, nonpolar molecules diffuse more easily across the cell membrane.

  True
• In which direction do substances move in passive transport relative to the concentration gradient?

  Down the gradient
• Simple diffusion is driven by the concentration gradient and requires no energy from the cell.


  True
• Higher temperatures increase diffusion rates due to increased molecular motion.


  True
• How does a larger membrane surface area affect diffusion rate?

  Increases it
• What is the direction of movement in simple diffusion?

  High to low concentration
• Examples of substances that undergo simple diffusion include oxygen, carbon dioxide, and some small lipids
• Facilitated diffusion requires ATP to move substances across the membrane.

  False
• What is osmosis driven by?

  Osmotic pressure
• In a hypotonic solution, cells swell and may burst due to water movement into the cell
• Oxygen, carbon dioxide, and small lipids are examples of substances that undergo simple diffusion
• Osmosis is the diffusion of water across a semipermeable membrane.


  True
• Match the solution type with its effect on cells:

  Isotonic ↔️ No net water movement

  Hypotonic ↔️ Cells swell and may lyse

  Hypertonic ↔️ Cells shrink (crenation)
• When red blood cells are placed in a hypotonic solution, water moves into the cells, causing them to swell and potentially burst.


  True
• The sodium-potassium pump in nerve cells uses ATP to pump sodium ions out and potassium ions into the cell against their concentration gradients
• Match the type of endocytosis with its key feature:

  Phagocytosis ↔️ Engulfs large particles

  Pinocytosis ↔️ Engulfs small fluid droplets

  Receptor-Mediated Endocytosis ↔️ Specific receptors bind to ligands
• Exocytosis requires energy and involves the fusion of vesicles with the cell membrane.


  True
• Match the transport mechanism with its example:

  Simple Diffusion ↔️ Gas exchange in the lungs

  Facilitated Diffusion ↔️ Glucose uptake by muscle cells

  Osmosis ↔️ Water absorption in the kidneys

  Active Transport ↔️ Sodium-potassium pump

  Exocytosis ↔️ Release of insulin by pancreatic cells
• In active transport, carrier proteins use energy from ATP
• What energy form is typically used in active transport?

  ATP
• Simple diffusion is the passive movement of substances across a cell membrane along the concentration gradient.
• Higher temperatures increase the rate of diffusion.


  True
• What effect does a larger membrane surface area have on diffusion?

  Increases rate
• In facilitated diffusion, substances move across the cell membrane using carrier proteins.
• Facilitated diffusion requires energy expenditure by the cell.

  False
• Osmosis is the diffusion of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration driven by osmotic pressure.
• What happens to a cell in a hypotonic solution?

  It swells
• Active transport moves substances down their concentration gradient.

  False
• Endocytosis is the process by which a cell engulfs substances from its surroundings by forming a vesicle.
• Which type of endocytosis is non-selective and engulfs extracellular fluid?

  Pinocytosis
• In exocytosis, substances are transported outward across the cell membrane.
• Exocytosis is the active transport mechanism by which cells export materials to the extracellular space.
• Which cellular organelle forms vesicles during exocytosis?

  Golgi apparatus
• What are three key functions of exocytosis?

  Secretion, signaling, waste disposal
• Exocytosis and endocytosis both require energy.


  True