Membrane Transport - AP Biology

1. What is the primary structural component of cell membranes?

   Phospholipid bilayer. Forms the basic structural framework of membranes.

2. What is meant by 'fluid mosaic model'?

   A model describing the cell membrane's structure. Phospholipids form fluid matrix with embedded proteins.

3. Identify the effect of a hypertonic solution on a cell.

   The cell will lose water and shrink. Higher solute concentration outside causes water loss.

4. What is antiport?

   Transport of two substances in opposite directions. Exchange transport using the same carrier protein.

5. What is the role of carrier proteins in membrane transport?

   To assist in the transport of substances across the membrane. Bind and transport specific molecules across membranes.

6. What is the primary function of the cell membrane?

   To regulate the passage of substances into and out of the cell. Controls what enters/exits to maintain cellular homeostasis.

7. State the term for the movement of molecules from high to low concentration.

   Diffusion. Net movement occurs until equilibrium is reached.

8. Identify the role of glycolipids in the cell membrane.

   To provide cellular recognition. Sugar chains help identify cell types and functions.

9. Identify the type of transport that involves vesicles.

   Bulk transport. Moves large quantities of materials using membrane vesicles.

10. State the role of cholesterol in the cell membrane.

    To maintain membrane fluidity and stability. Regulates membrane flexibility at different temperatures.

11. Which type of transport is exemplified by the sodium-glucose transport protein?

    Cotransport. Uses sodium gradient to transport glucose simultaneously.

12. Identify the molecule that provides energy for active transport.

    ATP (adenosine triphosphate). Energy currency that powers cellular work processes.

13. Identify the term for transport that moves two substances in the same direction.

    Symport. Coupled transport utilizing same carrier protein.

14. What is the reverse process of endocytosis?

    Exocytosis. Removes cellular waste and secretes products outside.

15. What is the function of integral proteins in the cell membrane?

    To transport substances and act as receptors. Span membrane providing transport and signaling functions.

16. What is the primary driving force for diffusion?

    Concentration gradient. Difference in solute concentration creates driving force.

17. Which type of transport involves movement down a concentration gradient?

    Passive transport. No energy required as molecules move naturally down gradients.

18. What determines the direction of osmosis?

    The water concentration gradient. Water moves from high to low water concentration.

19. What happens to a cell in a hypotonic solution?

    The cell will gain water and swell. Lower solute concentration outside causes water influx.

20. State the function of aquaporins in cells.

    To facilitate water transport across membranes. Specialized water channels for rapid water movement.

21. Name the type of transport that uses protein channels.

    Facilitated diffusion. Passive transport requiring specific membrane proteins.

22. Which structure in the cell membrane acts as a barrier to ions?

    Phospholipid bilayer. Hydrophobic core prevents charged particle passage.

23. Which term describes the cell membrane's selective permeability?

    Semi-permeable. Allows some substances through while blocking others.

24. Which cellular process involves the release of substances outside the cell?

    Exocytosis. Vesicle fusion releases contents to external environment.

25. Identify the type of transport that requires energy.

    Active transport. Moves substances against gradients using cellular energy.

26. Which type of transport is driven by a concentration gradient?

    Passive transport. Movement follows natural concentration differences.

27. What effect does temperature have on diffusion rate?

    Higher temperature increases diffusion rate. Increased kinetic energy accelerates molecular movement.

28. What is the term for the movement of ions across a membrane using proteins?

    Ion channel transport. Protein channels allow selective ion passage.

29. What is osmosis?

    The diffusion of water across a selectively permeable membrane. Specific type of diffusion involving only water molecules.

30. Identify the factor that affects membrane fluidity.

    Lipid composition. Fatty acid saturation determines membrane flexibility.

31. Which type of transport is used by glucose to enter cells?

    Facilitated diffusion. Large polar molecule requires protein assistance to cross.

32. Define isotonic solution in terms of cell environment.

    A solution where solute concentration is equal inside and outside the cell. No net water movement occurs in balanced conditions.

33. Identify the term for the pressure exerted by water in a solution.

    Osmotic pressure. Force created by water's tendency to move.

34. What is the role of peripheral proteins in the cell membrane?

    To support cell shape and function in signaling. Attached to membrane surface providing structural support.

35. Identify the process where cells engulf particles.

    Endocytosis. Bulk transport bringing materials into the cell.

36. Identify the type of transport that involves receptor-mediated endocytosis.

    Specific uptake of molecules. Targets specific molecules using receptor binding.

37. State the role of glycoproteins in the cell membrane.

    To facilitate cell-cell recognition and signaling. Carbohydrate-protein complexes enable cellular communication.

38. Which process is characterized by the engulfing of liquids?

    Pinocytosis. Cell drinking process for nutrient uptake.

39. Which component of the cell membrane is involved in signal transduction?

    Receptor proteins. Detect and respond to external chemical signals.

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