BIOLOGY
Chapter 6: The Tour of the Cell
Name:________________________
Section Goals: The student will relate diffusion and equilibrium, describe how passive transport occurs, relate
osmosis to solute concentrations, explain the difference between active and passive transport and describe how
a large molecule moves across a membrane.
Vocabulary:
1. Diffusion
2. Equilibrium
3. Selectively permeable membrane
4. Passive transport
5. Facilitated diffusion
6. Osmosis
7. Hypertonic
8. Hypotonic
9. Isotonic
10. Active transport
11. Exocytosis
12. Endocytosis
Notes:
Concept 6.3 Membranes regulate the traffic of molecules
I. Diffusion
A. ________________________ is the net movement of the particles of a substance from where they
are _________________ concentrated to where they are _______________ concentrated
B. ___________________________ is reached when the movement of particles in one direction is
______________________ to the number of particles moving in the other
II. Passive Transport
A. A _______________________________________________________ allows some substances to
cross the membrane more easily than others and blocks the passage of some substances altogether
B. Diffusion across a membrane is called _________________________________ because no energy
is expended by the cell, only the random motion of molecules is required to move them across
C. ______________________________________________ is when transport proteins provide a
pathway for certain molecules to pass
III. Osmosis
A. The ___________________________________________of water across a selectively permeable
membrane is called ____________________
B. A solution with a _______________ concentration of solute is called _______________________
hyper = “above”
C. A solution with a________________ concentration of solute is called _______________________
hypo = “below”
D. A solution that has an ____________ concentration of solute is called _______________________
iso = “equal”
- When an animal cell is placed in a hypotonic solution it swells
- When an animal cell is placed in a hypertonic solution it shrinks
IV. Active Transport
A. When a cell expends energy to move molecules or ions across a membrane it is called
____________________________________________
B.
A specific _______________________________________________ pumps a solute across a
membrane, usually in the opposite direction it travels in diffusion
V. Transport of Large Molecules
A. Large molecules have to be packed into __________________________, which are small
membrane sacs that specialize in moving products into, out of and within a cell
B. When a cell exports its protein products, a vesicle fuses with the plasma membrane and spills its
contents outside the cell-a process called _______________________________
C. The reverse process, __________________________________, takes materials into the cell within
vesicles that bud inward from the plasma membrane
Lesson Reflection:
Complete the two handouts titled: “How do materials move across the cell’s membranes?”
Lesson Assessment:
1. Distinguish between hypertonic, hypotonic and isotonic solutions and give an example of how each
affects an animal cell. Use the handout to complete this question.
Summary of Key concepts:
Complete the Summary of Key Concepts for section 6.3, and then turn into the box.
Technology/Application/Connection to real-world: (extra credit)
Write one paragraph explaining why someone in the medical field would need to know about how
membranes regulate the traffic of molecules.