Transport Tactics Study Guide Transport Tactics
Unit Study Guide: Cell Transport & Homeostasis
Name: ___________
Date: ___________
Core Concepts
Homeostasis
The process by which a cell maintains a stable internal environment .Example: A cell taking in water when dehydrated to stay balanced.
The Cell Membrane
Described as semi-permeable . It acts as a gatekeeper, allowing small molecules (water/O2) through while blocking large ones (starch).
The Transport Spectrum
Feature Passive Transport Active Transport Energy (ATP) No Energy Required Requires ATP Energy Direction High → Low Concentration Low → High Concentration Gradient "Down" the gradient "Against" the gradient Examples Diffusion, Osmosis, Facilitated Pumps, Endo/Exocytosis
Osmosis Check-In
Sketch what happens to the cell in these environments. Draw the water movement with arrows!
Hypotonic
Hypertonic
Isotonic
Flip over for Lab Scenarios →
Lab Scenario Analysis
1
The Naked Egg Experiment
"A student places a raw egg in vinegar to dissolve the shell. Once the shell is gone, the egg is placed in 100% distilled water overnight."
A. Predict the movement of water (In or Out?): ____________________
B. Explain WHY this happens (use "Osmosis"):
2
Dialysis & Molecular Size
"A dialysis bag contains white starch. It is placed in red iodine. The inside turns black (iodine entered), but the beaker water stays red (no starch left)."
C. What molecule was small enough to move across? Why?
D. What does this tell you about the membrane?
3
Quick Check
Q1. A protein channel moves glucose from high to low concentration without ATP. Identify the transport: ____________________
Q2. Which systems maintain homeostasis by adjusting urine production? ____________________
Membrane Master Slides Membrane Master
The Ultimate Cellular Logistics Review
Passive Transport
Active Transport
Homeostasis
Homeostasis
Maintaining internal stability despite external changes.
Cellular Goal:
Balance water and solute levels to survive in changing environments.
Temperature
Water Balance
Passive Transport
1
NO ENERGY
"Molecules roll downhill"
2
High to Low
Always down the gradient.
3
Small/Nonpolar
O2, CO2, and Water (Osmosis).
Rolling with the Flow
Active Transport
Needs ATP!
1
Pumping Energy
"Pushing things uphill"
2
Low to High
Against the gradient.
3
Bulk Goods
Endocytosis & Exocytosis.
The Naked Egg Review
The Result:
Egg placed in 100% water SWELLS.
Mechanism
Osmosis
Energy Used
None (Passive)
Why did it swell?
There was a higher concentration of water outside the egg than inside. Water flowed IN to reach balance.
Exit Ticket
"What property of a cell membrane allows some molecules through while blocking others?"
A. Active Transport
B. Semi-permeable
C. Homeostasis
D. Phagocytosis
Molecule Movement Anchor Chart Molecule Movement
Cellular Transport
Passive
No Energy (ATP) Needed
Diffusion
Molecules spread from High to Low.
Osmosis
Water diffusion through membrane.
Facilitated
Uses protein channels for big items.
High Concentration Low Concentration
Active
Requires ATP Energy
Protein Pump
Pushes molecules against gradient.
Bulk Transport
Endo (In) / Exo (Out) for masses.
ATP
Cellular Energy Source
The Goal
Maintain Homeostasis: A stable internal state required for life.
Cellular Border Quiz Cellular Border Quiz
Biology Unit CA 1B
Name: ____________________
Date: ________
1. When a cell is dehydrated, water moves across the cell membrane to restore balance. This is an example of:
A. A cell being invaded by a foreign virus.
B. The cell maintaining homeostasis.
C. The cell undergoing mitosis to divide.
D. The membrane becoming impermeable to water.
2. Identify which of these options is an example of PASSIVE transport:
A. The sodium-potassium pump using ATP energy.
B. Molecules moving from an area of LOW to HIGH concentration.
C. The facilitated diffusion of oxygen across the membrane.
D. Endocytosis of large particles into the cell cytoplasm.
3. Match the term to its correct description:
Osmosis X. Movement from high to low using a protein.
Exocytosis Y. The diffusion of water across a membrane.
Facilitated Diffusion Z. Pushing molecules OUT using energy.
CONTINUE ON PAGE 2 →
4. Dialysis Experiment Analysis:
"A bag of dialysis tubing containing white starch is placed in a beaker of red iodine. After 10 minutes, the starch inside the bag turns black (positive for iodine), but the water in the beaker remains red (negative for starch)."
A. Why was the iodine able to enter the tubing, but the starch was not able to leave?
B. Based on this observation, is the membrane semi-permeable? Explain.
5. Which case best illustrates the interaction between the ENDOCRINE and EXCRETORY systems for homeostasis?
A. The liver storing glucose when blood sugar levels rise.
B. Sweat glands producing sweat to cool the body down.
C. Kidney urine production decreasing when dehydrated.
D. Heart rate increasing during a sprint.
6. Read the definition and select the correct process:
"Molecules move from LOW to HIGH concentration using ATP energy."
ACTIVE TRANSPORT
PASSIVE TRANSPORT
End of Quiz
Logistics Key Teacher Guide Teacher Guide
Cellular Logistics Answer Key
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Study Guide Key
The Egg Scenario:
Water moves IN via osmosis. Water moves from high concentration (pure water) to low concentration (inside egg).
Dialysis Scenario:
Iodine = small (moved in). Starch = large (stayed in). Membrane is semi-permeable.
Quick Checks:
Q1: Facilitated Diffusion
Q2: Endocrine & Excretory
Quiz Key
Q1: B (Homeostasis)
Q2: C (Facilitated Diffusion of O2)
Q3: Matching:
Osmosis: Y
Exocytosis: Z
Facilitated: X
Q4A: Molecular size (Iodine small, starch large).
Q4B: Semi-permeable (selective movement).
Q5: C (Kidney production of urine).
Q6: ACTIVE TRANSPORT
Instructional Best Practices
Visual Anchors:
Use the "Sledding Analogy" for transport. Passive = Sledding down; Active = Dragging sled up (needs energy).
Common Pitfall:
Students assume "Facilitated Diffusion" is active because it uses a protein. Remind them it's still High → Low.
Cellular Logistics Unit • Teacher Support Document • 2026 Curriculum
