Cell Size Lab 159-9-15

EQ: Why are cells small?

Questions Small Cube Medium Cube Large Cube

(Level 1) DESCRIBE ______________________________________________________

(Level 2) EXPLAIN ______________________________________________________

(Level 3) WHY _____________________________________________________?

Prediction:

Hypothesis:

Observation:

Diagram:

Prediction:

Hypothesis:

Observation:

Diagram:

Prediction:

Hypothesis:

Observation:

Diagram:

CONCLUSION:

BellworkSet up page 15 in your journal to look like this.

*This is also at your table.

LAB CHAMPS C-Conversations are only about the Lab and only within your Lab group H-Follow instructions of the Lab. Ask group members before asking a teacher A-Make observations and work with your Lab partners M-Do not move from your group. P-Work as a team to complete the lab

PART 1 PROCEDURE1. You have 3 cm, 2 cm, and 1 cm agar cubes at

your table.

2. When treated agar cubes are placed into a sodium hydroxide (NaOH) solution, the solution will enter the cube.

a) With your group, PREDICT what you think will happen in the three different sized blocks (hint: how far into the cube will the solution go??).

3. Turn your predictions into HYPOTHESES (ex: If I put in a small cube in NaOH, then the solution will ___________ because__________).

4. Using your spoon, carefully place all three cubes in the NaOH solution.

a) Use caution with sodium hydroxide - it is caustic. It will burn your skin or clothes. WEAR GOGGLES AT ALL TIMES!!!!

5. Allow the cubes to soak while you complete the next tasks.

WHILE WE WAIT, TURN TO PAGE 14 IN YOUR JOURNAL.

TITLE: LAB ANALYSIS

COPY THE DATA TABLE AND ANALYSIS QUESTIONS ONTO PAGE 14.

PART 2 PROCEDURE4. Without pouring the cubes out of your

beaker, pour the NaOH solution down the sink and gently rinse the cubes. WEAR GLOVES AND GOGGLES UNTIL YOU’RE DONE.

5. At your table, use your spoon to remove the cubes from the beaker and lay them on your paper towel.

6. Cut the cubes in half and measure the depth of the colored area in cm.

7. Fill in your OBSERVATIONS, DIAGRAM, AND CONCLUSION spaces on the lab page.

8. Clean-up: ONE person take the paper towel and cubes to the trash. Leave your spoon and knife on the table.

HERE IS WHAT SHOULD HAVE HAPPENED…

Use the picture to answer the analysis questions.

DATA TABLELength / width /

height of cube (cm)Surface area (cm2)(length x width x 6)

Volume (cm3)(length x width x

height)

Surface Area: Volume ratio

(# : #)

1

2

3

1. Which cube has the greatest… a) surface area? b) volume? c) surface area : volume ratio?

2. As the cubes get larger, what happens to the…a) surface area?b) volume?c) surface area : volume ratio?

ANALYSIS QUESTIONS1.What do you notice about the

agar cubes as they increase in size? (hint: look at your data table AND your observations!)

2.What happens to a cell’s ability to feed itself and get rid of wastes as it grows?

3.If the sodium hydroxide were food and the cubes were cells, which cell is being fed most efficiently? (Explain your answer)

4.Explain why cells are so small.