Name: ______Hr: _____

CELLS & CELL ORGANELLES LAB

Purpose: In this lab, you will learn to identify different cell types and certain organelles.

Objectives: Students should be able to:

  1. Recognize the major visible organelles of the cell.
  2. Give the function of the major organelles.
  3. Draw animal and plant cells.
  4. Tell the difference between animal and plant cells.
  5. Demonstrate good lab technique and explain the techniques used.

PART A: Onion Skin.

  1. Using the procedure used in the microscope lab to prepare a microscope slide of an onion skin. (Thin skin layer only!)
  2. Do not forget to add one drop of Iodine to your slide before adding the cover slip.
  3. Draw and Label what you see, include these parts:cell wall, nucleus, and cytoplasm

Question #1: Why do we put stain on the onion?

PART B: Potato.

1. Cut an extremely thin piece of potato and place it on your slide.

  1. Add 1 drop of Iodine to the slide and then cover slip the slide.
  2. Examine the slide under low power and then high power.
  3. Draw and Label what you see, include these parts:cell wall, cytoplasm, plastid

Potatoes are an underground stem. Next years new potatoes will grow from these stems. The new potatoes will need a source of energy to liveoff of until they can grow leaves. This energycomes from starch stored in the potato’s plastid. You cansee how much starch there is because starch will turn the plastid dark purple when Iodine solution is added to it.

Question #2:What is the organelle that is responsible forchanging the glucose from photosynthesis into thelong term storage molecule starch?

Describe the shape of the potato cells:

QUESTION #3: Are these cells thin or thick? ______Explain how you can tell.

PART C: Tomato Skin.

  1. Cut a small piece of skin from a tomato.
  2. Scrape all of the “meat” off and place the skin on a slide skin side up.
  3. Add 1 drop of water and cover slip. Do not add stain.
  4. Draw and Label what you see, include these parts:cell wall, and plastid.

NOTE: There is color in these slides, even though there is no stain added. This color is called a “pigment.”

QUESTION #4: What organelle is responsible for making and storing this pigment?

QUESTION #5: What is the major function of the cells in the tomato skin?

Describe the shape of the tomato cells:

Cheek

Part D: Cheek Cells.

  1. Using a clean toothpick, gently scrap the inside of your mouth as demonstrated by your teacher.
  2. Place these cells on a clean slide and a add 1 drop of methyl blue stain.
  3. Put a cover slip on and examine the slide under low power, then under high power.
  4. Draw and Label what you see, include these parts:

cell membrane, cytoplasm, and nucleus.

Question #6: Are these slides animal or plant?

Describe the shape and thickness of the cheek cells:

Question #7: What is the relationship between the cell’s shape and its function?

Part E: Elodea Leaf.

  1. Place a young leaf from an elodea plant on a slide upside down.
  2. Add a drop of water and then cover with a cover slip.
  3. Examine the slide under low power, then under high power.
  4. Draw and Label what you see, include these parts:

cell wall, cytoplasm, chloroplast, and nucleus.

  1. Using low power, slowly turn the fine adjustment back and forth so you can observe the various layers of the leaf.
  2. Count and record the number of cell layers in the leaf. ______

Elodea

Question #8: Is there any evidence that this cell is living? ______If so, What?

Question #9: What organelle is the green color located in?

What chemical is responsible for the green color?