plant cells: 1) elodea 2) onion · plant cells: 1) elodea 2) onion. 40x largest field of view ......

Plant Cells:1) Elodea2) Onion

40X

Largest field of view

Pluck 1 Elodea frond & place it on a microscope slide. Add 1 drop of water & then a coverslip. Place the slide on the stage & bring the image into focus under LOW power.

Now, go to the next page.

100X

MEDIUM power

Rotate the objective to “10x” and use the fine focus knob. You can now see chloroplasts, cytoplasm, & cell wall.

Now, go to the next page.

400X

Elodea: Smallest field of view

Rotate the objective to “40x” and use the fine focus knob. You can still see chloroplasts, cytoplasm, & cell wall.

Draw & label this (cell wall, cytoplasm, chloroplast).

Onion: How to prepare cells for viewing.

• Remove a scale from the onion.• Snap the scale in half and peel a thin layer of tissue from its

inner surface.• Make a wet-mount: STAIN with iodine stain, as

demonstrated by the teacher.• Put on a cover slip; be sure to angle the cover slip to avoid

air bubbles.• Locate cells on LOW power (40x) and then bring up to

MEDIUM power and then HIGH power (400x).• Observe, draw, and label (cell wall, cytoplasm, nucleus).

400X

Animal Cells1) cheek cells2) red blood cells

Cheek (ex: of an epithelial cell)• With a flat clean toothpick, gently scrape

the inside of your mouth. You'll pick up many cheek lining cells, even though you won't be able to see them!

• Smear the toothpick on a slide to spread out the cells and saliva.

• Make a wet-mount: STAIN with methylene blue, as demonstrated by the teacher.

• Put on a cover slip; be sure to angle the cover slip to avoid air bubbles.

• Start looking for cells under MEDIUMpower (100x) since cells are so small.

• Can you magnify to 400x? Try.• Observe, draw, and label (cell membrane,

cytoplasm, nucleus).

Draw the image on the next page.

400X

Human Red Blood Cells: Just look & see how much smaller they are! (No need to draw these)

Cheek cell: approximately 60 μm in diameterRed blood Cell: between 6.2-8.2 μm in diameter

WOW! Look at those white blood cells!

After your drawings are complete,

• Answer post-lab questions!